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0000027093
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2025-02-10
2025-02-10
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UNITED
STATES
SECURITIES
AND EXCHANGE COMMISSION
Washington,
D.C. 20549
FORM
8-K
CURRENT
REPORT
Pursuant
to Section 13 or 15(d) of the Securities Exchange Act of 1934
Date
of Report (Date of earliest event reported): |
February
10, 2025 |
U.S.
GOLD CORP.
(Exact
name of registrant as specified in its charter)
Nevada |
|
001-08266 |
|
22-1831409 |
(State or other jurisdiction
of incorporation) |
|
(Commission
File
Number) |
|
(I.R.S. Employer
Identification Number) |
1910
E. Idaho Street, Suite 102-Box 604 Elko, NV |
|
89801 |
(Address
of principal executive offices) |
|
(Zip
Code) |
Registrant’s
telephone number, including area code: |
(800)
557-4550 |
(Former
name or former address, if changed since last report)
Check
the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under
any of the following provisions:
☐ |
Written
communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) |
|
|
☐ |
Soliciting
material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) |
|
|
☐ |
Pre-commencement
communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) |
|
|
☐ |
Pre-commencement
communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) |
Securities
registered pursuant to Section 12(b) of the Act:
Title
of each class |
|
Trading
Symbol(s) |
|
Name
of each exchange on which registered |
Common
stock |
|
USAU |
|
Nasdaq
Capital Market |
Indicate
by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405
of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).
Emerging
growth company ☐
If
an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying
with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
U.S.
Gold Corp. (the “Company”) has completed a Technical Report Summary detailing the results of its updated pre-feasibility
study for the CK Gold Project, titled “Technical Report Summary CK Gold Project for U.S. Gold Corp.” and effective as of
February 10, 2025. The Technical Report Summary was prepared by the Company and Samuel Engineering, Inc. in accordance with Subpart 1300
of Regulation S-K. A copy of the Technical Report Summary is attached as Exhibit 96.1 to this Current Report on Form 8-K.
Item
9.01 | Financial
Statements and Exhibits. |
SIGNATURES
Pursuant
to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by
the undersigned hereunto duly authorized.
|
U.S.
Gold corp. |
|
|
|
|
|
|
Date:
February 14, 2025 |
By:
|
/s/
Eric Alexander |
|
Name: |
Eric
Alexander |
|
Title: |
Chief
Financial Officer |
Exhibit 96.1
Technical
Report Summary
CK
Gold Project
For
U.S.
Gold Corp.
Responsible
Company |
Signature
& Date |
AKF
Mining |
|
Drift
Geo |
|
John
Wells |
|
Samuel
Engineering, Inc. |
|
Tierra
Group International, Ltd. (TGI) |
|
U.S.
Gold Corp (Registrant) |
|
PREPARED BY |
|
|
|
U.S. Gold Corp.
1807 Capitol Avenue
Cheyenne, WY. 82001 |
 |
|
|
Samuel Engineering, Inc.
8450 East Crescent Pkwy. Ste. 200
Greenwood Village, CO 80111-2816
303.714.4840 |
 |
|
|
SE Project No. 24128-01, Rev A
February 10, 2025 |
|
1.0 executive
summary |
1 |
|
|
1.1 property
summary and ownership |
1 |
1.2 Mineral
Resource Statement |
1 |
1.3 Mineral
Reserve Statement |
4 |
1.4 geology
and mineralization |
5 |
1.5 metallurgical
testing |
5 |
1.6 mine
design, OPTIMIZATION, and scheduling |
6 |
1.7 mineral
processing |
7 |
1.8 INFRASTRUCTURE |
8 |
1.9 environmental,
permitting, and community impact |
9 |
1.10 Capital
Costs, Operating Costs, and Financial Analysis |
12 |
1.11 conclusions
and recommendations |
13 |
1.11.1 General
Recommendations |
13 |
1.11.2 Specific
Work Plan |
14 |
|
|
2.0 introduction |
16 |
|
|
2.1 Terms
Of Reference And Purpose |
16 |
2.2 sources
of information |
16 |
2.3 details
of inspection |
17 |
2.4 Previous
Reports on the Project |
18 |
2.5 List
of abbreviations and units |
18 |
|
|
3.0 property
description |
22 |
|
|
3.1 property
location |
22 |
3.2 Mineral
Titles, Claims, Rights, Leases, and Options |
23 |
3.3 Environmental
Impacts, Permitting, Other Significant Factors, and Risks |
24 |
3.4 royalties
and agreements |
25 |
|
|
4.0 Accessibility,
Climate, Local Resources, Infrastructure and Physiography |
26 |
|
|
4.1 topography,
elevation, and vegetation |
26 |
4.2 accessibility
and Transportation to the Property |
26 |
4.3 climate
and operating season |
26 |
4.4 Local
infrastructure availability and sources |
27 |
|
|
5.0 History |
28 |
|
|
5.1 historical
exploration and production |
28 |
|
|
6.0 Geological
Setting, Mineralization, and Deposit |
30 |
|
|
6.1 regional
geologic setting |
30 |
6.1.1 Local
and Property Geology |
32 |
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i |
6.1.2 Lithology |
32 |
6.1.3 Alteration |
36 |
6.1.4 Mineralization |
40 |
6.2 deposit
Type |
43 |
6.2.1 Discussion |
43 |
6.2.2 Interpretations
and Conclusions |
46 |
|
|
7.0 exploration |
48 |
|
|
7.1 summary
of exploration activities |
48 |
7.2 exploration
drilling |
48 |
7.2.1 U.S.
Gold 2021 Drilling Campaign |
49 |
7.2.2 U.S.
Gold 2020 Drilling Campaign |
49 |
7.2.3 U.S.
Gold 2020-2017 |
49 |
7.2.4 Saratoga
2007 – 2008 |
50 |
7.2.5 Historical
Drilling |
50 |
7.3 Non-drilling
exploration activities |
51 |
7.3.1 Geophysics |
51 |
7.3.2 Geochemical |
52 |
7.4 geotechnical
data, testing, and analysis |
52 |
7.5 hydrogeology |
53 |
|
|
8.0 Sample
Preparation, Analysis, and Security |
55 |
|
|
8.1 sampling |
55 |
8.1.1 U.S.
Gold 2021 - 2017 |
55 |
8.1.2 CK
Gold – 2021-2017 |
55 |
8.1.3 Saratoga |
56 |
8.1.4 Historical
Exploration |
56 |
8.2 Analytical
PROCEDURES |
57 |
8.2.1 U.S.
Gold 2021 Campaign |
57 |
8.2.2 U.S.
Gold 2017 – 2020 Campaign |
57 |
8.2.3 2007
– 2008 Saratoga Campaign |
58 |
8.2.4 Legacy
Campaigns |
59 |
8.3 Results,
QC Procedures and QA Actions |
60 |
8.3.1 U.S.
Gold 2021 Campaign |
60 |
8.3.2 U.S.
Gold 2017 – 2020 |
60 |
8.3.3 2007
– 2008 Saratoga |
62 |
8.4 Opinion
of Adequacy |
62 |
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ii |
9.0 Data
Verification |
63 |
|
|
9.1 Procedures |
63 |
9.2 Previous
Audits / Owners |
66 |
9.2.1 Saratoga
2007 – 2008 |
66 |
9.2.2 Historical
Drilling |
66 |
9.3 data
adequacy |
66 |
|
|
10.0 Mineral
Processing and Metallurgical Testing |
67 |
|
|
10.1 sgs
testwork, 2008 - 2010 |
67 |
10.1.1 Program
11868-001 (2008 – 2009) |
67 |
10.1.2 Program
11868-002 (2010) |
69 |
10.2 kappes
cassiday testwork, 2020-21 |
69 |
10.2.1 Sampling |
70 |
10.2.2 Mineralogy |
71 |
10.2.3 Comminution |
72 |
10.2.4 Gravity
Concentration |
73 |
10.2.5 Flotation |
74 |
10.2.6 Cleaner
Flotation |
75 |
10.2.7 Locked
Cycle Testing |
77 |
10.2.8 Cyanidation
on Flotation Tailing |
77 |
10.2.9 Tailing
Thickening/Filtration |
77 |
10.3 Base
Metallurgical Labs (BL-0789, 2021) |
78 |
10.3.1 Sampling |
78 |
10.3.2 Rougher
Flotation |
79 |
10.3.3 Cleaner
Flotation |
80 |
10.3.4 Locked
Cycle Testing |
80 |
10.3.5 Ancillary
Testing |
81 |
10.4 Base
Metallurgical Labs (BL-0835/0882, 2021-2022) |
82 |
10.4.1 Sampling |
82 |
10.4.2 Mineralogy |
86 |
10.4.3 Comminution |
87 |
10.4.4 Rougher
Flotation |
88 |
10.4.5 Cleaner
Flotation |
89 |
10.4.6 Locked
Cycle Testing |
92 |
10.4.7 LCT
Final Concentrate Analysis |
93 |
10.4.8 LCT
Tailings Dewatering |
95 |
10.5 Base
Metallurgical Labs (BL-0980 & 1066, 2022) |
96 |
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iii |
10.5.1 Sampling |
96 |
10.5.2 Mineralogy |
97 |
10.5.3 Comminution |
98 |
10.5.4 Cleaner
Flotation |
98 |
10.5.5 Locked
Cycle Testing |
98 |
10.5.6 LCT
Final Concentrate Analysis |
99 |
10.6 METALLURGICAL
DISCUSSION |
101 |
10.6.1 General |
101 |
10.6.2 Sampling |
103 |
10.6.3 Mineralogy |
103 |
10.6.4 Primary
Grind |
104 |
10.6.5 Rougher
Concentrate Regrind |
105 |
10.6.6 Gravity
Concentration |
105 |
10.6.7 Flotation |
105 |
10.6.8 Tailings
and Concentrate Dewatering |
106 |
10.6.9 Jameson
Flotation Cell Testwork |
107 |
|
|
11.0 Mineral
Resource Estimates |
109 |
|
|
11.1 Introduction |
109 |
11.2 Geologic
Models |
109 |
11.3 Oxidation
Assignment |
113 |
11.4 Block
Model Orientation and Dimensions |
114 |
11.5 Compositing |
114 |
11.6 Exploratory
Data Analysis |
114 |
11.7 Bulk
Density Determination |
118 |
11.8 Grade
Capping/Outlier Restrictions |
120 |
11.9 Variography |
120 |
11.10 Estimation/Interpolation
Methods |
123 |
11.11 Classification
of Mineral Resources |
123 |
11.12 Grade
Model Validation |
125 |
11.13 Reasonable
Prospects of Eventual Economic Extraction |
128 |
11.14 Mineral
Resource Statement |
130 |
11.15 Relevant
Factors That May Affect the Mineral Resource Estimate |
136 |
11.16 Responsible
Person Opinion |
137 |
|
|
12.0 Mineral
Reserve Estimates |
139 |
|
|
12.1 Basis,
Assumptions, Parameters, and Methods |
139 |
12.1.1 Pit
Optimization |
139 |
12.1.2 Value
Per Ton Cut-off Grade Calculation |
140 |
12.1.3 Dilution |
141 |
12.2 Mineral
Reserves |
141 |
 |
iv |
12.3 Classification
and Criteria |
141 |
12.4 Relevant
Factors |
141 |
12.5 2025
PFS vs 2021 PFS RESERVES |
141 |
|
|
13.0 Mining
Methods |
143 |
|
|
13.1 introduction |
143 |
13.2 Geotechnical
Parameters |
143 |
13.2.1 Geotechnical
General Recommendations |
146 |
13.3 Hydrogeological
Parameters |
150 |
13.4 Mine
Design |
154 |
13.4.1 Mine
Design Parameters |
154 |
13.5 Mine
Schedule |
155 |
13.6 Mining
Fleet Requirements |
157 |
13.6.1 Equipment
Productivity and Usage |
157 |
13.7 Mine
Personnel Requirements |
158 |
13.8 Mine
END OF YEAR MapS |
160 |
13.9 2025
PFS vs 2021 PFS Mining METHODS |
160 |
|
|
14.0 Processing
and Recovery Methods |
164 |
|
|
14.1 Introduction |
164 |
14.2 PROCESS
PLANT DESIGN |
166 |
14.2.1 Major
Design Criteria |
166 |
14.2.2 Operating
Schedule and Availability |
166 |
14.3 PROCESS
PLANT DESCRIPTION |
166 |
14.3.1 Primary
Crushing |
166 |
14.3.2 Crushed
Ore Stockpile and Reclaim |
166
|
14.3.3 Comminution |
167 |
14.3.4 Flotation
and Regrind Circuits |
168 |
14.3.5 Concentrate
Handling |
169 |
14.3.6 Tailings
Handling |
170 |
14.3.7 Reagent
Handling and Storage |
170 |
14.3.8 Water
Supply |
171 |
14.3.9 Fresh-Water
Supply System |
172 |
14.3.10 Process
Water Supply System |
172 |
14.3.11 Air
Supply |
172 |
14.3.12 Process
Plant Manpower |
172 |
|
|
15.0 Infrastructure |
175 |
|
|
15.1 roads |
175 |
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v |
15.1.1 Project
Access Road |
175 |
15.1.2 Ex-Pit
Haul Roads |
176 |
15.2 Ore
Stockpile and Waste Rock Facilities |
176 |
15.2.1 Ore
Stockpile |
176 |
15.2.2 West
and East Waste Rock Facilities |
177 |
15.3 Tailings
Disposal |
177 |
15.3.1 Chemical
Characteristics |
177 |
15.3.2 TMF
Design and Construction |
178 |
15.3.3 TMF
Environmental Management |
182 |
15.3.4 Pit
Backfilling |
183 |
15.4 Plant
facility Earthwork |
184 |
15.5 Power
and Water |
186 |
15.5.1 Power
Supply |
186 |
15.5.2 Water
Supply |
186 |
|
|
16.0 Market
Studies |
188 |
|
|
16.1 Flotation
Concentrates |
188 |
16.1.1 Flotation
Concentrates |
188 |
16.1.2 General
Considerations |
188 |
16.1.3 Metal
Pricing |
189 |
16.1.4 Accountable
Metals |
189 |
16.1.5 Smelting
and Refining Charges |
189 |
16.2 MINING
CONTRACT |
190 |
16.3 OTHER
Contracts |
190 |
|
|
17.0 Environmental,
social, and Permitting |
191 |
|
|
17.1 environmental
studies |
191 |
17.1.1 Baseline
Characterization |
191 |
17.1.2 Groundwater
Modeling |
201 |
17.1.3 Tailings
Seepage and Stability Analysis |
205 |
17.1.4 Geochemical
Characterization of Mine Rock and Tailings |
205 |
17.2 REQUIREMENTS
AND PLANS FOR WASTE AND TAILINGS DISPOSAL, SITE MONITORING, AND WATER MANAGEMENT |
208 |
17.2.1 Waste
Rock and Tailings Management |
208 |
17.2.2 Site
Monitoring |
212 |
17.2.3 Water
Management |
213 |
17.3 REQUIRED
PERMITS AND STATUS |
220 |
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vi |
17.3.1 Approved
Jurisdictional Determination |
221 |
17.3.2 Public
Water Supply Permit |
221 |
17.3.3 Exploration
Permit |
222 |
17.3.4 Mine
Operating Permit |
222 |
17.3.5 Air
Quality Permit to Construct and Operate |
223 |
17.3.6 Industrial
Siting Permit |
224 |
17.3.7 Water
Quality Division Permits |
226 |
17.3.8 State
Engineer’s Office Permits for Water Use and Related Facilities |
227 |
17.3.9 State
Historical Preservation Office |
227 |
17.3.10 State
Fire Marshal Permits |
227 |
17.3.11 Laramie
County Permits |
227 |
17.4 LOCAL
INDIVIDUALS AND GROUPS |
228 |
17.5 MINE
CLOSURE |
228 |
17.6 ADEQUACY
OF PLANS |
230 |
17.7 COMMITMENTS
TO LOCAL PROCUREMENT OR HIRING |
230 |
|
|
18.0 Capital
and Operating Costs |
232 |
|
|
18.1 Capital
Cost Estimate |
232 |
18.2 Operating
Cost Estimate |
233 |
|
|
19.0 Economic
Analysis |
236 |
|
|
19.1 CAUTIONARY
statement |
236 |
19.2 Model
Parameters |
237 |
19.3 Capital
Costs |
238 |
19.4 Operating
Costs |
239 |
19.5 Taxes,
Royalties, Depreciation and Depletion |
239 |
19.6 Cashflow
Forecasts and Annual Production Forecasts |
240 |
19.7 Sensitivity
Analysis |
244 |
|
|
20.0 Adjacent
Properties |
248 |
|
|
21.0 Other
Relevant Data and Information |
249 |
|
|
21.1 Aggregate
production |
249 |
21.2 Aggregate
Market Study |
249 |
|
|
22.0 Interpretation
and Conclusions |
251 |
|
|
22.1 Results |
251 |
22.1.1 Metallurgical
Program |
251 |
22.2 Significant
Risks |
255 |
22.3 Significant
Opportunities |
254 |
|
|
23.0 Recommendations |
257 |
|
|
23.1 PROJECT
ADVANCEMENT |
257 |
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vii |
23.2 Project
Development |
257 |
23.2.1 Deposit
Understanding |
257 |
23.2.2 Future
Metallurgical Test Work |
257 |
23.2.3 Ore
Processing |
257 |
23.2.4 Design
And Engineering |
257 |
23.3 Environmental,
Permitting, and Social |
258 |
|
|
24.0 References |
259 |
|
|
25.0 Reliance
on information provided by registrant |
26 |
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viii |
Table
1.1: Mineral Resource Statement |
2 |
Table
1.2: Mineral Resource Statement (Metric) |
3 |
Table
1.3: Mineral Reserves Statement |
4 |
Table
1.4: Economic Model Results |
12 |
Table
1.5: Project Details |
13 |
Table
1.6: Metal Price Sensitivity |
13 |
Table
8.1: 2021 Drilling Program Results |
60 |
Table
8.2: Sample Standards |
61 |
Table
10.1: SGS Composite Head Assay |
67 |
Table
10.2: FLSmidth Mineralogical Analysis: Copper Deportment |
71 |
Table
10.3: FLSmidth Mineralogical Analysis: Copper Deportment |
72 |
Table
10.4: Comminution Test Work Results |
73 |
Table
10.5: Hole 4 Gravity + Flotation vs. Flotation Only, (KCA) |
73 |
Table
10.6: Rougher Flotation, Test 90134 (Hole 4) |
74 |
Table
10.7: Rougher Flotation, Test 90170 (Oxide) |
74 |
Table
10.8: Rougher Flotation, Test 90173 (Sulfide) |
75 |
Table
10.9: Cleaner Flotation, Test 90160 (Hole 4) |
75 |
Table
10.10: Oxide Composite Cleaner Flotation (KCA) |
76 |
Table
10.11: Cleaner Flotation, (KCA) |
76 |
Table
10.12: Cyanidation of Flotation Tailings |
77 |
Table
10.13: BL-0789 Composites |
78 |
Table
10.14: 2020 Metallurgical Composites Description |
79 |
Table
10.15: Batch Cleaner Test Results |
80 |
Table
10.16: Locked Cycle Test Conditions |
80 |
Table
10.17: Locked Cycle Test Results - Master Composites |
81 |
Table
10.18: Gravity Test on High-Grade Oxide LCT Tailings |
81 |
Table
10.19: BL-0835 Variability Samples Head Assays |
83 |
Table
10.20: BL-0835 Main Composite Head Assays |
85 |
Table
10.21: Mixed (C4) Composite Construction |
85 |
Table
10.22: Shallow Sulphide (C1) Composite Construction |
85 |
 |
ix |
Table
10.23: Deep Sulphide (C2) Composite Construction |
85 |
Table
10.24: Oxide (C3) Composite Construction |
86 |
Table
10.25: Master Composite Head Assays |
86 |
Table
10.26: BL-0882 Modal Mineralogy |
87 |
Table
10.27: Variability Samples, Comminution Results |
88 |
Table
10.28: Master Composites, Comminution Results |
88 |
Table
10.29: Variability Cleaner Test Work |
90 |
Table
10.30: Batch Cleaner Test Results |
92 |
Table
10.31: Locked Cycle Test Conditions |
92 |
Table
10.32: Locked Cycle Test Results |
93 |
Table
10.33: Locked Cycle Test Minor Element Analysis |
94 |
Table
10.34: Static Settling Test Results |
95 |
Table
10.35: BL-0980 Head Assay |
97 |
Table
10.36: Comminution Test work Results |
98 |
Table
10.37: Batch Cleaner Tests on LG Composites |
98 |
Table
10.38: LG Composites, LCT Conditions |
98 |
Table
10.39: LG Composites, LCT Results |
99 |
Table
10.40: Locked Cycle Test Minor Element Analysis BL-0980 |
100 |
Table
10.41: Locked Cycle Test Minor Element Analysis BL-1066 |
101 |
Table
10.42: Evaluation of the Primary Grind |
105 |
Table
10.43: Conventional Rougher Summarized Test Results |
107 |
Table
10.44: Conventional Cleaner Tests |
107 |
Table
10.45: Jameson Dilution Tests |
108 |
Table
10.46: Locked Cyce Tests |
108 |
Table
10.47: L150 Pilot Unit |
108 |
Table
11.1: Block Model Dimensions |
114 |
Table
11.2: Block Model Dimensions |
114 |
Table
11.3: Drillhole Database Summary |
115 |
Table
11.4: Bulk Density Values by Rock Type |
119 |
Table
11.5: Capping Thresholds and Metal Loss Table |
120 |
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x |
Table
11.6: Variogram Parameter Table |
122 |
Table
11.7: Estimation Search and Sample Parameters |
123 |
Table
11.8: Global Estimation Comparison |
127 |
Table
11.9: AuEq Definitions |
129 |
Table
11.10: AuEq Cut-off Grades |
129 |
Table
11.11: Metal Prices (LG and AuEq Cut-off) |
130 |
Table
11.12: Varying Metal Recoveries by Material Type (LG) |
130 |
Table
11.13: Mineral Resource Statement |
132 |
Table
11.14: Mineral Resource Statement (Metric) |
133 |
Table
11.15: Mineral Resource Statement – Exclusive of Reserves |
135 |
Table
11.16: Mineral Resource Statement (Metric) – Exclusive of Reserves |
136 |
Table
11.17: Global Mean Grades of Estimated Metals (Model Mean) vs. 2021 Drillhole Grades |
138 |
Table
12.1: Pit Optimization Parameters |
139 |
Table
12.2: Mineral Reserve Statement |
141 |
Table
13.1: Recommended Slope Designs for Presplit Blasted Benches |
144 |
Table
13.2: Mine Design Parameters |
155 |
Table
13.3: Mine Schedule |
156 |
Table
13.4: Variable Usage Equipment |
157 |
Table
13.5: Annual Schedule of Variable Usage Equipment |
157 |
Table
13.6: Fixed Usage Equipment |
158 |
Table
13.7: Project Employment |
158 |
Table
13.8: Mine Employment |
158 |
Table
13.9: Tailings Disposal Employment |
159 |
Table
13.10: Site G&A Employment |
159 |
Table
14.1: Major Design Criteria |
165 |
Table
14.2: CK Gold Salaried Personnel |
173 |
Table
14.3: CK Gold Hourly Personnel |
173 |
Table
15.1: North and South Haul Road Quantities |
177 |
Table
15.2: Plant Area Quantities |
184 |
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xi |
Table
16.1: Pre-Feasibility Study Base Case Metal Prices |
189 |
Table
16.2: Smelting and Refining Terms – LOM Average |
190 |
Table
17.1: Baseline Monitoring Wells with Constituent Concentrations Exceeding Water Quality Standards |
196 |
Table
18.1: Initial Capital Costs |
232 |
Table
18.2: Sustaining Capital Costs |
233 |
Table
18.3: Project Operating Cost Summary |
233 |
Table
18.4: Annual Operating Costs |
234 |
Table
18.5: Mining Costs LOM Summary |
235 |
Table
18.6: Process Operating Costs LOM Summary |
235 |
Table
19.1: Economic Model Parameters |
237 |
Table
19.2: Life of Mine Capital Cost Summary |
238 |
Table
19.3: Summary of Operating Costs |
239 |
Table
19.4:Summary of Royalties & Taxes |
240 |
Table
19.5: Economic Model Results |
240 |
Table
19.6: Project Details |
241 |
Table
19.7: Metal Projections |
242 |
Table
19.8: Cash Flow Projections |
243 |
Table
19.9: Metal Price Sensitivity |
247 |
Table
21.1: Aggregate Cost Buildup |
250 |
Table
25.1: Information provided by U.S. Gold |
262 |
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xii |
Figure
3.1: Regional and Local Map |
22 |
Figure
3.2: Project Map |
23 |
Figure
6.1: Regional Geologic Setting of the CK Project Area. Source: Sims et. Al (2001) |
30 |
Figure
6.2: Mesoproterozoic intrusive within the Cheyenne suture zone. |
31 |
Figure
6.3: Bedrock geology in the vicinity of the CK Gold Project area |
32 |
Figure
6.4: Typical Lithologic Cross Section |
33 |
Figure
6.5: Relatively undeformed granodiorite |
34 |
Figure
6.6: Mylonitized granodiorite |
34 |
Figure
6.7: Felsic (pegmatite) dike (top row) within granodiorite |
35 |
Figure
6.8: Typical mafic dike (center of photo) intruding granodiorite |
35 |
Figure
6.9: Moderate, localized potassic alteration in granodiorite |
37 |
Figure
6.10: Intense, pervasive potassic alteration in granodiorite |
37 |
Figure
6.11: Intense potassic alteration with associated stockwork epidote veining |
38 |
Figure
6.12: Localized weak potassic alteration with associated epidote veining |
38 |
Figure
6.13: Phyllically altered mylonite (phyllonite?) |
39 |
Figure
6.14: Silicified mylonite |
40 |
Figure
6.15: Oblique view of the distribution of gold mineralization, CK Gold Project |
41 |
Figure
6.16: Cross-sectional view central to the primary zone of mineralization |
42 |
Figure
6.17: Plan view of the location and trend of the Northwest and Copper King Faults |
43 |
Figure
6.18: Schematic illustration of the transformation of brittle to ductile deformation in granitic rocks at depth (Fossen, 2016) |
44 |
Figure
6.19: Pyrite +- chalcopyrite aligned with mylonitic foliation |
45 |
Figure
7.1: Drill hole Map |
48 |
Figure
8.1: Umpire Analysis Au Correlation |
61 |
Figure
8.2: Umpire Analysis Cu Correlation |
62 |
Figure
9.1: Oxide copper mineralization in outcropping granodiorite host rocks (2024). |
65 |
Figure
9.2: U.S. Gold’s CK21-11c drilling in-progress on July 11, 2021. |
65 |
Figure
10.1: Location of Metallurgical Holes, highlighted area represents the approximate mineralized area |
70 |
Figure
10.2 - Variability Program Copper Deportment |
84 |
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xiii |
Figure
10.3: Grind Analysis – Rougher Flotation Results |
89 |
Figure
10.4: Variability Samples, Au Recovery v CuOx/CuT Ratio |
91 |
Figure
10.5: Variability Samples, Copper Recovery v CuOx/CuT |
91 |
Figure
10.6: Pressure Filtration Testwork Results |
96 |
Figure
10.7: BL-980 Typical Sample |
97 |
Figure
11.1: Vertical Section Looking 030deg Showing Lithologic Boundaries and Drillhole Grades (AUEQ gpt). 2021 drillholes are displayed
with black collar points and downhole traces |
110 |
Figure
11.2: Vertical Section Looking 030° Showing Oxidation Boundaries and Drillhole Weathering. 2021 drillholes are displayed with
black collar points and downhole traces |
111 |
Figure
11.3: Fault Map with Drillhole Grades (≥ 1.5 gpt AUEQ). 2021 drillholes are displayed with thick black downhole traces |
112 |
Figure
11.4: Vertical Section A-A’ Looking 030° Showing Location of Interpreted NE 2 Fault Zone, Oxidation Boundaries and Drillhole
Grades (AUEQ gpt). 2021 drillholes are displayed with black collar points and downhole traces |
112 |
Figure
11.5: Vertical Section Looking 030° Showing Mineralized Domain, Modeled Oxidation, Structures and Drillhole Grades (AUEQ gpt).
2021 drillholes are displayed with black collar points and downhole traces |
113 |
Figure
11.6: Log box Plot for AUCAP (gpt) Variable by Host Rock |
116 |
Figure
11.7: Log Box Plot for CUCAP (%) Variable by Host Rock |
116 |
Figure
11.8: Contact plot showing binned mean sample grades for the Au (blue) and Cu (orange) variables within a 60 ft distance |
117 |
Figure
11.9: Geology and Mineralization (transparent gray wireframe) with Drillhole Grades (gpt AUEQ). 2021 drillholes are displayed with
black collar points and downhole traces. |
118 |
Figure
11.10: Density of Granodiorite vs Depth |
119 |
Figure
11.11: Sample Distribution |
120 |
Figure
11.12: Au Composite Points for Resource Drillholes, looking 026° at Plane of Best-fit Mineralization (green arrow indicating
100° pitch) used for Spatial Modeling (Variography) |
121 |
Figure
11.13: Cu Composite Points for Resource Drillholes, looking 026° at Plane of Best-fit Mineralization (green arrow indicating
100° pitch) used for Spatial Modeling (Variography) |
121 |
 |
xiv |
Figure
11.14: Pairwise relative variograms and modeled structures for Major (top), Intermediate (middle) and Minor axis (bottom) for AUCAP
(left), CUCAP (center), and AGCAP (right) |
122 |
Figure
11.15: Longitudinal (100 ft field of view), looking 030° through the 3D block model, showing Measured (red), Indicated (green)
and Inferred (blue) class resources with 2021 drillholes displayed with black collar points. |
124 |
Figure
11.16: Cross-section slice (100 ft field of view), looking 300° through the 3D block model, showing Measured (red), Indicated
(green) and Inferred (blue) class resources with 2021 drillholes displayed with black collar points. |
125 |
Figure
11.17: Model validation slices (longitudinal and cross-section), with 100 ft field of view looking 030° and 300° respectively,
through the Au (top), Cu (center) and Ag (bottom), 2021 drillholes are displayed with black collar points. |
126 |
Figure
11.18: X (left), Y (center) and Z (right) swath plots showing mean grades and volume histograms |
128 |
Figure
11.19 Cross section showing AuEq resources (>0.3 gpt cutoff) and constraining LG pit shell. |
131 |
Figure
11.20: Cross section showing above cutoff AuEq Resource with nested Resource and Reserves pit shells. Note excluded mineralization
located outside of the resource pit at depth and to the southeast. |
134 |
Figure
11.21: Plan Map of 2021 RC and core drillholes coded by material class |
138 |
Figure
13.1: Pit Sectors and Recommended Slopes |
145 |
Figure
13.2: Design Face (Df) versus Face Condition (Fc) Chart |
147 |
Figure
13.3: Predicted drawdown at the end of mining and post-mining year 150 |
152 |
Figure
13.4: Groundwater Monitoring Locations |
153 |
Figure
13.5: Predicted Open Pit Groundwater Inflows |
154 |
Figure
13.6: Mine Map End of Year 1 |
160 |
Figure
13.7: Mine Map End of Year 3 |
161 |
Figure
13.8: Mine Map End of Year 5 |
162 |
Figure
13.9: Mine Map End of Mine Life Year 8 |
163 |
Figure
14.1: Block Flow Diagram – Processing Facility |
165 |
Figure
15.1: Project Access Road |
175 |
Figure
15.2: Typical Cross Section of the Access Road |
176 |
Figure
15.3: TMF, WRF, & Ore Stockpile Plan View |
178 |
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xv |
Figure
15.4: TMF& Ore Stockpile Collection Drain Layout |
179 |
Figure
15.5: TMF Downstream and Side Buttress Typical Cross Sections |
180 |
Figure
15.6: Overdrain & Underdrain Collection System Cross Sections |
181 |
Figure
15.7: Open-Pit Backfill and Pit Wall Grading |
183 |
Figure
15.8: Mill and Truck Area |
184 |
Figure
15.9: Mill Area Plan View |
185 |
Figure
17.1: Project Site and Access Road Location |
192 |
Figure
17.2: Locations of the Meteorological Station & PM10 Monitoring Station (from Air Resource Specialists) |
193 |
Figure
17.3: Surface and Groundwater Sampling Locations |
195 |
Figure
17.4: Field Survey Soil Sample Locations and Map Unit Modifications |
198 |
Figure
17.5: USGS Land Cover Vegetation |
199 |
Figure
17.6: Hydrogeologic Units, Groundwater Level, and Flow Direction |
202 |
Figure
17.7: Cross-section of groundwater levels |
203 |
Figure
17.8: Predicted drawdown at the end of mining and 150 years post-mining |
204 |
Figure
17.9: Mine rock sample spatial distribution (from Geochemical Solutions 2023) |
206 |
Figure
17.10: Results of ABA Tests (from Geochemical Solutions 2023) |
207 |
Figure
17.11: Results of Humidity Cell Tests (from Geochemical Solutions 2023) |
207 |
Figure
17.12: Water Balance |
215 |
Figure
17.13: New Water Source and Approximate Alignment to Fresh Water Tank |
216 |
Figure
17.14: Proposed Water Transmission Infrastructure (from Trihydro 2023) |
217 |
Figure
17.15: Project Site Layout |
220 |
Figure
19.1: Pre-Tax NPV Sensitivity |
244 |
Figure
19.2: Pre-Tax IRR Sensitivity |
245 |
Figure
19.3: Post Tax NPV Sensitivity |
246 |
Figure
19.4: Post Tax NPV Sensitivity |
247 |
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xvi |
1.1 | property
summary and ownership |
Samuel
Engineering, Inc. (Samuel) was commissioned by U.S. Gold Corp. (U.S. Gold) to prepare a Pre-Feasibility Study (PFS) for the CK Gold Project
(Project). This is a Technical Report Summary (TRS) summarizing the findings of the PFS in accordance with Securities Exchange Commission
Part 229 Standard Instructions for Filing Forms Regulation S-K subpart 1300 (S-K 1300). This TRS aims to report mineral resources, mineral
reserves, and economics for the CK Gold Project. The effective date of this report is February 10, 2025.
The
CK Gold Project is in Laramie County, Wyoming, in the southeastern portion of the state, approximately 20 miles west of Cheyenne. It
is centered in the north half of Section 36, T14N, R70W. The property encompasses approximately 1,120 acres of mineral leases on Section
36, the south half of Section 25, and the northeast quarter of Section 35. Additionally, to accommodate the mine footprint for facilities,
primarily the tailings storage facility, which cannot be accommodated on State Section 36, an option agreement for a further 712 acres
on portions of Section 25 and Section 31 has been secured with the private landowner. Unless otherwise specified, all units are U.S.
Customary and U.S. dollars.
1.2 | Mineral
Resource Statement |
This
section remains largely unchanged from the “S-K 1300 Technical Report Summary CK Gold Project,” dated December 1,
2021. However, the modeled mineral resources have been updated to include datasets from the 2021 drilling program conducted by U.S. Gold.
Mark
Shutty, CPG, is the Qualified Person (QP) responsible for the mineral resource estimation. The updated estimate was prepared using Leapfrog
and MinePlan software, utilizing the geologic database accumulated throughout the project’s history. The 2021 drilling program
contributed to enhancing resource classification and expanding the modeled mineralized domain and contained resources. Gold (Au), copper
(Cu), and silver (Ag) mineralization observed in the 2021 drill intercepts closely aligned with previously modeled host lithologies,
exhibiting consistent metal grades with neighboring drill hole intercepts and the estimated grades in the block model.
In
the QP’s opinion, the updated resource estimate represents a reasonable representation of the in-situ resources for the CK Gold
Project based on all available data as of the effective date. Mineral resources are reported using a gold-equivalent (AuEq) cut-off grade,
incorporating metal recovery and pricing assumptions. The cut-off grade varies with the expected recovery of different material types
but averages 0.010 ounces per short ton (oz/st) AuEq, equivalent to 0.35 grams per metric tonne (gpt) AuEq. The resources are constrained
within an optimized pit shell that, in combination with the cut-off grade, provides reasonable prospects for economic extraction.
Table
1.1 and Table 1.2 present a detailed tabulation of the Mineral Resources, inclusive of Reserves, for the CK Gold Project as of the effective
date of this report.
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1 |
Table
1.1: Mineral Resource Statement |
|
Mass |
Gold
(Au) |
Copper
(Cu) |
Silver
(Ag) |
Au
Equivalent
(AuEq) |
Tonnes
(000's) |
Oz
(000's) |
oz/st |
lbs
(million) |
% |
Oz
(000's) |
oz/st |
Oz
(000's) |
oz/st |
Measured |
36,400 |
608 |
0.0167 |
138 |
0.189 |
1,703 |
0.047 |
975 |
0.0268 |
Indicated |
51,200 |
544 |
0.0106 |
163 |
0.159 |
1,901 |
0.037 |
1,001 |
0.0195 |
M
+ I |
87,600 |
1,152 |
0.0131 |
301 |
0.172 |
3,604 |
0.041 |
1,976 |
0.0226 |
|
Inferred |
34,900 |
334 |
0.009 |
112 |
0.161 |
1,073 |
0.031 |
653 |
0.0187 |
| 1. | Mineral
resources are estimated using Ordinary Kriging, constrained by geological domains based on
lithology and mineralization controls. The underlying datasets supporting the resource estimate
have been reviewed, validated, and verified by the Qualified Person (QP). |
| 2. | Mineral
resources are reported in short tons within an optimized pit shell, using a breakeven gold
equivalent (AuEq) cut-off grade of 0.011 oz/st for Oxide and Mixed material and 0.010 oz/st
for Sulfide material. The overall average AuEq cut-off grade for all reported resources is
0.010 oz/st. No dilution or mining recovery factors have been applied. |
| 3. | The
AuEq cut-off grade is calculated using realized metal prices of $1,860.10/oz Au, $3.92/lb
Cu, and $22.52/oz Ag, with average metallurgical recoveries by oxidation type as follows: |
| ● | Gold
(Au): 55% (Oxide/Mixed), 64% (Sulfide) |
| ● | Copper
(Cu): 30% (Oxide), 78% (Mixed), 87% (Sulfide) |
| ● | Silver
(Ag): 61% (Oxide/Mixed), 70% (Sulfide) |
| 4. | The
optimized pit shell was generated using the Lerchs-Grossman method, incorporating all classified
resources, realized metal prices, $2.50/ton mining costs, $9.20/ton processing costs, a 50°
slope angle, and varying metallurgical recoveries as detailed in Table 11.12. |
| 5. | No
dilution or mining recovery factors have been applied to the resource estimate. |
| 6. | No
known legal, environmental, or permitting issues impact the reported resources. |
| 7. | Resources
are reported within the company’s permitted land tenure/exploration license boundaries. |
| 8. | Mineral
resources are classified in accordance with S-K 1300 definitions and are reported inclusive
of mineral reserves. |
| 9. | Rounding
may result in minor discrepancies in tonnage, grade, and contained metal totals. |
| 10. | There
is no guarantee that mineral resources will be converted to mineral reserves. |
| 11. | The
mineral resource estimates were prepared, reviewed, and validated by Mark Shutty, CPG, the
independent Qualified Person (QP) for these estimates, in accordance with S-K 1300 Definition
Standards adopted on December 26, 2018. |
| 12. | The
mineral resource estimate effective date is January 6, 2025. |
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2 |
Table
1.2: Mineral Resource Statement (Metric) |
|
Mass |
Gold
(Au) |
Copper
(Cu) |
Silver
(Ag) |
Au
Equivalent
(AuEq) |
Tonnes
(000's) |
Oz
(000's) |
gpt |
Tonnes
(000's) |
% |
Oz
(000's) |
gpt |
Oz
(000's) |
gpt |
Measured
(M) |
33,000 |
608 |
0.57 |
62.4 |
0.189 |
1,703 |
1.60 |
975 |
0.92 |
Indicated
(I) |
46,500 |
544 |
0.36 |
74.0 |
0.159 |
1,901 |
1.27 |
1,001 |
0.67 |
M
+ I |
79,500 |
1,152 |
0.45 |
136.4 |
0.172 |
3,604 |
1.41 |
1,976 |
0.77 |
|
Inferred |
31,600 |
334 |
0.33 |
50.9 |
0.161 |
1,073 |
1.06 |
653 |
0.64 |
| 1. | Mineral
resources are estimated using Ordinary Kriging, constrained by geological domains based on
lithology and mineralization controls. The underlying datasets supporting the resource estimate
have been reviewed, validated, and verified by the Qualified Person (QP). |
| 2. | Mineral
resources are reported in short tons within an optimized pit shell, using a breakeven gold
equivalent (AuEq) cut-off grade of 0.39 g/t for Oxide and Mixed material and 0.34 g/t for
Sulfide material. The overall average AuEq cut-off grade for all reported resources is 0.35
g/t. No dilution or mining recovery factors have been applied. |
| 3. | The
AuEq cut-off grade is calculated using realized metal prices of $1,860.10/oz Au, $3.92/lb
Cu, and $22.52/oz Ag, with average metallurgical recoveries by oxidation type as follows: |
| ● | Gold
(Au): 55% (Oxide/Mixed), 64% (Sulfide) |
| ● | Copper
(Cu): 30% (Oxide), 78% (Mixed), 87% (Sulfide) |
| ● | Silver
(Ag): 61% (Oxide/Mixed), 70% (Sulfide) |
| 4. | The
optimized pit shell was generated using the Lerchs-Grossman method, incorporating all classified
resources, realized metal prices, $2.50/ton mining costs, $9.20/ton processing costs, a 50°
slope angle, and varying metallurgical recoveries as detailed in Table 11.12. |
| 5. | No
dilution or mining recovery factors have been applied to the resource estimate. |
| 6. | No
known legal, environmental, or permitting issues impact the reported resources. |
| 7. | Resources
are reported within the company’s permitted land tenure/exploration license boundaries. |
| 8. | Mineral
resources are classified in accordance with S-K 1300 definitions and are reported inclusive
of mineral reserves. |
| 9. | Rounding
may result in minor discrepancies in tonnage, grade, and contained metal totals. |
| 10. | There
is no guarantee that mineral resources will be converted to mineral reserves. |
| 11. | The
mineral resource estimates were prepared, reviewed, and validated by Mark Shutty, CPG, the
independent Qualified Person (QP) for these estimates, in accordance with S-K 1300 Definition
Standards adopted on December 26, 2018. |
| 12. | The
mineral resource estimate effective date is January 6, 2025. |
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3 |
The
estimates of Mineral Resources may be materially affected if mining, metallurgical, or infrastructure factors change from those currently
anticipated at the CK Gold Project. Estimates of Inferred Mineral Resources have significant geological uncertainty, and it should not
be assumed that all or any part of an Inferred mineral resource will be converted to the Measured or Indicated categories. Mineral Resources
that are not Mineral Reserves do not meet the threshold for reserve modifying factors, such as estimated economic viability, that would
allow for conversion to Mineral Reserves.
1.3 | Mineral
Reserve Statement |
Mineral
Reserves are based on an open pit mine design and production schedule using reasonable design parameters. AKF Mining Services Inc. (AKF)
performed economic pit-limit analysis using Vulcan’s Pit Optimizer software, which uses the Lerchs–Grossmann (LG) algorithm
to determine an economic excavation limit based on input optimization parameters. Antonio Loschiavo, P. Eng., is the QP responsible for
the Mineral Reserves statement.
Measured
Mineral Resources within the mine design and schedule convert to Proven Mineral Reserves , and Indicated Mineral Resources within the
mine design convert to Probable Mineral Resources. Metal prices used for the cut-off grade calculation and economics are $1,755/oz gold,
$3.77/lb. copper, and $23/oz silver. The Mineral Reserves are reported above a value per ton cut-off threshold of $0.01/st, as recovery
varies by material type.
Table
1.3 contains the tabulation of the Mineral Reserves for the CK Gold Project as of the effective date of this report. Mineral reserves
are reported inside a detailed pit design using suitable parameters for the site.
Table
1.3: Mineral Reserves Statement |
|
Mass |
Gold
(Au) |
Copper
(Cu) |
Silver
(Ag) |
Au
Equivalent
(AuEq) |
Tons
(000s) |
Oz
(000s) |
oz/st |
M
lbs |
% |
Oz
(000s) |
oz/st |
Oz
(000s) |
oz/st |
Proven
(P1) |
34,500 |
595 |
0.017 |
133 |
0.192 |
1,591 |
0.046 |
909 |
0.026 |
Probable
(P2) |
38,800 |
426 |
0.011 |
127 |
0.164 |
1,417 |
0.037 |
763 |
0.020 |
P1
+ P2 |
73,200
|
1,022
|
0.014 |
260
|
0.177
|
3,008
|
0.041
|
1,672
|
0.023
|
| 1. | Reserves
tabulated above a VPT cut-off value of $0.01/st (see text). |
| 2. | Note:
Only three significant figures are shown, and the sum may not be due to rounding. |
No
known relevant factors materially affecting the estimation of Mineral Reserves are discussed in this report.
AKF
completed the 2021 Pre-Feasibility Study (PFS) design pits based on the 2021 PFS metal prices and operating costs. During the 2024 PFS
update, metal prices and operating costs increased, which triggered a review of the Mineral Reserves by rerunning the LG optimizations
based on the latest metal prices and operating costs. As a result, the comparison between the 2021 and 2024 PFS Mineral Reserves shows
a 3% increase in ore tons and a 5% increase in waste tons.
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4 |
1.4 | geology
and mineralization |
The
Silver Crown Mining District, where the Project is located, is underlain by Proterozoic rocks that make up the southern end of the Precambrian
core of the Laramie Range. Metavolcanic and metasedimentary rocks of amphibolite-grade metamorphism are intruded by the approximately
1.4-billion-year-old Sherman Granite and related felsic rocks. Within the project area, foliated granodiorite is intruded by aplitic
quartz monzonite dikes, thin mafic dikes, and younger pegmatite dikes. Shear zones with cataclastic foliation striking N60°E to N60°W
are found in the southern part of the Silver Crown district, including at CK Gold. Copper and gold mineralization at the Project occurs
primarily in unfoliated to mylonitic granodiorite. The granodiorite typically shows potassium enrichment, particularly near contact with
quartz monzonite. Mineralization is associated with a N60°W-trending shear zone.
CK
Gold mineralization has been interpreted as a shear-zone controlled, disseminated, and stockwork gold-copper deposit in Proterozoic intrusive
rocks. Most mineralization is in granodiorite, with lesser amounts in quartz monzonite and thin mafic dikes. Hydrothermal alteration
is overprinted on retrograde greenschist alteration and includes a central zone of silicification, followed outward by a narrow potassic
zone, surrounded by propylitic alteration. Higher grade mineralization occurs within a central core of thin quartz veining and stockwork
mineralization surrounded by a zone of lower grade disseminated mineralization. Disseminated sulfides and native copper with stockwork
malachite and chrysocolla are present at the surface, and chalcopyrite, pyrite, minor bornite, primary chalcocite, pyrrhotite, and native
copper are present at depth. Gold occurs predominantly associated with chalcopyrite and a minor proportion of free gold.
Several
metallurgical testwork programs have been completed on multiple samples of mineralization from the CK Gold Project. The work dates to
2008 when Saratoga Gold Company (Saratoga) first contracted SGS Lakefield (SGS) to perform fundamental characterization work and scoping
level separation tests (flotation and cyanide leaching) on several composites of sulfide and oxide mineralization. This established that
flotation was the most suitable method to process CK Gold Project mineralization to recover copper, gold, and silver into a high value
concentrate.
No
further work was completed until 2020 when U.S. Gold commenced a drilling program that included several holes designed to generate sufficient
sample material for a metallurgical test work update. The metallurgical program that followed commenced in December 2020 at Kappes, Cassiday,
and Associates (KCA) Laboratory in Reno, Nevada, before it transitioned over to Base Metals Laboratory (BML) in Kamloops, Canada. Several
metallurgical programs have been completed at BML, including further flotation characterization, grindability, mineralogy, and dewatering.
This work has confirmed flotation as the most suitable processing method. The most recent test work program concluded at BML in August
2022, and the overall body of testwork is now judged to be of suitable depth and quality to act as a valid reference for the Pre-Feasibility
Study process design.
Although
the current QP (John Wells) was not directly involved with historical work pre-2020, the reports were reviewed, resulting in general
concurrence with the conclusions. Whilst the 2021 PFS work incorporated process plant designs that were based on early SGS test work
and 2021 BML results, this PFS also includes more recent work from BML. The most recent test work program concluded at BML in August
2022, and the overall body of testwork is now judged to be of suitable depth and quality to act as a valid reference for the
Pre-Feasibility Study process design.
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5 |
Three
composites, each 200-300 kg, were prepared for test work: a High-Grade Oxide composite, an Oxide composite, and a Sulfide composite.
A narrow band of "mixed" material is between the oxide and sulfide zones. As this only represented a small component of the
drill core it was included in the Sulfide Composite. However, as results subsequently showed, the impact was significant. The mineralogy
indicated 10-15% of the copper minerals in this "sulfide" composite were not sulfide. A second Sulfide Composite was prepared
from core more remote from the mixed zone and tested at BML in July 2021. This resulted in significantly better copper, gold, and silver
recoveries.
Sub-samples
of core from each composite were provided to Hazen Research in Denver for comminution test work. This showed the material to be of medium
hardness but relatively competent. This supports the selection of a SAG-Ball-Pebble crusher grinding circuit. A primary grind P80
of 90 µm appears to be close to optimal.
Open
circuit flotation of the High-Grade composite was successful at KCA, providing high recoveries of copper (55%), gold (69%), and silver
(40%) to a 25% Cu flotation concentrate. Locked Cycle Tests (LCTs) at BML confirmed these results.
Flotation
of the Oxide Composite proved to be more challenging. Flotation was moderately successful in that open circuit rougher and cleaner tests
produced a low-grade but high value copper concentrate, 10-15% Cu, that contained over 150 gpt gold and 100 gpt silver. This material
constitutes about 6-8% of the deposit. The mine plan could see this material treated on a campaign basis or combined with sulfide.
The
sulfide zone constitutes most of the deposit. LCTs on two sulfide composites gave high recoveries of copper (82-88%) and gold (67-74%)
to a 21-25% Cu, 76 gpt Au, 82 gpt Ag concentrate. Silver recovery was 59%.
Seven
variability samples were selected for test work. With less non-sulfide copper, the copper recovery was over 80%. Gold and silver recoveries
showed significant variation.
1.6 | mine
design, OPTIMIZATION, and scheduling |
The
CK Gold Project is planned as an open pit mine with a production life of approximately 10.3 years. Two independent mine planning and
sequencing studies have been accomplished and show broad agreement. U.S. Gold contracted AFK Mining to develop a mine design and schedule
for the Project. Lerchs-Grossmann pit optimization analysis was performed using reasonable design and economic parameters, and the result
was used to guide the mine design process. The final mine design is comprised of four phases, and material movement is scheduled on an
annual basis. Pit design parameters are based on a geotechnical drilling program and detailed stability analysis and are suitable for
the mining equipment selected.
Surface
mining is a cyclical process where the four main tasks, including drilling, blasting, loading, and haulage, occur concurrently at
different areas of the property. In areas to be excavated, vertical blast holes are drilled in a regular pattern and charged with
blasting agents. The material will be shot, loaded into 100 st class rigid frame haul trucks, and transported based on material type
to one of four different locations: run-of-mine (ROM) Crusher Stockpile, Tailings Facility, Ore Stockpile, or Waste Rock
Facility. Wherever possible Crusher Stockpile ore will be directly dumped into the primary crusher at the process plant.
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6 |
Owner
operator mining has been selected as the preferred method for this PFS. The owner will also operate the mine planning, ore control, process
plant, and general site administration (G&A). This decision is due to the location of the Project, local mining, and the availability
of potential labor within 30 miles of the site (Laramie and Cheyenne, Wyoming). Hybrid owner/contractor operations are still being evaluated
to leverage the regional mine contractor expertise and possibly reduce project capital costs.
The
primary driver of the mine schedule is the production of sufficient ore, which drives the excavation of waste and other materials to
ensure sufficient ore is exposed for mining. The nominal ore production rate was set at 20,000 stpd or 7.3M stpy (18,100 tpd, or 6.6
Mtpy) of ore delivered to the crusher. In the first year, ore production is 90% of full capacity to account for the commissioning of
the concentrator. Pre-production stripping is scheduled to start two years before production begins (Year -2 Q1) which consists of 1.200,000
st of material. Pit mining life is approximately eight years with almost another two additional years of ore stockpile processing.
The
CK Gold Project processing facility has been designed to process 20,000 stpd of gold/copper sulfide ore. The processing facility and
the unit operations therein are designed to produce a concentrate at 17.0% Cu or greater, with an average gold grade of 41 g/st.
The
process facility will consist of a ROM crushing circuit, crushed ore storage, a semi-autogenous grinding (SAG) mill/ball mill comminution
circuit, rougher flotation, regrind circuit, and cleaner flotation to liberate, recover, and upgrade the copper and gold from the ROM
ores. Flotation concentrate will be thickened, filtered, sent to a concentrate load out bin, and bagged for subsequent shipping.
Tailings
generated in the flotation process will be filtered to an optimum low moisture content to produce “dry stack” tailings. This
will maximize water conservation and structural strength and avoid the need for a conventional tailings dam and the associated environmental
and safety risks.
The
tailings slurry produced by flotation will first be thickened for initial water recovery, and thickener overflow water will be returned
to the process for reuse. The thickened slurry will be pumped to storage tanks ahead of a large pressure filtration plant comprising
multiple large pressure filters that further reduce the water content to <15% (typically 14%). This will leave the solids as a compressed
“cake” material that will be dropped from the press onto a conveyor going to a tailings bin where the dry filtered cake will
be loaded into haul trucks for transportation to the dry-stack Tailings Management Facility (TMF).
The
process plant will consist of the following unit operations and facilities:
| ● | Coarse
ore receiving and storage area from the open pit mine. |
| ● | Jaw
crushing system, crushed ore stockpile, and stockpile reclaim system to convey crushed ore
to the process. |
| ● | SAG/Ball
mill circuit incorporating cyclones for classification. |
| ● | SAG
mill pebble crushing circuit. |
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7 |
| ● | Rougher
flotation circuit. |
| ● | Rougher
concentrate regrinding circuit. |
| ● | Cleaner
flotation circuit incorporating three flotation stages and cleaner scavenger flotation cells. |
| ● | Concentrate
thickening and filtration circuit, including a concentrate bin and bagging station. |
| ● | Tailings
thickening and filtration circuits. |
| ● | Tailings
disposal at a dry-stack storage facility. |
| ● | Reagent
handling, utilities, process water, and fresh-water systems. |
An
access road approximately 4.2 miles long and 26 feet wide will be constructed, generally centered along a 60-foot-wide right-of-way outside
the project site boundary.
The
TMF is sited east of the process plant within a valley formed by the ephemeral South tributary of Middle Crow Creek. It begins to the
east of the South Crow Creek water transmission pipeline easement. The basin's topography contains and directs the placement of tailings
towards the northeast.
The
filtered tailings will be co-deposited with waste rock to provide structural buttresses for stability and a cover to protect against
weathering and wind erosion. The TMF will be developed in three phases, each consisting of a prepared subgrade, underdrain collection
system, composite liner system (CLS), seepage collection system, tailings, and waste rock. The tailings will be placed in the TMF in
10-to-20-foot lifts, and the waste rock buttress and shell will be installed in 10- to 20-foot lifts as the tailings increase in elevation.
Processed tailings will be hauled to and placed in the TMF until Year 8.25. After that, the remaining tailings produced will be hauled
to and placed in the open pit.
Designs
were prepared for the mine maintenance area, administration and warehouse building area, and other supporting facilities. The civil grading
designs utilized 3H:1V to 5H:1V slopes to balance the cut and fill areas, address stormwater runoff, and reduce erosion.
Electrical
power for the CK Gold Project will be supplied by a local utility company, Black Hills Energy (BHE), under an Industrial Contract Service
Agreement. The power demand for the Project requires that a new 115 kV power line be constructed for the Project by BHE. The power line
would be constructed from BHE’s West Cheyenne substation, located approximately 16 miles east of the Project, to a new BHE owned,
built, and operated 115 kV distribution substation (including transformer) near the mine. The estimated construction costs for the proposed
power line, easement cost, and substation can be amortized in addition to the base power unit rate charged.
The
Project will operate in a net water deficit situation, given that the mean annual evapotranspiration exceeds the mean annual
precipitation. The total average Project water consumption will be 562 gallons per minute (gpm). Water to meet processing, mining,
and potable water demand has been identified, and potential well sites have been investigated. A contract to supply water with the
Board of Public Utilities (BOPU) in Cheyenne, Wyoming, has been executed, outlining water sourced from the Lone Tree Creek well
field south of the site. However, under an agreement with the Ferguson Ranch, the surrounding landowner, a water exploration program
has successfully identified a nearby source in the Red Canyon approximately 1-mile north of the project. The Red Canyon water will
be less costly to develop and less costly to purchase under the agreement with the Ferguson Ranch, and adjustments to the identified
“source and use” specified in the two main project permits (ISC and MOP) will be made to reflect the Red Canyon water
supply once final development has been completed. Regardless of the source, water purchased will be used to make up the water
deficit. Local consultants conducted preliminary engineering to confirm the feasibility and costs associated with the Red Canyon
supply. Following studies by TGI, water generated from pit dewatering, surface runoff, and waste rock and tailings seepage will be
recycled for use in mineral processing and/or dust suppression, reducing the volume of make-up water.
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8 |
1.9 | environmental,
permitting, and community impact |
Environmental
studies began in October 2020 to establish the pre-mining site conditions and fulfill the requirements for permitting. The environmental
study reports, including baseline, groundwater modeling, seepage modeling, and geochemical characterization, have been submitted to the
State as part of the permitting process. Applications for the principal state have been granted the Industrial Siting Permit (ISP0, May
2023, and the Mine Operating Permit (MOP) in April 2024. The MOP was conditional on a water discharge permit (WYPDES), furnishing a reclamation
bond, and an Air Quality Permit (AQP), and these conditions were met in May, June, and November, respectively. The Project will occupy
state-owned and private land. Permitting is primarily at the state and local level; no major federal permits are required.
Mining
projects in Wyoming that are not located on Federal Land fall under the jurisdiction of the Wyoming Department of Environmental Quality,
Land Quality Division (DEQ-LQD), which issues the Mine Operating Permit (MOP). This is an operating permit, but it is needed to start
construction. The Project initially applied for the MOP in September 2022. The Project application went through two rounds of comments.
The MOP was granted to the Project in April 2024.
The
DEQ-LQD has permitted the Project's exploration activities to date. The Project has posted bonds to guarantee the reclamation of surface
disturbance caused by the development of exploration drill pads, test pits, and some roads. All such surface disturbance has been reclaimed,
including revegetation. Bond release is currently pending based on the re-establishment of revegetated areas.
In
February 2021 the US Army Corps of Engineers (USACE) issued an Approved Jurisdictional Determination, under which two surface water bodies
and associated wetlands in the Project area are considered Waters of the United States and subject to USACE jurisdiction and permitting
for discharging of dredged or fill materials. There are no plans for project discharges or dredge or fill material deposition in these
surface waters. Therefore, no further USACE permitting was anticipated. The USACE provided the Project with a no permit required letter
in April 2024.
The
Project required an Air Quality Permit to Construct and Operate issued by the DEQ’s Air Quality Division (DEQ-AQD). This permit
was approved in November 2024 with a New Source Review, including the development of the Project’s air emission inventory. Electrical
power will be supplied from a local utility rather than on-site generators (an on-site standby generator will be used in case of power
interruptions). It is expected that the Project will be classified as a Minor Source. Title V of the Clean Air Act is not expected to
apply. The permit application was submitted and underwent agency review and a public comment period before the final agency review. The
air quality permit was granted in November 2024.
The
Project also required an Industrial Siting Construction Permit issued by the DEQ’s Industrial Siting Division (ISD). This
permit is required for projects exceeding $253.8 million in construction costs. The application, including a socioeconomic and
environmental impact assessment, was submitted in February 2023, following public notifications to affected local government
agencies and two public informational meetings in Laramie County and the adjacent Albany County. DEQ-ISD granted the Industrial
Siting Construction Permit to the Project in June 2023.
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9 |
The
State Engineer’s Office (SEO) issues permits to appropriate water for beneficial use, as well as permits to construct and operate
water related infrastructure such as wells, mine dewatering systems, and reservoirs, including stormwater or sediment control structures.
SEO permits to construct and abstract water from the Project’s surface water diversion channels and detention ponds were received
in 2022 and 2023. Applications for permits to abstract groundwater flowing into the mine pit and to install a proposed on-site potable
water well were also approved in 2023.
The
DEQ Water Quality Division, State Fire Marshall, and Laramie County will require several other permits. Additionally, the US Environmental
Protection Agency has jurisdiction over public water supply systems in Wyoming and requires a permit to supply potable water from the
proposed on-site well. These permits will entail significantly less time and effort than the principal state permits granted.
In
addition to government agencies' permitting requirements, the project's development will require certain agreements with private local
entities. Agreements with Ferguson Ranch were negotiated for surface use rights, easements, and temporary rights to on-site water sources.
Planning for a power supply agreement is also ongoing with Black Hills Energy. Beyond the extensive outreach during the ISP, U.S. Gold
has and continues to reach out to and provide project information to various additional local public and private entities that may be
affected by and/or interested in the Project. Procurement of goods and services and hiring of personnel are governed by the Project’s
policy of prioritizing local and State of Wyoming sources.
Environmental
requirements and associated planning focus on avoiding or mitigating environmental impacts throughout the project life cycle. Waste rock
and tailings generated during mining and mineral processing will be deposited in engineered facilities on the project site. Geochemical
testing of mine rock and tailings using industry standard methods on representative samples indicates a limited probability of producing
acid rock drainage (ARD) and/or metal release to water. Static geochemical testing on tailings samples produced by locked cycle laboratory
testing indicates that the tailings are not acid generating. Static geochemical testing of waste rock samples indicates only a small
percentage of waste rock is potentially acid generating (PAG). Confirmatory kinetic and leach test results show no or low production
of acidic water or metal release for all tested samples.
The
tailings will be filtered to extract as much moisture as feasible prior to their deposition, maximizing their structural strength and
geotechnical stability, thereby avoiding the need for a tailings dam and the associated stability and seepage risks. Filtered tailings
also maximize the amount of water that can be recycled to mineral processing, reducing make-up water requirements and minimizing overall
water consumption. The tailings will be co-deposited in a Tailings Management Facility (TMF) with waste rock to provide structural buttresses
and a retention shell for stability. Slope stability analyses of the TMF under static, pseudo-static, and post-peak loading conditions,
including liquefaction assessment, were performed to verify that acceptable safety factors were obtained.
Runoff
and seepage from the TMF will be collected in detention ponds at the downstream toe. A liner will limit seepage to the subsurface. A
seepage collection drain installed above the liner will maintain a low hydraulic head in the bottom of the tailings mass and promote
free drainage of the tailings, minimizing tailings saturation. The seepage collection drain will discharge to the detention pond
downstream of the TMF.
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10 |
To
minimize fugitive dust emissions from the TMF, the top of the tailings surfaces will be compacted as quickly as feasible following tailings
deposition, spreading the tailings by dozers using a smooth roller compactor to seal the surface. Once the final tailings slope and elevation
have been achieved, the waste rock retention shells will be placed over the exposed tailings slopes. Speed limits will be imposed and
enforced for mobile equipment operating on and around the TMF. Water will be sprayed on active surfaces to control fugitive dust emissions
as required.
Waste
rock will be used for construction of haul roads, erosion control features, and buttresses forming the outer shell of the TMF. Surplus
waste rock will go into the West and East Waste Rock Facilities. These facilities are designed to have a slope angle of 3H:1V, which
is substantially flatter than the rock’s angle of repose, inherently providing an acceptable safety factor for geotechnical stability.
Runoff and seepage will be collected in sedimentation ponds constructed at the downstream toe of the waste rock facilities. While kinetic
testing on waste rock resulted in no ARD/metal leaching, the Project proposes segregating and isolating PAG waste rock, as determined
by NAG pH testing, representing less than 11% of the total waste rock to be excavated and handled. PAG waste rock is proposed to be deposited
in the interior of the lined TMF, as space allows, and, if needed, in the open pit after Year 8.
Extensive
hydrogeologic site characterization has been completed to support the development of a regional groundwater flow model. The model simulates
pre-mining conditions and hydrologic changes during mining and post-mining. Predicted mine-induced groundwater drawdown decreases rapidly
away from the pit. The 5-ft drawdown will generally remain within the Project site boundary. The nearest domestic wells are 2,000 ft
from the predicted 10 ft drawdown area and are not expected to experience discernable effects. Likewise, the effects on surface water
flow in nearby streams will be negligible. The average annual groundwater pit inflow is expected to be less than 15 gpm, which will be
captured using passive, in-pit sumps. After mining, groundwater and precipitation flowing into the backfilled pit will cause a gradual
rebound of the groundwater level. A pit lake is not expected to form since evaporation losses will keep the groundwater level below the
top of the backfill. This will result in the pit being a hydraulic sink with no groundwater outflows.
The
Project site will be in a net water deficit situation, given that the mean annual evapotranspiration exceeds the mean annual precipitation.
To minimize the overall demand for water from external sources, the Project will implement the following water conservation measures:
| ● | Tailings
filtration maximizes the amount of water recycled back into the flotation process, thereby
avoiding the need for a tailings dam where much of the water would be lost to seepage and
evaporation. |
| ● | Pit
inflow collection in a sump to use for dust control in the pit. |
| ● | Surface
runoff and seepage collection from waste rock facilities, TMF, and other facilities to use
for dust control on site. |
| ● | Conversion
of an existing on-site irrigation ditch providing water during the spring season. |
| ● | On-site
potable water supply well. |
| ● | Truck
wash water recovery and reuse for dust control. |
| ● | Recycling
of water used for in-pit and primary crusher dust control. |
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11 |
The
Project submitted a Reclamation Plan as part of the MOP application. The closure objective is to reclaim the site to enable the resumption
of its current use of cattle grazing and mule deer winter range. A reclamation cost estimate has been developed for the reclamation bonding
process. Concurrent reclamation will be practiced during the life of the mine to reclaim portions of the project site as soon as feasible
before the end of mining, securing corresponding early releases in bonding obligations. At the end of operations, the process plant and
supporting facilities will generally be demolished, and their footprints will be regraded. The disturbed areas, including the waste rock
facilities and TMF, will be covered in topsoil and revegetated. Micro-topographical undulations and rock outcroppings will be created
in the TMF slope for wildlife habitat and to promote revegetation. After the pit is fully excavated, it will be backfilled with tailings
produced during the last two years of post-mining mineral processing. With a combination of blasting and earthmoving, the pit rim will
be dozed into the pit to create a 3H:1V final pit wall slope covering the tailings. To help increase the local area’s long-term
water storage capacity, discussions have begun with BOPU about the possibility of converting the post-mining open pit into a water storage
reservoir.
1.10 | Capital
Costs, Operating Costs, and Financial Analysis |
An
after-tax, discounted cash flow model was developed to assess the economic performance of the CK Gold Project. This analysis relies on
this report's mining schedule, capital and operating cost estimates, and recovery parameters. The model assumes 100% equity funding,
a 5% discount rate, a gold price of $2,100/oz, copper price of $4.10/lb. and silver price of $27/oz. The results of the analysis are
shown in Table 1.4 and Table 1.5. The positive economic outcome of the financial analysis is used to delineate the CK Gold Mineral Reserve.
Table
1.4: Economic Model Results |
Key
Project Indicators |
Value
US$M |
Pre
Tax Economics |
|
IRR |
36.0% |
Cash
Flow (Undiscounted) |
$693.2 |
NPV
5% Discount Rate |
$459.2 |
Payback
(years) |
1.7 |
After
Tax Results |
|
IRR |
29.5% |
Cash
Flow (Undiscounted) |
$556.9 |
NPV
5% Discount Rate |
$355.9 |
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12 |
Table
1.5: Project Details |
Key
Project Indicator |
Value |
Gold
Ounces Sold (000's) |
663 |
Copper
Sold (Million Lbs.) |
196
|
AuEq
Ounces Sold (000's) |
1,069
|
Initial
Capital ($ Million) |
$272.8 |
Sustaining
Capital ($ Million) |
$16.6 |
Avg.
Cash Cost of Production ($/oz AuEq) |
$922.0 |
All
in Sustaining Cost ($/oz AuEq) |
$937.0 |
A
sensitivity analysis on metals pricing indicates additional potential for this project at higher metals pricing, Table 1.6. Additionally,
the sensitivity indicates the robustness of the project with positive economic outcomes at reduced metals pricing.
Table
1.6: Metal Price Sensitivity |
Metal
Pricing |
Pre-Tax
|
Post-Tax |
Gold
Price |
Copper
Price |
NPV |
IRR |
Payback
|
NPV |
IRR |
Payback
|
Au/oz |
Cu/lb |
$M |
% |
Years |
$M |
% |
Years |
$1,300 |
3.80 |
$35 |
8.1% |
5.55 |
($13) |
3.8% |
6.98 |
$1,700 |
3.90 |
$240 |
23.0% |
2.71 |
$177 |
18.4% |
3.44 |
$2,100 |
4.10 |
$459 |
36.0% |
1.73 |
$356 |
29.5% |
2.12 |
$2,500 |
4.30 |
$678 |
47.6% |
1.37 |
$532 |
39.4% |
1.63 |
$3,000 |
4.50 |
$945 |
60.4% |
1.10 |
$745 |
50.3% |
1.31 |
1.11 | conclusions
and recommendations |
1.11.1 | General
Recommendations |
U
S Gold’s CK Gold Project focuses on the historical Copper King deposit in the Silver Crown Mining district, which has been the
subject of sporadic mining activity for over 100 years. The CK Gold Project demonstrates a very low waste to ore ratio, the absence of
a large pre-strip period to expose mineralization, simple low-cost mineral extraction, and proximity to key infrastructure and support
services, which all favor positive project economics.
With
a life of mine cash cost per equivalent gold ounce of $922/oz, the margin compared to both the study price, set at $2,100 per gold
ounce, and the gold price at the time of writing of approximately $2,885 per gold ounce, indicates robust project economics. The
fact that the bulk of the revenue is split between sales of gold and copper suggests that the project may be less sensitive to
cyclical swings in the prices of either individual metal. A unique feature of the CK Gold Project is its proximity to growing
population centers and infrastructure, which may further offer opportunities to bolster revenue through the sale of waste rock as
aggregate. Investigations have proven the non-mineralized rock to be of very good quality for aggregate products. The aggregate
potential has not been included in this study; however, the Burgex Study, August 2024, investigates the regional market conditions
and summarizes the testwork concluded to date showing the non-metal bearing rock as an excellent source of aggregate and rail
ballast. The study concludes that up to 1 million tons could be sold into the local market utilizing truck haulage at a significant
margin. Greater tonnage could be sold if a rail haulage scenario could be arranged. More than 40 million tons of rock will be set
aside and reclaimed under the current plan; however, putting this rock to beneficial use can benefit the CK project, provide
additional royalty payments to the State, and reduce the project footprint and closure costs. The potential of creating a separate
business unit to benefit from the rock mined will be evaluated in follow-up studies.
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13 |
U.S.
Gold elected to focus on data capture to support a Pre-feasibility study and permit application with its 2020 and 2021 field season activities.
The resource model shows that there are potential extensions to the mineralization at depth and to the southeast of the deposit and these
should be investigated. Additionally, there is uncertainty as to the genesis of the mineralization, with the deposit not neatly fitting
a porphyry or Iron oxide copper gold (IOCG) type depositional model. The company is set to support study work with the University of
Wyoming, and we recommend that efforts continue to better understand the geological setting and assess district potential.
In
reviewing the Project, we conclude that the type of mining, rate of mining, and mineral processing technology selected in the PFS study
is appropriate. While evidence suggests that improved gold recoveries can be readily obtained through the implementation of flotation,
followed by cyanidation of the flotation tailings, other factors and considerations make the application of such technology difficult
to assess. Not least of these considerations is the public perception of the use of cyanide gold recovery. With the potential to recover
an additional 180,000 gold ounces with the addition of a cyanide circuit, we recommend that trade-off studies be conducted but tend to
agree with U.S. Gold management that further studies and permitting be advanced without the inclusion of a cyanide circuit, under current
price assumptions.
The
goal of the Pre-feasibility Study is to provide information to the directors of U.S. Gold so that they can make an informed decision
about the future development of the Project. To advance the CK Gold Project, it is recommended that a feasibility study be commenced
to advance project engineering and planning. The estimated budget to complete this is $3MM to develop the appropriate level of detail
and proceed with the recommendations provided in this report.
To
further assess the project's viability and feed into a more accurate and comprehensive assessment, plans for an EPCM strategy, construction,
and operations to support project development should be created. The development of a detailed owner’s team for development, contracting
strategy and transitional plan to operations should be identified.
At
the initial stage of this study, 20 and 30-foot benches were used as the basis for the mine bench design. Since the production rate of
plant throughput has since increased to 20,000 stpd and larger mining equipment would be used to accommodate the higher plant throughput,
it is recommended to re-design the mine using possibly 35 ft or 40 ft bench heights. This would reduce unit costs for drilling, blasting,
loading, and hauling.
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14 |
1.11.2.2 | Future
Metallurgical Test Work |
The
geometallurgical models prepared for the Pre-Feasibility Study highlight recovery relationships with head grade and oxidation level.
Additional variability testing, together with larger scale work on lower grade samples, would be useful.
Specialty
test work with the vendors of tailings and concentrate filtration, including the oxide and sulfide components. Specific test work on
the mixed ore zone.
Additional
vendor specific test work on flotation and regrinding is needed to quantify possible recovery and/or grade improvements utilizing different
flotation and grinding technologies.
1.11.2.3 | Mineral
Processing |
| ● | Conversations
with equipment vendors indicate that additional investigation into the utilization of alternative
flotation and/or regrind technologies could reduce the plant footprint, which would result
in structural cost savings. The alternative technologies have the potential to reduce operating
costs due to a reduction in electrical power usage. Realization of these savings would be
contingent on positive results from the metallurgical test work. |
1.11.2.4 | Design
and Engineering |
| ● | Additional
discrete studies should be pursued to develop possible capital and operating improvements.
A comprehensive list is in Section 23. Priority items would be coarse ore flotation tests
for capital and process improvements, Run of Mine ore testing for comminution improvements,
additional engineering to improve quantity takeoffs, and layout optimization. Also, alternative
building types and water management could decrease costs, and earthwork balancing could be
improved by layout optimizations. |
1.11.2.5 | Environmental,
Permitting, and Social |
| ● | Continue
activities needed to obtain the required state and local permits. |
| ● | Continue
disclosing project information and consulting with local stakeholders, especially focusing
on project impact assessment, local project benefits, and impact mitigation measures. |
| ● | Concluded
a wildlife mitigation agreement with the Wyoming Game and Fish Department. |
| ● | Concluded
the needed land use agreements with the Office of State Lands and Investments and the affected
private landowner. |
| ● | Identify
and secure a potential alternative backup water supply source. |
| ● | Continue
engagement with the City of Cheyenne regarding the potential post-mining conversion of the
pit to a water storage reservoir serving the city. |
| ● | Develop
and implement a Project Environmental Management System (EMS) consisting of site-specific
plans and procedures governing the environmental management of project activities causing
potential environmental impacts during construction, operations, closure, and post-closure. |
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15 |
2.1 | Terms
Of Reference And Purpose |
Samuel
Engineering, Inc. (Samuel) was commissioned by U.S. Gold Corp (U.S. Gold) to prepare an updated Pre-Feasibility Study (PFS) for the CK
Gold Project (“CK Gold Project” or the “Project”). This report is a Technical Report Summary (TRS), which summarizes
the findings of the PFS following the Securities Exchange Commission Part 229 Standard Instructions for Filing Forms Regulation S-K subpart
1300 (S-K 1300). This TRS aims to report mineral resources, mineral reserves, and economics for the CK Gold Project. The effective date
of this report is February 10th, 2025.
The
quality of information, conclusions, and estimates contained herein are consistent with the level of effort involved in Samuel’s
services based on the following:
| ● | Information
available at the time of preparation. |
| ● | Data
supplied by the client. |
| ● | The
assumptions, conditions, and qualifications outlined in this report. |
Any
opinions, analyses, evaluations, or recommendations issued by Samuel under this report are for the sole use and benefit of U.S. Gold.
Because there are no intended third-party beneficiaries, Samuel (and its affiliates) shall have no liability to any third parties for
any defect, deficiency, error, or omission in any statement contained in or in any way related to its deliverables provided under this
Report.
The
regional geologic setting of the CK deposit within the Cheyenne suture belt is significant, as is the nature of occurrence of sulfide
mineralization as disseminations in undeformed granodiorite and alignment with foliation in foliated to mylonitized granodiorite. Based
on the available data and information to date, we suggest that Klein’s (1974) description of the CK deposit as a “structurally
controlled base and precious metal deposit hosted in a Precambrian shear zone” is essentially correct if you want further refinement.
While Klein’s description does not present a conventional deposit model, it does provide a reasonable interpretation on which to
base plans for future exploration. Future drilling exploration (and petrographic and/or mineralogical analysis) should be carefully planned
to test Klein’s interpretation and target data useful in further developing an appropriate deposit model for the CK Project, whether
conventional or not.
2.2 | sources
of information |
The
information, opinions, conclusions, and estimates presented in this report are based on the following:
| ● | Information
and technical data provided by U.S. Gold. |
| ● | Review
and assessment of previous investigations. |
| ● | Assumptions,
conditions, and qualifications as outlined in the report. |
| ● | Review
and assessment of data, reports, and conclusions from other consulting organizations and
previous property owners. |
These
sources of information are presented throughout this report and in the References section. The Qualified Persons are unaware of any material
technical data other than that presented by U.S. Gold.
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16 |
Below
is a list of the qualified persons involved in preparing this TRS and details of their property inspection.
Antonio
Loschiavo, P.Eng visited the CK Gold Project property and site facilities, which include core logging facilities, pit and waste dump
areas, tailings facility, and plant location, on multiple occasions between 2022 and 2024. The last site visit was the week of June 3rd,
2024, touring the Komatsu Equipment suppliers (Power Motive).
Mark
Shutty, CPG, visited the CK Project site and US Gold’s logging and sample storage facilities in Cheyenne on July 26–27, 2021,
and again on July 11, 2024. Mr. Shutty has reviewed the drillhole datasets and geological information supporting the Mineral Resource
Estimate.
John
Wells visited the core storage and metallurgical labs on multiple occasions listed below throughout validating the metallurgy:
| ● | 2021-CORE
SHED AND SELECTION OF SAMPLES. |
| ● | 2021-Kappes
Cassidy Lab-RENO. |
| ● | 2022
and 2024, Base Metals Lab-KAMLOOPS, CANADA. |
Samuel
Engineering had Eric Brunk and Peter Clarke visit the site to assess topography and constructability, understand the site access, and
confirm proximity to existing infrastructure.
Tierra
Group visited the property on 19 April 2022 to assess general site topography, visible geology, and other site conditions.
Kevin
Francis, Vice President of Exploration and Technical Services with the registrant has management responsibility over the CK Gold project
and visits the site, logging and storage facilities frequently. The last visit was January 16, 2025 when Mr. Francis toured the project
site.
Responsible
Company |
QP
Individual(s) |
Responsible
Section |
AKF
Mining |
Antonio
(Tony) Loschiavo, P.Eng., President, AKF Mining & Mineral Services Inc. |
12,
13, 15.2, 15.3.4, 17.2.1.1 |
Drift
Geo |
Mark
C. Shutty, CPG, Drift Geo |
9
& 11 |
John
Wells |
John
Wells |
10 |
Samuel
Engineering, Inc. |
Cameron
Wolf, Steve Pozder, Matt Boling, Richard Morris, Jim Sorensen |
1,
2, 14, 15.4, 15.3, 15.5.1, 18, 19, 21, 22, 23, 24, 25 |
Tierra
Group International, Ltd. (TGI) |
Various |
15.1.2,
15.2.1, 15.3.2, 15.3.3, 17.1.3, 17.2.1.2, 17.2.3.3, 17.2.3.2 |
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17 |
U.S.
Gold Corp (Registrant) |
Kevin
Francis, SME-RM, VP, U.S. Gold Corp. |
3,
4, 5, 6, 7, 8, 15.1.1, 15.3.1, 15.5.2, 16, 17.1, 17.1.1, 17.1.2, 17.1.3, 17.1.4, 17.2, 17.2.1, 17.2.2, 17.2.3,17.2.3.1, 17.2.3.4,
17.2.3.5, 17.3, 17.4, 17.5, 17.6, 17.7, 20 |
2.4 | Previous
Reports on the Project |
The
first TRS U.S. Gold submitted for the CK Gold Project was the Gustavson Associates report, “S-K 1300 Technical Report Summary CK
Gold Project”, dated Dec. 1, 2021. The authors are unaware of any other TRS submitted by prior owners of the Project. However,
U.S. Gold did publish a Technical Report and Preliminary Economic Assessment for the CK Gold Project in December 2017. This previous
Technical Report did disclose a mineral resource for the Project under the reporting requirements of the Canadian Securities Administrators
National Instrument 43-101 (NI-43-101). The CK Gold Project was formerly referred to as the Copper King Project.
2.5 | List
of abbreviations and units |
All
measurement units are in the US Customary System (USCS), and currency is expressed in US dollars unless otherwise noted. Certain specific
abbreviations not listed here will be defined within the report text. The following abbreviations may be used in this report:
Abbreviation |
Unit
or Term |
A |
ampere |
AA |
atomic
absorption |
AACE |
Association
for Advancement of Cost Engineering |
ABA |
acid-base
accounting |
Ac |
Acre |
Ai |
Abrasion
index |
AJD |
Approved
Jurisdictional Determination |
AML |
Abandoned
Mine Lands Division |
amsl |
above
mean sea level |
ARD |
Acid
Rock Drainage |
Ag |
silver |
Au |
gold |
AuEq |
gold
equivalent grade |
bcy |
bank
cubic yards |
BLM |
US
Bureau of Land Management |
BOPU |
Cheyenne
Board of Public Utilities |
C$ |
Canadian
dollar |
°C |
Centigrade
degrees |
cfm |
cubic
feet per minute |
cfs |
cubic
feet per second |
CLS |
composite
liner system |
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18 |
Abbreviation |
Unit
or Term |
cm/s |
centimeters
per second |
COG |
cut-off
grade |
CRM |
certified
reference material |
Cu |
copper |
CV |
coefficient
of variance |
CWA |
Clean
Water Act |
° |
degree
(degrees) |
D |
day |
DEQ |
Wyoming
Department of Environmental Quality |
EWRF |
East
Waste Rock Facility |
EMS |
environmental
management system |
°F |
Fahrenheit
degrees |
FEL |
front
end loader |
FA |
fire
assay |
fasl |
feet
above sea level |
FIBCs |
Flexible
Intermediate Bulk Containers, e.g., bulk bags |
FS |
Feasibility
Study |
FSR |
freight,
smelting, and refining |
ft |
foot
(feet) |
ft2 |
square
foot (feet) |
ft3 |
cubic
foot (feet) |
Ga |
billions
of years |
g |
gram |
gal |
gallon |
GD |
granodiorite |
GDK |
potassic-altered
granodiorite |
G&A |
general
and administrative |
gpm |
gallons
per minute |
gpt |
grams
per tonne (metric) |
h |
hour |
HCT |
humidity
cell testing |
HDPE |
high-density
polyethylene |
hp |
horsepower |
HTW |
horizontal
true width |
ICP-MS |
inductively
coupled plasma mass spectrometry |
ID2 |
inverse-distance
squared |
ID3 |
inverse-distance
cubed |
IRR |
internal
rate of return |
k |
thousands |
kg |
Kilogram
(metric) |
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19 |
Abbreviation |
Unit
or Term |
koz |
thousand
troy ounces |
kst |
thousand
short tons |
kstpd |
thousand
short tons per day |
kstpy |
thousand
short tons per year |
kV |
kilovolt |
kW |
kilowatt |
kWh |
kilowatt-hour |
lb |
pound |
LG |
Lerch-Grossman |
LME |
London
Metal Exchange |
LCT |
locked
cycle test |
LOM |
Life-of-Mine |
LQD |
Land
Quality Division |
M |
million |
Ma |
million
years |
MD |
mafic
dikes |
mi |
mile |
min |
minute |
Moz |
million
troy ounces |
ms |
millisecond |
MSED |
metasediment
unit |
Mst |
million
short tons |
Mstpy |
million
short tons per year |
MW |
megawatt |
MWMP |
Meteoric
Water Mobility Procedure |
MYL |
Mylonite |
NAG |
net
acid drainage |
NEPA |
National
Environmental Policy Act |
NI-43-101 |
Canadian
Securities Administrators National Instrument 43-101 |
NPAG |
not
potentially acid generating |
NPV |
net
present value |
NRHP |
National
Register of Historic Places |
NRCS |
Natural
Resource Conservation Service |
oz |
troy
ounce |
opt |
troy
ounce per short ton |
OSLI |
Office
of State Lands and Investments |
P80 |
80-percent
passing size |
PEG |
pegmatites |
PFS |
Prefeasibility
Study or Pre-Feasibility Study |
pH |
negative
log of hydrogen ion concentration |
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20 |
Abbreviation |
Unit
or Term |
ppb |
parts
per billion |
ppm |
parts
per million |
QA/QC |
quality
assurance/quality control |
QC |
quaternary
cover |
RC |
rotary
circulation drilling |
ROM |
run
of mine |
ROW |
right
of way |
RQD |
Rock
Quality Designation |
SAG |
semi-autogenous
grinding |
SD |
standard
deviation |
sec |
second |
SG |
specific
gravity |
SHPO |
Wyoming
State Historic Preservation Office |
SPMDD |
Standard
Proctor Maximum Dry Density |
sq
mi |
square
mile |
st |
short
ton (2,000 pounds) |
stph |
short
tons per hour |
stpd |
short
tons per day |
stpy |
short
tons per year |
TRS |
Technical
Report Summary |
TMF |
Tailings
Management Facility |
µm |
micron
or microns |
USACE |
United
States Army Corps of Engineers |
US$ |
U.S.
dollar |
USFWS |
US
Fish and Wildlife Service |
USGS |
United
States Geological Survey |
V |
volts |
W |
watts |
WB |
Water
Balance |
WGFD |
Wyoming
Game and Fish Department |
WQD |
Water
Quality Division |
WWRF |
West
Waste Rock Facility |
y |
year |
yd2 |
square
yard |
yd3 |
cubic
yard |
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21 |
The
CK Gold Project is in Laramie County, Wyoming, in the southeastern portion of the state, approximately 20 miles west of Cheyenne. It
is centered in the north half of Section 36, T14N, R70W. The property footprint is approximately 1119 acres (453 hectares), subject to
surface disturbance. It includes the S ½ of Section 25, the NE ¼ of Section 35, all of Section 36, and north 2/3 of Section
31. A regional and local map is shown in Figure 3.1.

Figure
3.1: Regional and Local Map
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22 |

Figure
3.2: Project Map
3.2 | Mineral
Titles, Claims, Rights, Leases, and Options |
The
CK Gold property consists of two State of Wyoming Metallic and Non-metallic Rocks and Minerals Mining Leases listed below. Both mineral
leases listed can be renewed for successive 10-year terms if certain conditions are met.
Lease
#0-40828 for 640 acres (259 hectares), which includes all of Section 36, T14N, R70W, is a 10-year renewable lease that expires February
1, 2033. The current annual rental is $2.00 per acre, $1,280 total.
Lease
#0-40858 for 320 acres (130 hectares), which includes S½ Section 25 T14N, R70W and 160 acres within NE¼ Section 35, T14N,
R70W. The current annual rental is $2.00 per acre, $1,280 total. The lease is a 10-year renewable lease that expires February 1, 2034.
Surface
Lease Option Agreement Section 31 and Section 25. In August 2021, an option agreement to lease surface rights for project development
was executed, contemplating the use of a portion of 712 acres (288 hectares) for project development activities.
The
surface of S½ Section 25 and NE¼ Section 35 is privately owned. An easement agreement providing access has been
negotiated with Ferguson Ranch Inc. on the S½ Section 25, T14N, R70W, as well as the W½ Section 31, T14N, R69W. The
original access easement was first signed in November 2006 but replaced and superseded by one effective May 1, 2009; the agreement
is for one year and is renewable annually. Annual payments on the easement agreement are $5,000 for the first year and $10,000 for
the next four years if the agreement is renewed. U.S. Gold reports that the agreement has been renewed for the current year.
Additionally, a new temporary easement preferred by the landowner was established and celebrated in 2021. This new easement follows
the same path as the proposed project access and is subject to the Option Agreement on the land lease and Right-of-Way
(ROW).
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23 |
The
surface of Section 36 is owned by the State of Wyoming and is leased for agricultural use to Ferguson Ranch Inc. As part of the terms
for its surface-use lease option agreement with Ferguson Ranch Inc., U.S. Gold has an arrangement to compensate the Ferguson Ranch for
the loss of grazing. Prior to mining development, upon the celebration of the Option Agreement and exercising the Lease for the land,
annual payments identified in the Option Agreement would be split between the State of Wyoming and the surface lessee based on a sliding
scale (per current agreement based on a formula provided by the Wyoming Office of State Lands and Investments).
Various
private owners own the surface of Sections 25 and 35. While the open pit expands onto a small portion of the southern part of Section
25, there is no planned activity on Section 35 besides the placement of a freshwater header tank and communications equipment. U.S. Gold
owns 28 hectares (70.2 acres) immediately west of Section 36 in the NE ¼ Section of Section 35 and the water tank and communications
equipment will be placed on U.S. Gold property. There will be a minor amendment in the project description associated with the current
permit to incorporate this land into the project area. Otherwise, the land on Section 35 will serve as a buffer between the mine and
other residents in the area.
OTHER
PROPERTIES
In
2021 and 2022, the Company acquired two parcels of land immediately west of and adjacent to Section 36 T14N 70W on Section 35. The two
parcels, totaling approximately 70.2 acres, lie outside of Cheyenne city limits, and property tax payments are current. The Company owns
the surface rights and leases the mineral rights from the state of Wyoming. The Company believes that these parcels may be used for later
project development other than described above and are presently viewed as an investment.
3.3 | Environmental
Impacts, Permitting, Other Significant Factors, and Risks |
Since
2017, U.S. Gold has conducted a field exploration program for drilling, soils, geotechnical, and hydrological investigations. This program
is fully permitted, and the CK Gold Project currently holds a DEQ-issued Exploration Permit # DN0440, TFN 7 3/064, which includes cumulative
bonding presently totaling $155,000. In addition, an exemption of Stipulation 5 of U.S. Gold’s mineral lease 0-40828 has been obtained
from the Wyoming Game and Fish Department, addressing mineral lease terms that exclude activity in sensitive big game habitats between
November 15th and the end of April each year. Negotiations with Wyoming Game and Fish have been held to outline measures that
can be taken if the project proceeds to contribute to the enhancement of wildlife habitat. Discussions identified that mitigation measures
are reasonable to accomplish, such as programs to install wildlife-friendly fencing, invasive species (e.g., cheatgrass) mitigation,
and land swaps. Currently, U.S. Gold is contemplating a $300,000 mitigation effort agreed to, in coordination with Wyoming Game and Fish,
along with recognition that measures such as “game friendly” fence installation will be adopted during project development.
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24 |
The
current surface disturbance from exploration activities, including roads and test sites, is 40 acres. Costs associated with the reclamation
of the exploration disturbance are bonded through cash payments to the state and recoverable upon inspection and release by the DEQ.
3.4 | royalties
and agreements |
The
CK Gold Project is subject to a production royalty of 2.1%, payable to the Office of State Lands and Investments (OSLI) for the State
to fund appropriate education trust accounts. The royalty payment in the original lease package was negotiated, and the 2.1% royalty
supersedes the prior royalty provision as per the 2023 amendment. The royalty is calculated based on the gross sales value of the product
sold, less applicable deductions for costs incurred for processing, transportation, and related costs beyond the point of extraction
from the open pit mining operation. Once the Project is in operation, the Board of Land Commissioners has the authority to reduce the
royalty payable to the State. Before commercial production, a royalty of $2.00 per acre is payable to the OSLI. In addition to the permitting
requirements and associated interaction with the DEQ and other state and local agencies, the development of the CK Gold Project will
require exercising certain agreements with other local entities, including (1) Ferguson Ranch for land use rights and easements for access
road, power line and water supply well(s) and pipeline; (2) Negotiating a water pipeline route across private property, (3) an agreement
for a power line easement; and (4) a power supply agreement with Black Hills Energy, a subsidiary of Black Hills Corporation.
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25 |
4.0 | Accessibility,
Climate, Local Resources, Infrastructure and Physiography |
4.1 | topography,
elevation, and vegetation |
The
CK Gold Project is located on the eastern flank of the Laramie Range between the Rocky Mountains and High Plains sections of the Great
Plains physiographic province. The Laramie Range is an approximately 130-mile-long mountain range between Laramie and Cheyenne, WY, that
trends north from the Colorado-Wyoming border towards Casper, WY. The Laramie Range consists of granite/granodiorite peaks and rolling
hills bound to the east non-conformably by shallow eastward dipping sedimentary rocks of the White River Formation. East of the Project
area, towards Cheyenne, WY, the topography transitions to flatter plains along the western margin of the Great Plains physiographic province.
The
gradually sloping sedimentary deposits on the flank of the Laramie range created what was referred to as a land bridge, allowing the
main east-west rail line to pass the area, avoiding difficult mountainous terrain. Elevations within the Laramie Range in the vicinity
of the property reach over 8,000 ft above mean sea level (amsl), while the city of Cheyenne, located on the western edge of the Great
Plains Province, is at an elevation of 6,100 ft amsl. The Project property has elevations ranging from 6,625 ft to 7,311 ft amsl with
generally low to moderate relief. The exception is the northwest portion of the property, which covers a moderate to steep, northwest-facing
slope that bottoms at 6,900 ft elevation in a northeast-flowing intermittent stream drainage. The Project mineral resource area elevation
ranges from 6,950 ft to 7,172 ft amsl. The currently identified mineral resource is exposed at the surface along a west-northwest trending
ridge, and the topography is conducive to open-pit mining methods.
The
Project area consists primarily of rolling grassland/herbaceous habitat with forested and shrub/scrub-covered drainages. Most of the
project site consists of prairie grasslands, with some areas of xeric forest and sparse areas of foothills, sagebrush shrublands, and
riparian vegetation.
4.2 | accessibility
and Transportation to the Property |
The
Project is approximately 20 miles west of Cheyenne and is accessible from the paved State Road 210 (a.k.a Happy Jack Road) to the County
Road 210 (a.k.a. Crystal Lake Road), a maintained gravel road. The Project site access entryway is approximately two miles off the pavement
to the west on County Road 210 and crosses Ferguson Ranch land, subject to a Right-of-Way Option Agreement. From the County Road 210
entryway to Section 31 in the Project site area, approximately four miles of single-track gravel road will be upgraded and maintained
for the Project's life.
4.3 | climate
and operating season |
Based
on data compiled from the CK Gold Project site weather station and other surrounding stations (the latter over at least ten years), the
daily average temperature ranges from about 25° F in February to about 70° F in July. The average low temperature is -11°
F in February, and the average high is 90° F in July.
The
Project site is in a net water deficit condition. The average annual precipitation is about 17 inches, while the annual evaporation is
about 53 inches, as determined by the on-site meteorological station. May is the wettest month, with an average of about 3 inches; January
is the driest, with an average of about 0.6 inches. Snowfall typically occurs from September to May.
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The
site experiences relatively strong winds, with an average monthly wind speed ranging from about 8 mph in July to about 17 mph in December.
For those same months, the average maximum wind speeds are 43 and 63 mph, respectively, with peak wind speeds of 55 and 75 mph. The predominant
wind direction is westerly.
The
lease terms for Section 36 have been renegotiated to enable unrestricted full-time, year-round project construction, mining, and mineral
processing activities.
4.4 | Local
infrastructure availability and sources |
Given
the proximity to Cheyenne, the state capital of Wyoming, and the Front Range metropolitan area, personnel needs, delivery of consumables,
and infrastructure needs are available locally and regionally. This should not pose a material negative impact to the Project; on the
contrary, the infrastructure allows relatively easy access to major mine supply centers, the closest being Denver, Colorado, Salt Lake
City, Utah, and Gillette, Wyoming. The area has access to Union Pacific and Burlington Northern Santa Fe (BNSF) railroad lines, the intersection
of two major interstate highways, I-80 and I-25, and a regional airport.
Electrical
power for the Project will be supplied by a local utility company, Black Hills Energy (BHE), under an Industrial Contract Service Agreement.
The power demand for the Project requires that a new 115 kV power line be constructed for the Project by BHE. The power line would be
constructed from BHE’s West Cheyenne substation, located approximately 16 miles east of the Project, to a new BHE owned, built,
and operated 115/13.8 kV distribution substation (including transformer) adjacent to the mine. The powerline alignment would take advantage
of existing easements and planned county roads near the Project. The alignment would require easements from the City of Cheyenne, the
State of Wyoming, and local ranches. BHE will acquire the easements, construct the power line for the project at their expense, and recoup
the capital cost through demand charges added to the standard industrial mine power cost.
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The
CK Gold Project was originally known as the Copper King Mine. It was first discovered in 1881, along with the Climax and Potomac lodes,
by James Adams. The deposit was developed, and a 160 ft (48 m) shaft was sunk, along with the construction of a mill and smelter by the
Adams Copper Mining and Reduction Company. No production figures are available from this period; however, modest-sized waste dumps around
the shaft indicate that the underground mining wasn’t extensive. The Ferguson Ranch, which presently owns or leases most of the
surface land in the CK Gold Project’s area, was homesteaded in 1874 by the first native-born children of settlers to the area (Angus
Journal, 1996).
The
Copper King Mine was noted as idle by the State Geologist in 1890 when Wyoming attained statehood and assumed ownership of the associated
section of land (Section 36). In 1911, C.E. Jamison, the State Geologist of Wyoming, mentioned several active copper and gold mines within
the Silver Crown Mining District (SCMD) and near the CK Gold Project, including the Dan-Joe Prospect, Comstock Mine, Fairview Mine, Louise
Mine, Little London Mine, Bull Domingo Prospect, and several additional unnamed prospects.
Mineral
rights transferred several times over the next century, starting with the Otego Mining Company in 1907, followed by the Hecla Mining
Company until about 1910. By 1910, production at the Copper King Mine had reached 316 st (287 t), producing 27 ounces (oz) of gold, 483
oz of silver, and 25,782 lbs. (11,700 kg) of copper. From 1890 to 1938, there were at least eight drilling campaigns totaling 37,500
ft. (11,430 m) of drilling. Excavation of numerous prospect pits and developing two adits also likely occurred during this time.
The
American Smelting and Refining Company (ASARCO) acquired the property in 1938 and performed the first major drilling campaigns on the
project site. It was subsequently acquired by the Copper King Mining Company in 1952. ASARCO re-optioned the property in 1970. Henrietta
Mines Ltd gained rights to the property in 1972. At some point before 1987, Henrietta’s interest was folded into Wyoming Gold,
Inc., which William C. Kirkwood and Caledonia Resources Ltd., the parent company of Henrietta, jointly owned. Royal Gold, Inc. entered
an option agreement to buy Wyoming Gold in 1989. Compass Minerals Ltd. then acquired the property in 1993. Saratoga bought it in 2006.
Strathmore acquired the issued and outstanding shares of Saratoga in 2012, which were subsequently purchased by Energy Fuels. Energy
Fuels then sold the property to U.S. Gold in 2016.
5.1 | historical
exploration and production |
ASARCO
completed five exploration holes for 1,400 ft (427m) in 1938, two of the holes yielding significant gold and copper mineralization. Copper
King Mining then completed six more holes in 1952-54 for 2,630 ft (802 m) of drilling, partially subsidized by the U.S. Bureau of Mines.
When ASARCO took control again in 1970, they conducted soil geochemical sampling, geologic mapping, IP and aeromagnetic surveys, and
eight additional core holes totaling 3,263.1 ft (874 m).
Henrietta
completed the first reserve and resource estimate in 1973 after they had completed an 11-hole drilling campaign for 3,766 ft (1,148 m)
of drilling, a control survey, geologic mapping, IP and vertical-intensity magnetic geophysical surveys, geochemical soil sampling, re-logging
of historical core holes, and preliminary metallurgical studies.
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John
Nelson of Kirkwood Oil and Gas did a second reserve estimate around 1986. It does not appear any additional drilling was done before
this estimate; however, the company did collect 228 surface geochemical samples in 1982, and the Colorado School of Mines Research Institute
had done some metallurgical work on the property in 1980.
Caledonia
undertook a new drilling campaign in 1987 of 25 holes for 9,980 ft (3,042 m), designed to improve confidence and prove reserves within
the known extent of the deposit. They also funded a three-sample preliminary metallurgical study that year. Results were used to create
a preliminary resource estimate published in the Wyoming State Geological Survey Bulletin 70. Tenneco Minerals Company then produced
a reserve estimate in 1988. In 1989, both FMC Gold Company and Royal Gold, Inc. funded metallurgical studies and produced reports that
discussed small exploration campaigns, which were likely completed in that year but whose results were unavailable. The FMC study was
completed by Kappes, Cassiday & Associates (KCA) and references some work done to collect and test mine dump samples in 1986 and
1987. It is believed that the Royal Gold report, completed by Hazen Research, Inc. in 1989, used the same metallurgical sampling composites
in its study. It also includes two holes drilled for 505 ft (154 m) that year; however, this data is also lost.
Compass
funded an aeromagnetic survey over the area and 25 new drill holes for 9,202 ft (2,805 m) in 1994. They also conducted two metallurgical
studies in 1994 and 1996 by Metallurgy International and a preliminary resource study by Mine Development Associates (MDA).
Mountain
Lake Resources then funded a ground magnetometer and VLF-EM geophysical survey, drilled eight holes for 4,740 ft (1,445 m), including
two metallurgical test holes, and a metallurgical study by the Colorado Minerals Research Institute in 1998.
MDA
completed a technical report in 2006. 27 holes for 18,296 ft (5,577 m) were drilled during the spring and summer of 2007, and MDA created
an updated report to include these results through October 31, 2007. Saratoga completed another eight holes in 2008 for 7,167 ft (2,185
m).
Saratoga
commissioned further work focused on flotation methods to extract gold and copper, as reported in 2009 by SGS, Canada Inc. In a report
dated December 8th, 2010, a test program was conducted on oxide material from the Copper King deposit to determine a flotation
flowsheet to maximize recoveries of Au and Cu. The oxide portion of the resource is minor; however, the work was completed to follow
on from the successful results obtained on sulfide samples where a 26% copper concentrate was produced containing 98 grams per ton of
gold. The oxide concentrate produced was reported as being expected to be marketable. However, further work was identified to support
these conclusions.
Gustavson
(WSP) completed a PFS in December 2021, including RC drilling by U.S. Gold of two holes in 2017 and eight holes in 2018, totaling 12,040
ft (3,670 m). Both programs were designed to investigate magnetic and IP anomalies generated by geophysical surveys. Also included was
U.S. Gold drilling from 2020, comprising 25 drill holes totaling 20,449 ft. The PFS resulted in favorable economics, the first mineral
reserve, and a recommendation to advance to a feasibility study.
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6.0 | Geological
Setting, Mineralization, and Deposit |
6.1 | regional
geologic setting |
The
CK Gold Project area is located on the eastern flank of the southern Laramie Mountains, within the terrane of the Colorado Province and
just south of a northwest-trending crustal suture zone known as the Cheyenne Belt (Figure 6.1). The Cheyenne Belt represents the margin
along which the island-arc terrane of the Colorado Province (or Colorado orogen) accreted to the southern edge of the Wyoming Craton
during the Paleoproterozoic. As a result of this collision, older Archean rocks of the Wyoming Province were intensely deformed and metamorphosed
for at least 75 km inboard of the suture, which is marked today by the Laramie Mountains (Sims et al., 2001).
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Figure
6.1: Regional Geologic Setting of the CK Project Area. Source: Sims et. Al (2001)
The
Laramie Mountain Range is an asymmetrical Laramide uplift that exposes a core of Precambrian rocks that extends for approximately 140
miles from north to south. The mountain range is segmented by steeply dipping shear zones and regional-scale thrust faults. The northern
portion of the range is comprised of terrane belonging to the Archean Wyoming Province, while rocks of the Proterozoic Colorado Province
core the southern portion. Near the CK Gold Project area, the Laramie Mountains are bound to the east by an unconformity between overlying
Mesozoic sedimentary rocks and underlying Proterozoic igneous and metamorphic rocks of the Colorado orogen. The Colorado orogen consists
of metasedimentary-metavolcanic rocks and granitic-gabbroic rocks of island-arc affinity (Sims et al., 2001). In the Laramie Mountains,
the metavolcanic and metasedimentary rocks are modified by batholithic intrusions of two discrete generations, ~1.7 and ~1.4 Ga (Tweto,
1987).
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The
oldest (~1.7 Ga) and most abundant intrusions are mainly intermediate composition, foliated hornblende-biotite granodiorite, or monzogranite
of calc-alkalic affinity. These intrusions are generally synchronous with regional deformation attributed to the Colorado orogeny, with
U-Pb zircon ages in the 1.75-1.65 Ga (Reed et al., 1987; Reed et al., 1993). A second major intrusive episode is represented by the Mesoproterozoic
(~1.4 Ga) Laramie Anorthosite Complex (northern Laramie Range) and the ilmenite-bearing Sherman Granite, which outcrops immediately north
of the CK Project area (Figure 6.2). Both anorthosite and granite transect the Cheyenne Belt and intrude crystalline rocks of the Wyoming
Province. These intrusions comprise the northernmost segment of a wide belt of 1.4 Ga granitic intrusions throughout the Colorado orogen
(Sims et al, 2001).
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Figure
6.2: Mesoproterozoic intrusive within the Cheyenne suture zone.
The
red circle is the approximate vicinity of the Project area; the yellow star denotes the location of Vedauwoo. The basement (brown diagonally
lined) north of the Cheyenne Belt is the Archean Wyoming Province; the basement (purple squares with dots) south of the Cheyenne Belt
is the Paleoproterozoic Colorado Province. Source: Edwards and Frost (2000).
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6.1.1 | Local
and Property Geology |
Bedrock
geology in the vicinity of the Project area has been described in some detail in various previous reports (Brady, 1949; Hausel, 1982,
1989, 1997, and 2012; Klein, 1974; McGraw, 1954; MDA, 2017, etc.). Most of these existing reports rely solely on surface investigation,
though a few discuss observations of historical drill core. While somewhat dated, reports by Klein (1974) and McGraw (1954) are particularly
useful as they provide the results of petrographic analysis in conjunction with detailed field measurements and observations. The following
discussion draws partly from work completed during previous studies but is largely based on first-hand field observations and careful
examination of a combined total of more than 50,000 ft of historical and modern drill core.
Within
the Project area, bedrock is largely comprised of Proterozoic metasedimentary and intrusive granitic rocks, both of which are unconformably
overlain by the Tertiary White River Formation (Figure 6.3). The metasedimentary rocks are exposed in outcrop in the far eastern half
of the project area, and these rocks generally consist of interlayered metagraywacke, quartz-biotite schist, and greenschist, all widely
variable in grain size and degree of foliation. Trace amounts of very fine-grained, disseminated pyrite are commonly observed in metasedimentary
drill core.
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Figure
6.3: Bedrock geology in the vicinity of the CK Gold Project area
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A
typical cross-section illustrating the lithologic relationships in Figure 6.4
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Figure
6.4: Typical Lithologic Cross Section
The
metasedimentary rocks are intruded by granodiorite that displays a range of textures from primary igneous (Figure 6.5) to intensely mylonitic
(Figure 6.6). These textures are often wildly variable over very short drilling intervals. Undeformed granodiorite is typically hypidiomorphic-granular
with subhedral-to-euhedral hornblende and feldspar phenocrysts, generally less than 1 inch in diameter. Porphyritic granodiorite with
hornblende and/or feldspar phenocrysts in a fine-grained hornblende, feldspar, biotite, and quartz matrix is also common. Deformed granodiorite
varies considerably from proto-mylonitic/weakly foliated to ultra-mylonitic and fine-grained. Sulfide mineralization, predominantly disseminated
pyrite and chalcopyrite in the matrix or as inclusions in hornblende and feldspar, are associated with undeformed and deformed granodiorite.
Undeformed granodiorite exhibits primarily disseminated sulfide mineralization; however, blebs, sulfide veins, and veinlets also occur.
In weakly foliated- to-mylonitic granodiorite, sulfide crystals are commonly aligned with foliation and locally exhibit clustering and/or
veinlet-type mineralization. The intrusive contact between granodiorite and metasedimentary rocks is not exposed within the project area
but was encountered during drilling in drill holes CK20-18c, CK21-08c, and CK21-09c.
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Figure
6.5: Relatively undeformed granodiorite
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Figure
6.6: Mylonitized granodiorite
All
crystalline rocks in the Project area are locally crosscut by pegmatitic to aplitic dikes (Figure 6.7) and very fine-grained mafic
dikes (Figure 6.8). Based on the drill core and field exposures, the felsic dikes range in width from inches to roughly 30 feet,
while the mafic dikes are generally less than 10 feet in width. Occasional zones of potassic enrichment and/or local pyrite
mineralization occur within the felsic and mafic dikes. Potassic-alteration halos of highly variable width and intensity are
common along pegmatitic/aplitic margins.
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Figure
6.7: Felsic (pegmatite) dike (top row) within granodiorite
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Figure
6.8: Typical mafic dike (center of photo) intruding granodiorite
The
Sherman Granite is exposed immediately to the north of and adjacent to the CK Gold Project area. The Sherman Granite has been dated
at 1430 +/- 20 Ma by the Rb-Sr whole-rock method (Zielinski et al., 1981). Aleinikoff (1983) obtained a U-Pb upper-intercept age of
1412 +/- 13 Ma on zircons separated from different host minerals of the Sherman Granite and, because of possible Pb loss, interprets
this as a minimum age. The Sherman intrudes the host granodiorite, which is presumed to be of the ~1.7 Ga generation of regional
intrusive events. The dominant rock type of the Sherman Batholith is coarse-grained, biotite hornblende granite, a distinctly
reddish-orange rock that commonly weathers deeply to a thick grus. The Sherman Granite is sub-porphyritic, with a seriate,
hypidiomorphic-granular texture. Local augen gneiss within the Sherman indicates some late-stage deformation (Houston and Marlatt,
1997). Major phases are microcline, plagioclase, quartz, hornblende, biotite, and ilmenite, while accessory phases are zircon and
apatite with rarer allanite and fluorite (Houston and Marlatt, 1997). The contact between the Sherman Granite and granodiorite
appears gradational on the order of 5 to 20 ft (Klein, 1974), and (rare) dikes of Sherman Granite within the host granodiorite are
exposed in the field near the contact between the two.
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35 |
Several
alteration types are observed in the crystalline rocks within the Project area, both in the outcrop and the drill core. The most prevalent
type of alteration is potassium enrichment in host granodiorite with the replacement of primary plagioclase feldspar and hornblende by
alkali feldspar and secondary biotite. The extent of potassic alteration throughout the granodiorite is variable in terms of intensity
and nature of occurrence. In drill core, weak to moderate potassic alteration (Figure 6.9) is typically splotchy to highly localized
(i.e., halos around minor veins), while zones of pervasive, moderate to extreme potassic alteration (Figure 6.10) are encountered over
intervals of several to more than 100 ft. Potassic alteration occurs independent of deformation (or lack thereof) within the granodiorite,
and while it is certainly locally associated with aplitic and pegmatitic dikes, the origin of or driving force behind the more pervasive
and extensive zones of potassic alteration is unclear. Klein (1974) has suggested that these zones are a product of fluid transfer during
the emplacement of the Sherman Granite, which intrudes the granodiorite just north of the Project area. This seems a reasonable presumption,
and particularly so if the aplitic and pegmatitic dikes prove to be distal intrusive extensions of the Sherman Pluton, which should be
discernable via age determinations on the granodiorite and the felsic dikes in comparison to existing age data on the Sherman Granite.
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Figure
6.9: Moderate, localized potassic alteration in granodiorite
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Figure
6.10: Intense, pervasive potassic alteration in granodiorite
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Potassic
alteration also occurs in mafic dikes within the granodiorite and the metasedimentary rocks, though to a much lesser extent than within
the granodiorite proper. In general, intensely potassically altered granodiorite appears to be depleted of sulfide mineralization, with
only local, trace amounts of pyrite and extremely rare to no visible chalcopyrite mineralization. Potassic alteration is frequently accompanied
by epidote veining (Figure 6.11 and Figure 6.12), and less so by minor propylitic alteration. Propylitic alteration consists of the texturally
preserved replacement of plagioclase and hornblende with epidote and is visually much more prevalent in mafic dikes and metasedimentary
rocks, particularly in greenschist and discrete quartzite lenses in quartz-biotite schist and metagraywacke. Pyrite grains with epidote
halos are occasionally encountered in the granodiorite and, more frequently, in the mafic dikes and metasedimentary rocks.

Figure
6.11: Intense potassic alteration with associated stockwork epidote veining
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Figure
6.12: Localized weak potassic alteration with associated epidote veining
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While
much less prevalent than potassic alteration, phyllic alteration and silicification are also observed in drill core. Again, the extent
and intensity of these alteration styles vary across and within the individual crystalline rock types. Phyllic alteration (Figure 6.13)
is most often observed in intensely mylonitized granodiorite but also occurs in metasedimentary rocks, particularly near intrusive contact
and in significant structural zones. Phyllic alteration is indicated by fine-grained white mica (sericite), chlorite, pyrite, and quartz,
and often occurs together with silicification, though the two are not necessarily codependent. In some instances, phyllic alteration
identified in the drill core may be a product of cataclasis rather than hydrothermal alteration, wherein the rock has undergone dynamic
recrystallization and alignment of sheet silicates during shearing to produce an extreme grade of cataclastic rock known as phyllonite.
Phyllonites are often associated with major (crustal) structural zones and typically retain a penetrative cleavage oriented parallel
to the fault plane.
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Figure
6.13: Phyllically altered mylonite (phyllonite?)
Silicified
domains (Figure 6.14) exhibit blurred grain boundaries, moderate to extensive hairline quartz veining, and strong induration. Silicified
intervals are generally rich in relatively pure, microcrystalline quartz veins, with apparent associated silica flooding and replacement
within the local crystalline groundmass. So-called ‘stockwork’ quartz veining is rare and is generally limited to local zones
of brecciation rehealed by quartz or, more commonly, a combination of quartz and calcite.
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Figure
6.14: Silicified mylonite
Copper
and gold mineralization is largely disseminated, and based on available information to date, occurs solely within the granodioritic plutonic
body. Secondary copper minerals, primarily chrysocolla, cuprite, and trace malachite and azurite, as well as secondary iron minerals
(hematite, limonite, and jarosite), chalcocite and native copper (flecks and veins) are observed on the surface and define an oxide or
supergene zone that extends to depths up to 100 ft below the topographic surface and deeper in fractured or faulted localities. This
surficial oxide zone is essentially devoid of magnetite. An intermediate oxide-sulfide or ‘mixed’ zone observed in drill
core is characterized by secondary copper and iron minerals as well as primary pyrite and trace chalcopyrite. The mixed zone transitions
to a sulfide-dominant zone at depths ranging from 100 to 300 ft, with a significant decrease in oxide mineral content, increase in occurrence
of disseminated pyrite and chalcopyrite, and the appearance of magnetite. Within the sulfide zone, sulfide minerals are typically disseminated
and very fine-grained, though occasional sizeable pyrite and or chalcopyrite blebs and minor veins and veinlets are observed in drill
core.
Sulfide
content is modally highest in granodiorite and mylonitic granodiorite and generally ranges, based on visual analysis, from trace amounts
to less than 5% of whole-rock content. In addition to pyrite and chalcopyrite, bornite, covellite, molybdenite, and pyrrhotite are also
present, as well as trace amounts of very fine-grained native gold, 10 to 250 microns in size (Mountain Lake Resources Inc., 1997). Assay
data indicates a significant, if not direct, relationship between metal concentration and sulfide content, particularly chalcopyrite.
Copper-sulfides are virtually restricted to granodiorite, though trace amounts of chalcopyrite are observed both in mafic dikes within
the granodiorite and in the metasedimentary rocks immediately adjacent to the east. Trace to weight-percent amounts of pyrite is also
observed in drill core in metasedimentary rocks, aplitic dikes, pegmatites, and mafic dikes, all within the sulfide zone.
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Gold
mineralization at the CK Gold Project occurs in the west central portion of the Project area and is distributed in plan-view in an elongate
ovoid pattern trending roughly N60°W (Figure 6.15). The orientation of the mineralized zone is generally coincident with the local
trend of shear as interpreted by Klein (1974) and McGraw (1954) based on field measurements of exposed structural fabrics (cataclastic
foliation) and fault planes. The primary known mineralized zone is essentially vertical and “keel-like” in shape, as represented
by the 1 gpt Au cut-off grade shell with a surface length of 400 ft along strike, width of approximately 200 ft, and depth (thickness)
of 600 ft (Figure 6.16). This higher-grade, central core is surrounded by a halo of lower grade mineralization with an overall length
of roughly 760 ft along strike, an average width of approximately 500 ft, and thickness of at least 1,100 ft. Low-grade (<0.5 gpt
Au) gold mineralization is open and uniform along strike, both to the northwest and southeast, as well as at depth.
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Figure
6.15: Oblique view of the distribution of gold mineralization, CK Gold Project
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
Figure
6.16: Cross-sectional view central to the primary zone of mineralization
The
mineralized zone is crudely bound to the north and to the east by the Northwest fault and the Copper King Fault, respectively (Figure
6.17). The Northwest Fault is interpreted based on a combination of drillhole data, geophysical data, and downhole televiewer data from
2020 and 2021 drilling. The Northwest Fault strikes west-northwest and dips steeply to the northeast along the northern margin of the
mineralized zone. The fault represents an apparent structural control of the CK deposit, as copper-gold mineralization is essentially
restricted to south of the fault.
The
Copper King Fault trends roughly N30°E along the eastern extent of the CK deposit, truncating known mineralization in that direction.
Host granodiorite occurs to the west of the fault, and unmineralized metasedimentary and metavolcanic rocks occur to the east. Drillhole
intercepts indicate that the Copper King Fault dips somewhat steeply to the west, and that primary displacement along the fault plane
is reverse with the western hanging wall riding up to the east. This contradicts previous interpretations of the fault as normal with
a down-to-the-east, nearly vertical, dip slip offset (Hausel, 2012). Based on examination of exposures in prospect pits north and east
of the deposit, the Copper King Fault is thought to be Laramide or younger, though it may represent remobilization along a much older,
existing fault plane. Further investigation of the Copper King Fault, including orientation measurements on all available surface exposures
as well as additional drilling targeted to intercept the fault at depth, should be considered to verify the orientation of the structure
and to evaluate the direction and magnitude of offset. While the fault is presently considered a post-mineral structural control, a better
understanding of the direction and scale of offset may provide valuable insight for use during planning of future drilling exploration.
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Figure
6.17: Plan view of the location and trend of the Northwest and Copper King Faults
A
variety of other faults have been interpreted within the Project area based largely on surface expression, indications in drill core,
and televiewer data. As noted by Klein (1974), many local structures are generally concordant with the trend of Precambrian shear and
may represent more recent (Laramide or younger), shallow depth rejuvenation along previously existing fault planes. Several local structures
are discordant with the Precambrian trend of shear, and these are also generally thought to be Laramide or younger based on a lack of
cohesion and recrystallization in the faulted material (Klein, 1974). The significance of these structures relative to the CK deposit
is likely limited to an associated increase in intensity and/or depth of oxidation and supergene copper mineralization, and potential,
small-scale physical displacement of copper-gold mineralization at depth.
Gold
mineralization at the CK Gold Project occurs within a steeply dipping to near-vertical, brittle-ductile shear zone presumably generated
during Paleoproterozoic orogenesis of the Colorado Province. As previously stated by Klein (1964), the localization of metallic mineralization
at the Project is a product of both structural and lithologic control. The dominant structure appears to be the nearly east-west trending
zone of Precambrian shear and cataclasis, and, lithologically, mineralization is virtually confined to the granodiorite plutonic body.
Visual examination of barren to high grade drill core intervals shows that gold mineralization (or lack thereof) is not restricted to
any specific textural variation within the granodiorite, nor is it strictly associated with any type or intensity of alteration, except
for consistently low grades in zones of moderate to intense potassic alteration.
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Mylonitic
rocks return the highest gold and copper assay values on average. Mylonites form under specific circumstances at significant crustal
depths below brittle faults, in continental and oceanic crust (Figure 6.18). Mylonites are the result of extreme plastic deformation,
with original textures modified by dynamic recrystallization while the parent rock remains chemically unaltered.
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Figure
6.18: Schematic illustration of the transformation of brittle to ductile deformation in granitic rocks at depth (Fossen, 2016)
Gold
mineralization in the mylonitized granodiorite occurs in close association with sulfide minerals, which are largely disseminated, but
also frequently occur as veinlets or stringers aligned with mylonitic foliation (Figure 6.19). On a microscopic scale, pyrite in mineralized
intervals is often broken, indicating some deformation during or after mineralization. Sulfide minerals in the surrounding granodiorite
are widely disseminated, typically occur within igneous hornblende and plagioclase, and occasionally occur as clusters and stringers
which also tend to parallel weak to moderate foliation, where present.
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Figure
6.19: Pyrite +- chalcopyrite aligned with mylonitic foliation
The
mineralogical setting and physical character of the sulfide minerals in both the mylonitized and undeformed granodiorite suggests a primary
igneous origin, wherein mineralization occurred during magmatic crystallization, and syn-magmatic or post-magmatic mylonitization due
to brittle-ductile shearing served as physical means of concentrating metals simply via shortening of the host granodiorite. The metasedimentary
rocks intruded by the granodiorite may have served as a sulfur source to the crystallizing pluton, catalyzing base, and precious metal
mineralization through sulfur saturation of the magmatic fluid.
Emplacement
and crystallization of the host granodiorite was followed by a regionally extensive, felsic intrusive event represented by the Sherman
Granite and the Laramie anorthosite complex. Regional circulation of high temperature, potassium-rich magmatic-hydrothermal fluids exsolved
during emplacement of the Sherman Granite is indicated within the host granodiorite by alteration aureoles and halos along pegmatitic/aplitic
dike margins and alkali feldspar-quartz veins and by intense potassic alteration associated with significant brittle deformation features.
Hydrothermal alteration associated with post-mineral, brittle deformation attributed to emplacement of the Sherman Granite apparently
contributed to some degree of gold redistribution, as evidenced by the typically low gold grades within zones of moderate to intense
potassic alteration and occasional anomalous gold grades within silicified sample intervals.
Long
after formation of the CK deposit, during the Laramide orogeny (55-80 Ma), the host granodiorite was uplifted and exposed to erosion.
Reactions between hypogene sulfide minerals and descending, acidic meteoric waters resulted in the supergene enrichment (oxidized) zone
exposed at the modern topographic surface. The enriched zone is characterized by the presence of iron oxides, secondary copper minerals,
and rare native copper. Pervasive oxidation is typically encountered to a depth of about 100 to 150 ft, though locally (near fault structures)
is known to extend to depths approaching 300 ft.
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6.2.2 | Interpretations
and Conclusions |
The
CK copper-gold deposit does not neatly fit into any specific category or class of conventional deposit models, in part because of the
wide array of variability and overlap of assigned deposit model parameters such as geochemical signatures, geologic setting and time
frames, and the origin and mechanisms of emplacement of metal-bearing solutions.
Previous
authors (Hausel, 1997, 2012; Carson, 1998) have postulated that the CK deposit represents some portion of a copper (Au-Cu) porphyry system,
largely based on observations of the nature and occurrence of hydrothermal alteration assemblages exposed in outcrop. According to the
U.S. Geological Survey’s Porphyry Copper Deposit Model (John et. Al, 2010) and Preliminary Model of Porphyry Copper Deposits (Berger
et. Al, 2008), porphyry deposits consist of disseminated copper minerals and copper minerals in veins and breccias that are relatively
evenly distributed in large volumes of rock forming high tonnage, low to moderate grade ores. The USGS model descriptions further provide
the following (select) characteristics common to known porphyry copper deposits:
| ● | Host
rocks are altered and genetically related to granitoid porphyry intrusions and adjacent wall
rocks. |
| ● | Deposits
are centered in high-level intrusive complexes that commonly include stocks, dikes, and breccia
pipes, which generally form in the upper crust (less than 5–10 km depth) in tectonically
unstable convergent plate margins. |
| ● | Wall-rock
alteration is intimately linked to narrow veins, commonly 0.1 to 10 cm in width, that typically
make up less than 1 to 5% volume of ore but also are present in other alteration zones. |
| ● | Copper-bearing
sulfides are localized in a network of fracture-controlled stockwork veinlets and as disseminated
grains in the adjacent altered rock matrix. |
| ● | Hydrothermal
wall-rock alteration minerals and assemblages (namely potassic, sericitic, argillic, and
propylitic) are zoned spatially and temporally, with kilometer-scale vertical and lateral
dimensions. |
| ● | Zones
of phyllic-argillic and marginal propylitic alteration overlap or surround a potassic alteration
assemblage. |
| ● | Potassic
and sericitic alteration are invariably associated with sulfide mineralization and generally
are temporally, spatially, and thermally zoned with respect to one another. |
| ● | Potassic
alteration tends to be more centrally located, deeper, higher temperature, and earlier compared
to sericitic alteration. |
| ● | Owing
to the shallow depths of deposit formation (1–4 km), preserved deposits are predominantly
Mesozoic and Cenozoic. |
While
the alteration assemblages encountered within the CK deposit are indeed like those associated with porphyry copper deposits, hydrothermal
alteration zones at CK decidedly lack kilometer-scale vertical and lateral dimensions, and potassic and sericitic alteration are clearly
not invariably associated with sulfide mineralization, nor are they necessarily temporally, spatially, and thermally zoned with respect
to one another. The Proterozoic age of the CK deposit’s host granodiorite and apparent pre- or syn-deformational mineralization
further preclude it from classification as a sensu-strictu porphyry deposit.
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The
CK deposit also exhibits a variety of characteristics that are, individually or in combination, like those of known intrusion
related, iron oxide copper-gold (IOCG), and even orogenic deposits. In each instance, however, the similarities (i.e., age,
structural setting, geochemical signature, alterations styles, etc.) are either outweighed by significant differences or are too
limited, at present, to support a decisive association with the deposit model.
The
regional geologic setting of the CK deposit within the Cheyenne Suture belt is significant, as is the nature of occurrence of sulfide
mineralization as disseminations in undeformed granodiorite and in alignment with foliation in foliated to mylonitized granodiorite.
Based on the available data and information to date, we suggest that Klein’s (1974) description of the CK deposit as a “structurally
controlled base and precious metal deposit hosted in a Precambrian shear zone” is essentially correct if you want further refinement.
While Klein’s description does not present a conventional deposit model, it does provide a reasonable interpretation on which to
base plans for future exploration. Future drilling exploration (and petrographic and/or mineralogical analysis) should be carefully planned
to test Klein’s interpretation and target data useful in further developing an appropriate deposit model for the CK Gold Project,
whether conventional or not.
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7.1 | summary
of exploration activities |
The
CK Gold Project was reportedly discovered in 1881, high-graded, and saw limited mining. The first exploration work reported was drilling
by ASARCO in 1938. Several additional rounds of drilling have been conducted since that time. In 1972, Henrietta Mines Ltd. acquired
the property and completed a comprehensive exploration and development program. In addition to drilling, an induced polarization (IP)
survey, geologic mapping, geochemical sampling, and metallurgical testing were conducted (Nevin, 1973). Drilling campaigns were conducted
by Saratoga since 2006 and Strathmore since 2012, with a hiatus in drill exploration until the acquisition by U.S. Gold from Energy Fuels
in 2016. U.S. Gold conducted drilling programs in 2017, 2018, 2020, and 2021. Drilling in 2021 focused on data collection to support
post-PFS and PFS updates in 2022.
The
drilling record prior to 1997 is incomplete and much of the historical core has been lost. Contemporary drilling reports as well as comparisons
to recent drilling have been used to support the use of the pre-1997 drilling. In 2020, historical drill hole collars were located, surveyed
and the results compared closely to their location in the historical drilling database.
Figure
7.1 indicates a total of 173 holes with a total drill length of 98,415 ft (29,997 m) have been drilled on the CK Gold property. Figure
7.1 shows the location of all holes within the CK Gold mineral resource area. An additional six historic holes totaling 3,560 ft (1,085
m) are in the database but outside of the current resource area.
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Figure
7.1: Drill hole Map
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7.2.1 | U.S.
Gold 2021 Drilling Campaign |
U.S.
Gold began a drilling campaign in July of 2021 consisting of 48 holes and 40,930 ft (12,475 m), comprised of reverse circulation, rotary,
and core drilling. The primary purposes of this campaign were to continue to refine hydrologic and geotechnical subsurface conditions,
and minor exploration immediately southeast of the proposed project. Thirteen monitoring wells totaling 5,600 ft were proposed for sub-
surface groundwater studies. Results from this campaign were compared visually to the existing model, and a model was estimated using
the previous parameters and including the new holes. There is no material change in the mineral resource or mineral reserve estimate.
There have been no findings or observations following the 2021 exploration and data gathering program that materially affected the findings
of this study.
7.2.2 | U.S.
Gold 2020 Drilling Campaign |
In
October 2020, U.S. Gold conducted a drill program at the Project. Part of that work included surveying new and historical drill hole
collars that U.S. Gold could locate in the field and flag.
All
historical collar coordinates (pre-2020) were loaded into a handheld GPS unit and visited in the field. Those identifiable (cement, tags,
drill pipe, etc.) were flagged with lath and flagging, with the hole name on the lath. These collars were then surveyed at the same time
as the 2020 holes, on October 21st, 2020.
Surveying
was completed by Topographic Land Surveyors of Casper, WY, and the results were certified by Professional Land Surveyor Aaron Money,
#14558. The survey method was Real-Time Kinematic GPS using a Trimble R10 GNSS GPS system.
Drill
hole collars from the historical programs dating back to 1938 were identified in the field and resurveyed, confirming the locations recorded
in the drilling database.
Comparison
of the new-collar surveys with the old coordinates showed small variability in X and Y coordinates, typically less than 5 ft and around
25 ft at most, and a bit more in elevation (around 25 ft at most).
Two
permanent survey control points were placed on the Project for future use.
U.S.
Gold completed two RC drilling programs in 2017 and 2018. RC drilling comprised four holes in 2017 and eight in 2018, totaling 12,040
ft. (3,670 m). Both programs were designed to investigate magnetic and IP anomalies generated by geophysical surveys. Drilling was completed
by AK Drilling of Butte, Montana, using a Foremost MPD 1500 RC drill. Samples were collected at 5 ft (1.5 m) intervals from the discharge
of a rotary splitter attached to the drill. A chip tray was also filled from cuttings for geologic logging and archived. Samples were
delivered to Bureau Veritas of Sparks, Nevada, for analysis.
A
rotary, reverse circulation, and diamond core drill program was begun in September 2020, and 30 drill holes totaling 21,810 ft (6,647
m) were completed by early December 2020. Core drilling totaled 10,561 ft (3,219 m), and rotary drilling totaled 10,538 ft (3,312 m).
The focus of U.S. Gold’s work was to generate metallurgical composites, collect geotechnical data, and expand mineral resources.
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Alford
Drilling completed core drilling using an LF90 drill rig. HQ core was recovered using a split tube core barrel system to minimize core
damage. Holes are monumented using braided steel cable and a tag embedded in a concrete pad at the drill hole collar.
7.2.4 | Saratoga
2007 – 2008 |
Saratoga’s
drilling campaign focused on expanding the mineralized body outlined in previous campaigns and providing material for metallurgical testing
and future geotechnical studies. The diamond drill program began in 2007, paused over winter, and was completed in 2008. 35 holes were
completed for a total length of 25,462 ft (7,760 m). Logan Drilling, based in Nova Scotia, Canada, was the drilling contractor, and a
Longyear Fly 38 skid rig drilling NQ-size core (4.76 cm diameter) was used.
There
is limited information on drilling and sampling procedures for the ASARCO, Copper King Mining, and the U.S. Bureau of Mines (USBM) drill
programs. The original geology logs are not available, although Nevin (1973) provides summary geology logs for all but the ASARCO 1938
drilling and assay sheets for these drill programs. The assay sheets include collar coordinate information, bearing and dip of hole,
sample intervals, and Au, Ag, and Cu assay data. Defense Minerals Exploration Administration documents (0647_DMA) include identical logs
for the ASARCO which only contain assays and recoveries for ASARCO diamond drill holes A-1 through A-5 and state they were assayed by
Federal Mining and Smelting Co Wallace Testing Plant in Wallace, Idaho.
Previous
attempts to locate the drill core from ASARCO’s, and the USBM drill programs that had been housed at the USBM in Denver were unsuccessful.
According to Mountain Lake Resources Inc. (1997), the core collected from Henrietta’s holes was destroyed.
Soule
(1955) reported that the USBM's drilling was done by contract and that all three holes were core holes, but his report provided no further
information.
Henrietta
Mines drilled seven rotary holes totaling 482 m and six core holes totaling 666 m. Several of the holes were started as rotary and finished
as core. Boyles Brothers Drilling Company of Golden, Colorado, was the drilling contractor.
Compass
Minerals drilled 21 rotary holes and five diamond core holes. Hole CCK-16 was drilled rotary to a depth of 152 m and then cored with
NX core to a total depth of 341 m. Notes on the geologic log indicate the core was split before logging. Hole CCK-19 was cored for its
entire length with HQ core. Holes CCK-24 and CCK-25 were both started with RVC drilling, changing to NX core at 136 m and 136 m, respectively.
Hole CCK-26 was cored completely with NX core. There are no further details about Compass’s drilling program.
There
are few details on the Caledonia or Mountain Lake drill programs. No drill logs are available for the Caledonia holes; the collar locations
were taken from a map. The Caledonia holes ranged from 220 ft (65 m) to 550 ft (170 m) in depth and were intended to confirm the results
of prior drilling. A report by Gemcom (1987) describes the Caledonia drilling as spaced 50 ft (15 m) apart through the mineralization,
sampled every 10 ft (3 m), and assayed for gold. Gemcom entered and verified the Caledonia drilling data.
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Drill
logs of the Mountain Lake holes are available which do contain collar and drill orientation data. Summary geology from the Mountain Lakes
drill holes was entered into the database.
As
mentioned above, Henrietta’s core hole H-1 does not show evidence that any of the other holes drilled on the Copper King property
were downhole surveyed.
There
is inherent risk associated with these legacy drilling programs (pre-2007 drilling), and limited information is available. These risks
include errors in collar location, downhole orientation, assay grade precision and accuracy, and database transcription errors. Comparisons
to recent infill drilling continue to support the use of the legacy holes. To acknowledge the risk, no legacy holes are used in the classification
of measured resources.
7.3 | Non-drilling
exploration activities |
Magnetic
and two IP surveys were completed in the early 1970s. The magnetic survey measured vertical intensity using a Jalander instrument on
200 ft (60 m) line spacing and stations. Two significant positive anomalies are present. One, about 800 ft (245 m) wide and 1,500 ft
(460 m) long in a northwest direction, has a magnitude of 500 gammas above the background and coincides with the principal mineralization
direction. The anomaly is believed to be caused by the presence of magnetite in the mineralized rock.
The
initial IP survey showed a resistivity high extending northeast through the CK deposit, following a trend of thin overburden and chargeability
high of 18 ms against a background of 6 ms. The second IP survey was by McPhar Geophysics Inc. using a Scintrex I.P. R-7 unit over the
principal mineralized area. Line spacing was 300 to 800 ft (90 m to 240 m). Five north-south lines and two east-west lines were run.
Dipole spacing was 200 ft (60 m). An anomaly, principally a moderate to shallow metal factor anomaly, was detected, trending east-northeast
to the principal mineralized area. Both IP surveys established that the ore does not respond well to IP chargeability, and frequency
effects for the two methods are low and do not duplicate each other as expected.
In
1994, Pearson deRidder & Johnson, Inc. conducted an aeromagnetic survey on the property for Compass Minerals. Flight lines were flown
at a nominal altitude of 300 ft (90 m) above ground level, with north-south lines spaced 660 ft (200 m) apart and east-west lines spaced
1,320 ft (400 m) apart. Several major magnetic trends and features were observed. The primary mineralized area around the Copper King
Mine is identified as a magnetic high.
In
1997, Gilmer Geophysics, Inc. supervised and interpreted a ground magnetic survey and a VLF-EM survey. The ground survey was laid out
using GPS and total survey technologies with principal directions oriented N33E and N57W. This orientation was chosen to cross-mapped
features at right angles. Line spacing was 200 ft (60 m) between the N33E lines. Total field ground magnetometer data were obtained using
two GEM Systems GSM-19 units used in “walking mag” mode, obtaining data every two seconds, resulting in station spacings
of 2 ft to 10 ft (0.5 m to 3 m) along survey lines. The VLF-EM data was obtained using an IRIS T-VLF instrument.
In
June 2017, Magee Geophysical Services, supervised by Jim Wright of Wright Geophysics, completed a ground magnetic survey over the CK
Gold Project. 70 line miles (113 km) of magnetic data were surveyed using real-time corrected differential GPS and Geometrics
Model G-858 magnetometers. Lines were spaced 160 ft (50 m) apart and oriented N30E across the project. Magnetometers were mounted on
a backpack with data collected every two seconds. Data interpretation by Jim Wright essentially duplicated the 1997 Gilmer survey. A
strong magnetic anomaly was demonstrated over the CK Gold deposit along with several magnetic anomalies to the east and south of the
deposit. A prominent anomaly at the southeast corner of the project called the Fish Anomaly, was tested by RC drilling in 2017,
along with a couple of others to the east of the CK Gold deposit.
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In
October 2017, an IP survey was completed over the CK Gold Project area by Zonge International and interpreted by Wright Geophysics. A
total of eleven lines were completed using a standard 9-electrode dipole-dipole array with a dipole length (a-spacing) of 1,082 ft (330
m) as designed by Wright Geophysics. Data were acquired in the time-domain mode using a 0.125 Hz, 50% duty cycle transmitted waveform.
Data were acquired along eleven north-south oriented lines. Stations were located using a Garmin hand-held GPS, model GPSMAP 64CSx. The
GPS data were differentially corrected in real time using WAAS corrections. Accuracy of the GPSMAP 60CSx typically ranges from 6 ft to
16 ft (2 m to 5 m) line control in the field utilized UTM Zone 13N NAD27 datum. Measurements were made for continuous line coverage at
n-spacing of 1 through 7. Data were acquired in the time-domain mode using a 0.125 Hz, 50% duty cycle transmitted waveform. Chargeability
values (IPm) represent the Newmont Window with integration from 450 to 1100 milliseconds after transmitter turnoff. A discussion of the
time-domain acquisition program is presented with the digital data release. IP anomalies identified to the west of the CK Gold deposit
were tested by RC drilling in 2018.
Nevin
(1973) reports the results of soil geochemistry. Forty-four soil geochemical samples were taken on 100 ft and 200 ft (30 m and 60 m)
centers in widely separated traverses as a pilot study. All were analyzed for copper and arsenic, and some were analyzed for gold, zinc,
silver, and mercury. Three copper populations were sampled. The absolute background has values of about 20 ppm; a high background population
in proximity to the mineralized rock has values of about 500 ppm; four samples taken in thin soil directly over the mineralized rock
returned values of more than 1,000 ppm. Gold values appear to be a useful indicator of mineralization. Zinc, silver, and arsenic had
little contrast between mineralized and unmineralized areas. Mercury was found to have good contrast and was recommended for further
investigation.
7.4 | geotechnical
data, testing, and analysis |
Prior
to 2020, no previous geotechnical work was completed on the Project. U.S. Gold retained Piteau Associates of Reno, Nevada, to design,
complete, and analyze a geotechnical program that included field outcrop mapping, on-site geotechnical core logging, rock testing and
sampling, televiewer data validation, and interpretation. Four days were spent reviewing existing drill core and mapping surface outcrops
at the CK Gold Project. Surface mapping focused on joint and fracture set characterization for integration with sub-surface derived data.
Five
geotechnical core holes (CK20-16c to 20c) totaling 4,685 ft (1,428 m) were completed. Core from these holes was logged on-site, run
by run, in a designed-for-purpose logging trailer by Piteau staff or consultants. Geologists completing the geotechnical logging
also completed needed rock characterization testing and selected geomechanical samples for third-party testing. Logging parameters
included core recovery, hardness, RQD, RMR, fracture frequency, joint condition, and angle, degree of breakage, and degree of
alteration.
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Piteau
staff completed point load index (PLI) testing in the field on the five geotechnical core holes and two metallurgical holes (CK20-06c
and 07c). During geotechnical logging, 1,065 PLI tests were completed on the whole core.
Geomechanical
samples were collected at chosen intervals by Piteau staff during logging. These samples were utilized for the characterization of the
intact rock strength. 13 samples were collected for uniaxial compressive strength, 15 for triaxial compressive strength, 11 for indirect
tensile strength, and 25 for discontinuity direct shear testing. Sample testing was completed at the Wood Group, PLC Rock Mechanics Laboratory
in Hamilton, Ontario, Canada. In addition, one fault gouge sample from CK20-16c was taken and tested at Golder Associates Geotechnical
Laboratory in Denver, Colorado. Piteau Associates integrated the results of this testing into their mine design recommendations.
Piteau
Associates also validated, processed, and interpreted down-hole televiewer data from 13 holes completed in 2020, including the five geotechnical
core holes and holes CK20-01c, 03c, 04cB, 05c to 07c, 09rc, and 21c. For major faults and contacts, Ken Coleman with U.S. Gold completed
initial processing and structure picking, followed by Piteau work for joint and fracture set characterization. Televiewer surveys were
completed by either COLOG or DGI Geoscience.
No
previous hydrogeologic work was completed at the Project prior to 2020. During its 2020 drilling program, U.S. Gold and its consultants,
Neirbo Hydrogeology (Neirbo) and Dahlgren Consulting, completed a limited water characterization and hydrogeology program. Several designed-for-purpose
drill holes were completed, and data were collected from holes designed primarily for other uses.
Seven
water characterization wells (MW-xx series) were drilled and completed in 2020, five by DrillRite Drilling of Spring Creek, Nevada, and
two by McRady Drilling of Cheyenne, Wyoming. DrillRite drilling was completed using reverse-circulation methods and McRady work was completed
using conventional rotary methods. A total of 2,755 ft (840 m) was drilled and completed. Holes were completed as water wells, screened,
and cased at proper intervals with a locking cover and monuments placed at the surface. These wells are checked regularly for water levels
and water quality.
Eight
core and RC holes designed for metallurgical resource expansion and geotechnical purposes were also utilized for hydrogeologic purposes.
These holes totaled 7,511 ft (2,289 m) and consisted of two metallurgical core holes, one RC resource expansion hole, and five geotechnical
core holes. The two metallurgical core holes (CK20-04cB and CK20-06c) were kept open, cased, and capped, similar to the water characterization
wells. These two holes are utilized for water quality sampling and obtaining water levels. Televiewer surveys were completed in these
two holes as well to aid in hydrologic and geotechnical studies.
Three
geotechnical core holes (CK20-17c, 18c, 19c) and one RC hole (CK20-09rc) had vibrating wire piezometers (VWPs) installed in them. Packer
testing and televiewer surveys were also completed on the core holes. The two remaining geotechnical core holes, CK20-16c and 20c, only
had packer testing and televiewer surveys completed.
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Packer
testing was completed by Alford Drilling under the supervision of a Neirbo consultant. VWP installation was completed and supervised
by Call & Nicholas, Inc. of Tucson, Arizona. Televiewer surveys were completed by staff of either COLOG or DGI Geoscience at the
same time as downhole gyroscopic surveying at the end of drilling each hole. Additional details on the current program are available
in Section 13.3.
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8.0 | Sample
Preparation, Analysis, and Security |
8.1.1 | U.S.
Gold 2021 - 2017 |
Ordinarily
core was collected by the geologist four times per 24-hour shift and returned to the core logging facility. The core processing steps
were as follows:
| ● | Core
is washed and scrubbed. |
| ● | Core
is aligned in the box to represent the original condition of the core as accurately as possible
(i.e., all fractured/broken ends are matched and rotated to fit back together.) |
| ● | Core
is washed and scrubbed again. |
| ● | Beginning
and ending depths are marked on the inside core boxes while the core dries. |
| ● | When
the core is dry, it is marked top to bottom with blue and red orientation lines, blue on
the left, and red on the right, depths are marked and labeled in black on one-foot increments |
| ● | Core
is logged for recovery, RQD, and fracture frequency per run, and this information is recorded
on the log sheet, along with any structural features significant enough to be recorded at
the resolution of the log sheet. |
| ● | Gross
lithology breaks are identified and recorded in the graphic lithology log column. |
| ● | Core
is inspected in greater detail as sample intervals are selected on a nominal 5-foot sample
interval within consistent lithologies, and sample breaks on lithologic (or other appropriate,
i.e., significant variation in alteration type or intensity) contacts with a minimum sample
interval of 1 ft. |
| ● | Assay
sample intervals are marked in green, with a line perpendicular to the core axis indicating
the top and bottom of the interval, and the sample ID marked on the core (if possible) parallel
to the core axis. |
| ● | Sample
IDs are scribed on silver sample tags, which are stapled to the core box on the left-hand
side of the core. |
| ● | Detailed
information is recorded for each sample interval on the core log sheet (rock type, oxidation,
alteration, mineralization, sulfide content, mineral content, veins, fracture, etc. |
| ● | Magnetic
susceptibility meter measurements. |
| ● | Assay
samples are recorded on the lab's assay sample inventory form. The log sheet indicates the
core boxes in which each assay interval is contained (sample intervals often cross box boundaries). |
| ● | Logged
core is transferred from the logging table to the photo station, re-wetted, and photographed. |
| ● | Photographed
core boxes are reunited with their lids and moved either to the back of a waiting truck for
transport to the pick-up area at the back of the lot or to a secondary staging area near
the garage entrance to be moved to the back of the lot later. |
RC
samples were collected in five-foot intervals from the discharge of a rotary splitter attached to the drill and then delivered to ALS
in 2021 and to Bureau Veritas lab in Sparks, Nevada, in 2017 and 2018 for analysis. U.S. Gold staff labeled and inserted commercial QA/QC
samples.
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55 |
A
red cut line was drawn along the midline of the core by a geologist, and a blue line, which indicates the core direction, was drawn next
to it. During 2021, the core was sawn in half by U.S. Gold personnel. During 2017-2018, the core was sawn by Bureau Veritas in Reno,
NV, and the half core containing the blue line was sampled. Sample tags were affixed to the inside of each core box, and the sample number
was written on the core. Typically, samples were 5 ft (1.5 m) long, broken at lithologic or important geologic feature contacts.
Ordinarily,
the geologist collected the core four times per 24-hour shift and returned it to the core logging facility. The core was housed in the
garage of a residential home in Cheyenne, WY, or placed in the backyard prior to shipping. In 2021, all core was moved to a secured facility
in Cheyenne, WY. Shipping was by a commercial carrier using the chain of custody documents and delivered to the assay lab facilities
in Elko and Reno, NV.
The
core from the 2008 drill program was logged in the spring/summer of 2008, contemporaneous with the drilling, though sampling was delayed
until the fall of 2009 due to budgetary constraints.
Saratoga
sampled the 2007 and 2008 drill core on approximate 5 ft (1.5 m) intervals, although sample intervals did range from 1 to 10 ft (0.3
to 3 m) as warranted by the geology. Due to the pervasive alteration and potential for mineralization observed throughout all drill holes,
the core was continuously sampled with no gaps in the sample sequence. The samples were collected principally by sawing the core in half,
though some intervals, due either to the hardness of the rock or the unavailability of the saw, were split with a hydraulic splitter.
In those cases where the sample intervals were fractured, and many of the core pieces were too small to either saw or split, the sampling
technician sampled the core using a trowel, a small shovel, or by hand. One half of the core was bagged and sent for assay, while the
remaining half was placed back into the core box and put into storage.
The
geologic logging process for the first 15 core holes of the 2007 drill program included core photography and geotechnical rock quality
(RQD) measurements, along with structural and lithologic determinations. However, core-recovery data recording was missing.
For
the remaining 2007 core holes and all the 2008 drill holes, core photography, RQD, and core recovery measurements, geologic logging,
and sampling were conducted in an open-sided shed. Due to the limited covered space, some of the core was exposed to the weather.
The
proposed drill hole locations were in the field by Western Research and Development (Western), a professional survey company based out
of Cheyenne, Wyoming. Western used a LYCA XLS 1200 GPS survey instrument, which has a <0.5 ft (0.15 m) accuracy. Upon completion of
the drill program, Western returned to the project site and re-surveyed the actual drill collars.
8.1.4 | Historical
Exploration |
According
to Soule (1955) and the photocopied data provided to MDA, the ASARCO 1938 core samples were sampled at 5 ft (1.52 m) intervals, while
the Copper King core holes were sampled at 10 ft (3.1 m) intervals. The 1970 ASARCO sampling was variable, though most sample lengths
were 10 ft (3.1 m).
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Soule’s
(1955) report briefly described the USBM’s sampling procedures. For their three holes, all core and necessary sludge samples were
delivered to the USBM’s engineer. All core samples were logged and split, with one split half sent to the USBM’s Salt Lake
City laboratory for analysis. Sludge samples were taken when core recovery was less than 85-90%. All sludge samples from holes B-1 and
B-2 were saved until the end of the project; most from hole B-1 were analyzed, but only a few from hole B-2 were analyzed. No sludge
samples from B-3 were saved because core recovery was generally excellent. The USBM drill holes were sampled on variable length intervals
ranging from approximately 3 ft to 16 ft (1 m to 5 m) with most sample lengths between 6 ft and 10 ft (2 m and 3 m).
Henrietta’s
drill holes were sampled and assayed at about 10 ft (3.1 m) intervals for gold and copper and occasionally for silver and acid-soluble
copper (Nevin, 1973). The core was split, with one half sent for assay and the other half stored on site. For the dry intervals of the
rotary holes, a box and cyclone in series were used for sampling with splitting by a Jones riffle. Nevin (1973) estimated that about
1 to 2% of the sample was lost as very fine dust. For the wet drilling, cuttings were split in a long, metal sluice box equipped with
a longitudinal baffle set to retain about a 10% fraction for assay. Rejects were stored on site.
According
to Clarke (1987), Caledonia’s drill holes were sampled every 10 ft (3 m) and assayed for gold, but the historic data included only
composite intervals ranging from 3 m to >50 m.
The
Compass RVC holes were sampled at 5 ft (1.5 m) intervals, while the core holes were sampled at 10 ft (3.1 m) intervals. The Mountain
Lake drill holes were all samples at 5 ft (1.5 m) intervals. MDA has no further information on the Compass or Mountain Lakes drill sampling.
8.2.1 | U.S.
Gold 2021 Campaign |
For
the 2021 drilling campaign, Hard Rock Consulting (HRC), sub-contracted through Gustavson, conducted field activities, logging, core sawing,
and initial sample selection. ALS were selected to conduct assaying, and selected samples, along with standards and blanks, were sent
off to the laboratory by HRC. The program was initiated to provide additional data to support a FS and included the test necessary for
both the hydrological and geotechnical studies. There have been no material findings to date that would support a departure from the
findings in the PFS.
8.2.2 | U.S.
Gold 2017 – 2020 Campaign |
2020
samples were logged, and sample intervals were selected and passed along with cut sheets to Bureau Veritas (BV). BV cut the core and
analyzed a sample from the half core, with the other half returned to the core boxes for storage and reference. The retained half core
and sample rejects were initially stored in the warehouse at BV while assaying was conducted and have been subsequently moved for storage
in a facility in Cheyenne near the Project. During the sample submission process, a contract geologist, M. C. Newton, was on hand at
the BV facility to receive core, discuss and inspect procedures, on an intermittent basis as part of the chain of custody and QA/QC check
procedures.
BV
inserted commercial blanks and standard reference materials from cut sheets determined by U.S. Gold. Throughout 2017 – 2020,
BV of Reno, NV, was the primary laboratory responsible for cutting the core, sampling, preparation, and assaying. Some compromises
were needed during the 2020 COVID-19 outbreak as access to the BV lab and personnel was restricted. Video and careful consultation
with laboratory staff satisfied the role of the consulting geologist in verifying that correct handling and procedures were
followed.
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8.2.3 | 2007
– 2008 Saratoga Campaign |
The
Saratoga core samples from the 2007 drill program were shipped to ALS Chemex (Chemex) in Elko, Nevada for sample preparation and then
on to the Chemex facility in Sparks, Nevada, for analysis for gold and a 33-element geochemical suite. Results were received in December
2009. The Chemex sample preparation and analysis methods requested by Saratoga were “AA23” for gold and “ME-ICP61”
for the geochemical suite. Both methods employ the same sample preparation methods, which include crushing the whole sample to 70% passing
-2mm and then pulverizing 250 g to 85% less than 75 microns (-200 mesh). The “AA23” gold analysis consists of splitting out
a 30 g pulp sample and then using fire assay techniques followed by an atomic absorption (AA) finish. The detection level for this analysis
is 5 ppb Au, while the upper precision level is 10 ppm Au. Samples assaying over 10 ppm are re-assayed using a fire assay with a gravimetric
finish technique (Chemex lab code “Au-GRA21”), which has an upper precision level of 1,000 ppm Au. The “ME-ICP61”
analytical procedure consists of a four-acid digestion and analysis by inductively coupled plasma (ICP) followed by atomic emission spectroscopy
(AES). The reported range for copper values using this technique is between 1 and 10,000 ppm Cu. Samples with initial values over 10,000
ppm Cu are re-run using the same analytical techniques optimized for accuracy and precision at high concentrations (Chemex lab code “CU-OG62”
with an upper precision of 40% Cu).
The
core samples from the 2008 drill program were shipped in the fall of 2009 to American Assay Laboratories (American Assay) in Sparks,
Nevada for sample preparation and analysis for gold and copper only. The results were received in September 2009. The American Assay
sample preparation and analysis methods requested by Saratoga were “FA30” for gold and “D2A” for copper. Both
methods employ the same sample preparation methods, which include crushing the whole sample to 70% passing -2mm and then pulverizing
300 g to 85% less than 105 microns (-150 mesh). The “FA30” gold analysis consists of splitting out a 30 g pulp sample and
then using fire assay techniques. The detection level for this analysis is 3 ppb Au, while the upper precision level is 10 ppm Au. Samples
assaying over 10 ppm are re-assayed using a fire assay with a gravimetric finish technique (American Assay lab code “Au-GRAV”),
which has an upper precision level of 1,000 ppm Au. The “D2A” analytical procedure for copper consists of an aqua regia digestion
and analysis by AA. The reported range for copper values using this technique is between 1 and 10,000 ppm Cu. Samples with initial values
over 10,000 ppm Cu are re-run using the same analytical techniques optimized for accuracy and precision at high concentrations (lab code
“Cu Ore Grade”) with an upper precision of 40% Cu.
After
the analyses were completed and temporary storage at Chemex, Saratoga retrieved all of the pulps and selected coarse reject samples from
mineralized intervals and is currently in storage in Elko, Nevada.
The
drill crew, upon filling a core box, placed a wooden top over the core, and the box was secured using strapping tape. At the end of each
drill shift, the core was transported by the drill crew into Cheyenne, WY, about 20 miles (32 km), and placed in a locked commercial
storage unit. The storage unit is located within a secure, gated facility. About once per week, the core was transported on a trailer
to the logging and sampling facility in Casper, Wyoming, 200 miles (320 km).
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58 |
Logging
and sampling of the first 13 core holes drilled in 2007 were completed in a large, converted garage located on leased private property
outside of Casper, Wyoming. The property was fenced off and kept securely locked when personnel were not on-site. After being logged
and sampled, the remaining half-core was placed in a locked storage unit within a secure, commercial storage facility in Casper.
Saratoga’s
lease on the Casper logging facility ended on August 31, 2007, and the remaining 2007 core holes were transported 200 miles (320 km)
to Dubois, Wyoming, for storage and further core processing. Sampling was conducted within an open-sided ranch shed on private property
owned by Norm Burmeister, an officer with Saratoga. The core facility was within a fenced area. After sampling was complete, the core
was transported to a commercial storage facility and stored on racks in a locked storage unit. These same procedures were used for the
2008 drilling.
The
half-core samples to be shipped to the lab were given non-referential sample ID numbers. The individual bagged samples were placed into
larger shipping bags, which were securely closed using heavy wire ties and kept inside the logging facility awaiting shipment via a commercial
trucking company to Chemex in 2007, and Chemex and American Assay in 2008.
Very
little is known about the sample preparation, assaying and analytical procedures of the sampling at the CK Gold Project except as described
below. A table summarizing pre-1998 drilling on the property (Mountain Lake Resources Inc., 1997) gives detection limits for gold and
copper assays for six of the drill campaigns. For both the 1938 and 1970 assays by ASARCO, the detection limits were 0.001 opt Au (0.034
gpt Au) and 0.01% Cu (Mountain Lake Resources Inc., 1997). For Copper King Mining’s assays, the detection limit for gold was 0.01
opt Au (0.343 gpt Au), and the detection limit for copper was thought to be 0.10% (Mountain Lake Resources Inc., 1997).
For
the three holes drilled by the USBM, analysis was done by the USBM’s Salt Lake City laboratory (Soule, 1955). The detection limits
were 0.005 opt Au (0.171 gpt Au) and 0.05% Cu as indicated by Mountain Lake Resources Inc. (1997). The USBM also prepared composite samples
of the core from their three holes and analyzed them for molybdenum, tungsten, nickel, and for most of them, titanium. In addition, the
USBM ran multi-element spectrographic analyses on five composite samples from hole B-1, and Copper King Mining ran the same on five composite
samples from hole C-7 and one sample from hole C-8; results of these spectrographic analyses are reported in Soule (1955).
Skyline
Laboratories Inc. and Hazen Research Inc., both of Denver, Colorado, assayed Henrietta samples (Nevin, 1973). The detection limits for
the gold and copper assays were 0.005 opt Au (0.171 gpt Au) and possibly 0.001% Cu (Mountain Lake Resources Inc., 1997).
Little
information exists regarding Caledonia’s drill program other than that drill samples were only assayed for gold (Clarke, 1987).
MDA
(2010) found assay certificates for Compass holes CCK-19 and CCK-24 that showed the assays were performed by Barringer Laboratories Inc.,
in Reno, Nevada, using fire assay with an atomic absorption (“AA”) finish for gold and AA for copper. It was not evident
from the data reviewed by MDA whether Barringer assayed all of Compass’s holes. The detection limits for Compass’s assays
were 2 ppb gold and 5 ppm copper (Mountain Lake Resources Inc., 1997).
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59 |
Assaying
of the samples for Mountain Lake was performed by Barringer Laboratories Inc. in Reno, Nevada. MDA has seen no assay certificates for
Mountain Lake’s drill holes but did find a spreadsheet with the assays, which were entered into the database for Mountain Lake’s
eight drill holes. The detection limits were 2 ppb gold and 5 ppm copper (Mountain Lake Resources Inc., 1997). Metallurgical testing
of bulk composite samples from holes MLRM-1 and MLRM-2 was conducted by the Colorado Minerals Research Institute of Golden, Colorado.
8.3 | Results,
QC Procedures and QA Actions |
8.3.1 | U.S.
Gold 2021 Campaign |
As
described above, the data derived from the 2021 drilling program that commenced in August 2021 has not been included in support of the
PFS study which relies on 2020 and prior data. The purpose of the 2021 data collection was primarily to support additional geotechnical
and hydrological studies. There have been no material observations that would affect the PFS study as written. The 2021 drilling results
shown in Table 8.1 have been reviewed in the context of the existing resource and they are not material.
Table
8.1: 2021 Drilling Program Results |
Standard |
Au
(ppm) |
Cu
(ppm) |
Ag
(ppm) |
|
Expected |
StdDev |
Expected |
StdDev |
Expected |
StdDev |
CDN-BL-10 |
0.0064 |
0.0069 |
29.3511 |
5.5799 |
0.0316 |
0.0124 |
CDN-CM-19 |
2.11 |
0.11 |
20200 |
350 |
2.6414 |
0.2038 |
CDN-CM-37 |
0.171 |
0.012 |
2120 |
60 |
1.17 |
0.135 |
CDN-CM-38 |
0.942 |
0.036 |
6860 |
160 |
6 |
0.2 |
CDN-CM-47 |
1.13 |
0.055 |
7240 |
140 |
69 |
3 |
MEG-Au.17.01 |
0.38 |
0.015 |
723 |
19 |
6.525 |
0.203 |
MEG-SiBlank.17.12 |
0.0059 |
0.0164 |
3.0223 |
3.234 |
0.0148 |
0.0136 |
8.3.2 | U.S.
Gold 2017 – 2020 |
U.S.
Gold’s QA/QC program implemented for the 2017, 2018, and 2020 drilling campaigns included the analysis of certified reference materials
(CRMs), blanks, coarse rejects, and pulp duplicates inserted regularly into the sample stream. A random selection of samples from mineralized
intervals was also submitted to an umpire laboratory.
U.S.
Gold geologists evaluated the control sample results. When the control samples returned values outside of acceptable limits, the assay
laboratory was contacted, and the batch of samples was re-assayed.
Gustavson
compiled and reviewed the 2020 control sample results and found assay accuracy and precision acceptable for resource estimation. No significant
bias was observed in the gold, copper, or silver CRM results. Check assays showed no significant bias between Bureau Veritas original
assays and ALS check assays. No significant carryover contamination was observed in the blank results.
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60 |
Three
standards were used for the 2020 drilling program, CDN-CM-43 and CDN-CM-38 from CDN Resource Laboratories Ltd., and MEG-Au.17.01 and
MEG-Au.17.10 from MEG, Inc. The recommended values and standard deviations for Au, Cu, and Ag are found in Table 8.2.
Table
8.2: Sample Standards |
Standards |
gpt
Au |
Au_2SD |
%
Cu |
Cu_2SD |
gpt
Ag |
Ag_2SD |
CDN-CM-38 |
0.942 |
±0.072 |
0.686 |
±0.032 |
6.0 |
±0.4 |
CDN-CM-43 |
0.309 |
±0.040 |
0.233 |
±0.012 |
- |
- |
MEG-Au.17.1 |
0.382 |
±0.015 |
0.0723 |
±0.0019 |
6.525 |
±0.203 |
MEG-Blank.17.10 |
<0.003 |
- |
0.00015 |
- |
0.9 |
|
A
commercial 99% quartz sand standard MEG-Blank.17.10 was used during the 2020 drilling campaign. Results are reasonable, and blank assay
results exceed 90% less than two times the detection limit of .005 ppm gold. The blank has a reported average of less than 0.003 gpt.
The same blank has a reported average of 1.5 ppm copper and although not a blank, it showed carryover on 5 occasions but well below any
economic consideration. Silver was below detection 100% of the time. The blank samples demonstrate that the laboratory has reasonable
control over sample cross-contamination.
The
duplicate pulp performance of 64 pairs was greater than five times the gold detection limit, exceeding 90% of the pairs within a grade
difference of 5%. These results are reasonable.
A
subset of 110 randomly selected samples collected during the 2020 drilling campaign were submitted to ALS for umpire assay analysis.
The paired Au and Cu data were analyzed and found to agree with the ALS checks. The correlation coefficient (r) of the raw data is 0.97
for Au, Figure 8.1, and 0.997 for Cu, Figure 8.2.

Figure
8.1: Umpire Analysis Au Correlation
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61 |
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Figure
8.2: Umpire Analysis Cu Correlation
8.3.3 | 2007
– 2008 Saratoga |
Details
on QA/QC programs for the 2007 and 2008 drill campaigns can be found in Tietz (2010), Saratoga’s QA/QC program implemented for
the 2007 and 2008 drilling included 1) analytical standards and blanks inserted into the drill-sample stream, 2) duplicate assaying of
selected coarse-reject samples by the primary assay laboratory, and 3) re-assaying of selected original pulps by an umpire laboratory.
American Assay was used as the umpire laboratory for the 2007 drill program in which Chemex was the primary laboratory, while the roles
were reversed for the 2008 drilling.
A
total of 169 standard samples were submitted to Chemex and American Assay. One standard sample was inserted into the stream at an approximate
rate of one standard for every 40 drill samples. Standards were also used in the duplicate pulp and pulp re-assay check assay programs
at a higher rate, ranging from one standard per 10 to one standard per 25 samples. Five unique analytical standards were used. The standards
were inserted into the drill core sample stream with the same sample ID designation, though as pulps, they were not blind to the lab.
Tietz
found that the check assay analyses show good agreement between the Chemex duplicate pulp analyses on the original Chemex coarse rejects
and between the Chemex pulp re-assays of the original American Assay samples. No significant biases or assay variability issues were
found within these data. There are concerns, primarily within the copper analyses, with the December 2009 American Assay pulp duplicate
and pulp re-assay check analyses. Further examination and follow-up analytical work is warranted to determine the specific problem within
these data, though any resolution of these issues would not materially affect the resource model or stated resource.
The
QP believes that the sampling procedures are adequate for mineral estimation purposes and for reporting mineral resources and reserves.
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62 |
Site
visits by the Qualified Persons (QPs) authoring this report were conducted during the 2020–2021 exploration campaign and the Pre-Feasibility
Study (PFS) development in 2024. Mark Shutty, CPG, visited the CK Project site and U.S. Gold’s logging and sample storage facilities
in Cheyenne on July 26–27, 2021, and again on July 11, 2024
During
the site visits, the following observations and evaluations were made:
| ● | Mineralization:
Oxide copper mineralization was observed in outcropping granodiorite host rocks above the
core of the modeled mineralization (Figure 9.1). |
| ● | Drilling
Operations: Active drilling operations were reviewed in 2021, and monumented drill collars
from the 2021 and earlier campaigns were inspected in 2024 (Figure 9.2). |
| ● | Geologic
Facilities: Logging, sampling, and storage facilities were evaluated to confirm compliance
with industry standards. Drill core sampling was conducted using sawn core methods, and storage
facilities were found to be secure, well-organized, and inclusive of legacy core from previous
operators. |
Data
Validation
Drill
Collar Locations and Surveys:
| ● | Drill
collars were professionally surveyed, with elevations cross-checked against a digital terrain
model (DTM). Historical collar elevations not conforming to the DTM were adjusted to match
the digital surface, validated by observations of site disturbance, monuments, and historical
maps. |
Downhole
Survey Data
| ● | Downhole
survey data were visually inspected in 3D and checked for deviations using modeling software
tools. Errors were flagged for review and correction. A redundant true north correction factor
(±7.0° E declination) was identified in 2021 downhole survey data but had minimal
impact on the Inferred resources located below the constraining resource optimization pit
and no impact on the Measured and Indicated resources located within the Reserves pit limit. |
Quality
Assurance/Quality Control (QA/QC):
| ● | QA/QC
procedures (see Section 8) ensured the reliability of analytical data. Control samples, including
blanks, duplicates, and standard reference materials, were appropriately selected and used
at suitable frequencies. Their performance was evaluated using statistical methods to ensure
quality sample handling and analytical data accuracy. |
| ● | Digital
analytical record handling was utilized in modern drilling campaigns, minimizing errors during
data transfer from laboratories to the drill hole database and modeling systems. |
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63 |
Logging
and Database Management
Logging
Procedures:
| ● | Comprehensive
logging captured attributes required for modeling geology, oxidation, and structures. These
data were securely stored in a detailed project database integrating historical and modern
drilling information. |
Database
Compilation:
| ● | U.S.
Gold compiled a comprehensive Access database to preserve data quality while facilitating
digital verification and analysis. Drill traces, logged geology, and assay data were independently
reviewed in 3D. |
Resource
Dataset Overview
The
CK Project drilling datasets, compiled over several decades, originated from multiple operators employing varied drilling, sampling,
and analytical methods.
| ● | Modern
Era Drilling: Data generated since 2007 from U.S. Gold and Saratoga represent the most robust
datasets, supported by comprehensive QA/QC protocols, digital analytical records, and thorough
documentation. These datasets support most of the CK Project’s Measured and Indicated
Resources. |
| ● | Metal
Distribution Validation: The deposit’s well-defined metal distribution, with gradational
Au, Cu, and Ag zonation in granodiorite host rocks, enables results compliance checking for
modern and historical datasets. |
Independent
Verification
The
QP independently verified analytical data by:
| 1. | Reviewing
and cross-checking unit conversions (e.g., ppm to opt for Au and Ag assays and ppm to percentage
for Cu). |
| 2. | Calculating
the AuEq variable for use in modeling and resource reporting. |
| 3. | Evaluating
global and local metal grades by drill type for bias: |
| ● | Diamond
Core: 63% of resource drilling, well-dispersed across the deposit. |
| ● | RC
Drilling: 35%, primarily defining lower-grade margins. |
| | |
| ● | Rotary
Drilling: <2%, focused on the core of the deposit. |
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64 |

Figure
9.1: Oxide copper mineralization in outcropping granodiorite host rocks (2024). |

Figure
9.2: U.S. Gold’s CK21-11c drilling in-progress on July 11, 2021. |
Observations
and Compliance
| ● | Surface
disturbances from historical drill pads and access trails are well-preserved and/or have
been reclaimed. |
| ● | Verification
samples were not collected, but observed drilling, sampling, and data handling procedures
were consistent with industry standards. |
| ● | Drill
core recovery is excellent, as evident from core photographs, archived samples, and digital
logs. Hard Rock Consulting re-logged core from the 2017–2018 campaigns, further validating
geological observations. |
In
summary, the QPs confirm that the datasets used in the CK Project’s Mineral Resource Estimate (MRE) meet industry standards for
quality and reliability, providing a solid basis for resource modeling and reporting.
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9.2 | Previous
Audits / Owners |
9.2.1 | Saratoga
2007 – 2008 |
Data
verification of exploration activities before 2007 is not well documented, and there is no independent verification of the exploration,
sampling, or laboratory procedures.
Drilling
data from the 2007-2008 Saratoga drill programs was directly input from sources. Saratoga provided the original collar survey data files
and the downhole survey driller’s notebooks, while the assay data were digital data direct from the laboratories. After compiling,
these data were audited against the sources by randomly checking values and specifically checking downhole survey data that appeared
anomalous. Six individual down-hole surveys were removed from the database due to uncertain depths or atypical azimuth values. In all
cases, the atypical azimuth values coincided with anomalously high magnetic field readings.
There
was virtually no original historical data available to audit the database. Gustavson verified the drill-hole locations and values of
those samples from ASARCO’s holes A-1 through A-5, Copper King’s holes C-6 through C-11, and the USBM’s holes B-1 through
B-3 by crosschecking values in the database with those reported in Soule (1955), but no original assay certificates were available for
these or any other drill holes except Compass’s holes CCK-19 and the cored portion of CCK-24. Gustavson verified the assay values
in the database for Compass’s holes CCK-19 and CCK-24 by crosschecking the values in the database with those shown on the assay
certificates, and no errors were found. Gustavson verified gold values for the best gold intercepts in the holes drilled by Henrietta
by crosschecking assays included on geologic logs against values in the database. Gustavson found spreadsheets with assays from Barringer
Labs for Mountain Lake’s eight drill holes and confirmed their values in the drilling database.
In
1996, Mountain Lake ran check assays on selected mineralized intervals from 12 of Compass’s holes. The check analyses were conducted
by Barringer Laboratories, Inc. Gold was analyzed by fire assay with an AA finish, and copper was analyzed by AA. A preliminary evaluation
of the Mountain Lake check assay results by MDA in 2006 indicated general agreement between the original and the check assay Au values.
The mean grades of gold and copper for the original and check assays are as follows: 3.46 gpt Au and 0.465% Cu and 3.29 gpt Au and 0.570%
Cu, respectively. The absolute percent difference between the 185 check assays and originals averaged 16%, with a standard deviation
of those absolute differences of 29%. Of the 20 check sample assays that showed a 30% (one standard deviation) or greater difference
from the original assay, 14 were in the lower half of the grade range (<3.36 gpt Au), indicating greater variability within the lower-grade
mineralization. In non-absolute terms, the average difference between the check and original assays was -1%.
The
QP considers that the drill data are generally adequate for resource estimation. There are no additional limitations to the exploration
data, analysis, or exploration database for use in resource modeling and declaration of mineral resources and reserves.
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10.0 | Mineral
Processing and Metallurgical Testing |
Several
metallurgical testwork programs have been completed on multiple samples of mineralization from the CK Gold Project. The work dates back
to 2008 when Saratoga Gold Company (Saratoga) first contracted SGS Lakefield (SGS) to perform fundamental characterization work and scoping-level
separation tests (flotation and cyanide leaching) on several composites of sulfide and oxide mineralization.
No
further work was completed until 2020 when U.S. Gold commenced a drilling program that included several holes designed to generate sufficient
sample material for a metallurgical test work update. The metallurgical program that followed commenced in December 2020 at Kappes, Cassiday
and Associates (KCA) Laboratory in Reno, Nevada before it transitioned over to Base Metals Laboratory (BML) in Kamloops, Canada. Several
metallurgical programs have been completed at BML, including further flotation characterization, grindability, mineralogy, and dewatering.
Although
the QP for this section was not directly involved with historical work, the reports were reviewed, and the conclusions were generally
concurred with.
While
the recent PFS incorporated process plant designs based on early SGS test work and 2021 BML results, this PFS also includes more recent
work from BML.
The
various testwork programs are described in the following section in chronological order.
10.1 | sgs
testwork, 2008 - 2010 |
10.1.1 | Program
11868-001 (2008 – 2009) |
A
preliminary metallurgical program was initiated by Saratoga in 2008, and this covered grindability, mineralogy, flotation testing, and
environmental testwork on a master composite and four variability composites. Composite head analysis is summarized in Table 10.1 below.
Comp 1 represents the oxide material that overlies the deposit, Comp 2 represents the deposit's relatively small but higher-grade core,
and Comp 3 and 4 represent the east and west zones of the unoxidized volume within the deposit.
A
“Master Composite” was compiled at SGS for flowsheet development by blending equal portions of Comp 2, Comp 3, and Comp 4
composite material. This Master Composite did not include material from the Comp 1 (Oxide) composite.
Table
10.1: SGS Composite Head Assay |
Description |
%
CuT |
%CuCN |
gpt
Au |
gpt
Ag |
%S |
Master
Composite |
0.28 |
<0.002 |
1.41 |
<10 |
0.25 |
Comp
1 (Oxide) |
0.26 |
0.002 |
1.00 |
<10 |
0.02 |
Comp
2 (Mixed) |
0.39 |
<0.002 |
1.96 |
<10 |
0.21 |
Comp
3 (Sulphide East) |
0.22 |
<0.002 |
0.62 |
<10 |
0.21 |
Comp
4 (Sulphide West) |
0.19 |
<0.002 |
0.56 |
<10 |
0.34 |
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67 |
An
initial grindability study included Bond rod (RWI) and ball mill (BWI) tests for the Master Composite, and Bond ball mill tests for the
four variability composites. A Bond rod mill work index of 16.0 kWh/t (metric) was reported, along with a range of Bond ball mill work
indices from 13.0 to 14.8 kWh/t (metric). The results point to a material that is slightly harder than average, compared to the population
of results in SGS’s database.
A
QEMScan mineralogical program provided bulk mineralogy for each composite and identified several copper minerals across the sample set.
Chalcopyrite dominated, with a range of secondary copper minerals (mainly chalcocite) also noted. No native copper was identified, and
very low levels of pyrite were measured. Host minerals included feldspar (roughly 45%), quartz (roughly 25%), and micas (roughly 14%)
with other oxides and clays making up the balance. Chlorites made up roughly 4-5% of each composite.
Flotation
testing focused on the Master Composite. The work highlighted a general improvement in metallurgical performance at finer grinds (142
µm, 112 µm, 87 µm, and 65 µm were tested) although the test at 80% passing 65 µm did appear to suffer from
the effects of lower mass pull. SGS metallurgists concluded that a primary grind of 80-90 µm was preferred for the remaining work.
Raising
pulp pH with lime improved copper performance but had a very slight negative impact on gold recovery.
Early
batch cleaner tests highlighted the need for a rougher concentrate regrind, and an initial study on the Master Composite suggested that
a regrind target of approximately 80% passing 20 µm would be close to optimum.
An
assessment of gangue depressant and/or dispersant reagents was completed, and it was concluded that these were unlikely to improve metallurgical
performance.
Locked
cycle testing (LCT) of the Master Composite used a conventional SGS flowsheet with rougher concentrate regrind, three-stage counter-current
cleaning with cleaner one scavenging, and cleaner scavenger concentrate recycled back to the regrind mill. Two initial tests were completed
at coarse grinds (80% passing 110µm), giving relatively inferior results. A third LCT was completed at a finer grind (80% passing
83 µm), showing a distinct copper and gold performance improvement. The third LCT concentrate graded 26% Cu and 89.7 gpt Au with
overall recoveries of 77% Cu and 68% Au.
The
SGS metallurgists performed an initial study of final concentrate Cu grade vs. overall Cu and Au recovery, concluding that a higher mass
pull to concentrate could result in a Cu grade drop from 26% to 21% Cu, with an associated 1% increase in Cu and Au recovery.
A
variability flotation program tested the response of Comp 2, Comp 3, and Comp 4 material to the Master Composite flowsheet and gave results
that were generally in line with the Master Composite's performance.
An
initial environmental testwork program was conducted on a flotation tailings sample taken from LCT-2 on Master Composite material.
An acid-base accounting (ABA) test noted that acid generation would be highly unlikely given the sample's negligible sulfide
content. A net acid generation (NAG) test determined the net acid generation potential to be zero, meaning that no acid was produced
during the test. The tailing sample represented a very low acid generation and/or metal leaching risk.
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10.1.2 | Program
11868-002 (2010) |
Saratoga
approached SGS for a follow-up metallurgical program in the summer of 2010. The work was conducted on the Comp 1 (Oxide) material from
the previous program with the objective of developing a flotation flowsheet for copper and gold recovery.
A
variety of flotation activators and collectors were tested, and a locked cycle test was completed using the sulfide flowsheet as developed
in the previous program. The testing was generally positive, with an acceptable recovery of gold (54.8%) despite a low copper recovery
(8%). The copper concentrate grade was reasonable at 15.3% Cu, and the gold grade was excellent at 384 gpt Au. The performance was considered
acceptable for preliminary inclusion of this material in the overall mine/processing plan should a sulfide mill be the selected process
flowsheet for the Project.
10.2 | kappes
cassiday testwork, 2020-21 |
After
a change in ownership from Saratoga to U.S. Gold, a new metallurgical program was commissioned in 2020 with the following objectives:
| ● | Confirm
the 2008/2010 SGS results using samples from a new drilling campaign. |
| ● | To
develop a flotation flowsheet to improve the SGS results (specifically gold and copper recovery
and concentrate grade) for the oxide and sulfide zones. |
| ● | To
complete sufficient work to support PFS-level process engineering and to increase overall
confidence in the results. The overall work for this program included: |
| ◌ | Quantitative
mineralogy to better characterize the deposit, especially the non-sulfide minerals and native
copper, and provide gold deportment information. |
| ◌ | Optimization
of the primary grind and re-grind. |
| ◌ | A
more thorough investigation of flotation conditions and reagents. |
| ● | Variability
testwork is used to ascertain the impact of depth, area, lithology, and grade. |
| ● | A
more detailed evaluation of gravity recovery. The SGS test work was not successful in producing
a gravity concentrate, although the report concluded that this required further investigation.
Observation of the new core showed significant visually observable native copper in the high-grade
oxide, and the recovery of this might justify the addition of a gravity circuit to the flowsheet. |
Details
of the metallurgical composites used for this work are given in the following section, but the objective at the onset was to develop
the overall characterization of average-grade oxide and sulfide mineralization, and the composites reflect this. In addition, a High-Grade
Oxide composite (similar to SGS “Comp 1”) was included in the scope for comparison with previous studies. This “Hole
4” composite was prepared using shallow samples (less than 80 ft depth) from CK20-04cA&B where a centrally located oxide zone
was intercepted with average grades of 5.1 gpt Au, 0.98% Cu and less than 0.1% S, (assays of individual core sections). Below 80 ft,
the gold and copper grades remained high in this area, but the sulfur grade increased to an average of 0.5% S.
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69 |
The
initial test work on the Hole 4 Oxide composite produced recoveries and concentrate grades that exceeded expectations based on historical
SGS results. However, during April 2021 it became apparent that KCA were unable to reproduce the SGS results on the main Oxide and Sulfide
composites. As a result, a second test program was initiated at BML in Kamloops, Canada (described in Section 10.3 below). BML was immediately
able to duplicate and later improve upon the SGS results.
During
2020, U.S. Gold carried out a major exploration drilling campaign that included seven holes drilled specifically to provide core for
metallurgical test work. These metallurgical holes provided over 4,600 ft of mineralized core consisting of 1,100 sample intervals. The
plan view location and orientation of the seven metallurgical holes is illustrated in Figure 10.1 below.
The
metallurgical core was cut, prepared, and assayed at Bureau Veritas Analytical in Reno. One half was used for the assay, and the other
half contributed to the preparation of metallurgical composite samples.

Figure
10.1: Location of Metallurgical Holes, highlighted area represents the approximate mineralized area
 |
70 |
The
three metallurgical composites are described below in Table 10.2, with names, masses, and head assays listed for reference.
Table
10.2: FLSmidth Mineralogical Analysis: Copper Deportment |
Ref |
Description |
Mass,
kg |
%
CuT |
gpt
Au |
gpt
Ag |
%Fe |
%S |
90104A |
High-grade
oxide, Upper Zone (“Hole 4”) |
203 |
0.99 |
4.88 |
4.83 |
6.42 |
0.02 |
90150B |
Overall
Oxide Zone, holes 1-3 and 5-7 |
235 |
0.28 |
1.14 |
2.10 |
3.59 |
<0.01 |
90151B |
Overall
Sulphide Zone, holes 1-7* |
372 |
0.27 |
0.963 |
1.61 |
3.62 |
0.21 |
*
Note: This composite included the small amount of material identified as "mixed " between the oxide and sulfide zones.
Visual
inspection of the high-grade oxide Hole 4 core revealed that a significant proportion of the contained copper was native copper, much
of which was coarse-grained. Thus, the testing program on Hole 4 commenced with both gravity and flotation in the flowsheet.
High
Grade (“Hole 4”) Composite
The
Hole 4 Composite was prepared using material from three sources (described in detail within the KCA Report):
| ● | 43.5
kg of crushed, blended split core. |
| ● | 92.5
kg of assay rejects from hole CK20-04cA. |
| ● | 67.7
kg of assay rejects from hole CK20-04cB. |
Overall
Oxide Composite
Samples
were selected from six holes to make up an Overall Oxide composite. All the samples had sulfur assays less than 0.1% S. Gold grades ranged
between 0.5 and 1.5 gpt Au. Copper grades ranged between 0.2 and 0.5% Cu. The average grade of this composite was 1.14 gpt Au and 0.28%
Cu.
Sulfide
Composite
Samples
were collected from all seven holes to make up an Overall Sulfide composite. These samples had sulfur assays of more than 0.1% S and
generally over 0.2% S. Gold grades ranged from 0.5 gpt to 1.5 gpt Au. Copper grades ranged from 0.25% Cu to 0.8% Cu. The average grade
of the composite was 1.1 gpt Au and 0.3 % Cu.
Variability
Samples
In
addition to the overall composites described above, 24 oxide and 50 sulfide variability samples were selected, representing different
grades, depths, and lithologies. Testing of the oxide variability samples commenced during the third quarter of 2021, while the sulfide
samples were subsequently transferred to BML.
An
initial quantitative mineralogy (QEMScan) program was carried out at FLSmidth in Salt Lake City on samples of flotation feed and tailings
from the high-grade oxide composite. The mineralogy indicates the probable limits for copper recovery and the need for fine primary and
re-grinding.
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71 |
Table
10.3: FLSmidth Mineralogical Analysis: Copper Deportment |
Description |
Recovery
Potential |
Oxide
Head |
90131
Tails (G+F) |
Native
Copper |
Y |
0.346 |
0.001 |
Cuprite |
Y |
0.012 |
0.000 |
Chalcopyrite |
Y |
0.086 |
0.001 |
Bornite |
Y |
0.041 |
0.000 |
Chalcocite |
Y |
0.198 |
0.003 |
Covellite |
Y |
0.004 |
0.000 |
Cu/As/Sb
Sulfides |
Y |
0.002 |
0.000 |
Cu-bearing
clays |
N |
0.024 |
0.022 |
Cu/Chlorite |
N |
0.005 |
0.007 |
Cu/Biotite |
N |
0.004 |
0.003 |
Cu/Muscovite |
N |
0.009 |
0.007 |
Cu
Wad |
N |
0.001 |
0.001 |
Fe
Oxides |
N |
0.158 |
0.174 |
Fe
Oxide / Chrysocolla |
N |
0.018 |
0.025 |
Chrysocolla |
N |
0.179 |
0.192 |
Other
Cu |
N |
0.010 |
0.009 |
The
data also illustrates that for oxide zones within the deposit, the best copper recovery by gravity and flotation combined would be about
60%, which is close to the actual test results.
In
contrast to the initial SGS mineralogical assessment, the FLSmidth work also helped develop an understanding of gold and silver (electrum)
mineralogy to some extent. Of note:
| ● | Gold
appears very fine-grained, most less than 10-20 µm. |
| ● | Gold
is quite well liberated and is primarily not associated with copper minerals but located
on grain boundaries, as gold or electrum. |
| ● | Gold
association with pyrite appears minor. |
With
a relatively low pyrite content and the presence of acid consumers such as calcite, biotite, and chlorite noted in the samples, the tailings
from this project are not expected to generate acid, confirming the initial environmental work by SGS.
Sub-samples
of half-core were selected from the metallurgical composite crushing/blending process at KCA and shipped to Hazen Research for comminution
testing in early 2021. The Hazen work included SAG mill comminution (SMC), Bond ball mill work index (BWi) testing, and Bond abrasion
index (Ai) testing. Results are summarized in Table 10.4 below.
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72 |
Table
10.4: Comminution Test Work Results |
Ref |
Description |
SG |
BWi
(kWh/t)* |
Ai
(g) |
Axb |
ta |
SCSE
(kWh/t)* |
55432-1 |
High-grade
oxide, Upper Zone, Hole 4 |
2.66 |
14.0 |
0.2008 |
37.5 |
0.36 |
10.1 |
55432-2 |
Overall
Oxide Zone, holes 1-3 and 5-7 |
2.67 |
14.6 |
0.3430 |
33.3 |
0.32 |
10.7 |
55432-3 |
Overall
Sulphide Zone, holes 1-7 |
2.71 |
15.1 |
0.4033 |
27.8 |
0.27 |
11.8 |
*
Note: data is based on metric tonnes.
The
A x b results (drop weight test results) give an indication of resistance to impact breakage and in this case, show that the Sulfide
composite is slightly more resistant than the Oxide composites. The Sulfide composite is slightly more dense, more abrasive and more
competent at the finer grind sizes also.
10.2.4 | Gravity
Concentration |
One
of the opportunities identified by SGS was the addition of a gravity circuit to the flowsheet, especially in the oxide zones, where significant
native copper had been confirmed visually. Gravity tests using a bench-scale Knelson concentrator were scheduled on 40 lb samples of
each composite.
The
gravity tests on the overall Sulfide and Oxide composites were unremarkable, with low gold and copper recoveries and no obvious improvement
opportunity. For the Hole 4 Composite (high-grade oxide); however, a similar test produced a gravity concentrate with a weight recovery
of 1.6%, containing 51.5 gpt Au and 14.6% Cu, with recoveries of 15.4% Au and 22.7% Cu.
The
tailing solids from the Hole 4 gravity test were stored for later flotation test work and overall circuit (gravity + flotation) performance
comparisons.
In
general, the flotation testwork was carried out on the gravity tailings to determine if the inclusion of a gravity circuit before flotation
would provide better recoveries than by flotation alone. The results of this work are summarized in the below Table 10.5.
Table
10.5: Hole 4 Gravity + Flotation vs. Flotation Only, (KCA) |
Parameter |
Gravity
+ Flotation |
Flotation
Only |
Gravity
concentrate grade |
15.5
gpt Au 14.6% Cu |
- |
Recovery
to gravity concentrate |
15.4%
Au 22.7% Cu |
- |
Overall
flowsheet recovery:
Gold
Copper |
70%
60% |
70%
57% |
The
gravity test yielded recoveries of 15.4% gold and 22.7% copper. This was thought to generate higher recoveries for a gravity + flotation
circuit. However, the gold recovery (at 70%) was the same. It is concluded that gold recovered by gravity would be recovered in the flotation
circuit. The increase in copper recovery was 3%.
 |
73 |
Over
50 rougher flotation tests were carried out to investigate key flotation parameters (grind, reagents, pH, sulfidization, etc.) for each
of the three composites. All lab flotation tests were completed on 2-kg test charges. The testwork is summarized in the following subsections
and detailed in the KCA Report, “Copper King Test work for U.S. Gold,” dated July 2021.
Hole
4
32
tests were completed for the Hole 4 Composite (90104). The best results were achieved in Test 90134, and this is summarized in Table
10.6. These conditions were carried into the cleaner flotation test program.
Table
10.6: Rougher Flotation, Test 90134 (Hole 4) |
Parameter |
Value |
p80 |
106
μm |
pH |
9.0 |
CaO,
gpt |
153 |
NaSH |
n/a |
F507
(frother), gpt |
31 |
PAX,
gpt |
75 |
407,
gpt |
50 |
wt
to rougher, concentrate, % |
7.5 |
Gold
Recovery, % |
70 |
Silver
Recovery, % |
50 |
Copper
Recovery, % |
57 |
Overall
Oxide
10
tests were completed for the Overall Oxide Composite (90150), investigating similar parameters to the Hole 4 work above. The best results
were achieved in Test 90170, and this is summarized in Table 10.7.
Table
10.7: Rougher Flotation, Test 90170 (Oxide) |
Parameter |
Value |
p80 |
86
µm |
pH |
9.0 |
CaO,
gpt |
130 |
Frother,
gpt |
56 |
Collector,
PAX; 407 gpt |
76;
50 |
wt
to rougher concentrate, % |
7.0 |
Gold
Recovery, % |
61 |
Silver
Recovery, % |
18 |
Copper
Recovery, % |
21 |
The
relatively low recovery of copper directly reflects the copper mineralogy (i.e., a high content of non-floating copper minerals such
as chrysocolla).
 |
74 |
Overall
Sulfide
Twenty
rougher flotation tests were carried out on the overall Sulfide Composite (90151) investigating P80, pH, reagent addition
and types. The best result was achieved in Test 90173, and this is summarized in the below Table 10.8.
Table
10.8: Rougher Flotation, Test 90173 (Sulfide) |
Parameter |
Value |
p80 |
86
µm |
pH |
9.0 |
CaO,
gpt |
75 |
Frother,
gpt |
50 |
Collector,
PAX; 407 gpt |
51 |
wt
to rougher concentrate, % |
11.7 |
Gold
Recovery, % |
74 |
Silver
Recovery, % |
61 |
Copper
Recovery, % |
94 |
The
relatively high copper recovery reflects the more favorable mineralogy (i.e., mainly chalcopyrite) described in the FLSmidth report.
Batch
cleaner flotation tests on each composite used the optimized rougher flotation conditions achieved in the rougher flotation program discussed
above.
Hole
4
A
total of 13 cleaner tests were carried out, investigating the regrind P80 and a variety of reagents and addition rates. The
best result was obtained in Test 90160, which was repeated for confirmation. The results are shown in Table 10.9.
Table
10.9: Cleaner Flotation, Test 90160 (Hole 4) |
Parameter |
Test
1 |
Grind
P80, Primary Grind & Regrind |
86/20
µm |
pH |
9.0 |
Total
CaO, gpt |
172 |
Total
PAX, gpt |
76 |
Total
F-507, gpt |
51 |
Concentrate
Mass Pull, % |
2.0 |
Concentrate
Grade, % Cu |
25.3 |
Concentrate
Grade, gpt Au |
186 |
Concentrate
Grade, gpt Ag |
90 |
Recovery
Cu, % |
53 |
Recovery
Au, % |
68 |
Recovery
Ag, % |
35 |
The
rougher reagent suite used in this test is shown in Table 10.6. Reagents such as CMC, sodium silicate (Na2SiO3), and NaSH were not found
to be of benefit. The only reagent used in cleaning was a small frother addition.
 |
75 |
Overall
Oxide
18
cleaner tests were carried out, first with no regrind, then with regrind P80 of 20 µm. These tests also investigated
cleaner pH and various reagent suites, particularly gangue depressants. They were carried out throughout April 2021 to produce a saleable
concentrate grade without unduly sacrificing recovery. These cleaner tests were unsuccessful, and the best result is summarized in Table
10.10. Subsequently, it was established that the collector additions to the rougher flotation were too high, leading to overpromotion.
Table
10.10: Oxide Composite Cleaner Flotation (KCA) |
Parameter |
Test
1 |
Grind
P80, Primary Grind & Regrind |
90/20
µm |
Total
PAX, gpt |
14 |
Total
208, gpt |
16 |
Concentrate
Grade, % Cu |
8 |
Concentrate
Grade, gpt Au |
188 |
Concentrate
Grade, gpt Ag |
87 |
Recovery
Cu, % |
7 |
Recovery
Au, % |
48 |
Recovery
Ag, % |
12 |
KCA
decreased the collector addition, and a performance improvement was immediately realized. This reduced collector in the rougher circuit
eliminated the need for depressants and/or dispersants.
At
the end of April 2021, the highest copper concentrate grade achieved in the cleaner tests at KCA for Oxide was 8% Cu, significantly less
than the 15% Cu achieved at SGS. The best grade for sulfide was less than 20% Cu. As a result, U.S. Gold sent 30 kg of all three composites
to BML for cleaner flotation and Locked Cycle tests. This work commenced in the last week of April 2021.
Overall
Sulfide
28
batch cleaner tests were carried out on the overall Sulfide composite to investigate the regrind P80, pH, and reagents. In the initial
program, copper recovery to the cleaner concentrates was reasonable, but a commercial concentrate grade was difficult to achieve. The
best cleaner result for the Overall Sulfide composite is shown in Table 10.11.
Table
10.11: Cleaner Flotation, (KCA) |
Parameter |
Value |
P80
Regrind |
20
µm |
pH |
11.0 |
Concentrate
Grade, % Cu |
13.5 |
Concentrate
Grade, gpt Au |
34.6 |
Concentrate
Grade, gpt Ag |
55.0 |
%Cu
Recovery |
81% |
%Au |
62% |
%Ag |
74% |
As
a result, 40 kg of Sulfide composite material was sent to BML, Kamloops, for comparative testing. The results of the BML work are provided
in Section 10.3.
 |
76 |
KCA
subsequently repeated this test using reduced collector addition (PAX, AF208 and 3418) and achieved a copper concentrate grade of 23%
Cu, with recoveries of 83%, 64%, and 50% for copper, gold, and silver, respectively.
10.2.7 | Locked
Cycle Testing |
Using
the results of Cleaner Test 90160 as a guide, a single LCT was carried out on the Hole 4 Composite, with cleaner tails products recirculated
counter-currently throughout the test.
The
LCT could not produce a final copper concentrate of even 15% Cu, and the grade deterioration as the test progressed indicates that the
test had not reached a stable state. Further analysis of test results suggested that the most likely reason for this LCT's failure was
the addition of excessive collector reagent, resulting in over-promotion and a subsequent inability to reject low-grade middling in the
cleaner circuit.
As
a result, replicate Hole 4 Composite samples were shipped to BML in Kamloops, Canada for comparative rougher, cleaner and locked cycle
testing. The BML testing achieved concentrate grades more than 30% copper, containing over 500 gpt Au and 300 gpt Ag. These are discussed
in Section 10.3.4. BML generally uses 20-25% of the collector dosage used at KCA.
As
a result, samples were transferred to BML for the remainder of the test work program.
10.2.8 | Cyanidation
on Flotation Tailing |
Two
24-hour cyanidation tests were conducted on the Test 90139 flotation tailings at different cyanide strengths. These resulted in around
70% extraction of gold, with relatively low reagent consumption, as shown in Table 10.12.
Table
10.12: Cyanidation of Flotation Tailings |
Test |
P80 |
NaCN
gpL |
Head
gpt
Au |
Leach
Time
(h) |
NaCN
Cons.
Kg/t |
Ca(OH)2
Kg/t |
Extraction
% |
90139A
90139B
90139C
90139D |
87
85
87
85 |
1.0
1.0
5.0
5.0 |
1.92
1.56
1.92
1.56 |
24
24
24
24 |
0.88
1.06
1.46
1.67 |
0.60
0.60
0.60
0.60 |
69
70
64
73 |
10.2.9 | Tailing
Thickening/Filtration |
Samples
of flotation tailing solids and solution from the Hole 4 locked cycle flotation test program were shipped to Pocock Industrial Inc. in
Salt Lake City. Pocock’s scope of work was to investigate flocculants, gravity sedimentation, pulp rheology, vacuum filtration,
and pressure filtration. The objective of the test work was to provide data that could be used to assist in the selection and sizing
of the tailing’s thickener and filters.
Pocock
conducted a size fraction analysis of the Hole 4 flotation tailings and established the P80 to be 65 µm. This is much
finer than the primary grind used at KCA, which was 86 µm, but it is explained to some extent by the inclusion of the reground
cleaner tailings.
 |
77 |
Initial
work focused on screening potential flocculant types. A medium/high molecular weight anionic polyacrylamide was selected based on overall
performance, including overflow clarity, decantation rate, and underflow slurry viscosity characteristics. Two test methods were subsequently
used to characterize the settling/thickening performance, namely static tests in 2L cylinders and dynamic tests in a bench-scale continuous
unit. Pocock concluded that a conservatively sized high-rate thickener, using 55-60 gpt flocculant, with a heavy-duty rake mechanism
and adequate feedwell dilution would be appropriate for CK, producing an underflow slurry density of up to 62% solids.
The
apparent viscosity of underflow slurry collected from dynamic settling tests was measured across a range of solids concentrations and
shear rates, confirming the maximum underflow density limitation of 62%.
Pocock
investigated both vacuum and pressure filtration. The vacuum tests produced filter cakes with over 20% moisture at rates of 400-500 kg/m2.hr.
The pressure filtration tests achieved cakes with 12.8% moisture at rates over 2,000 kg/m2.hr; on this basis, plate and frame
filters (incorporating membrane squeeze) are recommended for CK.
10.3 | Base
Metallurgical Labs (BL-0789, 2021) |
The
BL-0789 program at BML commenced in April 2021, when a shipment of ½ core oxide material was received from the KCA program described
above. Subsequently, four sulfide and oxide material shipments were shipped as the metallurgical program developed.
This
short program was intended to provide an initial comparison to the KCA flotation results; therefore, it excludes mineralogy or comminution
programs.
Samples
were received in five shipments between April 10 and June 30, 2021, as summarized in Table 10.13.
Table
10.13: BL-0789 Composites |
Shipment |
Contents |
1 |
12
samples of ½ core weighing 27.8 kilograms combined to make the Oxide Composite (High Grade). |
2 |
16
samples in the form of ¼ core, weighing 55.3 kilograms.
Combined
with 23.2 kg of KCA 90151A (Shipment 3) to make the Sulfide Composite. |
3 |
KCA
Sample 90151A (Sulfide Composite) – 23.2 kilograms.
KCA
Sample 90150 (Oxide Composite) – 22.7 kilograms. |
4 |
6
samples of ½ HQ Core, weighing a total of 20.9 kilograms.
Combined
with 22.6 kilograms of KCA 90150A (Shipment 3) to make Oxide Composite 2. |
5 |
24
samples of ½ HQ Core, weighing 75.9 kilograms, combined to form Sulfide Composite 2. |
Upon
constructing the composites, the contents of each were stage crushed to pass 3.35 mm (6 mesh) and split into 2 kg test charges in preparation
testing. Only 48 kg of the material shipped for Sulfide Composite 2 was prepared into test charges, with the remaining material kept
and stored for future use.
 |
78 |
It
is worth noting that the original Sulfide Composite included some minor "mixed zone" material. As a result, between 10 and
15% of the copper minerals in this composite were non-sulfide (principally chrysocolla), which had a detrimental impact on the copper
recovery. The second Sulfide Composite (Sulfide Comp 2) was prepared later in the program to rectify this issue and avoid core samples
from or near the mixed zone.
The
names and chemical composition of the four composites tested in the BL-0789 program are listed in Table 10.14 below.
Table
10.14: 2020 Metallurgical Composites Description |
# |
Description |
%
CuT |
%CuOx |
%CuCN |
gpt
Au |
gpt
Ag |
%Fe |
%S |
1 |
Oxide
Comp |
1.15 |
0.43 |
0.15 |
5.95 |
3 |
6.6 |
0.06 |
2 |
Oxide
Comp 2 |
0.31 |
0.17 |
0.02 |
1.36 |
1 |
3.7 |
0.04 |
3 |
Sulphide
Comp |
0.27 |
0.04 |
0.06 |
1.13 |
1 |
3.1 |
0.33 |
4 |
Sulphide
Comp 2 |
0.35 |
0.004 |
0.02 |
0.92 |
1 |
3.3 |
0.47 |
The
analysis of copper deportment provided by the sequential copper assays is instructive: the oxide and cyanide soluble copper assay as
a fraction of the total copper assay is high in all but the Sulfide Comp 2 composite. This is expected in the oxide composites but has
implications for the original Sulfide Comp (#3), which has only 63% of the total copper assay in recoverable (primary sulfide) form.
On reflection, this composite might be more appropriately named “Mixed Comp,” with 10 and 15% of the copper content in oxide
form. Performance expectations for the Sulfide Comp should be moderated relative to the Sulfide Comp 2, despite similar copper grades.
Sulphur
values were relatively low for the oxide composites, particularly relative to copper, indicating the presence of only minor levels of
sulfide minerals, namely pyrite.
An
initial set of 8 rougher flotation tests was completed on the Sulfide Composite as part of an investigation into the recent work at KCA.
The tests evaluated different primary grinds and reagent recipes, including alternate collectors, sulfidizing agents, activators, and
promotors. All tests used 2-kg test charges.
These
preliminary tests gave results that were equal to the SGS results and significantly better than those achieved at KCA. Copper recovery
to a rougher concentrate varied between 76.3 and 80.0%, whilst gold recovery into this concentrate ranged between 72.1% and 75.9%. Rougher
concentrate mass pull varied between 5.3% and 7.8%.
At
the same primary grind, many chemical additives had little impact on metallurgical performance. The copper and gold-specific collectors
showed some promise at achieving higher overall recoveries, but generally at the cost of higher mass recovery.
 |
79 |
A
limited number of batch cleaner flotation tests were carried out on the four main composites, primarily to provide comparative data to
the ongoing KCA flotation program. For these 2-kg tests, BML worked with a 90 µm primary grind and reduced the collector additions
to "starvation" levels as compared to the KCA tests. This increased the concentrate grade to over 60% copper for the Oxide
Composite and generated reasonable (>20%) copper grades for the other three. Results for the cleaner flotation tests are summarized
in Table 10.15.
Table
10.15: Batch Cleaner Test Results |
Composite |
Cleaner
Concentrate Grade |
Cleaner
Concentrate Recovery |
%
Cu |
gpt
Au |
gpt
Ag |
Cu
% |
Au
% |
Ag
% |
Oxide
Comp |
62.2 |
1416 |
Not
reported |
12.9 |
49.9 |
Not
reported |
Oxide
Comp 2 |
25.3
13.2 |
1232
393 |
4.8
6.2 |
50.2
43.5 |
Sulfide
Comp |
30.2
19.9 |
110
65.2 |
64.2
69.0 |
55.2
59.1 |
Sulfide
Comp 2 |
23.1 |
61.9 |
83.9 |
66.5 |
The
test conditions noted to give superior results in the batch cleaner tests were subsequently carried through to the locked cycle program.
10.3.4 | Locked
Cycle Testing |
Seven
locked cycle tests examined the performance of each composite using batch test conditions, but with recycled slurry from the intermediate
streams. 2-kg test charges were utilized for the work and the primary grind in all cases was 90 µm. Test conditions and results
for each composite are summarized in Table 10.16 and Table 10.17. Note that PAX, AF208, PFSDB and PF7150 are all sulfide collectors.
Table
10.16: Locked Cycle Test Conditions |
Composite |
Regrind
p80 |
Lime
gpt |
PAX
gpt |
AF208
gpt |
PFSDB |
7150 |
MIBC |
H57 |
Oxide
Comp |
26
µm |
680 |
55 |
30 |
- |
- |
28 |
30 |
Oxide
Comp 2 |
21
µm |
310 |
51 |
26 |
- |
- |
28 |
60 |
Sulphide
Comp |
21
µm |
465 |
8 |
8 |
- |
- |
56 |
30 |
Sulphide
Comp 2 |
26
µm |
305 |
- |
- |
3.5 |
3.5 |
105 |
10 |
 |
80 |
Table
10.17: Locked Cycle Test Results - Master Composites |
Composite |
Final
Concentrate Grade |
Final
Concentrate Recovery |
%
Cu |
gpt
Au |
gpt
Ag |
Cu
% |
Au
% |
Ag
% |
Oxide
Comp |
63.4 |
587 |
359 |
39 |
61 |
70 |
Oxide
Comp 2 |
7.9 |
347 |
194 |
6 |
59 |
46 |
Sulphide
Comp |
25.0 |
76 |
82 |
75 |
66 |
47 |
Sulphide
Comp 2 |
21.3 |
42 |
60 |
88 |
75 |
60 |
Generally,
good concentrate copper grades were achieved, with a range of recoveries primarily dependent upon the copper mineral mix (i.e., CuOx:CuT).
The original sulfide and oxide composites (i.e., matching those tested at KCA) performed very differently from the KCA work, with better
results in most respects. The results also show that high recoveries of copper, gold, and silver can be achieved with “sulfide”
material containing only minor “non-sulfide” minerals. These results also help to confirm the 90 µm primary grind.
Collector addition is exceptionally low, in line with the low sulfide head grade. However, the high frother addition is to be noted.
Gravity
Recovery
Gravity
recovery tests using a lab scale Kelson Concentrator and shaking table (referred to as “Pan”) were carried out on LCT tailing
samples from the Oxide Comp, Oxide Comp 2, and the Sulfide Comp.
Results
for the Oxide Comp 2 and the Sulfide Comp were unremarkable, whilst the higher-grade Oxide Comp gave better results, as summarized in
Table 10.18 below.
A
significant amount of coarse native copper was observed in the higher-grade Oxide Comp LCT, which is apparent in the gravity concentrate.
Table
10.18: Gravity Test on High-Grade Oxide LCT Tailings |
|
%Weight |
%Cu |
gpt
Au |
Recovery
%Cu |
Recovery
%Au |
Pan
Conc. |
1.0 |
5.74 |
23.4 |
10.4 |
9.1 |
Pan
Tails |
2.8 |
0.54 |
4.2 |
2.6 |
4.3 |
Knelson
Tails |
96.2 |
0.52 |
2.4 |
87.0 |
86.6 |
Note
that the recovery data presented here represents recovery from the LCT tailings, not the original LCT mill feed. Calculating the contribution
to overall recovery gives a 6% copper and 3.5% gold recovery. It was noted that most gangue material in the pan concentrate is magnetite.
As discussed earlier, gravity has been eliminated from the flowsheet.
 |
81 |
Cyanidation
BML
also performed two cyanide leach tests on samples of flotation tailings from the Oxide Comp 2 LCT and the Sulfide Comp LCT. These 24-hour
bottle roll tests used 1,000 ppm NaCN and 250 gpt PbNO3 dosage, resulting in the gold dissolution of 81% and 74% for oxide and sulfide,
respectively, with cyanide consumption of 0.5 kg/t in both cases.
Cyanidation
of LCT tailings effectively increased total gold recovery to over 90% for both samples.
10.4 | Base
Metallurgical Labs (BL-0835/0882, 2021-2022) |
The
metallurgical work program continued at BML after the initial BL-0789 tests, including a variability program (BL-0835) that began in
September 2021. This was later expanded into a locked cycle testing program (BL0882) that included product characterization (minor elements
and tailings dewatering). The results of work completed under both contracts are described in a single BML report dated March 15th, 2022.
An
additional 473 kg of drill core and crushed core sample were shipped to BML in three shipments before the commencement of BL-0835 in
September 2021.
BL-0835
58
variability samples were prepared for this program by combining the mass from two or three similar individual samples (detailed in Appendix
A of the BL-0835 Report). From this initial suite of samples, ten were chosen for comminution, and 29 were selected for metallurgical
assessment using the developed process. Head assays for the 58 samples are summarized in Table 10.19 below. Copper speciation is indicated
by the Cu% Assay (Total Copper), the %CuOx assay (weak acid or oxide copper), and the %CuCN assay (cyanide soluble, or secondary/enriched
sulfide copper). Oxide copper species do not recover well in a sulfide flotation environment.
 |
82 |
Table
10.19: BL-0835 Variability Samples Head Assays |

This
sample set is sufficiently variable in grade with copper ranging between 0.02 and 1.41%, gold between 0.23 and 6.94 gpt and silver between
0.4 and 8.4 gpt. Sulfur assays ranged between 0.03 and 2.75% indicating that in common with previous programs, sulfide gangue mineral
(pyrite) content is a relatively minor constituent.
The
oxide (CuOx)and cyanide soluble (CuCN) copper analyses provide a good general indication of copper deportment. The deportment of copper
between oxide, sulfide, and cyanide soluble minerals is also quite variable, with relatively high oxide content noted in certain samples.
Examination of the ratios of CuOx and CuCN to total copper content indicates that:
| ● | 9
of the 58 samples had more than 20% oxide copper and are assumed to be influenced by the
high oxide copper content. |
| ● | 28
of the 58 samples had greater than 10% cyanide soluble copper and are assumed to be influenced
by the secondary enriched copper sulfide content. |
 |
83 |
| ● | 21
of the 58 samples had less than 10% combined oxide + cyanide soluble copper and are assumed
to be “primary sulfide” samples. These samples should perform well in a sulfide
flotation environment. |
The
distribution of CuOx and CuCN content is illustrated for all 58 samples in Figure 10.2 below.

Figure
10.2 - Variability Program Copper Deportment
 |
84 |
In
addition to the variability work, two sulfide composites were prepared for testing based on sulfide type (primary or secondary/enriched).
These two composites are summarized in Table 10.20 below.
Table
10.20: BL-0835 Main Composite Head Assays |
Composite |
Cu
% |
Fe
% |
S
% |
Au
gpt |
Ag
gpt |
CuOx |
CuCN |
Primary
Sulphide |
0.36 |
3.4 |
0.65 |
0.96 |
1.3 |
0.006 |
0.024 |
Enriched
Sulphide |
0.35 |
3.4 |
0.39 |
1.44 |
1.9 |
0.018 |
0.087 |
BL-0882
The
BL-0882 program focused on the characterization of four Master “Ore Type” composites, namely Shallow Sulfide (C1), Deep Sulfide
(C2), Oxide (C3), and Mixed (C4). These master composites were prepared from a variety of BL-0835 variability composites as described
in Table 10.21 to Table 10.24.
Table
10.21: Mixed (C4) Composite Construction |

Table
10.22: Shallow Sulphide (C1) Composite Construction |

Table
10.23: Deep Sulphide (C2) Composite Construction |

 |
85 |
Table
10.24: Oxide (C3) Composite Construction |

The
resultant master composites were submitted for head assay, with results summarized in Table 10.25 below.
Table
10.25: Master Composite Head Assays |
Composite |
Cu
% |
Fe
% |
S
% |
Au
gpt |
Ag
gpt |
CuOx |
CuCN |
C1-SS |
0.35 |
3.4 |
0.35 |
1.08 |
1.1 |
0.014 |
0.090 |
C2-DS |
0.2 |
3.5 |
0.59 |
0.78 |
1.5 |
0.005 |
0.010 |
C3-OX |
0.31 |
3.5 |
0.05 |
0.71 |
0.4 |
0.107 |
0.067 |
C4-Mix |
0.25 |
3.3 |
0.16 |
0.82 |
0.6 |
0.082 |
0.047 |
BL-0882
master composite samples were subjected to a QEMScan PMA analysis, giving quantitative bulk modal mineralogy and liberation data. The
data, summarized in Table 10.26 includes information regarding copper deportment and silicate gangue distribution and helps to explain
some of the differences in flotation response (copper recovery and concentrate grade).
 |
86 |
Table
10.26: BL-0882 Modal Mineralogy |

Mineral
liberation data from this program is also instructive: overall, the liberation at a nominal 90 µm P80 was not outstanding.
The two sulfide composites (C1 and C2) with approximately 50% copper sulfide liberation would be expected to perform reasonably well
in a sulfide flotation system, albeit with a somewhat high proportion of middling particles that might require longer residence times
and/or higher rougher mass pull. The Mixed and Oxide composites (C3 and C4) had lower liberation levels (40% and 38%, respectively),
suggesting a finer copper distribution and more challenging metallurgy in general.
The
data points to the requirement for a relatively fine concentrate regrind target in the 10-15 µm range. Coarser grinds than this
will tend to impact the copper concentrate grade negatively.
A
Hardness Index Testing (HIT) program was completed on a subset of ten samples from the variability program to improve the overall comminution
data set. The HIT tests were carried out on particles in the 19 mm – 22.4 mm size range and are designed to estimate the A x b
parameter defined by the JK Tech SMC test. HIT test results are summarized in Table 10.27 below.
 |
87 |
Table
10.27: Variability Samples, Comminution Results |
Sample
ID |
ECs
(kWh/t) |
t10(%) |
HIT-Axb
Full DWT (est) |
Oxide
1 |
0.17 |
6.1 |
45.6 |
Oxide
2 |
0.15 |
3.9 |
31.4 |
Oxide
3 |
0.17 |
4.7 |
35.2 |
Oxide
4 |
0.14 |
3.7 |
32.1 |
Oxide
5 |
0.17 |
4.8 |
34.4 |
Oxide
6 |
0.15 |
3.3 |
27.5 |
Oxide
7 |
0.14 |
2.8 |
24.6 |
CK20-04cb
Lot B |
0.16 |
3.5 |
26.3 |
CK20-04cb
Lot A |
0.16 |
3.4 |
26.4 |
CK20-03c
Lot B |
0.18 |
3.9 |
27.7 |
CK20-03c
Lot A |
0.19 |
5.0 |
32.6 |
CK20-01c
Lot B |
0.19 |
4.9 |
31.8 |
CK20-01c
Lot A |
0.18 |
3.9 |
27.6 |
The
range of the A x b parameter is reasonable, from the least impact-resistant sample (Oxide 1, measuring 45.6) to the most impact-resistant
sample (Oxide 7, measuring 24.6). Samples in this resistance range indicate mineralization amenable to SAG milling, albeit tending towards
the more competent side.
Comminution
tests on the master composites were limited to Bond BWi tests, and these are summarized in Table 10.28 below.
Table
10.28: Master Composites, Comminution Results |
|
Shallow
Sulphide
(C1) |
Deep
Sulphide
(C2) |
Oxide
(C3) |
Mixed
(C4) |
Bond
Ball Wi, kWh/mt
(CSS=106µm) |
15.5 |
16.7 |
16.4 |
15.1 |
These
values are slightly higher than earlier work (KCA, 2020), and the samples listed here are considered moderately hard for ball milling.
Rougher
flotation testing of the four master composites was limited to a short primary grind confirmation work program. Grind P80
sizes of 75 µm and 125 µm were tested against the baseline grind of 90 µm.
For
copper, no appreciable performance improvement was seen at the fine grind increment, but a decrease in performance was noted for the
coarse setting. In almost every case, the finer grind setting gave a higher, rougher concentrate mass recovery (and subsequently a lower
grade). The results are supported by mineralogical data, which indicates a very fine distribution of copper sulfides, fine enough to
remain poorly liberated at a P80 of 75 µm. Very fine primary grinds are costly (capex and opex) and would also negatively
impact the tailing filtration process.
 |
88 |

Figure
10.3: Grind Analysis – Rougher Flotation Results
A
slight improvement in gold recovery was noted at 75 µm with almost a 5% difference compared to the 125 µm result. This was
achieved at a higher mass pull and lower grade. The results support the conclusion SGS drew in 2009 that grinds finer than 80-90 µm
are likely not economically beneficial.
BML
concluded that the base case 90 µm primary grind was suitable for subsequent cleaner tests and LCTs.
Variability
Samples
The
BL-0835 work program tested 8 of the 58 variability samples through the standard flotation flowsheet (90 µm primary grind, pH
of 9.5 using lime, a 26-54 µm regrind and previously tested collectors) and the BL-0882 program tested another 21 samples.
Results were variable, again demonstrating the impact of copper mineralogy on grade and recovery. Copper recovery of 0.7% to 92.9%
and concentrate copper grades of between 9.4 and 42.5% clearly represent a wide range of feed mineralogy, although the metallurgical
response can be loosely linked to the ratio of %CuOx to %CuT. The results of this work are summarized in Table 10.29.
 |
89 |
Table
10.29: Variability Cleaner Test Work |

Plotting
copper and gold recovery as a function of “Oxidation Ratio” (i.e., CuOx/CuT), a tentative trend is apparent for copper
(Figure 10.5), but not for gold (Figure 10.4). The copper response seems intuitive, based on the mineralogical results obtained and
our knowledge of flotation rates for the different copper minerals. It should be noted, however, that the copper and gold recoveries
plotted in these charts are obtained at quite different final concentrate grades, meaning that results are not strictly like for
like. For example, test 17 and test 18 achieved 10.5% Cu grade and 26.2% Cu grade, respectively. As recovery is also generally
related to concentrate mass pull, the true recovery vs oxidation state relationship is likely not represented correctly in these
charts. Adjustments to these charts are discussed further in the metallurgical part of the Metallurgical Discussion (section
10.6).
 |
90 |

Figure
10.4: Variability Samples, Au Recovery v CuOx/CuT Ratio

Figure
10.5: Variability Samples, Copper Recovery v CuOx/CuT
 |
91 |
Master
Composites
Batch
cleaner tests were carried out on the BL-0882 master composites in preparation for locked cycle testing. Extra testing of the SS and
DS composites allowed for the optimization of concentrate copper grade whilst maximizing gold recovery. The results are summarized in
Table 10.30 below.
Table
10.30: Batch Cleaner Test Results |
Composite |
Final
Concentrate Grade |
Final
Concentrate Recovery |
%
Cu |
gpt
Au |
gpt
Ag |
Cu
% |
Au
% |
Ag
% |
C1-SS |
18.0 |
59 |
60 |
76.2 |
63.6 |
61.0 |
15.5 |
46 |
44 |
73.7 |
55.6 |
51.6 |
19.7 |
48 |
57 |
37.2 |
25.8 |
31.9 |
23.2 |
59 |
63 |
73.0 |
54.8 |
56.3 |
C2-DS |
19.7 |
39 |
97 |
82.9 |
60.2 |
72.6 |
18.9 |
38 |
77 |
87.3 |
65.7 |
71.9 |
22.2 |
43 |
87 |
83.2 |
62.0 |
46.3 |
C3-OX |
32.0 |
315 |
207 |
13.8 |
46.0 |
62.6 |
C4-MIX |
19.9 |
129 |
88 |
33.3 |
54.1 |
61.2 |
10.4.6 | Locked
Cycle Testing |
A
total of 11 locked cycle tests were completed on the main composites as part of the PFS/FS characterization program. Single tests were
completed on the BL-0835 composites (Primary Sul and Enriched Sul), while the BL-0882 composites had two or three tests completed. A
summary of the various LCT conditions is given in Table 10.31 below. All tests were completed using a primary grind of 80% -90 µm.
Most
of these tests used 2 kg test charges, with the last two using 4 kg charges to boost metal units in the cleaner circuit for improved
grade control.
Table
10.31: Locked Cycle Test Conditions |
Composite |
Regrind
p80 |
Lime
gpt |
CMC |
PFSDB |
7150 |
MIBC |
H57 |
Primary
Sul |
32µm |
275 |
- |
3.5 |
3.5 |
21 |
50 |
Enriched
Sul |
25µm |
315 |
- |
3.5 |
3.5 |
63 |
80 |
C1-SS |
24µm |
200 |
60 |
10 |
10 |
49 |
- |
31µm |
200 |
80 |
10 |
10 |
21 |
- |
C2-DS |
35µm |
380 |
30 |
10.5 |
10.5 |
175 |
- |
26µm |
410 |
35 |
10.5 |
10.5 |
147 |
40 |
26µm |
230 |
- |
10.5 |
10.5 |
40 |
75 |
C3-OX |
19µm |
200 |
|
10.5 |
10.5 |
63 |
- |
26µm |
200 |
|
10.5 |
10.5 |
14 |
80 |
C4-MIX |
26µm |
200 |
|
10.5 |
10.5 |
77 |
- |
18µm |
200 |
50 |
10.5 |
10.5 |
56 |
- |
 |
92 |
Table
10.32: Locked Cycle Test Results |
Composite |
Final
Concentrate Grade |
Final
Concentrate Recovery |
%
Cu |
gpt
Au |
gpt
Ag |
Cu
% |
Au
% |
Ag
% |
Primary
Sul |
15.9 |
31 |
65 |
88.4 |
67.2 |
86.9 |
Enriched
Sul |
25.8 |
93 |
145 |
85.7 |
69.6 |
69.2 |
C1-SS |
18.3 |
51 |
52 |
81.9 |
66.1 |
76.1 |
18.9 |
56 |
58 |
81.9 |
65.7 |
52.8 |
C2-DS |
22.3 |
49 |
84 |
84.2 |
67.6 |
54.6 |
17.4 |
44 |
76 |
87.5 |
74.4 |
60.7 |
19.9 |
50 |
76 |
88.5 |
73.8 |
83.6 |
C3-OX |
28.0 |
292 |
144 |
19.1 |
62.2 |
54.8 |
28.7 |
203 |
138 |
21.6 |
54.2 |
55.1 |
C4-MIX |
16.8 |
121 |
82 |
33.4 |
59.2 |
53.9 |
22.7 |
156 |
103 |
34.8 |
59.8 |
48.7 |
The
results of this LCT work showed good consistency within the different composite types and above-average performance considering the head
grades. Copper recoveries were once more heavily dependent upon the ratio of copper oxide to total copper content.
10.4.7 | LCT
Final Concentrate Analysis |
Samples
of final concentrate from each of the BL-0882 LCT’s were submitted for minor element analysis. Results are summarized in the below
Table 10.33. These results generally indicate that a relatively clean copper concentrate will be produced, and commercial penalties from
smelters will be very rare.
 |
93 |
Table
10.33: Locked Cycle Test Minor Element Analysis |

 |
94 |
10.4.8 | LCT
Tailings Dewatering |
The
final tailing slurry from a selection of the main composite LCTs was used as feed for a settling and filtration testwork program at BML.
The work included flocculant scoping and static settling tests, with subsequent pressure filtration testing of thickened slurries.
The
scoping tests considered several well-known flocculant products and tested different addition rates and pH adjustments. The work demonstrated
that a very high molecular weight, slightly anionic polyacrylamide flocculant (Magnafloc 10), was effective and that adding lime helped
improve the supernatant clarity.
Therefore,
the static settling test series was completed using the MF10 flocculant and a pH adjustment to 11.0 with lime. Different flocculant dosages
give a variety of settling rates and final underflow densities. Underflow density of between 55% and 63% solids was achievable, although
rheology tests were not conducted to determine pumping characteristics at these densities.
In
general, a 20-40 gpt flocculant addition was deemed sufficient to obtain good settling rates, and the addition of lime to thickener feed
helped to give superior overflow clarities.
Table
10.34: Static Settling Test Results |

Batches
of tailing slurry from 3 of the BL-0882 LCTs were thickened to 60% solids then presented to a lab scale pressure filtration unit equipped
with membrane squeeze and air-blow. The results of this work are plotted on a single chart (Figure 10.6), showing the filtration rate
vs cake moisture trends for each composite.
 |
95 |

Figure
10.6: Pressure Filtration Testwork Results
Each
sample gives a slightly different response, with the Deep Sulfide (DS) sample providing the highest filtration rates at the target moisture
of 14% (w/w). As this composite represents mineralization that will dominate the reserve tonnage, the DS data is suitable for design
purposes, but with the understanding that occasional periods of additional mixed or oxide mineralization might de-rate the filtration
process.
10.5 | Base
Metallurgical Labs (BL-0980 & 1066, 2022) |
As
the PFS-level geometallurgical studies continued at BML, it became apparent that the average reserve grade for the Project was somewhat
lower than composite grades in earlier programs. BL-0980 and 1066 were therefore appended to address head grade-related concerns. Lower-grade
drill core intervals were targeted as part of the sample selection algorithm, and composite grades reflect this. BL-980 and BL-1066 sample
sets were shipped on separate dates.
For
the BL-980 program, 21 samples of ½-core and two samples of reject material totaling 100 kg were selected from six holes within
the PFS pit outline. For BL-1066, 22 samples of ½-core and four samples of RC material (6 mesh) totaling 91 kg were selected from
eight holes within the PFS pit outline.
 |
96 |

Figure
10.7: BL-980 Typical Sample
Replicate
cuts were removed from each composite sample as part of the blending, crushing, and subsampling process. Average head assays for each
pair are summarized in Table 10.35.
Table
10.35: BL-0980 Head Assay |
Ref |
Description |
%
CuT |
%
CuOx |
%CuCN |
%Fe |
%S |
gpt
Ag |
gpt
Au |
LG
Comp |
BL-980
Master Comp |
0.18 |
0.002 |
0.012 |
3.8 |
0.45 |
0.9 |
0.45 |
LG
Comp 2 |
BL-1066
Master Comp |
0.16 |
0.01 |
0.03 |
3.2 |
0.38 |
0.9 |
0.35 |
Of
note, the most significant pay metals, gold, and copper, are in close agreement with the life of mine PFS reserve grades. Secondary sulfide
and oxide copper species were slightly higher in the second composite (LG Comp 2) but still represent minor fractions. As such, these
composites are useful reference points for performance predictions.
The
first LG composite was subjected to a QEMScan PMA analysis, giving quantitative bulk modal mineralogy and liberation data. The modal
data is detailed in the BML report but is very similar to previous studies, albeit with a lower sulfide content (1.1% in this sample).
The copper deportment data shows Chalcopyrite as the dominant copper mineral (92.2%), with Bornite and Chalcocite/Covellite as minor
species (3.5% and 4.2% respectively). Only traces of oxide copper minerals were noted, making this composite sample a deep sulfide equivalent
with limited copper recovery downside.
 |
97 |
Sub-samples
of half-core were selected from the LG Comp crushing/blending process and tested in-house at BML. Results are summarized in Table 10.36
below.
Table
10.36: Comminution Test work Results |
Ref |
Description |
SG |
BWi
(kWh/t)* |
DWi
(kWh/m3) |
A
x b |
ta |
SCSE
(kWh/t)* |
LG
Comp |
BL-980
Master Comp |
2.72 |
14.8 |
8.4 |
32.4 |
0.31 |
10.96 |
*
Note: data is based on metric tonnes.
The
A x b results give an indication of resistance to impact breakage and, in this case, show that the LG Sulfide composite is on the competent
side of average, similar to the results of previous work.
10
kg cleaner tests were conducted on the LG composite to calibrate equipment and fine-tune locked cycle test conditions. A 10 kg charge
size was used in this work, as the larger, rougher concentrate mass tends to help with cleaner circuit grade control. A primary grind
of 90 µm was used in all tests.
Table
10.37: Batch Cleaner Tests on LG Composites |
Composite |
Final
Concentrate Grade |
Final
Concentrate Recovery |
%
Cu |
gpt
Au |
gpt
Ag |
Cu
% |
Au
% |
Ag
% |
LG
COMP |
18.3 |
42.8 |
97 |
87.2 |
63.4 |
89.7 |
25.1 |
59.7 |
114 |
74.4 |
53.4 |
60.2 |
LG
COMP 2 |
16.8 |
34.7 |
81 |
85.6 |
67.8 |
59.6 |
24.4 |
45.0 |
118 |
82.0 |
58.4 |
51.3 |
Copper
concentrate grades were reasonable in most tests, with the first LG COMP 2 test being a little off-spec. Due to the lower head grade
in these samples, copper and gold recoveries tended to be slightly lower than past performance.
10.5.5 | Locked
Cycle Testing |
2
x 10-kg locked cycle tests were completed on the LG composites.
A
summary of the various LCT conditions is given in Table 10.38. All tests were completed using a primary grind of 80% -90 µm, and
pH was controlled to 9.5 using lime. 10-kg test charges were used for these tests, allowing far greater control over mass pull in the
cleaner circuit. These larger LCTs utilized a 40-litre rougher flotation cell, and the normal 4-lire D12 was used for cleaner flotation.
Table
10.38: LG Composites, LCT Conditions |
Composite |
Regrind
p80 |
Lime
gpt |
PFSDP |
7150 |
MIBC |
H57 |
LG
COMP |
28
µm |
245 |
10 |
10 |
80 |
- |
LG
COMP 2 |
17
µm |
265 |
8.5 |
7.5 |
90 |
8 |
 |
98 |
Table
10.39: LG Composites, LCT Results |
Composite |
Mass
Pull % |
Final
Concentrate Grade |
Final
Concentrate Recovery |
%
Cu |
gpt
Au |
gpt
Ag |
Cu
% |
Au
% |
Ag
% |
LG
COMP |
0.9 |
17.6 |
40.4 |
91 |
86.5 |
65.1 |
75.8 |
LG
COMP 2 |
0.6 |
24.9 |
47.9 |
116 |
86.6 |
67.0 |
70.7 |
The
results of the LCT work showed that, as expected, the lower head grade samples tend to give rise to slightly lower recoveries. The BL-980
LCT gave a slightly disappointing result, with similar recoveries despite the higher mass pull (and lower copper concentrate grade).
Throughout this test, the 40-litre rougher flotation cell was challenged by inferior froth characteristics, whereas in the LG COMP 2
test, this issue was addressed by adding a stronger frother in addition to the MIBC. This helped froth stability and improved performance.
The LG COMP 2 LCT is judged to be a better representation of flotation circuit performance for the bulk of the deposit (i.e., primary
sulfide material) at the life of mine average head grades. Based on the low-grade LCT result, Wells suggests that an 18% Cu concentrate
grade and a 69% gold recovery should be used in the financial analysis for low-grade material. Two new low-grade samples must be prepared
to confirm this result and investigate a finer regrind.
10.5.6 | LCT
Final Concentrate Analysis |
Samples
of final concentrate from the BL-0980 and BL-1066 LCTs were submitted for minor element analysis. Results are summarized in Table 10.40
and Table 10.41 below. As with previous results, this data indicates that a clean copper concentrate can be produced, and commercial
penalties from smelters will be very rare.
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99 |
Table
10.40: Locked Cycle Test Minor Element Analysis BL-0980
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100 |
Table
10.41: Locked Cycle Test Minor Element Analysis BL-1066
10.6 | METALLURGICAL
DISCUSSION |
Various
companies carried out metallurgical test programs between 1985 and 2022. The work helped identify froth flotation as the preferred processing
technology for the Project, and the QP (Wells) concurs with that decision.
 |
101 |
A
good deal of effort was put into identifying and understanding factors affecting the flowsheet performance, with reagent recipes and
grind targets modified and progressively optimized. The selection of samples for composites and the style of mineralization within the
deposit were also given considerable focus, resulting in a series of tests between 2020 and 2022. A brief chronology of the work and
sample selection criteria is given below.
The
2009-2010 work at SGS Lakefield characterized composite samples of sulfide and oxide mineralization and indicated gold and copper recovery
of 68% and 77%, respectively, for sulfide and 55% gold and 10% copper recovery for oxide. Copper concentrate grade was 25-26% Cu for
sulfide and 15% Cu for the Oxide composite. Whilst lower in copper, this oxide concentrate had an exceptionally high gold content of
380 gpt Au. By industry standards, these grades and recoveries would be considered reasonable, considering the relatively low copper
head grade and the mineralogy.
The
subsequent 2020 test program at KCA scheduled work on drill core samples from seven dedicated metallurgical holes, which were used to
produce three main composites, namely high-grade oxide, oxide, and sulfide. The work program commenced with the high-grade oxide test,
and these tests produced results that were better than anticipated, considering the high proportion of non-sulfide copper minerals present.
Concentrate grades of 25% copper, with gold and copper recoveries of 69% and 56%, respectively, were achieved from open circuit cleaner
tests. A 3% overall increase in copper recovery (included in the 56%) was achieved by adding a gravity circuit, which recovered coarse,
liberated native copper from flotation tailings. It was later discovered that the High-Grade Oxide zone represents only a small part
of the deposit (less than 2% by weight), so the motivation for this additional processing step disappeared, and the step was dropped
from future programs.
Following
the encouraging results on the high-grade oxide composite, test work then commenced in parallel on the Oxide and Sulfide composites,
which represent about 6-8% and 90%, respectively, of the deposit. The initial rougher tests, using conditions established for the High-Grade
Oxide, gave high recoveries of copper (90%), gold (74%), and silver (61%), albeit with a higher mass recovery and low copper concentrate
grade. These results encouraged the commencement of cleaner tests, which consistently encountered difficulty upgrading the concentrates
to a commercially acceptable grade. Attempts to increase the final cleaner concentrate grade above 20% Cu resulted in unacceptable copper,
gold, and silver losses to the tailings streams.
A
single locked cycle test was attempted on the high-grade oxide composite, and this, too, resulted in a low final concentrate grade (around
10% Cu).
At
this point (April 2021), U.S. Gold decided to transfer samples to BML in Kamloops, Canada. Test work at BML commenced shortly thereafter,
and after adjusting the reagent recipe, they could replicate the recoveries and concentrate grades achieved by SGS in 2010. A full test
program was then initiated at BML to test all three composites, including rougher optimization tests, rougher-cleaner open cycle tests,
and finally, a series of LCTs.
This
work was successful and confirmed the favorable mineralogy reported earlier by FLSmidth. The principal difference between BML and KCA
was the much lower collector addition at BML, which essentially used “starvation” quantities of these chemicals. As confirmation,
KCA was able to improve its results in line with SGS and BML after switching to the revised reagent schedule.
 |
102 |
As
the flowsheet development continued at BML, it was noted that the Sulfide composite contained 10-15% non-sulfide copper minerals that
originated from a mixed ore zone within the deposit. This likely accounted for some of the difficulties experienced with copper recoveries.
A second Sulfide composite (Sulfide Comp 2) was prepared, avoiding the mixed zone, which immediately realized improved recoveries.
A
variability program included comminution testing of 10 samples and open circuit flotation testing of 29 samples. The variability work
forms a basis for geometallurgical modelling discussed elsewhere in this document.
A
program of locked cycle tests was completed on composites of oxide, mixed shallow sulfide, and deep sulfide mineralization. These results
are incorporated into the variability data set and highlighted within the scatter plots as higher-confidence data points.
Finally,
several tests were run on lower-grade sulfide samples to ensure the data set covered the grades noted in PFS mine plans. Two locked-cycle
tests were run on low-grade composites.
The
results of the variability batch cleaner test and locked cycle test have been used to prepare metallurgical models for incorporation
into mine plans and project cashflows. The PFS recovery model is summarized in Section 14.0.
A
significant sample mass has been shipped from the site to the various metallurgical laboratories:
| ● | 2008
– roughly 500 kg of oxide, mixed and sulfide ½-core from an unknown number of
drill holes. |
| ● | 2020
– roughly 800 kg of oxide, mixed and sulfide ½-core from seven drillholes. |
| ● | 2021
– roughly 100 kg of oxide and sulfide from multiple drillholes. |
| ● | 2022
- roughly 200 kg of lower-grade sulfide from multiple drillholes. |
Sample
mass is considered sufficient, and sample location is sufficiently diverse spatially to achieve good coverage. Sampled holes are generally
within or near the Pre-Feasibility study pit shell.
No
relationships linking sample location to metallurgical recovery have been discovered. As geometallurgical programs are developed, this
aspect could be examined, although all indications are that samples are metallurgically consistent within the different oxidation zones.
Sample
grades have tended to be high, and most composites have had grades significantly higher than average reserve grades. This fact drove
the selection of samples for the two final LG composites, tested during the summer of 2022 at BML.
Quantitative
mineralogical work by SGS, FLSmidth, and the BML has improved understanding of copper deportment throughout the deposit, and currently
represents a good foundation for more comprehensive geometallurgical modelling that would ideally be carried through into operations.
The work by FLSmidth in 2021 provides some additional insight into gold deportment and liberation.
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103 |
Copper
is primarily found in chalcopyrite, with lesser amounts in secondary sulfides such as bornite or chalcocite, or in oxides such as chrysocolla,
cuprite or clays/micas. In a small, centrally located high grade oxide zone, native copper is common, although this is only noted occasionally
through the bulk of the deposit. The metallurgical response of samples from different locations within the deposit depends upon the specific
blend of oxide and sulfide copper minerals.
The
main sulfide gangue component within the deposit is pyrite, although this generally occurs in lower concentrations (relative to copper)
than in many porphyry deposits. Base metal sulfides such as sphalerite and galena are noted in trace concentrations. Although these recover
to the flotation concentrate, they do so in amounts that avoid smelter penalties.
The
host rocks are mainly feldspar (about 45%), quartz (about 25%), and mica (about 14%).
Liberation
data is variable but suggests that copper sulfides are not well liberated at a P80 of 100-125 µm, and therefore, rougher
concentrate regrinding is an essential aspect of the flowsheet. In general, the very small quantities of rougher concentrate generated
in laboratory scale tests make concentrate regrind optimization studies difficult, but the program has settled on a regrind P80 target
in the 20-25 µm size range for the PFS. Whilst this is a workable range, the opportunity to run the cleaner flotation circuit with
a finer grind is significant.
By
the grades involved, the statistical significance of gold deportment data is less than that for the sulfides. However, the measurements
made by FLSmidth suggest that most gold/silver particles are less than 10 µm in size and locked or associated with various sulfides,
silicates and oxides. Again, much finer (likely uneconomic) grinds are necessary to realize significant performance gains.
The
primary grind used in most flotation tests at SGS, KCA, and BML has been in the P80 range of 75 to 125 µm. Early work
by SGS concluded that the optimum (cost vs benefit) primary grind appeared to be between 90 µm and 100 µm.
As
discussed above, the measurements provided by mineralogical studies indicate that both the copper sulfides and the gold/silver/electrum
are fine-grained, which points to a relatively fine primary grind. More recent results from studies by BML indicated the optimum grind
to be between 75 µm and 90 µm, although there is some variability. Metallurgical performance appears to deteriorate rather
quickly at grinds coarser than 100 µm.
The
PFS included an order of magnitude trade-off study for five P80 grind sizes that evaluated the recovery of copper and gold
and capital and operating costs. The fundamentals of this analysis have not changed, and the results of this 2021 trade-off study are
summarized in Table 10.42 below.
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104 |
Table
10.42: Evaluation of the Primary Grind |
p80
(µm) |
differential
capex
US$M |
differential
opex,
US$/t |
Au
recovery (%) |
Cu
recovery (%) |
differential
NPV,
US$M |
80 |
+1.1 |
+0.07 |
73.5 |
86.0 |
+21M |
86 |
+0.8 |
+0.05 |
72.5 |
85.5 |
+6M |
90 |
Base
Case |
0 |
72.0 |
85.0 |
0 |
106 |
-0.5 |
-0.06 |
69.0 |
84.0 |
-37M |
120 |
-1.9 |
-0.12 |
67.5 |
83.0 |
-58M |
Copper
recovery is relatively insensitive to grind size. However, gold recovery drops more rapidly at coarser sizes, which is a major revenue
driver. The NPV is similar for P80s between 80 and 90 µm. At coarser grind sizes, the revenue drops quite rapidly due
to reduced gold recovery.
A
P80 of 90 µm was selected for the PFS process plant design and subsequent work in 2022 has not deviated from this assertion.
A finer grind would surely improve the copper and gold grade vs. recovery relationship, but grinding costs, together with the negative
impact of fines on the tailing filtration process effectively cancel these gains.
Further
optimization of the grind can form part of more detailed post-PFS economic optimizations.
10.6.5 | Rougher
Concentrate Regrind |
Much
of the recent metallurgical test work has targeted a regrind P80 of between 20 µm and 25 µm, although rougher
concentrate mass pull variability has resulted in regrind P80 of up to 40 µm on occasion. Mineralogical studies by BML
suggest that a regrind P80 of 15-20 µm might provide performance gains.
Although
somewhat limited by sample mass, implementing larger-scale flotation tests (10 kg or larger feed mass) will allow better control of the
laboratory regrinding process, and this data will allow a more accurate assessment of regrinding requirements.
10.6.6 | Gravity
Concentration |
Although
laboratory-scale gravity tests were unsuccessful for the KCA Oxide composite and the Sulfide composite, a reasonable gravity concentrate
was achieved for the Hole 4 high-grade oxide composite due to of higher gold grades and significant concentrations of native copper.
Adding gravity to a standard flotation circuit results in an overall copper recovery increase of 3% for the Hole 4 sample.
Despite
the reasonable Hole 4 performance, comparisons of overall flowsheet performance with and without the gravity stage show similar gold
and copper performance, suggesting that a simple “no gravity” approach will be most effective. Gravity has not been included
in the Pre-Feasibility Study flowsheet design.
Certain
elements of the flotation circuit, such as the flowsheet configuration and the primary grind, have remained consistent since the SGS
work in 2008/9. Reagent recipes and dosages have changed, with the most notable change being the reduction in collector dosage to
starvation levels ahead of cleaning. This change helped improve selectivity within the cleaner circuit and removed the need for
excessive depressant addition, which in turn helped to improve recovery.
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105 |
pH
adjustment to levels >8.5 helps to depress the flotation of pyrite, although, for many tests, the sulfur recovery suggests that pyrite
has been well-recovered to concentrate. The lime added to raise pH also helps with froth stability, and this, in turn, can assist flotation
performance. The calcium ions in solution from lime addition can also help with settling and filtration.
CMC
addition in certain areas of the deposit (where chlorite and/or talc may be present in minor concentrations) may be required, although
it is presently assumed that any areas containing active gangue minerals will be diluted down by surrounding material. The addition of
CMC can be harmful to gold recovery.
Flotation
kinetics are quite reasonable, so flotation residence times are not excessive, and the primary flotation circuit need not be enormous
to achieve low tailing grades. High sulfide recoveries have been achieved at very high upgrade ratios for several composites, which speaks
to the host rock's non-floatable nature (feldspar and quartz).
The
regrind target is discussed above, but ultra-fine regrinds followed by modern fine particle cleaner flotation technology (Jameson cell,
column flotation, etc.) should be viewed as an opportunity to shift the grade vs. recovery curve into positive territory. Cavitation
reactor technology such as the MACH reactor might also be considered.
10.6.8 | Tailings
and Concentrate Dewatering |
The
project flowsheet includes a dewatering circuit designed to filter tailings and deposit the plant residues as a 14% moisture filter cake.
This eliminates a wet tailings dam and reduces the demand for fresh make-up water.
Vacuum
and pressure filtration testwork was carried out on samples of LCT tailing at Pocock in 2021 as part of the KCA metallurgical program
and again in 2022 at BML using a laboratory-scale pressure filtration unit to dewater samples of LCT Tailings. The somewhat fine primary
grind used in these tests reduces tailing filtration rates, and vacuum filtration tests all produced cake with high moisture levels.
Pressure filtration is therefore judged to be the only suitable process for dewatering tailings to the specified 14% moisture levels,
deemed necessary to aid site water balances.
At
a primary P80 of 90-100 µm, the tailings filter well uses pressure filtration technology. At finer grinds, performance
is expected to deteriorate somewhat.
Flotation
concentrate masses generated in laboratory scale tests are particularly small when lower-grade mineralization is tested. For this reason,
no specific pressure filtration testwork has been completed for the Project to date. However, equipment vendors carry significant databases
for this type of material and are comfortable sizing equipment based on regrind P80, mineralogical composition, and pH alone.
The PFS has assumed that a final concentrate product can be dewatered to 8 or 9% moisture before bagging in FIBC containers.
 |
106 |
10.6.9 | Jameson
Flotation Cell Testwork |
In
2024, U.S. Gold and Glencore Technologies discussed the possible application of Jameson Flotation Cells in the plant flowsheet. Glencore
claimed that the Jameson technology improved metallurgical performance (concentrate grade and/or recovery) and potentially reduced installed
capital cost and operating costs.
A
proposal was requested from Base Metals Laboratory (BML) in Kamloops, Canada, with input from Glencore, to evaluate Jameson flotation.
Two composites were prepared, "Sulfide Composite" (0.30%Cu, 0.9 g/t Au) and "Sulfide Composite 2" (0.36%Cu, 0.9 g/t
Au), using available material in the Wyoming core shed. These composites were prepared using the same or similar core to the previous
test programs at BML in 2021-22.
The
test work commenced in September 2024 and was completed at the end of November 2024, with the final report issued in January 2025. This
was too late for thorough evaluation and inclusion in this PFS.
The
testwork comprised five stages of work, which were:
| ● | Conventional
rougher flotation tests, |
| ● | Conventional
three-stage cleaner tests, |
| ● | Finally,
rougher tests were performed with the Jameson L150 Pilot Unit. |
The
results are provided in the January 2025 BML Report, Project 1702, and are summarized here.
Conventional
Rougher Tests were carried out to ensure that the samples responded similarly to previous sulfide composites. Results summarized in Table
10.43 below.
Table
10.43: Conventional Rougher Summarized Test Results |
|
%Wt |
%Cu |
g/t
Ag |
g/t
Au |
Recovery
%Cu |
Recovery
%Ag |
Recovery
%Au |
Sulfide
Comp, Ro Conc |
5.0 |
5.27 |
18.4 |
13.5 |
89.0 |
76.2 |
75.5 |
Sulfide
Comp2, Ro Conc |
6.6 |
4.80 |
12.2 |
9.4 |
89.5 |
74.3 |
74.2 |
These
recoveries are in line with previous test work. Collectors were PF4782 and PF7150, with H57 and MIBC frothers at pH9.1, and nominal grinds
of 90u and 25u. These conditions were then applied to all tests.
Table
10.44: Conventional Cleaner Tests |
|
%Wt |
%Cu |
g/t
Ag |
g/t
Au |
Recovery
%Cu |
Recovery
%Ag |
Recovery
%Au |
|
Sulfide
Comp, Cleaner Conc |
1.0 |
23.4 |
84.6 |
91.6 |
79.5 |
64.7 |
72.3 |
|
Sulfide
Comp 2, Cleaner Conc |
1.2 |
22.6 |
60.2 |
50.8 |
84.5 |
74.8 |
68.5 |
|
Again,
these results confirm previous work. They suggest gold recovery of 70-75% should be possible at the lower target concentrate grade of
18%Cu.
 |
107 |
Glencore
specifically developed this test procedure to predict performance in Jameson cells.
Table
10.45: Jameson Dilution Tests |
|
%Wt |
%Cu |
g/t
Ag |
g/t
Au |
Recovery
%Cu |
Recovery
%Ag |
Recovery
%Au |
|
Sulfide
Comp, Ro Conc |
4.4 |
5.5 |
21.0 |
14.3 |
87.2 |
76.5 |
72.7 |
|
Sulfide
Comp 2, Ro Conc |
5.6 |
5.2 |
14.6 |
10.4 |
87.5 |
74.0 |
73.7 |
|
These
results are confirmation of and similar to the results of the conventional rougher tests.
Table
10.46: Locked Cyce Tests |
|
%Wt |
%Cu |
g/t
Ag |
g/t
Au |
Recovery
%Cu |
Recovery
%Ag |
Recovery
%Au |
|
Sulfide
Comp, Cleaner Conc |
0.9 |
25.1 |
90.0 |
63.7 |
83.0 |
81.0 |
64.8 |
|
Sulfide
Comp2, Cleaner Conc |
1.0 |
27.1 |
68.0 |
55.8 |
83.9 |
74.1 |
65.5 |
|
Note:
the high copper concentrate grade. Both results suggest a 68-70% gold recovery with an 18%Cu concentrate grade could be possible. The
regrind p80 was +/- 30u, now considered too coarse.
Glencore
provided a new L150 pilot unit for rougher tests. Only a limited program was possible as approximately 18-20 kg of material is required
for each test. After two trials, L150 tests were completed on both samples.
Table
10.47: L150 Pilot Unit |
|
%Wt |
%Cu |
g/t
Au |
Recovery
%Cu |
Recovery
%Au |
Sulfide
Comp, Ro Conc |
8.4 |
2.93 |
8.24 |
85.2 |
71.0 |
Sulfide
Comp2, Ro Conc |
6.0 |
4.35 |
9.07 |
88.0 |
67.4 |
These
results might be disappointing after the previous rougher, cleaner, and dilution tests. Mitigating this were the relative inexperience
of operating staff, limited material to optimize, and some issues associated with commissioning new equipment.
Based
on these results, Wells considers that Jameson might not offer improved metallurgy for Copper King. A study commissioned by Glencore
with an independent engineer has shown that capital and operating cost advantages exist with a Jameson circuit. Also, Glencore has offered
to do a more comprehensive test work program at their own laboratory. This would, however, require the preparation of new, larger composites
(preferably with more representative copper and gold LOM grades). Application of Jameson technology may, therefore, be worthy of further
study if time allows.
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108 |
11.0 | Mineral
Resource Estimates |
This
Section has been updated from the “S-K 1300 Technical Report Summary CK Gold Project,” dated Dec. 1, 2021, to include new
drillhole datasets.
The
most recent CK resource estimate for gold, copper, and silver was last updated by Gustavson Associates in the report, "S-K 1300
Technical Report Summary CK Gold Project," dated December 1, 2021. The 2021 Mineral Resource Estimate (MRE) incorporated data from
35 infill drillholes, including 12 reverse circulation holes totaling 12,340 ft (3,760 m) and 23 core holes totaling 19,057 ft (5,810
m) completed by U.S. Gold, as well as five additional reverse circulation holes totaling 2,370 ft (830 m) and two rotary holes totaling
380 ft (115 m) intended as monitoring wells, drilled between 2017 and 2020. Drilling completed by U.S. Gold in 2021, which totaled 29,562
ft (9,010 m) in 24 reverse circulation and core holes, was ongoing and incomplete during the development of the 2021 MRE but is now included
in this update.
Mark
Shutty, CPG, Principal of Drift Geo LLC, used Leapfrog Geo/Edge software (2024.1) to construct the geologic models of the CK Gold deposit
for the updated MRE. The constraining pit shell and in-pit resource reporting were completed using MinePlan (v16.2.1). This updated MRE
includes all available drillhole datasets, including the previously unavailable 2021 drilling data completed by U.S. Gold.
A
three-dimensional (3D) block model was constructed using the following standard procedures:
| ● | Import
topographic data to create a digital terrain model of the current surface topography. |
| ● | Import
and review drillhole interval datasets using Leapfrog Geo tools. |
| ● | Construct
implicit geological and mineralized domain models using Leapfrog, interpret oxidation state
based on visual logging, and assign specific gravity values. |
| ● | Evaluate
and model experimental variograms aligned with observed mineral trends, establishing ranges
of sample influence for grade estimation. |
| ● | Estimate
and validate gold, copper, and silver grades within the 3D block model. |
| ● | Classify
mineral resources into confidence categories: Measured, Indicated, and Inferred. |
| ● | Apply
economic constraints for resource reporting within an optimized pit shell. |
Beginning
in 2020, U.S. Gold facilitated the relogging of all available legacy drill core to ensure consistent interpretation of rock types across
the 2020 and 2021 drilling programs. U.S. Gold's geologic datasets were used to evaluate samples and construct 3D geological models in
Leapfrog. The lithologic model predominantly consists of granodiorite (GD), with discrete occurrences of mylonite (MYL) and potassic-altered
granodiorite (GDK). Mafic dykes, pegmatites and veins are relatively small bodies, and the drilling density is insufficient to model
these as throughgoing features. Therefore, mafic dyke bodies were constructed in Leapfrog as discrete volumes and pegmatites were not
modeled and assigned the host rock type.
The
primary lithologic model for the CK Gold Project includes Proterozoic granodiorite (GD), with varying intensities of potassic alteration
(GDK) and mylonitic fabrics (MYL). Mafic dikes (MD), younger pegmatites
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109 |
(PEG),
and undifferentiated veins (VN) represent a smaller volume within the mineralized granodiorite domain. Unmineralized domains were also
modeled, including a metasediment unit (MSED) east of the Copper King Fault and overlying Quaternary cover (QC).
Leapfrog
software was used to aggregate and model the GDK, MYL, and MD intrusive sub-units within the GD domain. The CK deposit trends NW-SE (290°-110°),
and the general orientation for all modeled intrusive domains is at -70°, 020° (dip, dip direction). An anisotropy of 3:3:1 (ratio
of maximum, intermediate, minimum) was applied for the GD domain, while an anisotropy of 5:5:1 was used for the internal GDK and MYL
lithologies.
The
geological model was employed to assign varying rock densities throughout the block model and establish an eligible volume for grade
estimation. Longitudinal and cross-sectional reviews of the deposit show that mineralization generally follows the anisotropies of the
lithologies, with most mineralization occurring within the central portion of the deposit. Figure 11.1.

Figure
11.1: Vertical Section Looking 030deg Showing Lithologic Boundaries and Drillhole Grades (AUEQ gpt). 2021 drillholes are displayed with
black collar points and downhole traces
An
oxidation model was created using drillhole data in Leapfrog. Surfaces were generated to produce oxide, mixed, and sulfide solids based
on logging in the database, Figure 11.2. A global isometric trend was applied for all surfaces. The oxidation methodology is discussed
in Section 11.3.
 |
110 |

Figure
11.2: Vertical Section Looking 030° Showing Oxidation Boundaries and Drillhole Weathering. 2021 drillholes are displayed with black
collar points and downhole traces
U.S.
Gold geologists modeled fault surfaces in Leapfrog using surface exposure, geophysical survey data, and downhole televiewer data. Structure
orientation data from the televiewer reconciliation work, interpreted by Piteau Associates, facilitated U.S. Gold’s interpretation
of additional faults for evaluation within the model space Figure 11.3. Mineralized drill samples within the fault-bound blocks were
reviewed visually and statistically.
CK
mineralization is bounded by a hard structural/lithologic boundary to the east by the Copper King Fault and constrained to the north,
northwest, and west by more ambiguous NW Fault, NE 1 Fault, and West Block Faults, respectively. While the NE 2 Fault is projected to
intersect the CK deposit, it remains a poorly defined feature, characterized by drillhole data as a broad zone of deeper oxidation and
lower-grade mineralization Figure 11.4 and Figure 11.5. Therefore, bounding structures were used to constrain a single mineralized domain
that accommodates the influence of the internal NE 2 Fault on mineralization and oxidation for use in the resource model.
 |
111 |

Figure
11.3: Fault Map with Drillhole Grades (≥ 1.5 gpt AUEQ). 2021 drillholes are displayed with thick black downhole traces

Figure
11.4: Vertical Section A-A’ Looking 030° Showing Location of Interpreted NE 2 Fault Zone, Oxidation Boundaries and Drillhole
Grades (AUEQ gpt). 2021 drillholes are displayed with black collar points and downhole traces
 |
112 |
A
hybrid numerical indicator model was developed using a calculated gold equivalent (AUEQ) variable at a 0.2 gpt cut-off. The model incorporates
a varying structural trend that aligns with bounding faults, observed mineralization trends, and modeled intrusive anisotropies. This
mineralization model represents a single domain that constrains estimated mineral resources within the modeled intrusive rock complex.
The
AUEQ variable was calculated in Leapfrog using capped assay values for Au (AUCAP), Cu (CUCAP), and Ag (AGCAP), weighted by their respective
price ratios relative to gold. The calculation employed the following metal prices: $1,900.00 USD/oz (Au), $23.00 USD/oz (Ag), and $4.00
USD/lb (Cu). The formula is as follows:
| ● | AUEQ=[AUCAP]+([AGCAP]×0.01)+([CUCAP]×1.67) |
The
capping methodology is discussed in detail in Section 11.8.

Figure
11.5: Vertical Section Looking 030° Showing Mineralized Domain, Modeled Oxidation, Structures and Drillhole Grades (AUEQ gpt). 2021
drillholes are displayed with black collar points and downhole traces
Metallurgical
testing of mineralized rock indicates that sulfide recovery is a function of oxidation state. During core logging, geologists visually
estimated the oxidation state and categorized it as either oxide, mixed, or sulfide. The oxidation boundary contacts were modeled in
Leapfrog to encompass logged oxidation intervals and modeled structures, resulting in a series of surfaces used to code the block model.
 |
113 |
11.4 | Block
Model Orientation and Dimensions |
A
3D model with 20 ft x 20 ft x 30 ft block dimensions was defined to accommodate the CK deposit and optimization pit shell while facilitating
the use of a 30’ bench height mining unit. All work was conducted using the NAD83 Wyoming State Plane East coordinate reference
system, using imperial units of feet. The block model maintains a north-south and east-west orientation with no rotation and is not sub-blocked.
The block model dimensions, and model limits are shown in Table 11.1.
Table
11.1: Block Model Dimensions |
Parameter |
Minimum |
Maximum |
Unit
Block Size |
Number
of Blocks |
Northing |
233,2000 |
237,000 |
20 |
250 |
Easting |
648,810 |
653,810 |
20 |
200 |
Elevation |
5,090 |
7,400 |
30 |
977 |
Nominal
sample lengths vary by drill program, but drillholes used in the resource model have a global mean sample length of 5.1 ft. Capped assay
intervals were composited to 10-foot fixed-length intervals within the mineralized domain for use through Ordinary Kriging estimation,
described in Section 11.10, with the model’s block size (20’x20’x30’). This method computes 10-foot composite
intervals down each drillhole, and length-weight averages the portions of assay intervals that fall within the 10-foot interval. Composites
were broken at the mineralized domain boundary using a 50% threshold, with specified handling of residual lengths of less than 5 ft to
be added to the previous interval. Descriptive statistics of lengths and metal grades for the raw (original) and composited samples were
compared and reviewed in 3D as a means of validation, Table 11.2.
Table
11.2: Block Model Dimensions |
|
Au |
Cu |
Ag |
|
Composited |
Original |
Composited |
Original |
Composited |
Original |
Count |
8,099 |
15,819 |
8,099 |
15,819 |
6,015 |
12,393 |
Length |
80,926 |
80,910 |
80,926 |
80,910 |
60,141 |
59,948 |
Mean |
0.58 |
0.58 |
0.19 |
0.19 |
1.48 |
1.48 |
SD |
0.79 |
0.85 |
0.15 |
0.17 |
1.59 |
1.75 |
CV |
1.37 |
1.46 |
0.83 |
0.92 |
1.07 |
1.18 |
Variance |
0.63 |
0.71 |
0.02 |
0.03 |
2.53 |
3.08 |
Minimum |
0.00 |
0.00 |
0.00 |
0.00 |
0.05 |
0.05 |
Maximum |
9.94 |
11.00 |
3.00 |
3.00 |
20.00 |
20.00 |
11.6 | Exploratory
Data Analysis |
Raw
drillhole sample data and logged lithology data were reviewed visually within Leapfrog's 3D environment and statistically using a merged
assay-lithology dataset. Attributes such as drillhole program, type, operator, and location were evaluated against the primary Au and
Cu variables, as well as an Au equivalency variable (AUEQ), to identify a subset of drillholes suitable for resource estimation.
 |
114 |
In
the mineralized resource area, Caledonia's 1987-era drilling—comprising 25 vertical percussions rotary drillholes totaling 9,980
ft—was deemed unsuitable for inclusion in the resource model. This decision was based on potential sample contamination associated
with the drilling method, the vertical orientation of the drillholes, missing Cu assays, and the use of composited sample intervals.
Drillholes far outside the mineralized resource area were also excluded from the resource drillhole database.
Datasets
from 24 RC and core drillholes completed by U.S. Gold in 2021, totaling 29,562 ft (9,010 m), were integrated into the drillhole database.
These datasets were evaluated for compliance and utilized to refine the modeled geology, oxidation, and mineralization. All other drillholes
meeting the required criteria were included in the resource drillhole database Table 11.3.
Table
11.3: Drillhole Database Summary |
Operator
& Program |
Drillhole
Count |
Sum
of Drilling (ft) |
U.S.
Gold |
59 |
60,132 |
2021 |
24 |
29,562 |
2020 |
25 |
20,449 |
2018 |
8 |
8,090 |
2017 |
2 |
2030 |
Saratoga
Gold |
35 |
25,462 |
2008 |
8 |
7,167 |
2007 |
27 |
18,295 |
Mountain
Lake 1997 |
4 |
1,880 |
Compass
1994 |
25 |
9,202 |
Henrietta
1973 |
9 |
3,073 |
ASARCO/Henrietta
1973 |
1 |
700 |
ASARCO |
12 |
3,963 |
1970 |
7 |
2,563 |
1938 |
5 |
1,400 |
USBM |
3 |
2,630 |
Copper
King |
6 |
2,630 |
Grand
Total |
154 |
109,673 |
| 1. | Table
of drillholes used in the resource model. |
Furthermore,
metal grades were evaluated against logged and modeled lithologic, structural, and oxidation domains in combination with surface geology
and interpretive geophysical overlays to delineate mineralized trends and define domains for geostatistical analysis.
A
series of contact plots and box plots for the principal metals (Au and Cu) were generated to evaluate the distribution of these variables
within the CK’s major mineralized host rock types (GD, GDK, and MYL). Statistical box plots, Figure 11.6 and Figure 11.7, for the
intrusive host rocks reveal similarly elevated metal grades and contact plots.
 |
115 |

Figure
11.6: Log box Plot for AUCAP (gpt) Variable by Host Rock

Figure
11.7: Log Box Plot for CUCAP (%) Variable by Host Rock
 |
116 |
Figure
11.8 demonstrates gradational Au and Cu grade changes between the logged lithologies. The GD and MYL hosts generally have nearly identical
Au and Cu sample populations, while metal grades in the altered GDK host are lower.
GD
(l) GDK (r)
Contact
Plots |
 |
 |
GD
(l) MYL (r)
Contact
Plots |
 |
 |
MYL
(l) GDK (r)
Contact
Plots |
 |
 |
|
Au
(g/t) Contact Plots – 60’ range |
Cu
(%) Contact Plots – 60’ range |
Figure
11.8: Contact plot showing binned mean sample grades for the Au (blue) and Cu (orange) variables within a 60 ft distance
For
the resource model, the major mineralized rock types were grouped based on sample population similarities and shared lithologic genesis
(Figure 11.9).
 |
117 |
Granodiorite
(GD), potassic-altered granodiorite (GDK), and mylonite (MYL) are interpreted to originate from the same granodiorite protolith. MYL
exhibits superimposed mylonitic textures, while GDK displays gradational potassic alteration.
Approximately
94% of the deposit's total contained gold (Au) and copper (Cu) is hosted within samples logged as GD or MYL, while the remaining ~6%
is associated with GDK. Potassic-altered granodiorite (GDK) is primarily located at the periphery of the deposit's higher-grade GD-MYL
core.
Modeled
sediments to the east of the Copper King Fault are unmineralized and sparsely drilled.

Figure
11.9: Geology and Mineralization (transparent gray wireframe) with Drillhole Grades (gpt AUEQ). 2021 drillholes are displayed with black
collar points and downhole traces.
11.7 | Bulk
Density Determination |
There
are no records of bulk density measurements before 2007-2008, during which Saratoga performed 1,336 drill core sample density tests.
U.S. Gold later added 80 density measurements through their drilling programs, bringing the current bulk density database to 1,416 determinations.
Approximately
47% of the samples are from the primary mineralization host, granodiorite. The results reveal minimal variation in specific gravity with
depth and a small standard deviation for each rock type, indicating consistent bulk density characteristics across the deposit.
A
comparison of bulk density relative to depth for granodiorite is presented in Figure 11.10, the other rock types exhibit a similar uniformity
with depth.
 |
118 |

Figure
11.10: Density of Granodiorite vs Depth
The
bulk density values were converted to tonnage factor (st/ft3) and assigned to the block model by rock type, Table 11.4. The
core is generally whole “stick rock” with infrequent broken zones. Therefore, no deduction from density measurements to account
for fracture zones is warranted at this time and should continue to be monitored.
Table
11.4: Bulk Density Values by Rock Type |
Rock
Type |
#
of
Determinations |
Density
Average
(g/cm3) |
Std
Dev of Density |
Tonnage
Factor
(st/ft3) |
Granodiorite |
665 |
2.70 |
0.08 |
0.0843 |
Potassic-Altered
Granodiorite |
273 |
2.68 |
0.06 |
0.0837 |
Mafic
Dike |
55 |
2.81 |
0.10 |
0.088 |
Mylonite |
372 |
2.70 |
0.07 |
0.0843 |
Not
Logged |
13 |
2.69 |
0.10 |
0.0843 |
Pegmatite |
33 |
2.94 |
0.06 |
0.0821 |
Unknown |
5 |
2.70 |
0.10 |
0.0843 |
Total |
1,416 |
2.70 |
0.08 |
0.0843 |
 |
119 |
There
is no density data available for overburden. An SG value of 1.8 g/cm3 (0.0562 st/ft3 was assigned to blocks coded
as quaternary cover.
11.8 | Grade
Capping/Outlier Restrictions |
Raw
gold, copper, and silver assays were evaluated within the Resource drillhole database with histogram and probability plots to identify
statistical outliers. These data are generally reflective of a single sample population with few outliers. Outliers were examined to
ensure they were not the result of a database transcription error and were geologically reasonable; the location of high-grade samples
with respect to nearby samples, lithology, and oxidation was reviewed ahead of establishing capping thresholds, which generally occur
at distribution changes noted in the individual metal probability plots Figure 11.11.

Figure
11.11: Sample Distribution
Capping
was applied using a calculation within the database, with capped results stored in newly defined fields (AUCAP, CUCAP, and AGCAP), which
were used for sample compositing and resource estimation.
Gold
(Au) is capped at 11.0 gpt, Cu is capped at 3.0 % and Ag is capped at 20.0 gpt. The impact of capping is presented in the table below,
which summarizes the number of samples affected by capping and the total metal reduction Table 11.5.
Table
11.5: Capping Thresholds and Metal Loss Table |
Grade
Item |
Capping
Threshold |
Capped
Samples |
Metal
Loss (%) |
Au |
11.0
gpt |
4 |
0.28% |
Cu |
3.00% |
5 |
0.36% |
Ag |
20.0
gpt |
8 |
1.54% |
Experimental
pairwise relative variograms for the AUCAP, CUCAP, and AGCAP variables were generated to evaluate sample variance, establish search ellipse
parameters, and model variograms for grade estimation via ordinary kriging within Leapfrog’s Edge module. All variography was completed
using 10.0 ft fixed-length composite samples from resource drillholes falling within the mineralized wireframe domain, with a -74.0°
(dip), 26.0° (dip dir.), 100.0° (pitch) orientation, Figure 11.12 and Figure 11.13. This geometry accommodates the apparent steep,
NNE-dipping Au-Cu core and shallow SSW-dipping mineralization observed outside of the mineralized core.
 |
120 |

Figure
11.12: Au Composite Points for Resource Drillholes, looking 026° at Plane of Best-fit Mineralization (green arrow indicating 100°
pitch) used for Spatial Modeling (Variography)

Figure
11.13: Cu Composite Points for Resource Drillholes, looking 026° at Plane of Best-fit Mineralization (green arrow indicating 100°
pitch) used for Spatial Modeling (Variography)
 |
121 |
Variograms
were modeled for the AUCAP, CUCAP, and AGCAP variables using a nugget component and two additional structures, Figure 11.14. The best-fit
orientation of the major, intermediate, and minor axis (-74°, 026°, 100°) for the primary AUCAP and CUCAP variables was applied
to AGCAP variable, Table 11.6.

Figure
11.14: Pairwise relative variograms and modeled structures for Major (top), Intermediate (middle) and Minor axis (bottom) for AUCAP (left),
CUCAP (center), and AGCAP (right)
Table
11.6: Variogram Parameter Table |
General |
Direction
(deg.) |
|
Structure
1 |
Structure
2 |
Variogram |
Dip |
Dir. |
Pitch |
Nugget |
Sill |
Structure |
Major
(ft) |
Semi-
major
(ft) |
Minor
(ft) |
Sill |
Structure |
Major
(ft) |
Semi
major
(ft) |
Minor
(ft) |
AUCAP |
74 |
26 |
100 |
0.12 |
0.07 |
Spherical |
100 |
110 |
99 |
0.38 |
Spherical |
1200 |
700 |
431 |
CUCAP |
74 |
26 |
100 |
0.14 |
0.48 |
Spherical |
200 |
40 |
25 |
0.17 |
Spherical |
850 |
380 |
325 |
AGCAP |
74 |
26 |
100 |
0.08 |
0.00 |
Spherical |
50 |
20 |
20 |
0.20 |
Spherical |
900 |
500 |
300 |
 |
122 |
11.10 | Estimation/Interpolation
Methods |
The
behavior of metal-grade populations within the modeled mineralization domain was analyzed to establish appropriate estimation procedures
for the Au, Cu, and Ag variables. Hard boundaries were applied to restrict the influence of composites within the mineralized domain,
ensuring that only composites inside the domain contributed to grade estimation for blocks within the same domain. For estimation, original
sample grades, capped as necessary, were composited to fixed 10-foot lengths within the mineralized domain. A two-pass Ordinary Kriging
(OK) strategy was employed to estimate metal grades throughout the mineralized domain within the 3D block model. This approach utilized
metal-specific variogram models for the primary AUCAP (gold) and CUCAP (copper) variables, while AGCAP (silver) was estimated using a
single OK pass. Estimation search parameters and sample criteria for each OK pass for Au, Cu, and Ag are summarized in Table 11.7.
A
hierarchical approach was applied for the Au and Cu estimators, with high-confidence estimates requiring composites from multiple drillholes
over shorter ranges superseding lower-confidence estimates based on composites sourced from greater distances. Nearest Neighbor (NN)
estimators were also defined and used to validate the estimated resource models.
Table
11.7: Estimation Search and Sample Parameters |
|
Ellipsoid
Ranges (ft) |
Ellipsoid
Directions |
Number
of Samples |
(deg.) |
Interpolant |
Maximum |
Intermediate |
Minimum |
Dip |
Dip
Azimuth |
Pitch |
Min |
Max |
Max
per
Hole |
AUCAP_OK1 |
400 |
220 |
140 |
74 |
26 |
100 |
4 |
30 |
2 |
AUCAP_OK2 |
200 |
110 |
70 |
74 |
26 |
100 |
4 |
30 |
2 |
CUCAP_OK1 |
400 |
220 |
160 |
74 |
26 |
100 |
4 |
30 |
2 |
CUCAP_OK2 |
200 |
110 |
80 |
74 |
26 |
100 |
4 |
30 |
2 |
AGCAP_OK1 |
400 |
200 |
160 |
74 |
26 |
100 |
4 |
12 |
2 |
11.11 | Classification
of Mineral Resources |
The
estimated block grades were classified into Measured, Indicated, and Inferred resource categories based on a combination of estimator
attributes and composite sample parameters to ensure cohesive resource block assignment.
| ● | Measured
Classification: Blocks were assigned a Measured classification if their metal grades were
estimated during the high confidence pass for the primary metal (AUCAP_OK2), using composites
from two or more drillholes and an Ordinary Kriging (OK) variance ≤ 0.20. |
| ● | Indicated
Classification: Blocks were assigned an Indicated classification if they were estimated with
the same interpolant (AUCAP_OK2) using composites from two or more drillholes and an OK variance
≤ 0.225. |
| ● | Inferred
Classification: All remaining estimated blocks within the constraining mineralized domain
were classified as Inferred. |
 |
123 |
The
Kriging variance parameter is an additional distance-correlation metric derived from the more restrictive Au spatial model. This approach
ensures that resource classification reflects the confidence in grade estimation and spatial continuity of sample locations.
Figure
11.15 and Figure 11.16, display a longitudinal section and a cross-section, respectively, of the classified estimated blocks.

Figure
11.15: Longitudinal (100 ft field of view), looking 030° through the 3D block model, showing Measured (red), Indicated (green) and
Inferred (blue) class resources with 2021 drillholes displayed with black collar points.
 |
124 |

Figure
11.16: Cross-section slice (100 ft field of view), looking 300° through the 3D block model, showing Measured (red), Indicated (green)
and Inferred (blue) class resources with 2021 drillholes displayed with black collar points.
11.12 | Grade
Model Validation |
The
estimated Ordinary Kriging (OK) grades and the extent of interpolated mineralization were reviewed visually against drillhole composites
using bench-level and section slices in Leapfrog’s 3D environment and validated through statistical methods Figure 11.17. A strong
correlation between drillhole composite grades and estimated block grades was observed.
 |
125 |
Figure
11.17: Model validation slices (longitudinal and cross-section), with 100 ft field of view looking 030° and 300° respectively,
through the Au (top), Cu (center) and Ag (bottom), 2021 drillholes are displayed with black collar points.
 |
126 |
These
model validation slices (longitudinal and cross-section), have a 100 ft field of view looking 030° and 300° respectively, through
the Au (top), Cu (center), and Ag (bottom) showing estimated resource block models with 10 ft composites displayed along drillhole traces.
Analytical results for the 2021 drillholes display black collar points and downhole traces showing the grade and distribution of Au,
Cu, and Ag sample intervals against estimated block grades within the constraining mineralized domain.
Global
estimated OK metal grades were compared to global estimated Nearest Neighbor (NN) grades at a 0.0 AuEq cut-off for all classified resources
within the modeled mineralized domain as a means of identifying global bias (Table 11.8). The estimated metal grades between the OK and
NN models for Au, Cu, and Ag were found to be within acceptable tolerances (±1.5%):
| ● | Au
(OK vs. NN): OK grades are 0.39% lower than NN grades. |
| ● | Cu
(OK vs. NN): OK grades are 1.06% higher than NN grades. |
| ● | Ag
(OK vs. NN): OK grades are 0.31% higher than NN grades. |
Table
11.8: Global Estimation Comparison |
Domain |
Cut-off
(AUEQ) |
Density |
Mass |
AUOK |
AUNN |
AGOK |
AGNN |
CUOK |
CUNN |
|
gpt |
ft³/sh.
Ton |
kt |
gpt |
gpt |
gpt |
gpt |
% |
% |
MDMN |
0.00 |
11.81 |
162,854 |
0.333 |
0.334 |
1.25 |
1.24 |
0.147 |
0.145 |
Local
bias was evaluated using directional swath plots (Figure 11.18) to compare mean grades and volumes of OK and NN estimations for Au, Cu,
and Ag. Differences in mean grades observed between the two models existed in areas outside the pit-constrained resources, representing
relatively small volumes of Inferred Class fringe mineralization along the margins of the modeled deposit.
 |
127 |

Figure
11.18: X (left), Y (center) and Z (right) swath plots showing mean grades and volume histograms
These
X (left), Y (center) and Z (right) swath plots show mean grades and volume histograms for the AUOK/AUNN models (blue/gray, top), the
CUOK/CUNN models (red/gray, middle), and the AGOK/AGNN models (green/gray, bottom)
An
additional validation step was completed to evaluate the introduction of any litho-metal bias, particularly within the lower-grade GDK
lithologic domain. Estimated OK resources within the modeled GDK domain contained 6% (±2%) of the deposit’s combined Au
and Cu, while the more similar GD and MYL lithologic domains contained the remaining 94% (±2%). While no matching lithologic/block
coding between blocks and composites was used during estimation, drill density was sufficient to yield resources that retain identical
original logged coding to raw assay litho-metal ratios.
11.13 | Reasonable
Prospects of Eventual Economic Extraction |
The
Mineral Resources presented are confined within a pit optimization excavation limit, with a breakeven cut-off grade applied. The Lerchs–Grossmann
(LG) pit optimization method establishes an economic excavation limit based on project parameters, including metal prices, recovery rates,
operating costs, 50° slope and a 150ft (45.7m) drainage buffer. The metal prices used for pit optimization and the determination
of the gold-equivalent cut-off grade are based on historical data and are intended to reflect long-term
estimates. Metal prices and recoveries used in the LG pit optimization process are shown in Table 11.11 and Table 11.12, respectively.
 |
128 |
A
cut-off grade is applied to differentiate resource material from waste within the excavation limit. The internal cut-off grade is based
on the gold-equivalent grade (AuEq) and is calculated as follows: Cut-off Grade = Cost / (Metal Value * Metallurgical Recovery %)
The
AuEq grade item simplifies the representation of secondary metals (Cu and Ag) by expressing them as an equivalent grade of the primary
metal (Au). This conversion allows the mass of copper and silver in each resource block to be expressed as an equivalent mass of gold,
which is then added to the gold content of the block. The AuEq ratio for secondary metals is calculated on a recovery-weighted basis
for each ore type (oxide, mixed, and sulfide). The following example illustrates the calculation of the cut-off grade for sulfide material:
| 1. | Calculate
the AuEq ratio for copper (Cu): Cu AuEq ratio = (Realized Cu price × Cu recovery) /
(Realized Au price × Au recovery) |
| 2. | Calculate
the AuEq ratio for silver (Ag): Ag AuEq ratio = (Realized Ag price × Ag recovery) /
(Realized Au price × Au recovery) |
| 3. | Determine
the sulfide AuEq grade: Sulfide AuEq grade = Au grade + (Cu × Cu AuEq ratio) + (Ag
× Ag AuEq ratio) |
This
process ensures that all metal grades are expressed consistently, facilitating the accurate application of economic and technical criteria
in resource estimation and reporting.
Table
11.9: AuEq Definitions |
Value |
Equation |
Realized
gold price |
Au
Market Price * (1-Royalty %) |
Realized
copper price |
Cu
Market Price * (1-Royalty %) |
Realized
silver price |
Ag
Market Price * (1-Royalty %) |
Au
recovery |
Varying
Avg. (55% Oxide/Mixed, 64% Sulfide) |
Cu
recovery |
Varying
Avg. (30% Oxide, 78% Mixed, 87% Sulfide) |
Ag
recovery |
Varying
Avg. (61% Oxide/Mixed, 70% Sulfide) |
Table
11.10 contains the AuEq cut-off grades used in the Mineral Resource statement. Table 11.11 shows the metals pricing used in the LG cut-off
grade calculation, and Table 11.12 indicates the LG recovery parameters for metals assigned oxide, mixed and sulfide material types.
Table
11.10: AuEq Cut-off Grades |
Material
Type |
|
Imperial |
Metric |
|
Oxide |
0.011 |
oz/ton |
0.39 |
g/tonne |
Mixed |
0.011 |
oz/ton |
0.39 |
g/tonne |
Sulfide |
0.010 |
oz/ton |
0.34 |
g/tonne |
 |
129 |
Table
11.11: Metal Prices (LG and AuEq Cut-off) |
Royalty* |
2.1 |
% |
Gold
Market Price |
1900 |
$/oz |
Gold
Realized Price |
1860.10 |
$/oz |
Copper
Market Price |
4.00 |
$/lb. |
Copper
Realized Price |
3.92 |
$/lb. |
Silver
Market Price |
23.00 |
$/oz |
Silver
Realized Price |
22.52 |
$/oz |
*Net
royalty value is sourced from table 12.1.1
Table
11.12: Varying Metal Recoveries by Material Type (LG) |
Metal |
Material
by Grade Bin |
Oxide |
Mixed |
Sulfide |
Au |
Oxide
(<0.30 gpt) |
50% |
|
|
Oxide
(0.30gpt - 1.30 gpt) |
60% |
|
|
Oxide
(>1.3 gpt) |
84% |
|
|
Mixed
(<0.27 gpt) |
|
50% |
|
Mixed
(0.27gpt - 1.00 gpt) |
|
60% |
|
Mixed
(>0.65 gpt) |
|
87% |
|
Sulfide
(<0.35 gpt) |
|
|
60% |
Sulfide
(0.35gpt - 0.65 gpt) |
|
|
67% |
Sulfide
(>1.3 gpt) |
|
|
88% |
Cu |
Oxide/Mixed
(<0.10%) |
20% |
50% |
|
Oxide/Mixed
(0.10% - 0.40%) |
30% |
78% |
|
Sulfide
(<0.15%) |
|
|
84% |
Sulfide
(0.15% - 0.40%) |
|
|
78% |
Oxide/Mixed/Sulfide
(>0.40%) |
35% |
80% |
88% |
Ag |
Oxide/Mixed/Sulfide
(<0.5 gpt) |
50% |
58% |
0% |
Oxide/Mixed/Sulfide
(>0.5 gpt) |
61% |
61% |
70% |
11.14 | Mineral
Resource Statement |
Mark
Shutty, CPG is the Qualified Person (QP) responsible for the mineral resource estimation in Table 11.13 and Table 11.14. The QP believes
that the presented resources reasonably represent the in-situ resources for the CK Gold Project using all available data as of the effective
date. The resources are reported with an applied AuEq cut-off grade and inside an optimized pit shell, ensuring reasonable prospects
for eventual economic extraction.
 |
130 |

Figure
11.19 Cross section showing AuEq resources (>0.3 gpt cutoff) and constraining LG pit shell.
 |
131 |
Table
11.13: Mineral Resource Statement |
|
Mass |
Gold
(Au) |
Copper
(Cu) |
Sliver
(Ag) |
Au
Equivalent (AuEq) |
Tons
(000’s) |
Oz
(000’s) |
oz/st |
lbs
(millions) |
% |
Oz
(000’s) |
oz/st |
Oz
(000’s) |
oz/st |
Measured
(M) |
36,400 |
608 |
0.0167 |
138 |
0.189 |
1,703 |
0.047 |
975 |
0.0268 |
Indicated
(I) |
51,200 |
544 |
0.0106 |
163 |
0.159 |
1,901 |
0.037 |
1,001 |
0.0195 |
M
+ I |
87,600 |
1,152 |
0.0131 |
301
|
0.172 |
3,604 |
0.041 |
1,976 |
0.0226 |
|
Inferred |
34,900 |
334 |
0.0096 |
112 |
0.161 |
1,073 |
0.031 |
653 |
0.0187 |
| 1. | Mineral
resources are estimated using Ordinary Kriging, constrained by geological domains based on
lithology and mineralization controls. The underlying datasets supporting the resource estimate
have been reviewed, validated, and verified by the Qualified Person (QP). |
| | |
| 2. | Mineral
resources are reported in short tons within an optimized pit shell, using a breakeven gold
equivalent (AuEq) cut-off grade of 0.011 oz/st for Oxide and Mixed material and 0.010 oz/st
for Sulfide material. The overall average AuEq cut-off grade for all reported resources is
0.010 oz/st. No dilution or mining recovery factors have been applied. |
| | |
| 3. | The
AuEq cut-off grade is calculated using realized metal prices of $1,860.10/oz Au, $3.92/lb
Cu, and $22.52/oz Ag, with average metallurgical recoveries by oxidation type as follows: |
Gold
(Au): 55% (Oxide/Mixed), 64% (Sulfide)
Copper
(Cu): 30% (Oxide), 78% (Mixed), 87% (Sulfide)
Silver
(Ag): 61% (Oxide/Mixed), 70% (Sulfide)
| 4. | The
optimized pit shell was generated using the Lerchs-Grossman method, incorporating all classified
resources, realized metal prices, $2.50/ton mining costs, $9.20/ton processing costs, a 50°
slope angle, and varying metallurgical recoveries as detailed in Table 11.12. |
| | |
| 5. | No
dilution or mining recovery factors have been applied to the resource estimate. |
| | |
| 6. | There
are no known legal, environmental, or permitting issues that impact the reported resources. |
| | |
| 7. | Resources
are reported within the company’s permitted land tenure/exploration license boundaries. |
| | |
| 8. | Mineral
resources are classified in accordance with S-K 1300 definitions and are reported inclusive
of mineral reserves. |
| | |
| 9. | Rounding
may result in minor discrepancies in tonnage, grade, and contained metal totals. |
| | |
| 10. | There
is no guarantee that mineral resources will be converted to mineral reserves. |
| | |
| 11. | The
mineral resource estimates were prepared, reviewed, and validated by Mark Shutty, CPG, the
independent Qualified Person (QP) for these estimates, in accordance with S-K 1300 Definition
Standards adopted December 26, 2018. |
| | |
| 12. | The
effective date of the mineral resource estimate is January 6, 2025. |
 |
132 |
Table
11.14: Mineral Resource Statement (Metric) |
|
Mass |
Gold
(Au) |
Copper
(Cu) |
Sliver
(Ag) |
Au
Equivalent
(AuEq) |
Tonnes
(000’s) |
Oz
(000’s) |
gpt |
Tonnes
(000’s) |
% |
Oz
(000’s) |
gpt |
Oz
(000’s) |
gpt |
Measured
(M) |
33,000 |
608 |
0.57 |
62.4 |
0.189 |
1,703 |
1.60 |
975 |
0.92 |
Indicated
(I) |
46,500 |
544 |
0.36 |
74.0 |
0.159 |
1,901 |
1.27 |
1,001 |
0.67 |
M
+ I |
79,500 |
1,152 |
0.45 |
136.4
|
0.172 |
3,604 |
1.41 |
1,976 |
0.77 |
|
Inferred |
31,600 |
334 |
0.33 |
50.9 |
0.161 |
1,073 |
1.06 |
653 |
0.64 |
| 1. | Mineral
resources are estimated using Ordinary Kriging, constrained by geological domains based on
lithology and mineralization controls. The underlying datasets supporting the resource estimate
have been reviewed, validated, and verified by the Qualified Person (QP). |
| | |
| 2. | Mineral
resources are reported in short tons within an optimized pit shell, using a breakeven gold
equivalent (AuEq) cut-off grade of 0.39 g/t for Oxide and Mixed material and 0.34 g/t for
Sulfide material. The overall average AuEq cut-off grade for all reported resources is 0.35
g/t. No dilution or mining recovery factors have been applied. |
| | |
| 3. | The
AuEq cut-off grade is calculated using realized metal prices of $1,860.10/oz Au, $3.92/lb
Cu, and $22.52/oz Ag, with average metallurgical recoveries by oxidation type as follows: |
Gold
(Au): 55% (Oxide/Mixed), 64% (Sulfide)
Copper
(Cu): 30% (Oxide), 78% (Mixed), 87% (Sulfide)
Silver
(Ag): 61% (Oxide/Mixed), 70% (Sulfide)
| 4. | The
optimized pit shell was generated using the Lerchs-Grossman method, incorporating all classified
resources, realized metal prices, $2.50/ton mining costs, $9.20/ton processing costs, a 50°
slope angle, and varying metallurgical recoveries as detailed in Table 11.12. |
| | |
| 5. | No
dilution or mining recovery factors have been applied to the resource estimate. |
| | |
| 6. | There
are no known legal, environmental, or permitting issues that impact the reported resources. |
| | |
| 7. | Resources
are reported within the company’s permitted land tenure/exploration license boundaries. |
| | |
| 8. | Mineral
resources are classified in accordance with S-K 1300 definitions and are reported inclusive
of mineral reserves. |
| | |
| 9. | Rounding
may result in minor discrepancies in tonnage, grade, and contained metal totals. |
| | |
| 10. | There
is no guarantee that mineral resources will be converted to mineral reserves. |
| | |
| 11. | The
mineral resource estimates were prepared, reviewed, and validated by Mark Shutty, CPG, the
independent Qualified Person (QP) for these estimates, in accordance with S-K 1300 Definition
Standards adopted December 26, 2018. |
| | |
| 12. | The
effective date of the mineral resource estimate is January 6, 2025. |
 |
133 |
All
Inferred Resources, along with Measured and Indicated Resources exclusive of Reserves, primarily located in area between the Reserves
pit and the Resource pit are presented in Table 11.15 and Table 11.16.
The
relatively small difference between Measured and Indicated Mineral Resources (exclusive of reserves) and Mineral Reserves is primarily
due to the presence of modeled mineralization located outside the current Resource pit shell, particularly at depth and to the southeast
(Figure 11.20). These areas are defined by limited and wide-spaced drilling, which, combined with prevailing metal prices and economic
considerations, precludes their inclusion within the current Resource pit shell.
At
present, drilling density is insufficient to support the classification of additional mineral resources that could materially impact
the geometry of the constraining Resource pit shell. While higher metal prices could potentially justify a larger Resource pit shell,
current economic, metallurgical, and drilling constraints limit the conversion of additional resources. The primary constraint is the
lack of sufficient drill data rather than a lack of in-situ mineralization.

Figure
11.20: Cross section showing above cutoff AuEq Resource with nested Resource and Reserves pit shells. Note excluded mineralization located
outside of the resource pit at depth and to the southeast.
 |
134 |
Table
11.15: Mineral Resource Statement – Exclusive of Reserves |
|
Mass |
Gold
(Au) |
Copper
(Cu) |
Sliver
(Ag) |
Au
Equivalent (AuEq) |
Tons
(000’s) |
Oz
(000’s) |
oz/st |
Lbs
(millions) |
% |
Oz
(000’s) |
oz/st |
Oz
(000’s) |
oz/st |
Measured
(M) |
1,900 |
13 |
0.011 |
5 |
0.135 |
112 |
0.065 |
66 |
0.041 |
Indicated
(I) |
12,400 |
118 |
0.009 |
36 |
0.143 |
484 |
0.037 |
238 |
0.018 |
M
+ I |
14,400 |
131 |
0.009 |
41 |
0.147 |
596 |
0.041 |
304 |
0.021 |
|
Inferred |
34,900 |
334 |
0.010 |
112 |
0.161 |
1,073 |
0.031 |
653 |
0.019 |
| 1. | Mineral
resources are estimated using Ordinary Kriging, constrained by geological domains based on
lithology and mineralization controls. The underlying datasets supporting the resource estimate
have been reviewed, validated, and verified by the Qualified Person (QP). |
| | |
| 2. | Mineral
resources are reported in short tons within an optimized pit shell, using a breakeven gold
equivalent (AuEq) cut-off grade of 0.011 oz/st for Oxide and Mixed material and 0.010 oz/st
for Sulfide material. The overall average AuEq cut-off grade for all reported resources is
0.010 oz/st. No dilution or mining recovery factors have been applied. |
| | |
| 3. | The
AuEq cut-off grade is calculated using realized metal prices of $1,860.10/oz Au, $3.92/lb
Cu, and $22.52/oz Ag, with average metallurgical recoveries by oxidation type as follows: |
Gold
(Au): 55% (Oxide/Mixed), 64% (Sulfide)
Copper
(Cu): 30% (Oxide), 78% (Mixed), 87% (Sulfide)
Silver
(Ag): 61% (Oxide/Mixed), 70% (Sulfide)
| 4. | The
optimized pit shell was generated using the Lerchs-Grossman method, incorporating all classified
resources, realized metal prices, $2.50/ton mining costs, $9.20/ton processing costs, a 50°
slope angle, and varying metallurgical recoveries as detailed in Table 11.12. |
| | |
| 5. | No
dilution or mining recovery factors have been applied to the resource estimate. |
| | |
| 6. | There
are no known legal, environmental, or permitting issues that impact the reported resources. |
| | |
| 7. | Resources
are reported within the company’s permitted land tenure/exploration license boundaries. |
| | |
| 8. | Mineral
resources are classified in accordance with S-K 1300 definitions and are reported exclusive
of mineral reserves. |
| | |
| 9. | Rounding
may result in minor discrepancies in tonnage, grade, and contained metal totals. |
| | |
| 10. | There
is no guarantee that mineral resources will be converted to mineral reserves. |
| | |
| 11. | The
mineral resource estimates were prepared, reviewed, and validated by Mark Shutty, CPG, the
independent Qualified Person (QP) for these estimates, in accordance with S-K 1300 Definition
Standards adopted December 26, 2018. |
| | |
| 12. | The
effective date of the mineral resource estimate is January 6, 2025. |
 |
135 |
Table
11.16: Mineral Resource Statement (Metric) – Exclusive of Reserves |
|
Mass |
Gold
(Au) |
Copper
(Cu) |
Sliver
(Ag) |
Au
Equivalent
(AuEq) |
Tonnes
(000’s) |
Oz
(000’s) |
gpt |
Tonnes
(000’s) |
% |
Oz
(000’s) |
gpt |
Oz
(000’s) |
gpt |
Measured
(M) |
1700 |
13 |
0.202 |
2 |
0.171 |
112 |
1.968 |
66 |
1.288 |
Indicated
(I) |
11300 |
118 |
0.298 |
16 |
0.156 |
484 |
1.332 |
238 |
0.670 |
M
+ I |
13100 |
131 |
0.298 |
18 |
0.131 |
596 |
1.410 |
304 |
0.719 |
|
Inferred |
31,600
|
334 |
0.33 |
50.9 |
0.161 |
1,073 |
1.06 |
653 |
0.64 |
| 1. | Mineral
resources are estimated using Ordinary Kriging, constrained by geological domains based on
lithology and mineralization controls. The underlying datasets supporting the resource estimate
have been reviewed, validated, and verified by the Qualified Person (QP). |
| | |
| 2. | Mineral
resources are reported in short tons within an optimized pit shell, using a breakeven gold
equivalent (AuEq) cut-off grade of 0.39 g/t for Oxide and Mixed material and 0.34 g/t for
Sulfide material. The overall average AuEq cut-off grade for all reported resources is 0.35
g/t. No dilution or mining recovery factors have been applied. |
| | |
| 3. | The
AuEq cut-off grade is calculated using realized metal prices of $1,860.10/oz Au, $3.92/lb
Cu, and $22.52/oz Ag, with average metallurgical recoveries by oxidation type as follows: |
Gold
(Au): 55% (Oxide/Mixed), 64% (Sulfide)
Copper
(Cu): 30% (Oxide), 78% (Mixed), 87% (Sulfide)
Silver
(Ag): 61% (Oxide/Mixed), 70% (Sulfide)
| 4. | The
optimized pit shell was generated using the Lerchs-Grossman method, incorporating all classified
resources, realized metal prices, $2.50/ton mining costs, $9.20/ton processing costs, a 50°
slope angle, and varying metallurgical recoveries as detailed in Table 11.12. |
| | |
| 5. | No
dilution or mining recovery factors have been applied to the resource estimate. |
| | |
| 6. | There
are no known legal, environmental, or permitting issues that impact the reported resources. |
| | |
| 7. | Resources
are reported within the company’s permitted land tenure/exploration license boundaries. |
| | |
| 8. | Mineral
resources are classified in accordance with S-K 1300 definitions and are reported exclusive
of mineral reserves. |
| | |
| 9. | Rounding
may result in minor discrepancies in tonnage, grade, and contained metal totals. |
| | |
| 10. | There
is no guarantee that mineral resources will be converted to mineral reserves. |
| | |
| 11. | The
mineral resource estimates were prepared, reviewed, and validated by Mark Shutty, CPG, the
independent Qualified Person (QP) for these estimates, in accordance with S-K 1300 Definition
Standards adopted December 26, 2018. |
| | |
| 12. | The
effective date of the mineral resource estimate is January 6, 2025. |
11.15 | Relevant
Factors That May Affect the Mineral Resource Estimate |
The
CK Gold Project is subject to factors that may affect this Mineral Resource estimate:
| ● | Metal
Prices: Fluctuations in metal prices can influence the cut-off grade, affecting the estimated
quantity of resources. |
| ● | Operating
Costs: Variations in assumed operating costs may alter the cut-off grade and the quantity
of estimated resources. |
 |
136 |
| ● | Tonnage
and Grade Estimates: Additional drilling, new assay data, and updated tonnage factor
information may change tonnage and grade estimates. |
| ● | Recovery
Assumptions: Modifications to recovery rates can affect the quantity of estimated resources. |
| ● | Regulatory
and Operational Assumptions: The ability to maintain mining claims and surface rights, secure site access, obtain environmental
and other regulatory permits, and achieve a social operating license may also influence the resource estimate. |
11.16 | Responsible
Person Opinion |
The
mineral resource estimate is well-constrained by three-dimensional wireframes representing geologically realistic volumes of mineralization
within the granodiorite intrusive host rocks. Exploratory data analysis conducted on assays and composites shows that the wireframes
define appropriate domains for mineral resource estimation. Grade estimation was performed using an interpolation strategy designed to
minimize bias in the resulting grade models.
Mineral
resources are constrained and reported using economic and technical criteria to ensure a reasonable prospect for economic extraction.
The resources are presented at a cut-off grade and further constrained within a pit optimization shell. The application of a pit shell
constraint prevents the projection of discontinuous resources to uneconomic depths, even at elevated concentrate prices. Together, these
constraints form the basis for establishing reasonable prospects for economic extraction.
U.S.
Gold’s 2021 drilling program datasets were integrated with the existing resource drillhole database, modeled mineralization, geological
interpretations, oxidation domains, and estimated grades of gold (Au), copper (Cu), and silver (Ag), as well as block classifications.
This drilling validated previously modeled resources and methodologies, particularly in developing the constraining mineralized domain
and within the pit shell envelope.
Drillhole
samples from the 2021 program passing through Measured and Indicated resource blocks within the constraining pit intersected the same
host lithologies and exhibited mean Au and Cu grades consistent with the global mean grades of the modeled resource (Table 11.17). For
samples intersecting Inferred resource blocks within the constraining pit (Figure 11.21), metal grades were generally in line locally
but slightly lower globally than previously modeled. In contrast, drillholes passing through Inferred resource blocks on the margins
of modeled mineralization showed decreasing grades with distance from the deposit’s higher-grade core. Notably, mean Ag grades
in the 2021 drilling are slightly elevated relative to the modeled resource.
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Table
11.17: Global Mean Grades of Estimated Metals (Model Mean) vs. 2021 Drillhole Grades |
Class
(Domain) |
Metal |
Sample
Count |
Length
(ft) |
Sample
Mean |
Model
Mean |
Measured |
AUCAP
(gpt) |
394 |
1,657 |
0.68 |
0.62 |
CUCAP
(%) |
394 |
1,657 |
0.23 |
0.19 |
AGCAP
(gpt) |
394 |
1,657 |
1.27 |
1.70 |
Indicated |
AUCAP
(gpt) |
732 |
3,135 |
0.37 |
0.35 |
CUCAP
(%) |
732 |
3,135 |
0.17 |
0.16 |
AGCAP
(gpt) |
732 |
3,135 |
1.00 |
1.11 |
Inferred |
AUCAP
(gpt) |
741 |
3,290 |
0.27 |
0.35 |
CUCAP
(%) |
741 |
3,290 |
0.12 |
0.15 |
AGCAP
(gpt) |
741 |
3,290 |
0.81 |
0.50 |
| 1. | Table
of mean grades of estimated metals (Model Mean) vs. 2021 drillhole grades (Sample Mean) by
Class (Domain) within the constraining pit shell. |
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Figure
11.21: Plan Map of 2021 RC and core drillholes coded by material class
Mark
Shutty, CPG, is the QP responsible for resource estimation and resource tabulation. The QP believes that this mineral resource estimate
for the CK Gold Project is an accurate estimation of the in-situ resources based on the available data and that the available data and
the mineral resource model are sufficient for mine design and planning.
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12.0 | Mineral
Reserve Estimates |
The
Mineral Resources described in Section 11 are the primary basis for the estimate of Mineral Reserves described in this report section.
The parameters discussed in Section 12.1 are part of the qualifiers that allow the conversion of Mineral Resources to Mineral Reserves.
The Mineral Resources described in Section 11 are the primary basis for the Mineral Reserve estimate described in this section. The parameters
discussed in Section 12.1 are part of the qualifiers that allow the conversion of Mineral Resources to Mineral Reserves. The Mineral
Resource refers to the inventory of mineralization that can reasonably be expected to become economic under stated parameters, while
the Mineral Reserves identified report a subset of the Mineral Resource that is economic under more rigorous parameters that conform
to industry standards and practice, principally metal prices.
The
CK Gold Project Mineral Reserve estimate lies inside an open pit design. The pit sits inside a larger, potentially economic resource
shell for the property. The pit design is guided by an economic pit limit analysis based on the economic parameters described in this
section. The designed pit is then scheduled in a mine plan spanning the project life, and a discounted cash-flow model to assess the
Project’s economic viability.
12.1 | Basis,
Assumptions, Parameters, and Methods |
AKF
Mining Services Inc. (AKF) performed economic pit-limit analysis using Vulcan’s Pit Optimizer software, which uses the Lerchs–Grossmann
(LG) algorithm to determine an economic excavation limit based on input optimization parameters shown in Table 12.1.
Table
12.1: Pit Optimization Parameters |
Item |
Unit |
Value |
Gold
Price |
$/oz |
1,755.00 |
Copper
Price |
$/lb |
3.77 |
Silver
Price |
$/oz |
23.00 |
NSR
Royalty* |
% |
2.1 |
Concentrate
Smelting & Transport — Oxide |
$/lb
Cu recovered |
0.29 |
Concentrate
Smelting & Transport — Mixed |
$/lb
Cu recovered |
0.32 |
Concentrate
Smelting & Transport — Sulfide |
$/lb
Cu recovered |
0.37 |
Cu
Refining Charge |
$/lb
Cu |
0.07 |
Au
Refining Charge |
$/oz |
5.00 |
Ag
Refining Charge |
$/oz |
0.45 |
|
|
|
Oxide—Cu
Recovery (>0.1% & <0.4%) |
% |
30 |
Oxide—Au
Recovery (>0.3gpt & <1.3 gpt) |
% |
60 |
Oxide—Ag
Recovery (>0.5 gpt) |
% |
61 |
Mixed—Cu
Recovery (>0.1% & <0.4%) |
% |
78 |
Mixed—Au
Recovery (>0.27 gpt & <1.0 gpt) |
% |
60 |
Mixed—Ag
Recovery (>0.5 gpt) |
% |
61 |
Sulfide—Cu
Recovery (>0.15% & <0.4%) |
% |
87 |
Sulfide—Au
Recovery (>0.3 5gpt & <0.65 gpt) |
% |
67 |
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Table
12.1: Pit Optimization Parameters |
Item | Unit |
Value |
Sulfide—Ag
Recovery (>0.5 gpt) |
% |
70 |
Smelter
Payable — %Cu |
% |
97 |
Smelter
Payable —Au oz/st |
% |
98 |
Smelter
Payable — Ag oz/st |
% |
95 |
Concentrate
Grade %Cu — Oxide |
% |
23 |
Concentrate
Grade %Cu — Mixed |
% |
21 |
Concentrate
Grade %Cu — Sulphide |
% |
18 |
|
|
|
Mining
Cost |
$/st |
2.50 |
Process
Cost |
$/st
processed processed |
7.00 |
Tailings
Cost |
$/st
processed |
1.65 |
Site-Wide
General & Administrative Cost |
$/st
processed |
1.50 |
|
|
|
Pit
Slope |
Degrees |
48 |
| * | Note:
See definition of Royalty for Wyoming State Land Lease, Section 3.4. |
The
pit optimization used for guiding the final pit design considers only Measured and Indicated Resources; metal classified as Inferred
Resource is ignored. The metal pricing used in the optimization parameters is weighted long-term forecast comprising a three-year trailing
average. The QP believes that this is a reasonable assumption; additional information is provided in Section 16.
The
economic excavation boundary (pit shell) indicated by the pit optimization is used to guide the final pit design, which becomes a hard
boundary in the conversion of Mineral Resources to Mineral Reserves. Mineral Resources in the Measured and Indicated categories inside
the final pit design can convert, or classify, as Mineral Reserves, subject to resource classification and cut-off grade. Section 13
contains additional details about the mine design.
12.1.2 | Value
Per Ton Cut-off Grade Calculation |
The
value per ton (VPT) “milling cut-off value” calculation for all areas was completed as follows:
| ● | VPT
= (Block Revenue – Milling Cost – G&A Cost)/Resource Tons |
| ◌ | Block
Revenue = Resource tons x Grades x Recovery x Net Price for each metal |
| ◌ | Milling
Cost = Resource tons x Milling Cost per ton |
|
◌ |
General & Administrative (G&A) Cost = Resource tons
x G&A Cost per ton |
This
calculation is sometimes called the “milling cut-off value” because the mining cost is not considered. The mining cut-off
uses a similar calculation but includes the mining cost. The mining cut-off is used to determine the boundary of an economic pit shell,
and the milling cut-off has been used in this case to determine the reserves contained within that same shell. For the reserves, the
block was considered mill feed if the VPT milling cut-off was equal to or greater than a value of $0.01/st. If the value was less than
this, the block was considered waste.
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Due
to the disseminated nature of mineralization, dilution is not expected to be an issue during mining, and a dilution factor is not used
in the Mineral Reserves determination. A grade-control program would likely be sufficient to prevent excessive dilution or ore losses.
CK
Gold Mineral Reserves are given in Table 12.2. Antonio Loschiavo, P. Eng., is the QP responsible for the Mineral Reserves statement.
Mineral Reserves are reported inside a detailed pit design using suitable parameters for the site, which was guided by pit optimization.
Table
12.2: Mineral Reserve Statement |
|
Mass |
Gold
(Au) |
Copper
(Cu) |
Sliver
(Ag) |
Au
Equivalent
(AuEq) |
Tons
(000s) |
Oz
(000s) |
oz/st |
M
lb |
% |
Oz
(000s) |
oz/st |
Oz
(000s) |
oz/st |
Proven
(P1) |
34,500 |
595 |
0.017 |
133 |
0.192 |
1,591 |
0.046 |
909 |
0.026 |
Probable
(P2) |
38,800 |
426 |
0.011 |
127 |
0.164 |
1,417 |
0.037 |
763 |
0.020 |
P1
+ P2 |
73,200
|
1,022
|
0.014 |
260
|
0.177
|
3,008
|
0.041
|
1,672
|
0.023
|
| 1. | Reserves
tabulated above a “milling cut-off value” per ton (see text). |
| 2. | Note
only 3 significant figures shown, may not sum due to rounding. |
12.3 | Classification
and Criteria |
Section
11.11 discusses resource classification. Measured and Indicated Resources inside the designed pit are classified as Proven and Probable
Mineral Reserves, respectively. Mineral Reserves use the same cut-off grade definitions as Mineral Resources. This reserve classification
does not affect the Mineral Resource statement.
The
CK Gold Project is subject to factors that may impact the Mineral Reserve statement:
| ● | Economic
factors such as changes in metals prices, operating costs, or capital expenditures. |
| ● | Changes
to the estimated Mineral Resources. |
| ● | Metallurgical
factors affecting recovery. |
| ● | Maintenance
of social and environmental license to operate. |
12.5 | 2025
PFS vs 2021 PFS RESERVES |
AKF
completed the 2021 PFS design pits based on the 2021 PFS metal prices and operating costs. During the 2025 PFS update, metal prices and
operating costs increased, which triggered a review of the Mineral Reserves by rerunning the LG optimizations based on the latest metal
prices and operating costs. As a result, the comparison between the 2021 PFS and 2024 PFS Mineral Reserves shows a 3% increase in ore
tons and a 5% increase in waste tons.
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●
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Open
pit, surface mining is the selected mining method for the CK Gold Project. This mining method is selected based on the size, shape, location,
and value of the mineralization on the property. The Project’s disseminated type mineralization has a large extent and is located
near to or outcropping at surface. Additionally, open pit optimizations attempting to maximize the recovery of the in-situ resource show
economic excavation results using current project parameters and base case metal prices.
Surface
mining is a cyclical process where the four main tasks including drilling, blasting, loading, and haulage are occurring concurrently
at different areas of the property. In areas to be excavated vertical blast holes are drilled in a regular pattern and charged with blasting
agents. The material will be blasted, loaded into 100 st class rigid frame haul trucks, and transported based on material type to one
of four different locations, run-of-mine (ROM) Crusher Stockpile, Co-Disposal Tailings Facility, Ore Stockpile or Waste Rock Facility.
Wherever possible Crusher Stockpile ore will be directly dumped into the primary crusher at the process plant.
Owner
operator mining has been selected as the preferred method for the purposes of this PFS. This decision, in large part, is due to the location
of the Project, local mining and the availability of potential labor within 30 miles of the site (Laramie and Cheyenne, Wyoming). As
part of the studies, mining costs were estimated from first principles with equipment depreciation. Contractor mining is only considered
for the blasting crew but is not eliminated as an option for mine development, pending further review.
13.2 | Geotechnical
Parameters |
Piteau
Associates (Piteau) conducted a geotechnical investigation for the project. Piteau issued a technical memorandum dated September 6th,
2022, titled “Recommended Feasibility-Level Geotechnical Slope Designs for the Copper King Open Pit.” This section contains
a summary of the report. Following the September 6th report, an updated May 1st, 2024 report was completed due to the change in bench
height from 20ft to 30ft.
The
following list summarizes the scope of work that Piteau performed as part of the geotechnical investigation:
| ● | Full
geotechnical logging of 5 core holes, detailed structure logging. |
| ● | Rock
mass strength assessments, laboratory testing and analysis. |
| ● | Structure
assessment, Kinematic analysis. |
| ● | Recommended
end of life slope design. |
| ● | An
assessment of the effects of ground water and pore pressure on slope stability. |
Table
13.1 and Figure 13.1 outline the latest slope design recommendations and pit design sectors based on the 30ft bench design.
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Table
13.1: Recommended Slope Designs for Presplit Blasted Benches |
Design
Sector |
Max
Interramp
Slope
Angle |
Max
Interramp
Slope
Height |
Catch
Bench
Width |
Face
Angle |
I |
52 |
410 |
38.8 |
75 |
II |
54 |
380 |
36.7 |
75 |
III |
54 |
370 |
34.6 |
75 |
IV |
54 |
480 |
41.1 |
75 |
V |
53 |
460 |
36.7 |
75 |
VI |
54 |
480 |
41.1 |
75 |
VII |
53 |
470 |
36.7 |
75 |
VIII |
52 |
510 |
41.1 |
75 |
IX |
53 |
500 |
38.8 |
75 |
X |
54 |
490 |
36.7 |
75 |
XI |
53 |
460 |
38.8 |
75 |
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144 |

Figure
13.1: Pit Sectors and Recommended Slopes
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13.2.1 | Geotechnical
General Recommendations |
Below
is a summary of the General recommendations:
13.2.1.1 | Blending
and Finalizing Designs |
Where
a range of interramp angle (IRA) is indicated between adjacent design sectors, blending should occur within the design sector with the
steeper (greater) design IRA. Similarly, blending from weaker to stronger materials should occur in the stronger (better quality) rock
mass materials.
In
the early stages of mining below the overburden and weathered bedrock horizon, benching trials for 80 ft high benches should be considered
in areas where bench performance is expected to have the least impact on the stability of haul roads or other critical slope areas to
confirm that structural continuity of adversely oriented joint sets is limited and therefore has limited impacts on the bench designs.
Bench designs should be updated based on ongoing evaluation of bench performance.
13.2.1.3 | Transitioning
from Single to Double Benches |
At
the transition from single- to triple-benches, the triple-bench catch bench width should be implemented at the crest level of the first
triple-bench to avoid steepening the design IRA.
13.2.1.4 | Controlled
Blasting |
The
following recommendations are made with respect to the potential for benches to be excavated up to 90 ft high:
| 1. | Optimizing
slope designs to maximize IRA while maintaining safe working conditions requires controlled
blasting on final walls to minimize the damage to intact rock bridges and preserve cohesion
on discontinuity surfaces. |
| a. | Pre-split
blasting (with trims) should be considered to improve (increase) effective bench face angles
(BFAs) and catch bench widths. |
| b. | Pre-split
blasting could provide increased success for the proposed double benching below the overburden
and weathered bedrock zone near the slope crest. |
| c. | Blast
monitoring and pre/post blast inspection should be conducted to continually assess potential
blast damage and improve blast performance. |
| 2. | Once
a revised CK Gold Project mine plan is developed with the enclosed feasibility-level slope
design recommendations, ongoing evaluation of potential hazards and risks should be carried
out through the implementation of standard operating procedures (SOPs), a ground control
management plan (GCMP), and regular geotechnical inspection. |
| 3. | An
inspection and sign-off system should be used to confirm that the bench crests throughout
the pit are adequately scaled, significant breakback is not occurring, and bench face conditions
are acceptable. An evaluation of bench design achievement should be carried out to verify
that face and crest conditions are adequate for safe development of multiple-lift (double)
benches. A qualitative bench design achievement system presented by Read and Stacey (2009)
can be modified for specific site conditions as shown in Figure 13.2, and includes evaluation
of: |
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146 |
| a. | Design
face achievement (Df) for the bench configuration; and |
| b. | Face
condition (Fc). |
| c. | The
components of the system are summarized in the following ratings tables and chart shown below.
For consideration of double benching, bench design achievement results should fall under
the “Good Results” category. |

Figure
13.2: Design Face (Df) versus Face Condition (Fc) Chart
| 4. | To
minimize rockfall potential in bedrock, careful bench scaling should be carried out with
the shovel bucket during bench excavation. Depending on bench performance, the following
additional items may be required: |
| a. | Daylight-only
mining with a spotter; and regular geotechnical inspection. |
| b. | Construction
of rockfall impact berms or other rockfall control measures (e.g., wire mesh, rockfall attenuation
fences, etc.) that are appropriately sized to contain rockfall hazards using rockfall modeling. |
| c. | Local
step-outs to gain adequate bench catchment width. |
| d. | Scaling
of the bench crest and face using chain pulled behind a dozer (provided adequate bench width
is available). |
| e. | Scaling
with a long-reach backhoe to remove potential rockfall hazards. |
| f. | Crest
trenching with a backhoe in advance of excavation in areas of weaker or highly fractured
rock (e.g., weathered bedrock, exposed fault zones or dykes). |
| g. | Implementing
angled pre-split blasting with small diameter blastholes; and/or h. Manual scaling using
a scaling contractor with ropes. |
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13.2.1.5 | Changes
to the Slope Design |
As
a general comment for future advancement of the CK Gold Project, it is recommended that any new pit designs or significant revisions
to the mine plan (for example to the bench, interramp or overall slope angles or heights) be forwarded to Piteau for review, conformance
check, and comment. Additional geotechnical evaluations and analyses may be necessary to check stability.
13.2.1.6 | Bench
Scaling and Cleaning Catch Benches |
Bench
scaling should be carried out with the shovel bucket during bench excavation. Depending on bench performance, additional scaling may
be required with scaling chain. Careful pull-back procedures should be carried out to minimize filling of subsequent benches with spilled
material.
All
slopes should be visually inspected at regular intervals for signs of distress and overall slope movement. Also, a slope displacement
monitoring system consisting of survey prisms should be established during early stages of mining and maintained throughout the mine
life and operation. Current practice is to measure prisms with automated systems such as robotic total stations (RTS) that include data
acquisition and management tools for processing, interpretation, and reporting so that results can be evaluated regularly to assess slope
behavior. This can also be supplemented with radar monitoring equipment (if needed) that can provide near real-time monitoring of slope
deformations should the need arise. Both prism and radar monitoring provide advanced warning of possible large-scale instability and
allow time for appropriate remedial measures to be implemented or mining plans to be modified, to accommodate the instability. Manual
or automated wireline extensometers could be used to augment prism or radar monitoring in areas of observed surface deformation and cracking.
If
slope movements are measured, monitoring (velocity) thresholds and trigger action response plans (TARPs) should be developed based on
the observed slope performance and adjusted as required, to account for the effects of error and noise and to verify and maintain their
effectiveness.
Other
monitoring slope monitoring techniques such as inclinometers and time domain reflectometers (TDR) (for monitoring subsurface ground movements),
or satellite-based surface surveying with global positioning systems (GPS) or InSAR (Interferometric Synthetic Aperture Radar) may need
to be incorporated into the slope monitoring system if the need arises.
13.2.1.8 | Visual
Inspection Monitoring |
Regular
inspection of the crest and exposed benches on the mine plan should be carried out to identify any signs of tension cracking, increased
raveling/rockfall, or other signs of instability. The locations of observed tension cracks should be surveyed and added to geotechnical
plans to allow assessment of slope deformation with respect to slope monitoring data and any potential mechanism(s) of instability. Any
unusual signs of slope raveling or distress should be communicated to the Mine Geotechnical Team and assessed accordingly.
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13.2.1.9 | Ongoing
Data Acquisition, Verification and Updating Design Criteria |
Systematic
documentation of bench performance (achieved BFA) and structural mapping (by manual or photogrammetric methods) is recommended to be
carried out while mining the Copper King pit. If ongoing bench or slope performance is unfavorable and/or structural mapping indicates
adverse conditions as new geology is exposed, local revisions to the mine plan may be required.
Documentation
of the as-built bench performance of mined slopes is recommended using reliable methods such as photogrammetry models, high-resolution
laser scan digital terrain models (DTM), or manual bench documentation mapping. This information can be used to calibrate breakback angles
calculated from the kinematic CFA assessments and support potential optimization of the IRAs during mining.
In
addition, rockfall field testing and modelling is recommended to calibrate rockfall model input parameters and develop a “site-specific”
design catch berm width for rockfall protection instead of the Modified Richie Criteria (Equation 3) which was adopted for this study.
Such rockfall calibration could also support potential optimization of the IRAs.
It
is recommended that future drilling in bedrock should include geotechnical logging of all parameters comprising RMR (according to Bieniawski,
1976) and consistent PLI testing as described in Section 2.5 in the final (Piteau) report. This geomechanical information should be incorporated
into the current geomechanical and rock strength databases developed for the feasibility study and would support future geotechnical
evaluations of the CK Gold Project.
13.2.1.10 | Slope
Depressurization Measures |
Deep-seated
stability analysis of the slopes indicated that the east and southeast walls (Design Sectors V and VI near Section E1 and Design Sectors
VI and VII near Section SE1) require slope depressurization to meet the design acceptance criteria of a minimum FOS of 1.20 for overall,
interramp, and compound slopes. Depressurization targets at these two sections are defined in terms of Hu and are based on the EOM groundwater
surface provided by Neirbo. To achieve acceptable stability, it is required that pore pressures in the east wall slopes (Section E1,
west of the Copper King fault) be reduced to levels equivalent to a 1.0 Hu (hydrostatic conditions) (from a 1.4 Hu defined by Neirbo).
In the southeast slope (Section SE1, north of N 234,025) it is required that pore pressures be reduced to levels equivalent to a 1.2
Hu (from a 1.4 Hu). Both Hu targets are for the lower slopes and assume that a 0.8 Hu will be present in the MS-MV unit in the upper
slope east of the Copper King fault (at Section E1) and that a 1.0 Hu will be present in the granodiorite rock mass in the upper slope
south of N 234,025 (at Section SE1).
Based
on these Hu targets, it is recommended that additional 3D hydrogeological modeling be performed that includes simulation of active
depressurization measures (such as pumping wells and/or horizontal or inclined drains) in the east and southeast slopes to determine
what measures are needed to achieve the depressurization targets. This hydrogeologic modeling should also incorporate a mine plan
that uses the feasibility slope design recommendations and that has been checked by Piteau for conformance to the design. After
hydrogeologic modeling of active depressurization is complete, it is recommended that the calculated pore pressures be provided to
Piteau (for example, as a “grid” defined by x, y, z coordinates and pore pressure, u) to perform new 2D anisotropic
stability analyses of the east and southeast slopes to
check if the depressurization targets have been achieved and confirm that the FOS of the overall, interramp, and compound slopes meet
the 1.20 design acceptance criteria.
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149 |
13.2.1.11 | Hydrogeologic
Monitoring |
Stability
of the east and southeast slopes is dependent on achieving specific depressurization targets and these areas will likely require some
form of active depressurization (i.e., pumping wells and/or drains) which can be defined through additional hydrogeological modeling
as described in the Piteau report. As integral part of active depressurization, it is also recommended that hydrogeological monitoring
(such as multi-level vibrating-wire piezometers or VWPs) be installed to monitor pore pressures and verify that the required targets
in the critical areas of the slope are being achieved in advance of mining and during the life of mine.
13.2.1.12 | Surface
Water Control |
To
assist achieving and maintaining depressurization targets as well as avoid development of erosional gullies and slope instabilities within
the mine plan, the following surface water controls are recommended:
| 1. | Use
perimeter ditches behind the pit crest to capture and divert surface water away from the
pit. |
| 2. | Grade
haul roads inwards to divert surface water away from the outside edge of the haul roads and
create a ditch along the inside lane to capture the water. |
| 3. | Collect
surface water in appropriately placed sumps (for example, pit bottom or intermediate locations
along haul roads) and pump to proper discharge points outside the pit. |
13.2.1.13 | Contingency
Planning |
The
mine plan has only one main haul road providing access to the pit. Single haul road access could pose potential risks to the mining sequence
and ore delivery if instabilities develop above or below the haul roads. Ongoing slope monitoring and visual stability inspections should
be carried out to prevent the loss of this single main access point into and out of the mine plan.
13.3 | Hydrogeological
Parameters |
A
hydrogeology investigation for the Project was conducted by Neirbo Hydrogeology (Neirbo). Neirbo issued a technical report in December
2023 titled “Hydrogeological Characterization and Groundwater Flow Model.” This section contains a summary of the report.
The
CK Gold Project property is located in the Silver Crown mining district of southeast Wyoming, approximately 20 miles west of the city
of Cheyenne. The property comprises about 1,120 acres (2 square miles) on the southeastern margin of the Laramie Mountains. The Project
is fully-owned by U.S. Gold. The Project facilities include an open pit, tailings management facility, two waste rock facilities, plant
site, and an ore stockpile area.
The
highest elevation in the open-pit area is about 7,100 ft and the pit will be excavated to 6,120 ft. The mine plan has eight years of
mining and passive dewatering as the open pit is advanced. The post-mining phase includes pit backfilling with tailings and waste rock.
The first two years after mining ends will be dedicated to site reclamation.
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150 |
The
orebody is hosted in granitic rocks that have limited permeability and limited water-storage capacity. Groundwater wells completed in
the granite rocks have typically yielded 0 to 5 gpm. The Project has completed an extensive hydrogeologic site characterization to support
development of a regional groundwater flow model (Flow Model). Aquifer testing has included pumping tests and discrete depth-interval
packer testing. Hydraulic conductivity and specific storage properties were estimated from these tests. Groundwater levels and pore pressures
were obtained from wells and Vibrating Wire Piezometers.
A
calibrated Flow Model was developed to represent the hydrogeologic system. The Flow Model simulates pre-mining conditions and hydrologic
changes during the mining and post-mining phases. The Flow Model predicts groundwater system changes due to passive pit dewatering, natural
recharge changes due to facility construction, and pit backfill during the post-mining phase.
Predictions
during the mining and post-mining periods included groundwater-level, pit inflow, streamflow, and evapotranspiration changes. Predicted
mine-induced drawdown was greatest near the pit and it decreased rapidly away from the pit. Predicted drawdown was 10 ft or less outside
the Operating Permit Boundary at the end of mining. After 150-years, the discernable predicted drawdown extended 180 ft outside the Permit
operating boundary in a small area shown on Figure 13.3. The nearest domestic wells were 2,000 ft from the predicted 10-feet drawdown
area. At this distance, any mine induced drawdown would likely not be discernable from natural variation and groundwater-level changes
induced by the domestic wells themselves.
The
Middle Fork of Crow Creek is the nearest stream, and its flow was predicted to decrease 0.02 cubic feet per second ten years after mine-ending.
The other stream segments had zero to 0.01 cubic feet per second changes in flow.
Average
annual groundwater pit inflow was expected to be less than 15 gpm. This low pit inflow would be manageable using passive, in-pit sumps.
Dewatering wells are not expected to be necessary. Cumulative pit inflows during mining were predicted to be 130 acre-feet.
After
mining ends, the pit will be backfilled with tailings and waste rock. Groundwater and precipitation will flow into the backfill material
and water-levels will slowly rise until they stabilize at 6,717 ft after about 130 years. A pit lake is not expected to form since evaporation
losses will keep the groundwater level below the top of backfill. This will result in the pit being a hydraulic sink with no groundwater
outflows.
Quarterly
background groundwater quality data have been obtained in seven project area wells from 2020 Quarter 4 to 2022 Quarter 1. The background
water samples indicate the water quality is generally below regulatory standard concentrations. However, a few constituents in select
wells have exceeded the standards for domestic, agriculture, and livestock uses. The domestic water-quality standard for fluoride and
pH was consistently exceeded in four of the seven wells. Each well has exceeded standards for iron, manganese, mercury, adjusted gross
alpha, or sodium adsorption ratio on at least one occasion. Well MW-7, in the middle of the proposed pit, has consistently exceeded the
standard for uranium and gross alpha. The adjusted gross alpha standard was exceeded in three of the six samples in MW-7.
 |
151 |
Figure
13.3, Figure 13.4 and Figure 13.5 show the predicted drawdown at the end of mining and 150 years post mining, groundwater monitoring
locations and predicted open pit groundwater inflows, respectively.

Figure
13.3: Predicted drawdown at the end of mining and post-mining year 150
 |
152 |

Figure
13.4: Groundwater Monitoring Locations
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153 |

Figure
13.5: Predicted Open Pit Groundwater Inflows
U.S.
Gold contracted AFK Mining to develop a mine design and schedule for the Project. The final mine design is guided by the pit optimization
described in Section 12.1.1. The final mine design is comprised of four phases to divide and schedule the excavation. Design parameters
are suitable for the mining equipment selected and the geotechnical parameters provided in Section 13.2.
13.4.1 | Mine
Design Parameters |
A
summary of the mine design parameters is shown in Table 13.2.
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154 |
Table
13.2: Mine Design Parameters |
Parameter |
Value |
Road
Width (Dual/Single) |
90
ft / 70 ft |
Road
Gradient |
10% |
Bench
Height (Single/Quad) |
30
ft / 90 ft |
Catch
Bench |
Every
3 benches |
Catch
Bench Width |
31
ft – 41 ft |
Face
Angle |
75
degrees |
Inter-Ramp
Angle |
52-55
degrees |
The
primary driver of the mine schedule is the production of sufficient ore, which drives the excavation of waste and other materials to
ensure sufficient ore is exposed for mining. The nominal ore production rate was set at 20,000 stpd or 7.3 Mstpy (18,100 t/calendar day,
or 6.6 Mt/year) of ore delivered to the crusher. In the first year, ore production is 90% of full capacity to account for commissioning
of the concentrator. Mine life is approximately eight years with almost another two years of ore stockpile processing.
Pre-production
stripping is scheduled for the year before production begins (Year -2 Q1) which consists of 700,000 st of material. There are no other
development requirements to achieve the mine schedule.
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155 |
Table
13.3: Mine Schedule |
|
Ore
Mined |
Waste
Mined |
Total
Material
Mined |
|
Ore
to
Stockpile |
Stkple
Mined |
|
Mill
Total |
Au
(oz/st) |
Cu
(%) |
Ag
(oz/st) |
Au
(000's
Ounces) |
Cu
(Mlbs) |
Ag
(000's
Ounces) |
Total |
73,200
|
68,100
|
141,300
|
|
24,300
|
24,300
|
|
73,200
|
0.0140
|
0.177
|
0.0411
|
1,022
|
260
|
3,008
|
Year-2 |
- |
700
|
700
|
|
- |
- |
|
- |
|
|
|
|
- |
|
Year-1 |
- |
- |
- |
|
- |
- |
|
- |
- |
- |
- |
- |
- |
- |
Year
1 |
10,400
|
9,100
|
19,500
|
|
4,000
|
200
|
|
6,570
|
0.0264
|
0.231
|
0.0685
|
173
|
30
|
450
|
Year
2 |
13,000
|
6,500
|
19,500
|
|
6,200
|
500
|
|
7,300
|
0.0201
|
0.205
|
0.0535
|
147
|
30
|
391
|
Year
3 |
9,500
|
10,000
|
19,500
|
|
2,900
|
700
|
|
7,300
|
0.0146
|
0.187
|
0.0392
|
107
|
27
|
286
|
Year
4 |
6,400
|
13,100
|
19,500
|
|
2,000
|
2,900
|
|
7,300
|
0.0151
|
0.185
|
0.0455
|
111
|
27
|
332
|
Year
5 |
8,200
|
11,300
|
19,500
|
|
1,600
|
700
|
|
7,300
|
0.0146
|
0.183
|
0.0354
|
107
|
27
|
259
|
Year
6 |
7,600
|
11,900
|
19,500
|
|
1,700
|
1,400
|
|
7,300
|
0.0124
|
0.185
|
0.0345
|
91
|
27
|
252
|
Year
7 |
12,400
|
4,400
|
16,800
|
|
5,100
|
- |
|
7,300
|
0.0126
|
0.192
|
0.0324
|
92
|
28
|
237
|
Year
8 |
5,800
|
1,000
|
6,800
|
|
800
|
2,300
|
|
7,300
|
0.0120
|
0.182
|
0.0325
|
87
|
27
|
237
|
Year
9 |
- |
- |
- |
|
- |
7,300
|
|
7,300
|
0.0064
|
0.113
|
0.0340
|
47
|
17
|
248
|
Year10 |
- |
- |
- |
|
- |
7,300
|
|
7,300
|
0.0074
|
0.123
|
0.0383
|
54
|
18
|
280
|
Year
11 |
- |
- |
- |
|
- |
945
|
|
945
|
0.0065
|
0.125
|
0.0388
|
6
|
2
|
37
|
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156 |
13.6 | Mining
Fleet Requirements |
The
basis for the calculation of mining fleet is the mining schedule and the haulage model. The amount and type of material moved, and the
destination of that material determines the total number operational hours that is needed for each category of mining equipment. The
total operational hours required then determine the number of units needed and costs associated with operation.
Owner
operator mining has been selected as the preferred method for the purposes of this PFS. The owner will also operate the mine planning,
ore control, process plant and general site administration (G&A). This decision is due to the location of the Project, local mining
and the availability of potential labor within 30 miles of the site (Laramie and Cheyenne, Wyoming). Hybrid owner/contractor operations
are still being evaluated to leverage the regional mine contractor expertise and possible reduction in project capital costs.
13.6.1 | Equipment
Productivity and Usage |
For
major pieces of mining equipment, the productivity of each unit is estimated based on manufacturer specifications, job site parameters
and observed parameters from similar surface mines. Mining equipment has either a variable annual usage basis on the mining schedule
or a fixed annual usage. Variable usage equipment has a maximum number of annual hours available for work and a productivity associated
with it, shown in Table 13.4. The annual available hours for each piece of equipment are based on the expected availability and utilization.
6,300 hours per year equates to an availability and utilization of approximately 85% each except for drills and dozers at 80%. Table
13.5 shows the annual fleet hours and unit requirements.
Table
13.4: Variable Usage Equipment |
Equipment |
Annual
Hours
Available |
Productivity |
Units |
Excavator |
6,300 |
1,950 |
stph |
Loader |
6,300 |
1,500
|
stph |
Haul
Truck |
6,300 |
430
- 250 |
stph |
Dozer |
5,600 |
1,000 |
stph |
Drill |
5,600 |
1,000 |
stph |
Table
13.5: Annual Schedule of Variable Usage Equipment |
Year |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
Total |
Excavator
Hours (000s) |
6.2 |
6.2 |
6.2 |
6.2 |
6.2 |
6.2 |
6.2 |
3.5 |
|
|
|
46.9 |
Excavator
Units |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
|
|
|
1 |
Loader
Hours (000s) |
9.4 |
10.1 |
10.3 |
11.8 |
10.3 |
9.8 |
8 |
6.4 |
9.7 |
9.7 |
1.3 |
96 |
Loader
Units |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
1 |
2 |
Truck
Productivity (stph) |
499 |
445 |
582 |
372 |
409 |
361 |
381 |
250 |
226 |
223 |
|
375 |
Truck
Hours Req’d 000s) |
52.2 |
60.2 |
46.1 |
72 |
65.5 |
72.4 |
56.7 |
47.2 |
32.3 |
28.5 |
3.2 |
536 |
Truck
Units |
10 |
10 |
10 |
10 |
10 |
10 |
10 |
8 |
6 |
6 |
2 |
10 |
Dozer
Hours (000s) |
18.5 |
23.3 |
22.6 |
21.2 |
20.3 |
19.5 |
20.1 |
17.9 |
17 |
17 |
7.5 |
205 |
Dozer
Units |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
3 |
4 |
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157 |
Haul
truck productivity is variable and is based on a haulage model that calculates cycle times based on the location of the material mined
and the destination. Cycle times and the mine schedule are used to estimate the truck hours needed to meet the schedule. The annual available
hours are based on the distance and the average speed for the haulage segment, with allowances for loading, dumping, and waiting. For
excavators and wheel loaders the estimated productivity is based on the calculated loading times to position and fill the selected haul
trucks. Dozer productivity is based on manufacturer nomographs. Blasthole drill productivity is based on average penetration rates and
blast spacing to break the scheduled rock. Other minor and support equipment does not have a calculated productivity, but a fixed annual
usage is assigned based on similar surface mining operations. Table 13.6 shows the fleet size and scheduled hours for the fixed usage
equipment.
Table
13.6: Fixed Usage Equipment |
Equipment |
Hours
Scheduled
per
Unit |
Fleet
Size |
Water
Truck |
3,000 |
1 |
Motor
Grader |
3,000 |
1 |
Service/Fuel
Truck |
6,000 |
1 |
Crane
Truck |
1,000 |
1 |
Excavator |
3,000 |
1 |
13.7 | Mine
Personnel Requirements |
Hourly
mine personnel requirements for equipment operators and mechanic labor are based on the annual equipment hourly usage. Salaried based
employees are specified at typical staffing levels. All hourly mine employees and supervision of all mine employees are by the mine owner.
The owner also provides Site General and Administrative (Site G&A) labor, mine planning and engineering, and environmental compliance.
Table 13.7 shows the total project employment over the life of the Project and subsequent tables provide mine employment, Table 13.8;
Mine Employment, Table 13.9; Tailings Disposal Employment, and Table 13.10 Site G&A Employment.
Table
13.7: Project Employment |
Year |
-2 |
-1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
Max |
Total
Project Employment |
14
|
15
|
173
|
174
|
174
|
174
|
174
|
174
|
174
|
141
|
112
|
105
|
63
|
174
|
Mine
Employment |
5
|
2
|
111
|
108
|
108
|
108
|
108
|
108
|
108
|
79
|
58
|
51
|
22
|
112
|
Tailings
Employment |
0 |
0 |
40 |
44 |
44 |
44 |
44 |
44 |
44 |
40 |
36 |
36 |
24 |
44 |
Site
G&A |
9
|
13
|
22
|
22
|
22
|
22
|
22
|
22
|
22
|
22
|
18
|
18
|
17
|
22
|
Table
13.8: Mine Employment |
Year |
-2 |
-1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
Max |
Mine
Employment |
5
|
2 |
112 |
108 |
108 |
108 |
108 |
108 |
108 |
79 |
58 |
51 |
22 |
112 |
Loading
and Hauling |
- |
- |
48 |
44 |
44 |
44 |
44 |
44 |
44 |
34 |
26 |
26 |
8 |
48 |
Excavator/Loader
Orators |
- |
- |
8
|
8
|
8
|
8
|
8
|
8 |
8 |
8 |
4 |
4 |
2 |
8 |
 |
158 |
Table
13.8: Mine Employment |
Year |
-2 |
-1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
Max |
Mine
Employment | 5 |
2 |
112 |
108 |
108 |
108 |
108 |
108 |
108 |
79 |
58 |
51 |
22 |
112 |
Truck
Operators |
- |
- |
24
|
20
|
20
|
20
|
20 |
20 |
20 |
16 |
12 |
12 |
4 |
24 |
Mechanics/Welders |
- |
- |
16
|
16
|
16
|
16
|
16
|
16
|
16
|
10
|
10
|
10
|
2
|
16 |
Drill
and Blast (CONTR) |
5 |
0 |
26 |
26 |
26 |
26 |
26 |
26 |
26 |
11 |
0 |
0 |
0 |
26 |
Lead
Blaster (Contractor) |
1
|
- |
1
|
1
|
1
|
1
|
1 |
1 |
1 |
1 |
0 |
0 |
0 |
1 |
Equipment
Operators |
1
|
- |
16
|
16
|
16
|
16
|
16
|
16 |
16 |
6 |
0 |
0 |
0 |
16 |
Labor |
3
|
- |
3
|
3
|
3
|
3
|
3 |
3 |
3 |
3 |
0 |
0 |
0 |
3 |
Mechanics/Welders |
- |
- |
6
|
6
|
6
|
6
|
6
|
6
|
6
|
1
|
0
|
0 |
0 |
6 |
Mine
Support |
- |
- |
33
|
33
|
33
|
33
|
33
|
33
|
33
|
29
|
27
|
22
|
11
|
33 |
Equipment
Operators |
- |
- |
21
|
21
|
21
|
21
|
21
|
21
|
21
|
17
|
17
|
14
|
8
|
21 |
Labor |
- |
- |
8
|
8
|
8
|
8
|
8
|
8
|
8
|
8
|
8
|
6
|
1
|
8 |
Mechanics/Welders |
- |
- |
4
|
4
|
4
|
4
|
4
|
4
|
4
|
4
|
2
|
2
|
2
|
4 |
Mine
G&A |
- |
2 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
5 |
3 |
3 |
5 |
Mine
Manager |
- |
1
|
1
|
1
|
1
|
1
|
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Mine
Foreman |
- |
1
|
4
|
4
|
4
|
4
|
4 |
4 |
4 |
4 |
4 |
2 |
2 |
4 |
Table
13.9: Tailings Disposal Employment |
Year |
-2 |
-1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
Max |
Tailings
Disposal Employment |
0 |
0 |
40 |
44 |
44 |
44 |
44 |
44 |
44 |
40 |
36 |
36 |
24 |
44 |
Tailings
Foreman |
0 |
0 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
Technician |
0 |
0 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
Loader
Operators |
0 |
0 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
2 |
4 |
Truck
Operators |
0 |
0 |
16 |
20 |
20 |
20 |
20 |
20 |
20 |
16 |
12 |
12 |
2 |
20 |
Equipment
Operators |
0 |
0 |
16 |
16 |
16 |
16 |
16 |
16 |
16 |
16 |
16 |
16 |
16 |
16 |
Table
13.10: Site G&A Employment |
Year |
-2 |
-1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
Max |
Site
G&A Total |
9
|
13 |
22 |
22 |
22 |
22 |
22 |
22 |
22 |
22 |
18 |
18 |
17 |
22 |
Accountant |
1
|
1
|
1
|
1
|
1
|
1
|
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1
|
Admin/Contract |
1
|
2
|
2
|
2
|
2
|
2
|
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
Safety/Trainer |
0 |
3
|
3
|
3
|
3
|
3
|
3 |
3 |
3 |
3 |
3 |
3 |
3 |
3 |
Warehouse
Clerk |
0 |
1
|
1
|
1
|
1
|
1
|
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
Payroll |
2
|
2
|
2
|
2
|
2
|
2
|
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
Engineer |
0 |
0 |
3
|
3
|
3
|
3
|
3 |
3 |
3 |
3 |
2 |
2 |
2 |
3 |
Geologist |
0 |
0 |
2
|
2
|
2
|
2
|
2 |
2 |
2 |
2 |
0 |
0 |
0 |
2 |
Technician |
1
|
0 |
4
|
4
|
4
|
4
|
4 |
4 |
4 |
4 |
3 |
3 |
2 |
4 |
Security |
4
|
4
|
4
|
4
|
4
|
4
|
4 |
4 |
4 |
4 |
4 |
4 |
4 |
4 |
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159 |
13.8 | Mine
END OF YEAR MapS |
End
of year topographic maps showing the excavation progression are shown for Year 1, Figure 13.6; Year 3, Figure 13.7; Year 5, Figure 13.8;
and Year 8 final pit limits, Figure 13.9.
13.9 | 2025
PFS vs 2021 PFS Mining METHODS |
AKF
completed the 2021 PFS final design pits and phases based on the 2021 PFS geotechnical report. In May 2024 Pre-Feasibility Study Geotechnical
report was to update the bench height parameters from 20ft to 30ft.

Figure
13.6: Mine Map End of Year 1
 |
160 |

Figure
13.7: Mine Map End of Year 3
 |
161 |

Figure
13.8: Mine Map End of Year 5
 |
162 |

Figure
13.9: Mine Map End of Mine Life Year 8
 |
163 |
14.0 | Processing
and Recovery Methods |
he
CK Gold processing facility has been designed to process 20,000 stpd of gold/copper sulfide ore. The processing facility and the unit
operations therein are designed to produce a concentrate at 17.0% Cu or greater, with an average gold grade of 41 g/st.
The
processing facility will consist of a ROM crushing circuit, crushed ore storage, a semi-autogenous grinding (SAG) mill/ball mill comminution
circuit, rougher flotation, regrind circuit, and cleaner flotation to liberate, recover, and upgrade the copper and gold from the ROM
ores. Flotation concentrate will be thickened, filtered, sent to a concentrate load-out bin, and bagged for subsequent shipping.
Tailings
from the process will be filtered and conveyed to a tailings bin, where the dry-filtered cake will be loaded into a haul truck for transportation
to the dry-stack tailings facility.
The
process plant will consist of the following unit operations and facilities:
| ● | Coarse
ore receiving and storage area from the open pit mine. |
| ● | Jaw
crushing system, crushed ore stockpile, and stockpile reclaim system to convey crushed ore
to the process. |
| ● | SAG/Ball
mill circuit incorporating cyclones for classification. |
| ● | SAG
mill pebble crushing circuit. |
| ● | Rougher
flotation circuit. |
| ● | Rougher
concentrate regrinding circuit. |
| ● | Cleaner
flotation circuit incorporating three flotation stages and cleaner scavenger flotation cells. |
| ● | Concentrate
thickening and filtration circuit, including a concentrate bin and bagging station. |
| ● | Tailings
thickening and filtration circuits. |
| ● | Tailings
disposal at a dry-stack storage facility. |
| ● | Reagent
handling, utilities, process water, and fresh-water systems |
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164 |
The
block flow diagram for the processing facility is shown below in Figure 14.1

Figure
14.1: Block Flow Diagram – Processing Facility
14.2.1 | Major
Design Criteria |
The
processing facilities were designed to process 20,000 stpd, equivalent to 7,300,000 stpy. The major design criteria used in the design
are outlined in Table 14.1.
Table
14.1: Major Design Criteria |
Criteria |
Unit |
Value |
Operating
Days per Year |
day/y |
365 |
Plant
Availability (Crushing) |
% |
65.0 |
Plant
Availability (Concentrate) |
% |
92.0 |
Mine
Life |
y |
10 |
Daily
Dry ROM Feed |
stpd |
20,000 |
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165 |
Annual
Dry ROM Feed |
stpy |
7,300,000 |
Copper
Feed Assay |
% |
0.176 |
Gold
Feed Assay |
g/mt |
0.48 |
Gold
Feed Assay |
ozt/st |
0.014 |
Annual
Dry Concentrate Production |
stpy |
61,063 |
Annual
Dry Concentrate Production |
mtpy |
55,396 |
Copper
Concentrate Assay |
% |
17.0 |
Gold
Concentrate Assay |
g/mt |
45.2 |
Gold
Concentrate Assay |
ozt/st |
1.32 |
Copper
Recovery |
% |
72.4 |
Gold
Recovery |
% |
68.1 |
14.2.2 | Operating
Schedule and Availability |
The
processing plant will be designed to operate in two 12-hour shifts per day, 365 days per year.
The
crushing circuit availability is expected to be 65% throughout the LOM, and the comminution and flotation circuit availability is expected
to be 92% throughout the LOM. This will allow sufficient downtime for scheduled and unscheduled maintenance of process plant equipment.
Major
scheduled maintenance commonly requires five consecutive days and occurs twice yearly (10 days total). The remaining 19.2 operating days
per year allocated to maintenance reflect minor scheduled and unscheduled maintenance.
14.3 | PROCESS
PLANT DESCRIPTION |
Ore
from the open pit will be delivered by haul trucks (or loader) to a dump hopper, where an apron feeder will feed the ore across a vibrating
grizzly. The fine material will fall through to a discharge conveyor, and the oversize will report to the jaw crusher. The discharge
from the jaw crusher will report to the same discharge conveyor and be conveyed to the crushed ore stockpile.
The
crushing circuit will be equipped with a fog dust suppression system to control the fugitive dust generated during ore dumping and crushing.
14.3.2 | Crushed
Ore Stockpile and Reclaim |
The
crushed ore stockpile will have a live ore capacity of 13,333 st (16 hours) and a total capacity of 30,000 st (36 hours). Ore from the
crushed ore stockpile will be reclaimed using apron feeders under controlled feed rate conditions. These feeders will discharge the reclaimed
ore onto a conveyor belt feeding the semi-autogenous mill (SAG mill).
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166 |
A
belt scale will control the feed to the SAG mill by controlling the rate at which the apron feeders operate.
The
grinding circuit will be a comminution circuit with a SAG mill in series with a ball mill. It will be a two-stage operation with the
SAG mill in a closed circuit with a pebble crusher and the ball mills in a closed circuit with the classifying hydrocyclones. The SAG
mill will be equipped with pebble ports to remove coarse pebbles. Grinding will be conducted as a wet process at a nominal rate of 906
stph of material (dry basis).
The
grinding circuit will include:
| ● | SAG
mill feed conveyor. |
| ● | Pebble
crusher feed and discharge belts. |
| ● | Conveyor
belts. |
| ● | Conveyor
belt weigh scales and metal detectors. |
| ● | SAG
mill, 34 ft diameter x 15 ft, 2 x 6,000 hp motors. |
| ● | Ball
mill, 22 ft diameter x 35.5 ft , 2 x 6,000 hp motors. |
| ● | Pebble
crusher, 500 hp. |
| ● | SAG
mill discharge vibrating screens. |
| ● | Cyclone
feed slurry pumps. |
| ● | Hydrocyclone
cluster with 14 (11 operating, three spare) hydrocyclones. |
Crushed
ore reclaimed from the stockpiles will be fed to the SAG mill at a controlled rate. Water will be added to the SAG mill feed for wet
ore grinding. The SAG mill will generally operate at 78% of its theoretical critical speed.
The
SAG mill discharge will be equipped with pebble ports to remove critical-size material. Oversize material removed at the SAG mill discharge
will be conveyed via transfer conveyors to the pebble crusher. A cone crusher will crush the pebbles to a P80 of 0.5 inch.
The crushed material will be returned to the conveyor belt feeding the SAG mill for further grinding. The SAG mill discharge screen underflow
will be discharged into the cyclone feed pumpbox.
The
ball mill, subsequent to the SAG mill, will operate in closed-circuit with classification hydrocyclones mounted in a cluster. The product
from the ball mill will be discharged into the cyclone feed pumpbox combining with the SAG mill discharge to become the cyclone feed.
The classification size for the cyclones will be a P80 of 90 µm, and the circulating load to the ball mills will be
targeted at 250% with the cyclone underflow returning to the ball mill as feed material. Dilution water will be added to the grinding
circuit as required.
Cyclone
overflow from the classification circuit will discharge into the feed of the rougher flotation circuit at the head of the flotation process.
The pulp density of the cyclone overflow slurry will be approximately 37% solids.
Grinding
media will regularly be added to the SAG and ball mills to maintain charge level and grinding efficiency. An automatic ball charging
system will add steel balls to each mill.
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167 |
14.3.4 | Flotation
and Regrind Circuits |
Milled
pulp will be processed using rougher flotation to recover the targeted minerals. The regrinding of rougher concentrate and cleaner flotation
processes will be used to upgrade the rougher concentrate further into a high-grade copper/gold concentrate. Tank style flotation cells
will be used in the rougher flotation, 1st and 2nd cleaner flotation, and the cleaner scavenger flotation. The
3rd cleaner flotation will be performed in a column flotation cell.
The
flotation circuit will include the following equipment:
| ● | Flotation
reagent addition facilities. |
| ● | Rougher
flotation tank cells, 5 x 7,063 ft3 each. |
| ● | Regrind
tower mill feed distribution box. |
| ● | One
concentrate regrind tower mill, 2,000 hp. |
| ● | Regrind
cyclone feed pumpbox. |
| ● | Regrind
circuit classification cyclone cluster. |
| ● | 1st
cleaner flotation tank cells – 4 x 706 ft3 each. |
| ● | Cleaner
scavenger flotation tank cells – 5 x 353 ft3 each. |
| ● | 2nd
cleaner flotation tank cells – 4 x 353 ft3 each. |
| ● | 3rd
cleaner column flotation cell, 10 ft diameter x 26 ft tall. |
| ● | Pumpboxes
and standpipes. |
| ● | Slurry
and concentrate pumps. |
| ● | Sampling
system. |
The
cyclone overflow from the grinding circuit will feed the flotation circuit by gravity flow from the ball mill grinding circuit cyclone
cluster. The slurry will be monitored for P80 particle size, and flotation feed samples will be taken periodically for process
control and metallurgical accounting.
Cyclone
overflow from the ball mill will discharge into the feed end of the five rougher flotation cells operating at a design solids total feed
rate of 906 stph. Flotation reagents will be added to the flotation circuit as defined through testing. The flotation reagents added
will be the collectors, PFSPD as well as PF7150 and the frother, MIBC. Provision will be made for supplementary reagent addition to the
cleaner stages of the flotation circuit.
The
sulfide minerals will be selectively floated into a rougher concentrate away from the other minerals-gangue components present in the
ore slurry. The rougher concentrate will constitute approximately 10.4% mass of the plant feed. The rougher tailings will be sampled
automatically before being discharged into the final tailings pumpbox for process control and metallurgical accounting purposes. The
tailings thickener pumpbox will also receive the cleaner scavenger tailings. This combined stream will constitute the final tailings
leaving the plant.
Regrinding
and upgrading via cleaner flotation will be incorporated to more fully liberate the fine grains of sulfide minerals from the gangue constituents
and enhance the copper/gold concentrate grade. A single stage of regrinding, three stages of cleaner flotation, and a stage of cleaner
scavenger flotation are the selected methods for producing a final concentrate of acceptable grade and recovery.
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168 |
Rougher
concentrate enters the cleaner flotation section and is combined with regrind mill discharge at the regrind cyclone feed pumpbox. The
regrind circuit cyclone cluster separates reground flotation concentrate into a fine cyclone overflow product and a coarse cyclone underflow
product according to a target design particle size P80 22 µm. The regrind mill will be a single vertical stirred tower
mill. The regrind mill will discharge finely milled material into a cyclone feed pumpbox. This will be combined with rougher flotation
concentrate and the cleaner scavenger concentrate, constituting the feed for classification by the cyclones.
The
regrind cyclone overflow will become feed to the 1st cleaner flotation stage. Tailings from the 1st cleaner stage
will report directly to the cleaner scavenger flotation stage. Tailings from the cleaner scavenger flotation stage will report to the
final tailings pumpbox. The 1st cleaner scavenger concentrate will report to the regrind cyclone feed pumpbox for re-classification.
The
1st cleaner concentrate will feed the 2nd cleaner flotation stage. The 2nd cleaner concentrate will
be fed to the 3rd cleaner column flotation cell. Tailings from the 3rd cleaner stage will be recycled back to the
feed of the second cleaner stage. The concentrate of the 3rd cleaner stage will be the final concentrate with a design copper
concentrate grade of 17.0% and a design gold grade of 41 g/st.
The
concentrate will feed directly to the concentrate thickener for dewatering. Provision will be made for the copper concentrate thickener
overflow water to be re-used in the grinding and flotation circuit as process water, providing this does not have a deleterious effect
on the flotation of the sulfide minerals.
14.3.5 | Concentrate
Handling |
Cleaner
flotation concentrate will be thickened, filtered, and stored before shipment. The concentrate handling circuit will have the following
equipment:
| ● | Concentrate
thickener of 29-foot diameter. |
| ● | Concentrate
thickener overflow pumps. |
| ● | Concentrate
thickener underflow slurry pumps. |
| ● | Concentrate
filter feed tank. |
| ● | Concentrate
filter press feed pumps. |
| ● | Concentrate
filter press. |
| ● | Filter
press washing and filtrate handling equipment. |
The
copper concentrate produced will be pumped from the 3rd cleaner flotation stage to the concentrate thickener feed well. Flocculant
will be added to the thickener feed to aid the settling process. Thickened concentrate will be pumped to the concentrate filter feed
tank using thickener underflow slurry pumps. The underflow density will be approximately 62% solids. The concentrate filter feed tank
will be agitated. The concentrate filter will be a vertical filter press. Since filtration will be a batch process, the concentrate filter
feed tank will also act as a surge tank for the filtration operation. The filter press will dewater the concentrate, producing a final
concentrate with a moisture content of approximately 10%. Filtrate will be returned to the concentrate thickener. Filter press solids
will be discharged directly onto the concentrate filter cake bin. Dewatered concentrate will be stored in the concentrate filter cake
bin to be loaded into supersack bags. Concentrate thickener overflow will be collected in the process water tank for recycling within
the mill circuit.
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169 |
The
final tailings for the Open Pit Process Facility will be thickened, filtered, and dry-stacked in the tailings compound.
The
following process equipment will be required in the tailings handling area:
| ● | Tailings
thickener at 138-foot diameter. |
| ● | Tailings
thickener overflow pumps. |
| ● | Tailings
thickener underflow slurry pumps. |
| ● | Tailings
filter feed tank (with agitator). |
| ● | Tailings
filter feed pumps. |
| ● | Three
tailings filter presses. |
| ● | Filter
press washing and filtrate handling equipment. |
| ● | Filter
press belt feeders. |
| ● | Filter
press transfer conveyor. |
| ● | Tailings
filter cake bin. |
The
rougher flotation tailings, together with the cleaner scavenger tailings, will be the final plant tailings. This combined stream will
be pumped to the tailings filtration area, where it will be thickened and filtered, producing dry stack tailings as part of the tailings
handling process. Once filtered, these tailings will be loaded into trucks and hauled to the tailings impoundment area for dry stacking.
The
final plant tailings will initially be thickened in the tailings thickener to an underflow density of 60% solids. Flocculant will be
used to facilitate the settling of the solids and aid in supernatant clarity.
Thickened
tailings will be pumped to the tailings filter feed tank using thickener underflow slurry pumps. The tailings filter feed tank will be
agitated. Tailings filtration will be done in multiple filter press units. Since filtration will be a batch process, the tailings filter
feed tanks will also act as a surge tank for the filtration operation. There will be six presses, and each filter press will dewater
the tailings to produce a “dry” cake with a moisture content of about 14%. The filtrate will be returned to the process water
pond. The filter press solids will be discharged onto belt feeders, which in turn feed the transfer conveyor, which will feed the tailings
filter cake bin.
Thickening
and filtration of the tailings will facilitate the recovery of process water required for re-use in the plant before the final deposition
of the plant tailings. Reclaim process water will be recovered as overflow from the tailings thickener and as filtrate from the tailings
filters.
14.3.7 | Reagent
Handling and Storage |
Various
chemical reagents will be added to the process slurry streams to facilitate the recovery of the copper and gold minerals during the flotation
process. Preparation of the various reagents will require:
| ● | A
bulk handling system. |
| ● | Mix
and holding tanks. |
| ● | Metering
pumps. |
| ● | A
flocculant preparation facility. |
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170 |
| ● | A
lime mixing and distribution facility. |
| ● | Eye-wash
stations and safety showers. |
| ● | Applicable
safety equipment. |
Various
chemical reagents will be added to the grinding and flotation circuit to modify the mineral particle surfaces and enhance the floatability
of the valuable mineral particles into the concentrate product. Fresh water will be used to prepare the various reagents, which will
be supplied in powder/solids form or as solutions, which require dilution prior to addition to the slurry. These reagent solutions will
be added at the addition points of the various flotation circuits and streams using metering pumps.
The
PFSPD and PF7150 collector reagents will arrive at the plant as a solution in reagent totes. The solution will be pumped from the reagent
totes directly to additional points in the circuit. The frother reagent, MIBC, will be delivered in bulk, transferred to a holding tank,
and pumped to the appropriate addition points using metering pumps.
Flocculant
will be prepared in a flocculant mix system to produce a dilute solution with a 0.40% weight solution strength. This solution will be
further diluted using in-line mixers. Two flocculant make-up facilities will be required, one for the concentrate area and one for the
dry stack tailings area.
Hydrated
lime will be delivered in bulk and will be off-loaded pneumatically into a silo. The lime slurry will then be prepared as a 20% weight
concentration slurry in a lime mixing tank. This lime slurry will be pumped to the points of addition. Discharge valves on the closed
loop will be controlled by pH monitors that will regulate the amount of lime added.
Grinding
media will be added to the various mills used throughout the process as required. Mill charging will be conducted using automatic ball
charging systems.
The
estimated consumption rate for grinding media is based on historical data from similar projects, using the average abrasion index of
the deposit and the estimated equipment power consumption. To ensure spill containment, the reagent preparation and storage facility
will be located within a containment area designed to accommodate 110% of the content of the largest tank. In addition, each reagent
will be prepared in its own bounded area to limit spillage and facilitate its return to its respective mixing tank. The storage tanks
will be equipped with level indicators and instrumentation to ensure that spills do not occur during normal operation. Appropriate ventilation,
fire, safety protection, emergency shower and eye wash stations, and Material Safety Data Sheet stations will be provided at the facility.
Each reagent line and addition point will be labeled following the Mine Safety and Health Administration (MSHA) standards. All operational
personnel will receive MSHA training and additional training for safely handling and using the reagents.
The
process plant will have individual fresh and process water distribution systems. The freshwater supply will come from mine dewatering
and purchased water from local sources.
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171 |
14.3.9 | Fresh-Water
Supply System |
Fresh
water from the combined fresh and fire water tank will be supplied to each area. Fresh water will be used primarily for the following:
| ● | Fire
water for emergency use. |
| ● | Dust
suppression in the crushing system. |
| ● | Gland
service for slurry pumps. |
| ● | Reagent
preparation water. |
| ● | Concentrate
and tailings filter wash water. |
| ● | Make
up water for the main process facility. |
The
fresh/fire water tank will be equipped with a fresh-water standpipe to ensure that at least half of the 1,227,000 US gallon tank is available
for fire water supply.
14.3.10 | Process
Water Supply System |
Process
water recovered from the concentrate and tailings thickener overflows will be re-used in the plant’s process circuit via the facility’s
process water pond.
Reclaimed
water from the concentrate and tailings filters will be recycled back to the process water pond for distribution to the usage points.
As process water demand in the flotation and grinding circuit is expected to be greater than the amount reported to the process water
pond, including the portion returning from the tailings facility, fresh water make-up will be required for the main process.
Process
air service system will supply air to the following areas:
| ● | Low-pressure
air for flotation cells. |
| ● | Drying
air and pressing air for the concentrate filter press operation. |
| ● | Drying
air and pressing air for tailings filter press operations. |
| ● | Air
compressors are also supplied for general plant distribution. |
| ● | Instrument
air will be prepared from the plant air compressors, dried, and stored in a dedicated air
receiver. |
14.3.12 | Process
Plant Manpower |
Process
plant salaried personnel estimates were developed to provide adequate supervision and technical support for the daily operation of the
process facility. The required salaried personnel for the process facility is estimated at 13 persons, as detailed in Table 14.2.
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172 |
Table
14.2: CK Gold Salaried Personnel |
Area |
Position |
Count |
Management |
|
4 |
|
Plant
Manager |
1 |
|
Maintenance
Manager |
1 |
|
Assistant
Mill Manager |
1 |
|
Operations
Clerk |
1 |
|
|
|
Technical |
|
3 |
|
Chief
Metallurgist |
1 |
|
Senior
Metallurgist |
1 |
|
Junior
Metallurgist |
1 |
|
|
|
Operations |
|
4 |
|
Shift
Supervisor |
4 |
|
|
|
Maintenance |
|
2 |
|
Maintenance
Foreman (day) |
1 |
|
Maintenance
Planner (day) |
1 |
|
|
|
Total
Salaried Manpower |
13 |
Salaried
personnel will supervise a total of 65 hourly employees, as detailed in Table 14.3. Process positions, both salaried and hourly, that
require 24-hour coverage per day will be staffed by rotating 12-hour shifts.
Table
14.3: CK Gold Hourly Personnel |
Area |
Position |
Count |
Operations |
|
41 |
|
Control
Room Operator (shift) |
4 |
|
Crusher/Conveying
Area Lead Operator (day) |
4 |
|
Crusher/Conveying
Area Laborer (day) |
4 |
|
Shift
Operators Grinding |
4 |
|
Shift
Operators Flotation |
4 |
|
Shift
Operators Concentrate Handling/Bagging |
8 |
|
Shift
Operators Tailings Thickening/Filtration |
4 |
|
Reagent
Area Operators (day) |
1 |
|
Utility
Operator (day) |
2 |
|
Non-Specialty
Operator (Roaming) |
4 |
|
Concentrator
General Laborer (day) |
2 |
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173 |
|
|
|
Maintenance |
|
24 |
|
Electrician
(shift) |
4 |
|
Mechanical
Fitter (shift) |
4 |
|
Mechanical
Fitter (day) |
4 |
|
Boilermaker
(day) |
2 |
|
Electrician
(day) |
3 |
|
Instrument
Technician (day) |
2 |
|
Trades
Assistant (day) |
5 |
|
|
|
Total
Hourly Manpower |
65 |
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174 |
15.1.1 | Project
Access Road |
As
shown in Figure 15.1, the CK Gold Project (Project) access road is a gravel road that initiates at County Road 210 (also named Crystal
Lake Road), heads south and then west to the Project site boundary. The access road is approximately 4.2 miles long and 26 ft wide, generally
centered along a 60-foot-wide right-of-way. The Project site boundary extends to County Road 210 following the access road right-of-way.
A typical cross section of the access road is shown on Figure 15.2.
Fencing
will be installed along the right-of-way boundary. The access road does not cross any streams. The material for sub-base, base, and gravel
surfacing will be sourced from borrow areas within the Project site.
Access
road construction will be one of the first tasks performed in the construction phase, following stripping and stockpiling of topsoil.
The Project will obtain a permit for the access road connection to County Road 210 from Laramie County.

Figure
15.1: Project Access Road
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175 |
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Figure
15.2: Typical Cross Section of the Access Road
Ex-pit
haul roads are designed to be 80 ft in width to accommodate 100 st haul trucks and will generally follow the existing two-track roads
within the Project area where possible. Construction of the internal haul roads assumes that material for the haul roads can be sourced
from within the Project area from the pit.
15.2 | Ore
Stockpile and Waste Rock Facilities |
The
Project will utilize an Ore Stockpile storage facility for storing mineralized material and the West and East Waste Rock (storage) Facilities
(WWRF/EWRF) for storing non-mineralized material from the pit. Figure 15.3 (in the next section) shows the location of each storage area
in proximity to the pit, mill area, truck area, and Tailings Management Facility (TMF). Each storage facility will have the topsoil stripped
and stockpiled in designated areas prior to placing rock material.
The
Ore Stockpile is located entirely within Section 36 in the valley to the south and west of the pit. It will be used to store up to 20
Mst of mineralized material for future processing. The Ore Stockpile will have a composite liner system (CLS) consisting of geomembrane
overlying a prepared subgrade of compacted Project area clays and silts. The CLS will have an effective permeability of 10-7
cm/s or lower, as required by the DEQ – WQD. The Ore Stockpile CLS will be covered with a gravel protection layer to allow for
Project equipment to place mineralized material. An underdrain will be installed prior to installing the CLS and a collection drain will
be installed prior to receiving mineralized material. The Ore Stockpile is designed to have a stack height of up to approximately 214
ft for a top elevation of 7,230 ft above mean sea level (amsl). Erosion control measures will also be implemented to control stormwater
runoff. Future studies should develop a stacking plan for the ore stockpile and evaluate slope stability including the liner interface.
As
a final note, the Ore Stockpile facility is a temporary facility as the Ore Stockpile will be completely depleted over the life-of-mine.
Once the Ore Stockpile facility has been depleted, the CLS will be removed, topsoil replaced, and revegetation performed for closure
purposes.
Table
15.1 summarizes estimated cut and fill volumes associated with haul road construction for the Project. The road construction costs are
included in the mining costs.
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176 |
Table
15.1: North and South Haul Road Quantities |
|
North |
South |
Total |
Haul
Rd Const. / Cut (BCY) |
12,850 |
132,200 |
145,050 |
Haul
Rd Const. / Fill (LCY) |
358,450 |
779,100 |
1,137,550 |
15.2.2 | West
and East Waste Rock Facilities |
The
WWRF and EWRF are located mostly in Section 36 and partially in Section 31 in the valley in the ephemeral Middle tributary to Middle
Crow Creek (to the southeast of the pit). The WWRF will accommodate approximately 17 Mst of waste rock and the EWRF will accommodate
approximately 15 Mst of waste rock. The WWRF and EWRF will both be 7,130 ft amsl at full height. The slopes of the WWRF and EWRF are
designed to 3H:1V. At the end of the mine life, replacement of topsoil and revegetation is planned for closure purposes.
Tailings
generated in the flotation process will be filtered to an optimum low moisture content to produce “dry stack” tailings, thereby
maximizing water conservation and structural strength and avoiding the need for a tailings dam and the associated environmental and safety
risks. The tailings slurry produced by flotation initially containing about 65% water (by weight) will first be thickened for initial
water recovery. The water content of the thickened underflow slurry will be reduced to about 45%, while the thickener overflow water
will be returned to the process for reuse. The thickened slurry will be pumped to storage tanks ahead of a large pressure filtration
plant comprising multiple large pressure filters that further reduce the water content to less than 15% (typically 14% metallurgical1).
This leaves the solids as a compressed “cake” material that will be dropped from the press onto a conveyor for transportation
to the TMF.
Approximately
2,400 stph of slurry will be sent to the tailings thickener, with approximately 1,057 stph of tailings produced on average. Processed
tailings will be hauled to and placed in the TMF until Year 8.25. After that, the remaining tailings produced will be hauled to and placed
in the open pit (as described in Section 15.3.4).
15.3.1 | Chemical
Characteristics |
Geochemical
testing of mine rock and tailings using industry standard methods on representative samples (Geochemical Solutions 2023) indicates limited
probability to produce acid rock drainage (ARD) and/or metal release to water. Static geochemical testing on tailings samples produced
by locked cycle laboratory testing indicates that the tailings are not acid generating. Static geochemical testing of waste rock samples
indicates only a small percentage of waste rock is potentially acid generating (PAG). Confirmatory kinetic and leach test results show
no, or low, production of acidic water or metal release for the tested samples. Section 17.1.4 presents additional details on the geochemical
characterization of tailings and pit rock.
1 Metallurgical water content is tailings
moisture by total weight. Geotechnical water content is measured by dry weight. A 14% tailings moisture metallurgical is equivalent to
16.3% geotechnical.
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177 |
15.3.2 | TMF
Design and Construction |
The
TMF is sited east of the process plant within a valley formed by the ephemeral South tributary to Middle Crow Creek (Figure 15.3). The
TMF begins near the northeast corner of Section 31. The basin’s topography contains and directs the placement of tailings down-valley
to the east of the South Crow Creek water transmission pipeline.

Figure
15.3: TMF, WRF, & Ore Stockpile Plan View
 |
178 |
Tailings
filtration produces tailings near their optimum moisture content for compaction, maximizing their geotechnical strength and stability.
The risk of spills and the magnitude of seepage to groundwater are thereby significantly reduced. The filtered tailings will be co-deposited
with waste rock to provide structural buttresses for stability and a cover to protect against weathering and wind erosion. Tierra Group
(2025a) has performed limited equilibrium stability analyses of the TMF under static, pseudo-static and post-peak loading conditions,
including liquefaction assessment, to verify that acceptable factors of safety are obtained for all cases.
The
TMF will be developed in three phases, as shown on Figure 15.4. The TMF will ultimately store 52 Mst of tailings over the facility’s
life. Each phase of the TMF will consist of a prepared subgrade, underdrain collection system, CLS, seepage collection system (overdrain),
tailings, and waste rock. The tailings will be placed in the TMF in 10- to 20-foot lifts and the waste rock buttress and shell will be
installed in 10- to-20-foot lifts as the tailings increase in elevation. The waste rock starter berm built prior to Phase 1 of the TMF
will be constructed in 2- to 3-foot lifts. The TMF underdrain collection system is shown on Figure 15.4 and Figure 15.5 and illustrates
the TMF cross-sections. The tailings are contained by a waste rock retention shell functioning as a buttress. The top of the TMF is capped
with 3 ft of waste rock. The ultimate configuration will have tailings built out at 1.8H:1V slopes and waste rock at 3H:1V slopes around
the TMF’s perimeter. A vegetated soil cover will be placed over the closed TMF to promote the conveyance of stormwater, prevent
surface water ponding, disperse runoff, limit erosion, and promote native vegetation.

Figure
15.4: TMF& Ore Stockpile Collection Drain Layout
 |
179 |
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Figure
15.5: TMF Downstream and Side Buttress Typical Cross Sections
TMF
foundation preparation will include clearing, grubbing, and stripping of topsoil. Unsuitable overburden material will also be removed,
including soils that are unable to be compacted and used in the CLS subgrade, such as saturated soils or soils that are not clay or silt.
Saturated soils may be reworked and dried for later use. Unsuitable soils will be segregated depending on type and either used in other
mine operations (e.g., pond embankment construction, road maintenance, waste rock facility pad development, etc.) or stockpiled south
of the access road segregated from the topsoil piles. The portions of the soil within the White River Formation will be ripped and worked
to remove the light cementing structure in the material and make it suitable for compaction and use in the CLS subgrade. The metasediments
rock outcrop where the valley narrows in the Phase 2 of the TMF will be drilled, blasted, and dozed to a slope of approximately 2.5H:1V.
The slope will be dressed and covered with at least 6 inches of compacted soil prior to liner construction. The excess rock will be used
in applications that require crushed rock if the rock quality is deemed suitable. The remaining subgrade will be compacted to a minimum
of 90% Standard Proctor Maximum Dry Density (SPMDD) to provide a firm surface for underdrain and CLS construction. Figure 15.6 shows
the typical cross sections of the primary and secondary underdrain and overdrain (seepage collection drain system).
 |
180 |
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Figure
15.6: Overdrain & Underdrain Collection System Cross Sections
An
underdrain will be installed below the liner to segregate the tailings from groundwater and convey incident groundwater seeps beneath
the TMF down the thalweg (line of lowest elevation) of the TMF valley. The underdrain will consist of a central artery in the thalweg
fed by secondary drains set in the minor valley bottom topography as shown on Figure 15.6. This underdrain system is comprised of perforated
HDPE drainpipes wrapped in non-woven geotextile and placed in a gravel-lined trench. It will discharge to TMF-3, downstream of the TMF.
Underdrain flows were estimated based on the spring observed in the TMF area. Each secondary drain was assumed to carry a flow equivalent
to the observed spring flow. Flows will be cumulative in the underdrains, with the maximum flow in the primary drainpipe aligned at the
bottom of the valley’s low point. The primary and secondary drainpipes will be a minimum 6-inch diameter, designed for inspection
and maintenance, and capable of conveying the maximum design flow. Figure 15.6 shows the typical primary and secondary underdrain cross
sections.
Above
the underdrain, the TMF will have a CLS consisting of geomembrane overlying a prepared subgrade of compacted Project area clays and silts.
The CLS will have an effective permeability of 10-7 cm/s or lower, as required by the DEQ – WQD.
A
seepage collection drainage system will be installed on the liner and prior to the placement of tailings. The purpose of the seepage
collection system is to maintain low hydraulic head in the bottom of the tailings mass, to promote free drainage of the tailings, and
minimize the possibility for the tailings to become saturated. Like the underdrain, the above-liner seepage collection system consists
of a primary drain that is constructed to follow the valley thalweg and secondary drains that are set in the minor valley
 |
181 |
bottom
topography as shown on Figure 15.6. The primary drain will be solid HDPE pipe wrapped in non-woven geotextile surrounded by drainage
gravel. The secondary drains will be perforated HDPE pipe wrapped in non-woven geotextile surrounded by drainage gravel. The primary
seepage collection drainpipe will be 12 inches in diameter. The secondary seepage collection drainpipe will be 6 inches in diameter.
Phase
1 will consist of approximately 3,230 ft of primary underdrains, 2,740 ft of primary seepage collection drains., 11,460 ft of secondary
underdrains, and 10,100 ft of seepage collection drains. Phase 2 will include approximately 2,700 ft of primary underdrains, 2,700 ft
of seepage collection drains, 6,295 ft of secondary underdrains, and 5,470 ft of seepage collection drains. Phase 3 will include approximately
2,400 ft of primary underdrains, 1,940 ft of seepage collection drains, 3,820 ft of secondary underdrains, and 3,450 ft of seepage collection
drains.
Tailings
will be placed and compacted adjacent to and above the seepage collection drains. The tailings will be hauled by trucks from the tailings
loadout bin at the mill along the south haul road to the TMF, where they will be end-dumped in 10- to 20-foot-thick lifts and spread
with low-ground-pressure dozers. Tailings consist primarily of silt-sized grains with lesser fine sand and clay that will be unlikely
to damage the seepage collection drains or the CLS. Tailings will be placed and spread in a manner that prevents damage to the drains
or CLS. Placement of waste rock on the tailings surface will be necessary to form access roads to support the haul trucks. The waste
rock roads will also serve as drains and connect to the buttress to prevent build-up of pore pressure within the tailings. Haul road
development will precede the placement of tailings in each lift. The crest of the tailings will be graded to prevent standing water from
pooling on top of the tailings. Surface water run-on will be controlled with temporary ditches around the perimeter to divert water around
the TMF. The top lift in areas where tailings are not being actively placed will be rolled with a smooth drum compactor to 90% SPMDD
to reduce infiltration and prevent fugitive dust from being generated on the tailings.
Waste
rock will be placed concurrently with the tailings to form a retention shell once the tailings are at the design levels and to form a
buttress providing structural support and protecting the tailings from erosion due to precipitation and wind. The minimum width of the
waste rock buttress is 90 ft as determined by geotechnical analyses and modeling by Tierra Group (2025b). Additional waste rock buttress
width is required when exceeding the slope heights determined in Tierra Group’s geotechnical stability analyses. The waste rock
will be dumped in 10- to 20-foot-thick lifts, spread with dozers, and compacted by compactors and haul truck traffic. The tailings will
be placed with a maximum outer slope angle of 1.8H:1V, with the outer structural rock retention shell at a maximum outer slope angle
of 3H:1V. The TMF is stable when the waste rock retention shell is built out to the maximum section of 3H:1V with a minimum waste rock
width of 90 ft at the crest. The slopes and the final crest of the facility will be covered with waste rock (retention shell and cap)
to protect against wind and water erosion.
15.3.3 | TMF
Environmental Management |
The
following specific environmental management aspects will be incorporated into the TMF operation and maintenance plan:
| ● | Erosion
and sediment control |
| ● | Water
management and seepage control |
| ● | Dust
control |
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182 |
| ● | Off-specification
tailings management |
| ● | PAG
waste rock disposal |
| ● | Monitoring
and inspection |
| ● | Reclamation |
These
environmental management controls are further described in Section 17.2.1.
The
pit is planned to be excavated for approximately 8.25 years and will generate an ore stockpile to be fed to the process plant. The stockpiled
ore will be depleted during the last two years of post-mining mineral processing and the associated tailings will be transported to the
pit bottom for backfilling up to an elevation of 6,630 ft amsl (assuming this plan is consistent with other possible closure plans for
the pit concerning its potential alternative use as a water storage reservoir). Then, with a combination of blasting and earthmoving,
the pit rim will be dozed into the pit to create a 3H:1V final pit wall slope. The final backfilled pit elevation will be approximately
6,720 ft amsl, as shown on Figure 15.7 The associated long-term ARD implications and effects on groundwater are described in Sections
17.1.2 and 17.2.1.

Figure
15.7: Open-Pit Backfill and Pit Wall Grading
 |
183 |
15.4 | Plant
facility Earthwork |
The
Project’s mill and infrastructure facilities are located south of the pit in Section 36 and are shown in Figure 15.8. Figure 15.9
shows the layout of the mill facilities in more detail. Proposed ground grading designs were prepared for the mill area, mining equipment
maintenance area, substation, administration building and warehouse area, primary crusher, and coarse ore stockpile, and supporting facilities.
The site grading design looked to balance the cut and fill volumes as well as possible, address stormwater runoff and reduce erosion.
Generally, each pad was designed with a slight slope to facilitate drainage. Table 15.2 summarizes the bank cut and loose fill volumes
and overall grading area.
Table
15.2: Plant Area Quantities |
Grading
Area |
Value |
Grading
Cut Volume |
500,000
yd3 |
Grading
Fill Volume |
610,000
yd3 |
Total
Cut + Fill Volume |
1,100,00
yd3 |
Net
Cut + Fill Volume |
110,000
yd3 |
Grading
Area (Plant Area) |
60
Acres |

Figure
15.8: Mill and Truck Area
 |
184 |

Figure
15.9: Mill Area Plan View
 |
185 |
Electrical
power for the CK Gold Project will be supplied by a local utility company, Black Hills Energy, under an Industrial Contract Service Agreement.
The anticipated Connected Power Load for the Project is approximately 40.4 megawatts (MW) with a Demand Power Load of 27.2 MW. The power
demand for the Project requires that a new 115 kV power line be constructed for the Project by Black Hills Energy. The power line would
be constructed from Black Hills Energy’s West Cheyenne substation, located approximately 16 miles east of the Project to a new
Black Hills Energy owned, built and operated 115/13.8 kV (50 MVA) distribution substation (including transformer) near the mine. The
powerline alignment would take advantage of existing easements and planned county roads in the vicinity of the CK Gold Project. The alignment
would require easements from the City of Cheyenne, State of Wyoming, and two local ranches.
The
mine electrical facilities would be required to provide sufficient reactive support for the mine’s electrical system to maintain
reliability and voltage levels on the Black Hills Energy system. Black Hills Energy performed a load addition report to determine the
impact of the CK Gold proposed mining operation.
Unit
costs for construction of the infrastructure for the power line and unit rates for the delivered power under an Industrial Contract were
provided by Black Hills Energy in August 2022. A cost estimate for the right-of-way easement was also provided by Black Hills Energy.
The estimated construction costs for the proposed power line, easement cost and substation have an option to be amortized in an addition
to the base power unit rate charged. The estimated construction cost for the proposed power line is $17 to $18 million and the easement
costs are $140,000 per mile. The power unit rate is 7.5₵/kWh inclusive of amortized power supply construction costs the unit rate
is estimated to be 7.9. c/kWh.
The
Project will operate in a net water deficit situation, given that the mean annual evapotranspiration exceeds the mean annual precipitation.
The project’s total average water consumption is 562 gpm. This number is the estimated total consumption, excluding reductions
in demand for water from off-site sources associated with planned water saving measures. Water consumption includes use for mineral processing,
general operations and dust control. Tierra Group developed a site-wide water management plan to maximize water reuse and minimize freshwater
make-up. Details of the site-wide water management plan can be found in Section 17.2.3.
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186 |
The
Project has a water supply agreement with the Cheyenne Board of Public Utilities (BOPU). Sunrise Engineering was retained to provide
a hydraulic analysis for a transmission main and a service line from the Lone Tree Wellfield, located south of Interstate 80 in
section 17 of Township 13N and Range 69W, to the proposed CK Gold water storage tank, located on the CK Gold site in section 36 of
Township 14N and Range 70W. After discussion with the BOPU in Cheyenne Wyoming, a twelve-inch minimum pipe was analyzed to determine
the required head to lift raw water from the Lone Tree Wellfield to a proposed BOPU diversion structure located East of the CK Gold
Site. A bore under Interstate 80 and the Union Pacific Railroad was determined to be feasible after a geotechnical report was
completed for the site. At the diversion structure, a sixteen-inch pipeline will be used to convey water to and from South Crow
Creek Reservoir.
An eight-inch line was determined to be sufficient to convey the needed water from the proposed sixteen-inch waterline to the CK Gold
water storage tank, although it does require a booster pump to provide the needed head pressure. A construction and final engineering
cost estimate was provided at $17,259,500 and $930,000 respectively.
Potential
sources of water for the Project include the BOPU water supply system, on-site existing surface water rights and potential new on-site
wells. The BOPU has sufficient capacity currently to supply the Project’s needs. The Cheyenne City Council has approved an outside
water agreement allowing BOPU to contract with the Project to provide water. Water generated from pit dewatering, surface runoff, and
waste rock and tailings seepage will be recycled for use in mineral processing and/or dust suppression.
U.S.
Gold, operating under a water agreement with Ferguson Ranch, is conducting a water exploration program on land immediately north of the
Project area. The Casper Formation, a significant water-bearing rock, has been intercepted twice in the Red Canyon area one mile north
of the proposed project water tank. Significant sandy intervals have been logged and the geophysical log indicates high resistivity consistent
with sand-bearing intervals. U.S. Gold is conducting draw down tests and will model the hydrology and estimate the water well pumping
capacity. The potential ease of construction, operation and cost savings make the Red Canyon water well the primary source of water and
the BOPU agreement and pumping from the Lone Tree well field. The costs to construct and operate the Red Canyon well field are estimated
and included in the cash flow model.
Water
will be transported to site via an HDPE pipeline from the well field to the project water tank. Pumps, SCADA control equipment, pumphouses,
and well field infrastructure have been engineered and costed.
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16.1 | Flotation
Concentrates |
16.1.1 | Flotation
Concentrates |
This
section considers the smelting and refining terms available for the flotation concentrate generated over approximately ten years of project
life. This filter cake product will include marketable concentrations of copper, gold, and silver, will be largely free of deleterious
elements, and is expected to be of significant interest to domestic and overseas smelters alike. The concentrate will contain 8 to 9%
moisture and be stored and transported in Flexible Intermediate Bulk Containers (FIBCs), also known as Bulk Bags.
Increased
demand for copper in the Asian markets has stimulated the expansion of processing capacities for copper raw materials in the East, and
this has driven a reduction and/or elimination of similar processing capacities elsewhere in the international market. The balancing
of supply and demand is expected to continue, where the newly created processing capacity should absorb much of the new copper concentrate
production capacity that will be realized.
The
quantity, quality, and estimated value of the Project’s flotation concentrate product allow shipment to a wide range of geographic
regions; therefore, as the Project advances, those regions and consumers providing the least commercial risk and the optimum return to
the Project should be considered. Of note, the concentrate's relatively high gold and silver content suggests that those locations providing
high accountability for these precious metals must be considered.
16.1.2 | General
Considerations |
Based
on the results of recent metallurgical testwork, the flotation concentrate will be a clean product that will be in demand for its contained
gold and lack of deleterious elements. While the planned average copper content is slightly lower than many copper concentrates with
an 18 to 19% copper grade, the higher gold grade of 40 to 90 gpt and a sulfur-to-copper ratio of approximately 1:1 will make it attractive
to several domestic smelter facilities.
As
the Project develops toward production, it is recommended that focus is maintained on selective smelting and refining complexes that
currently process copper concentrates in North America. Compared to overseas markets, transportation logistics and timelines should be
more streamlined, resulting in more attractive payment terms.
As
a result of the total contained metal value of this product, a flotation concentrate bagging facility has been included in the process
plant design. Whilst logistics considerations will vary slightly from those of bulk concentrate shipments, shipment of this product in
4,500lb FIBCs will improve overall metals accountability by minimizing the losses of gold during transportation.
Normal
deviations in moisture content and the methods established to sample and determine the settlement dry weight must be closely
examined and controlled to ensure appropriate confidence in the metallurgical balance. It is recommended that moisture samples be
taken when the filter cake product batches are weighed and sampled for assay. Care must be taken to immediately seal the moisture
sample and follow the established procedures for drying and determination of dry weight. Sampling for assay determination should be
carefully monitored but is expected to follow normal procedures. Samples will be taken from the bags via representative
“spearing” when departing the mine area, and this sampling process can be automated if required.
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Note
that final settlement results will be determined from samples taken at the receiving smelter, at which the Seller may be present and/or
represented.
Assaying,
exchange of assay results, and the splitting limits for determining settlement results must be professionally managed. The use of bagged
products should avoid unnecessary precious metals loss due to handling and transportation.
Gold,
copper, and silver each contribute to the project revenue stream and so future price predictions are necessary for this Pre-feasibility
Study. The metal price assumption outlined below for purposes of the economic analysis in this study differ from the metal prices used
to establish the resource and reserve inventories which are cast at lower levels, see relevant sections. A conservative approach was
adopted in outlining resource and reserve inventories. Commodity Price Forecasts use a combination of analysis of three-year rolling
averages, long-term consensus pricing, and benchmarks to pricing used by industry peers over the past year, when considering long-term
commodity price forecasts. Higher metal prices are used for the mineral resource estimates to ensure the mineral reserves are a subset
of, and not constrained by, the mineral resources, in accordance with industry-accepted practice. The base-case metal prices used in
the Project’s economic evaluation within this Pre-Feasibility Study shown in Table 16.1.
Table
16. 1: Pre-Feasibility Study Base Case Metal Prices |
Metal |
Unit |
Base
Case Price for PFS |
Gold |
$US/oz |
2100 |
Copper |
$US/lb |
4.10 |
Silver |
$US/oz |
27 |
The
flotation concentrate shipped from the Project will contain accountable copper, gold, and silver levels.
16.1.5 | Smelting
and Refining Charges |
The
smelting and refining terms used within the Prefeasibility Study economic models are consistent with current market trends. No forward-looking
adjustments are made to these terms in later years.
Discussions
with several concentrate offtake companies have progressed and two indicative term sheets have been received for Project
concentrate. No definitive smelter agreements have been obtained for the concentrate, although it is apparent that it will not be
difficult to market under normal market conditions. This is partly due to the higher gold grade in the copper concentrate and the
lack of deleterious elements Metallurgical testwork results indicate that deleterious element penalties need not be applied in the
terms for the concentrate.
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Table
16.2 summarizes the indicative smelter terms utilized for PFS economic analysis received from a confidential 3rd party. These
terms have been applied quarterly for the first three years and so account for short-term variability in payable metal grades as the
mix of plant feed ore type changes. The determination of concentrate grade is discussed within Section 10 of this Report.
Table
16. 2: Smelting and Refining Terms – LOM Average |
Term |
Unit |
Copper |
Gold |
Silver |
Cu
Minimum Deduction |
% |
1.2 |
|
|
Au
Minimum Deduction |
g/dmt |
|
0 |
- |
Base
Smelting Charge |
$US/dmt |
80 |
- |
- |
Cu
Refining Charge |
$US/lb
payable |
0.080 |
- |
- |
Payable
Metal |
% |
96.5 |
97.5 |
90.0 |
Au/Ag
Refining Charge |
$US/oz |
- |
5.00 |
0.50 |
Concentrate
Moisture |
% |
10 |
- |
|
Transportation
costs of $187.00 per wet short ton have been assumed, based on estimated north American destination.
A
mining contract will be negotiated for the pre-production mining of approximately 1.200,000 st of waste in Year -1 Q1. Waste material
mined as part of these operations will be used in project construction activities. At the end of Year -1 Q1 this mining contract will
be closed.
It
is contemplated that one of a number of contractors will be selected to conduct topsoil stripping, ground preparation and pre-production
mining to satisfy initial construction needs. Run-of-mine rock will be crushed and screened to provide various crushed product sizes
to serve as aggregate, material for drainage infrastructure, top-dressing for roads and around the site, and over-liner material.
Besides
power supply, negotiation will be held for major consumer item supplies encompassing fuels oils and grease, reagent supply. Proximal
to the project is a major prill manufacturer for ANFO explosives and contractors for the downhole supply of explosives for blasting on
site. Additionally, contracts for several non-core activities such as employee bussing, security and waste disposal will be established.
Where possible contract services for administrative functions will be sought in nearby Cheyenne.
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17.0 | Environmental,
social, and Permitting |
This
chapter summarizes the status of environmental compliance, permitting and community engagement, including the following specific topics:
| ● | Results
of environmental studies (Section 17.1): Environmental studies began in October 2020 to establish
the pre-mining site conditions and fulfill the information requirements for Project permitting.
The scope and results of these studies, which include environmental baseline characterization,
groundwater and seepage modeling, and geochemical characterization of tailings and mine rock,
are summarized herein. |
| ● | Requirements
and plans for waste and tailings disposal, site monitoring, and water management during operations
and after mine closure (Section 17.2): Based on the Project mine plan and results of the
environmental studies, specific requirements, and plans have been identified and summarized
for management of waste rock and tailings, site monitoring and water management, to avoid
or mitigate environmental impacts throughout the Project life cycle. |
| ● | Project
permitting requirements, the status of permit applications, and requirements to post a reclamation
bond (Section 17.3): Permitting is primarily at the state and local level; no major federal
permits are required. The principal state permits have been obtained and are described herein.
Additional required state and local level permitting is also identified. Bonding is in place
for the reclamation of areas to be disturbed during the first year of construction and mining
operations, and additional reclamation bonding will be required annually for subsequent operations. |
| ● | Plans,
negotiations, and agreements with local individuals and groups (Section 17.4): Other than
permitting, various agreements with local stakeholders needed for the construction and operation
of the Project are described. |
| ● | Mine
closure plan, including remediation and reclamation, and associated costs (Section 17.5):
The state has approved a reclamation plan covering the full extent of the project, which
is summarized herein. The state also developed a reclamation cost estimate, which it accepted
as part of the reclamation bonding process. |
| ● | The
qualified person's opinion on the adequacy of current plans to address issues related to
environmental compliance, permitting, and local individuals or groups (Section 17.6). |
| ● | Commitment
to local procurement and hiring (Section 17.7). |
17.1 | environmental
studies |
17.1.1 | Baseline
Characterization |
Baseline
characterization studies began in October 2020 to establish the pre-mining site conditions and fulfill the information requirements for
Project permitting. The baseline studies have been concluded and the associated reports submitted to the state as part of the various
permit applications required by the Wyoming Department of Environmental Quality (Section 17.3).
The
Project site is located on land owned by the State of Wyoming (Section 36) and the Ferguson Ranch (south half of Section 25 and Section
31), as shown on Figure 17.1. In Section 36, the surface and minerals are owned by the State of Wyoming and the surface is leased for
grazing to the Ferguson Ranch, Inc. The Project site has been used as rangeland for cattle grazing and mineral exploration.
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191 |
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Figure
17.1: Project Site and Access Road Location
Past
mining activity occurred on the site and in the surrounding historical Silver Crown Mining District since the district was established
in 1879, including prospecting, exploration drilling, surface mining, and expansive underground excavation. The Project is centrally
located in, and the focus of, past exploration and mining activities associated with the historic Copper King Mine. The mine is considered
one of the top five gold deposits in the state of Wyoming (Hausel 2019). The deposit was first discovered by James Adams of the Adams
Copper Mining and Reduction Company in 1881. The deposit was primarily developed as an underground copper mine. But despite several mining
campaigns spanning several generations and transfers of ownership, much of the deposit is still intact. At least 13 exploratory drilling
programs with over 173 drillholes have been developed on the site since 1930 for metallurgical, technical, hydrological, and resource
expansion purposes.
The
CK Gold Project has operated a weather station on the Project site since November 2020. Figure 17.2 shows the location of the Project
weather station. Additionally, more than 20 weather stations are located between Laramie and Cheyenne and provide temperature, precipitation,
wind speed, and wind direction measurements.
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192 |
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Figure
17.2: Locations of the Meteorological Station & PM10 Monitoring Station (from Air Resource Specialists)
Based
on data compiled from the site weather station and other surrounding stations (the latter over at least a ten-year period), the daily
average temperature ranges from about 25° F in February to about 70° F in July. The average low temperature is -11° F in
February and the average high is 90° F in July.
The
Project site is in a net water deficit. The average annual precipitation is about 17 inches, while the annual evaporation is about 53
inches, as determined by the on-site meteorological station. May is the wettest month, with an average of about 3 inches; January is
the driest, with an average of about 0.6 inches. Snowfall typically occurs from September to May.
The
site experiences relatively strong winds, with an average monthly wind speed ranging from about 8 mph in July to about 17 mph in December.
For those same months, the average maximum wind speeds are 43 and 63 mph, respectively, with peak wind speeds of 55 and 75 mph (86 mph
for January). The predominant wind direction is westerly.
The
Project has monitored baseline air quality since November 2020 to collect ambient air quality data and establish the pre-mining air
quality. The air quality monitoring station is located approximately 0.2 miles north of the Project site on the Ferguson Ranch along
County Road 210, as shown on Figure 17.2. The location was selected in general accordance with 40 CFR Part 58 Ambient Air Quality
Surveillance. The station collects integrated particulate matter data sized less than 10 microns (PM10) once every six days over 24
hours using two collocated BGI PQ200 particulate air samplers. The samplers collect integrated 24-hour
samples in accordance with EPA protocols (Quality Assurance Guidance Document 2.11, Reference Method for the Determination of Particulate
Matter as PM10 in the Atmosphere).
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193 |
To
date, the background air quality has met the National Ambient Air Quality Standard 24-hour PM10 level of 150 micrograms per cubic meter
(μg/m3), with PM10 measurements ranging from 0 to 45 μg/m3.
17.1.1.4 | Surface
Water and Wetlands |
An
Aquatic Resources Inventory (ARI) was performed in September 2020 (Trihydro 2020) to identify jurisdictional Waters of the United States
in and around the CK Gold Project site. The United States Army Corps of Engineers (USACE) regulates jurisdictional Waters of the US,
which are defined and regulated by Section 404 of the Clean Water Act (CWA) 33 CFR Part 328.3 and Section 10 of the Rivers and Harbors
Act (RHA) 33 USC 1344, including streams and wetlands. The jurisdictional waters and wetlands were identified to facilitate Project infrastructure
planning to prevent impacts on the Waters of the US.
The
surface water features investigated under the ARI are shown on Figure 17.3. They include the intermittent South Crow Creek, the ephemeral
South and Middle tributaries of Middle Crow Creek, and the perennial/intermittent North tributary of Middle Crow Creek. Based on the
findings of the ARI, on 5 February 2021 the USACE issued an Approved Jurisdictional Determination (AJD) for the drainages and wetlands
within the CK Gold Project area. The AJD is the official determination from the USACE on the Waters of the US that are present in the
Project area. The jurisdictional Waters of the US identified in the AJD include South Crow Creek and the North tributary to Middle Crow
Creek. The AJD concluded that the drainages and wetlands associated with the South and Middle tributaries to Middle Crow Creek are not
jurisdictional Waters of the US. The Project mine facilities have been designed to avoid and will not impact jurisdictional Waters of
the US.
In
November 2023, Western EcoSystems Technology (WEST) prepared an additional ARI report (WEST 2023a) for the proposed Project access road
and vicinity. This ARI identified one dry drainage with a defined channel that may be jurisdictional. The access road will not cross
the drainage, and mine activities will not affect it.
A
surface water baseline monitoring program was initiated in October 2020 and completed in April 2022. The program included a collection
of surface water quality samples, field water quality parameters, and stream flow measurements monthly at up to six monitoring locations
within the Project site, as shown in Figure 17.3. The monitoring locations are located along the primary surface water features within
the Project and include the intermittent South Crow Creek, the South and North tributaries to Middle Crow Creek, and one spring in the
South tributary of Middle Crow Creek.
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194 |
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Figure
17.3: Surface and Groundwater Sampling Locations
Surface
water flow in the drainages is typically derived from snowmelt runoff, rainfall-runoff following precipitation events, and contributions
from groundwater (springs). The six monitoring points were established at the upgradient and downgradient locations along the primary
drainages as they cross the Project boundary in general accordance with the Wyoming Department of Environmental Quality - Land Quality
Division (DEQ-LQD) Guideline 8 baseline hydrology recommendations.
Surface
water flow has been observed to be inconsistent due to the intermittent and ephemeral nature of the drainages. Measured flow rates at
the surface water monitoring points between October 2020 and April 2022 ranged from zero to approximately six cubic feet per second,
with the highest flow rates observed from April to June. Three of the monitoring points, including two points within the ephemeral South
tributary of Middle Crow Creek (site of the proposed TMF) and one point in the north tributary of Middle Crow Creek, had no observed
flow during the entire 19-month monitoring program.
Surface
water samples have been analyzed for the recommended constituents in DEQ-LQD’s Guideline 8, including additional trace metals.
The baseline surface water quality is relatively good and meets the Wyoming DEQ - Water Quality Division’s (DEQ-WQD’s) Surface
Water Quality Standards for livestock, irrigation water, and drinking water.
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195 |
Groundwater
monitoring at the Project site began in 2020 to characterize the potentiometric surface, groundwater flow, and groundwater quality (Neirbo
Hydrogeology 2023). Data has been collected over a period of approximately 18 months using monitoring wells, standpipe wells, vibrating
wire piezometers (VWP), HQ core holes, and reverse-circulation boreholes. This data formed the basis for development of a groundwater
flow model, as described in Section 17.1.2.
Quarterly
groundwater monitoring has been performed at seven monitoring wells within the Project site (MW-1, MW-3, MW-4, MW-5 MW-7, MW-8a, MW-8b),
as shown on Figure 17.3. Groundwater sampling started in the fourth quarter of 2020. Results from six quarterly sampling events were
included in the Mine Operating Permit application submitted to the DEQ-LQD in January 2024.
Results
indicate that the groundwater is generally a bicarbonate type. Wells MW-7 and MW-8a are drilled in granodiorite and alluvium, respectively,
and have calcium-bicarbonate type water, whereas MW-1, 3, 4, and 5, drilled in granodiorite and metasediments, have sodium bicarbonate
water. Monitoring well MW-8b has a mixed calcium-sodium bicarbonate water and is the only well screened in the White River Formation
(Neirbo Hydrogeology 2023).
Water
quality has mostly met standards, although some measurements have been above DEQ limits, variably between domestic, agricultural, and
livestock standards. Table 17.1 summarizes the baseline groundwater quality that exceeds DEQ standards in each monitoring well for each
quarter, as reported by Neirbo Hydrogeology (2023).
Table
17.1: Baseline Monitoring Wells with Constituent Concentrations Exceeding Water Quality Standards |
Constituent |
2020
Quarter
4 |
2021
Quarter
1 |
2021
Quarter
2 |
2021
Quarter
3 |
2021
Quarter
4 |
2022
Quarter
1 |
Fluoride |
1,
3, 4, 5 |
1,
3, 4, 5 |
1,
3, 4, 5 |
1,
3, 4, 5 |
1,
3, 4, 5 |
1,
3, 4, 5 |
pH |
1,
3, 4, 5 |
1,
3, 4, 5 |
1,
3, 4 |
1,
3, 4, 5 |
1,
3, 4, 5 |
1,
3, 4 |
Dissolved
Iron |
3,
5 |
5 |
-- |
-- |
7 |
-- |
Total
Iron |
1,
3, 5, 7 |
3,
5 |
3,
4, 5 |
-- |
5,
7 |
4,
7 |
Mercury |
-- |
7 |
7 |
-- |
-- |
-- |
Manganese |
3,
7, 8a, 8b |
7,
8a, 8b |
7,
8a, 8b |
7,
8a, 8b |
7,
8b |
4,
7 |
Sodium
Adsorption Ratio (SAR) |
1,
4 |
4 |
4 |
1,
4 |
4 |
4 |
Dissolved
Uranium |
7 |
7 |
7 |
7 |
7 |
7 |
Total
Uranium |
* |
* |
* |
* |
7 |
7 |
Gross
Alpha |
7 |
3,
7 |
7 |
3,
7 |
7 |
3,
7 |
Adjusted
Gross Alpha |
-- |
3 |
7 |
-- |
7 |
7 |
From
Neirbo Hydrogeology 2023
Notes:
Well
names are preceded by “MW-”
Wells
listed for each constituent exceeded at least one of the DEQ water-quality standards for Class 1 Domestic, Class 2 Agriculture, or Class
3 Livestock uses
--
No wells exceeded standards
*
Not measured
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196 |
The
Project site is located on the eastern flank of the Laramie Range between the Rocky Mountains and High Plains sections of the Great Plains
physiographic province. The Laramie Range is an approximately 130-mile-long mountain range between Laramie and Cheyenne, WY, that trends
north from the Colorado-Wyoming border towards Casper, WY. The Laramie Range consists of granite/granodiorite peaks and rolling hills
bound to the east non-conformably by shallow eastward dipping sedimentary rocks of the White River Formation. East of the CK Gold Project
area, towards Cheyenne, WY, the topography transitions to flatter plains along the western margin of the Great Plains physiographic province.
The Project site geology is further described in Section 6.
The
Natural Resource Conservation Service (NRCS) database of mapped soil units was reviewed. The nine soil units described by the NRCS soil
database at the Project site were identified and field verified in July 2021. Preselected sample locations and respective field survey
soil profile descriptions were used to confirm or modify the coverage of the nine soil map units. For soil map units that were modified,
the acreages were revised (Figure 17.4).
A
test pitting subsurface exploration program was implemented around the same time to evaluate the soils in the proposed development areas
(Trihydro 2022). The ore body is exposed at the hilltop and is generally surrounded by granite. Weathered soil is located around the
base of the slopes. The north and western faces of the hill are the steepest portions of the Project site and have the least amount of
soil cover. The northeast and southern saddle areas have gentler slopes and generally contain more soil.
Topsoil
was generally encountered throughout the Project site at the ground surface with localized areas of outcropping bedrock. The topsoil
consists of brown to dark brown silt with trace sand and gravel and decomposing organic matter. The topsoil typically ranges from approximately
0.25 to 4.25 feet in thickness with an average thickness of 1.1 feet. Generally, topsoil was found to be thickest in the drainages and
valley bottoms and thinner along slopes and ridges.
Subsoils
are typically aeolian or colluvial soils or were derived from the lightly cemented White River Formation, which is composed primarily
of lightly cemented alternating layers of siltstone, sandstone, and claystone.
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197 |
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Figure
17.4: Field Survey Soil Sample Locations and Map Unit Modifications
Silty
soil is common, as the White River Formation has a primarily silty matrix. Silty soil tends to be low plasticity and lie above massive
siltstone beds. The silt is predominantly dark brown and either dry or slightly moist and contains sand. Silts observed in test pits
were predominantly under 5 feet thick, with some reaching up 10 feet thick. Silty sand layers were also encountered and generally found
overlying sandstone beds. They tend to be olive brown in color, lean, dry to slightly moist and up to a few feet thick.
The
clayey soil encountered is primarily lean clay with brown to gray color and tends to have noticeable sand content. The lean clays, as
classified by the Unified Soil Classification System, are primarily associated with the B soil horizon where fine grained particles migrate
down from the topsoil into the subsoil regions and create the silty clay layer. Lean clays can be found primarily in the Mill Area, the
Ore Facility, and the TMF. Fat clays were encountered primarily to the southeast of the Mill Area and portions of the TMF. The fat clays
also have noticeable sand and gravel content. Fat clays are likely to have a shrink or swell potential in response to moisture changes;
they shrink as the soil dries and swell as more water is added.
Loose
sand and gravel are commonly found overlying sandstone or claystone with significant sand or gravel content. These loose soils are typically
light gray or brown with significant silt content. Gradation ranges from poor to well graded.
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198 |
The
Project area consists primarily of rolling grassland/herbaceous habitat with forested and shrub/scrub-covered drainages. Most of the
Project site consists of prairie grasslands, with some areas of xeric forest and sparse areas of foothill, sagebrush shrublands, and
riparian vegetation. Habitat to be disturbed by Project development consists almost entirely of the grassland/herbaceous type.
Trihydro
performed a desktop review of national and state vegetation databases in 2021 as part of the Mine Operating Permit application to identify
vegetation types in the Project area and potential special status plant species. Figure 17.5 shows the different vegetation types at
the Project site according to the US Geological Survey’s National Land Cover Database.

Figure
17.5: USGS Land Cover Vegetation
Based
on field surveys conducted in July 2021 by Trihydro and June 2023 (WEST 2023b), it was concluded that the Project site does not contain
suitable habitat associated with special status plant species, and no such species were observed. The most common native species identified
during the field survey were in the grassland/herbaceous habitat and include needle and thread (Hesperostipa comata), western wheatgrass
(Pascopyrum smithii), blue grama (Bouteloua gracilis), prairie junegrass (Koeleria macrantha), and Sandberg bluegrass (Poa secunda).
Notably, cheatgrass (Bromus tectorum), a non-native, aggressively invasive weed species in Laramie County, was the sixth-most common
species found.
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A
desktop study reviewed national and state data sources to determine the potential for listed wildlife species within the Project site.
The US Bureau of Land Management (BLM) Wyoming Sensitive Species List includes 16 species potentially occurring at the Project site,
including four mammals, 11 birds, and one amphibian. The US Fish and Wildlife Service (USFWS) Planning and Conservation website further
identified four federally listed species potentially present at the site, including the Preble’s meadow jumping mouse (Zapus hudsonius
preblei), piping plover (Charadrius melodus), whooping crane (Grus Americana), and pallid sturgeon (Scaphirhynchus albus). No critical
habitat was identified within the Project site. However, a portion of the Project site falls within the pronghorn antelope (Antilocapra
americana) crucial winter range, and the whole Project site and surrounding area is within the mule deer (Odocoileus hemionus) crucial
winter range. In consultation with the WGFD, mitigation action will be taken for the disturbance of mule deer crucial winter range during
Project construction and mining operations, including minimization of vehicular traffic by worker busing, installation of wildlife-friendly
fencing, and a $300,000 payment to the WGFD.
A
field wildlife survey was conducted in and around the Project site by Trihydro in June 2021 as part of the Mine Operating Permit application,
focused primarily on the BLM sensitive species and the federally listed species. WEST conducted additional field surveys from May to
July 2023 (WEST 2023c, d, e), focused on raptors, fish, and species designated by WGFD as Species of Greatest Conservation Need (SGCN),
including upland sandpiper (Bartramia longicauda), swift fox (Vulpes velox), smooth greensnake (Opheodrys vernalis), western tiger salamander
(Ambystoma mavortium), and northern leopard frog (Lithobates pipiens).
Two
BLM sensitive bird species were observed: the northern goshawk and the Brewer’s sparrow. The Project site was determined to contain
potentially suitable habitat only for one of the four USFWS federally listed species, the Preble’s meadow jumping mouse, although
this species was not found and its associated potential habitat along the creeks is degraded from cattle grazing.
No
raptor nests were found within planned areas of Project disturbance, and no golden eagle nests were observed within the Project site.
None of the SGCN species were seen or heard on the Project site, though the site is within the upland sandpiper and swift fox predicted
distribution areas. Project development will avoid the flowing streams that offer potential habitats for amphibians and fish. Almost
all the wildlife field observations occurred in the riparian corridors along South Crow Creek and the North tributary of Middle Crow
Creek, both outside of the planned Project disturbance areas.
In
a concurrence letter for the Mine Operating Permit, WGFD recommended ongoing consultation with the agency regarding raptors and monitoring
for swift fox (Vulpes velox) before disturbing the ground within the Project area between April 1 and September 30 each year.
17.1.1.9 | Archeology
and Paleontology |
A
Class I cultural resource data review was completed in June 2021 (Western Archaeological Services 2021). The review examined the
State Historic Preservation Office (SHPO) records for documented cultural resources within the Project boundary. Two sites were
identified near or within the Project boundary: the Fort D. A. Russell to Fort Sanders Wagon Road, which is eligible for nomination
to the National
Register of Historic Places (NRHP); and the historic Copper King Mine, which is ineligible for nomination to the NRHP.
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The
wagon road passes north of County Road 210 in the northeast portion of the south half of Section 25 within the Project site boundary.
It is a previously documented cultural site and is eligible for nomination to the NRHP with SHPO concurrence. No Project activity is
proposed north of County Road 210. Therefore, this site will not be disturbed by the Project.
The
historic Copper King Mine, located within the Project site, had two mine shafts, three adits, nine exploratory pits, and an excavation.
The Class I data review found that the Copper King Mine is not eligible for NRHP nomination. The DEQ reclaimed the mine features - Abandoned
Mine Lands Division (AML) in July 2017. Before the reclamation, the DEQ-AML performed a National Environmental Policy Act (NEPA) determination
and verified that the reclamation conformed with exclusion criteria and was exempted from further NEPA compliance.
A
Class III cultural resources field survey was conducted on the Project site in September 2024 (Centennial 2024) to identify potential
additional cultural sites. No identified sites were recommended for National Register of Historic Places classification. Management measures
will be implemented to protect additional cultural sites during Project construction, mining, and reclamation operations.
Most
of the construction and mining-related excavation will take place within the Pre-Cambrian age granite formation, an igneous intrusive
rock that does not contain fossils. According to the USGS, some activity will occur in the sedimentary White River formation, which could
host paleontological resources but is considered unlikely to contain preserved fossils (Bartos et al. 2014). Project activities will
be subject to “chance finds” protocol, requiring notification of state agencies in the event of a cultural or paleontological
find and a work stoppage at the affected location.
The
Project is not located adjacent to indigenous, Native American, or Bureau of Indian Affairs lands.
17.1.2 | Groundwater
Modeling |
The
orebody is hosted in Precambrian granitic rock with limited permeability and water-storage capacity. Groundwater wells completed in the
granite typically yield 0 to 5 gallons per minute (gpm). The granite groundwater flows from the higher elevation areas of the Laramie
Range, west of the project area, to the east. The White River formation is underlain by Cretaceous formations east of the mine. Figure
17.6 shows the hydrogeologic units, groundwater level and flow direction.
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Figure
17.6: Hydrogeologic Units, Groundwater Level, and Flow Direction
The
Project has completed extensive hydrogeologic site characterization to support the development of a regional groundwater flow model.
Aquifer testing has included pumping tests and discrete depth-interval packer testing. These tests estimated hydraulic conductivity and
specific storage properties. Groundwater levels and pore pressures were obtained from wells and vibrating wire piezometers.
Neirbo
Hydrogeology (2023) developed a calibrated groundwater flow model to represent the hydrogeologic system and assess the interactions between
the proposed mine and the groundwater system. The model incorporates hydrogeologic features, including streams, reservoirs, irrigated
land, and wells in the project area, as well as aquifers, faults, stream-aquifer interactions, recharge, evapotranspiration, and external
boundary conditions.
The
model simulates pre-mining conditions and hydrologic changes during the mining and post-mining phases. The model predicts groundwater
system changes due to passive pit dewatering, natural recharge changes due to facility construction, and pit backfill during the post-mining
phase.
Model
predictions during the mining and post-mining periods include groundwater level, pit inflow, streamflow, and evapotranspiration
changes. The predicted mine-induced drawdown is greatest near the pit and decreases rapidly away from the pit (Figure 17.7).
Predicted drawdown is generally 5-feet or less outside the Project site at the end of mining. After 150 years the discernable
predicted drawdown is at its maximum, extending about 180 feet outside the Project site boundary (Figure 17.8). The nearest domestic wells
are 2,000 feet from the predicted 5-feet drawdown area. At this distance, mine induced drawdown would likely not be discernable from
natural variation and groundwater level changes induced by the domestic wells themselves.
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Figure
17.7: Cross-section of groundwater levels
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Figure
17.8: Predicted drawdown at the end of mining and 150 years post-mining
The
Middle Crow Creek is the nearest stream, and its flow is predicted to decrease by 0.03 cubic feet per second 10 years after mining. The
other stream segments have zero to 0.02 cubic feet per second changes in flow.
The
average annual groundwater pit inflow is expected to be less than 15 gallons per minute. This low pit inflow would be manageable using
passive, in-pit sumps, and dewatering wells are not expected to be necessary.
After
mining, the pit will be backfilled with tailings and waste rock. Groundwater and precipitation will flow into the backfill material,
and water levels will slowly rise until they stabilize at 6,717 feet after about 130 years. A pit lake is not expected to form since
evaporation losses will keep the groundwater level below the top of the backfill. This will result in the pit being a hydraulic sink
with no groundwater outflows.
The
groundwater modeling conducted to date precedes the recent development of Project water supply wells in the vicinity of the Project site
approximately 1.25-miles northwest of the pit (see Figure 17.13). The Project supply wells will extract groundwater from the Casper Formation,
which underlies the formations previously investigated and modeled. The new wells are not expected to induce significant drawdown in
the overlying units hosting the neighboring domestic water supply wells; however, this is pending confirmation through additional hydrogeologic
assessment.
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17.1.3 | Tailings
Seepage and Stability Analysis |
Tailings
stability was analyzed by Tierra Group (2025b). The tailings were modeled overlying the Tailings Management Facility’s (TMF’s)
composite liner system (CLS), which in turn overlies a prepared foundation consisting of native soils that are underlain by weathered
bedrock.
The
DEQ-LQD review of the MOP application required a rework of the liner system, and the Project will now use a CLS. The CLS will consist
of a geomembrane overlying a prepared subgrade composed of compacted Project area clays and silts. As required by WQD R&R, the CLS
will have an effective permeability of 10-7 cm/s or lower. The inclusion of the CLS means that tailings seepage modeling was not required
by WDEQ-LQD for the TMF.
Limit
equilibrium stability analyses were performed on the TMF for static (long-term) conditions, seismic loading conditions using pseudo-static
method, and post-peak (post-liquefaction) conditions. The slope stability models assumed a phreatic surface at the interface between
the upper and lower foundation soils (approximately 20 feet below the ground surface). The model also assumes a phreatic surface along
the CLS and tailings interface, as a phreatic surface is not likely to develop within the tailings mass. Slope stability analyses were
completed for the downstream and side buttress sections. Slope stability for the downstream section was modeled as the TMF advanced construction
to its full height in Year 3. The side buttress section was selected at the greatest embankment height, where the starter berm had not
been constructed.
The
requisite factors of safety are met for the stability analyses completed for the two sections when the ultimate waste rock retention
shell is constructed. Additional analyses were completed to analyze the TMF during construction and allow for operating flexibility.
The TMF stability results are detailed in the TMF Stability Analyses Technical Memo (Tierra Group, 2025b).
17.1.4 | Geochemical
Characterization of Mine Rock and Tailings |
Geochemical
Solutions (2023) evaluated the potential to generate acid rock drainage (ARD) and metal leaching from the mine rock and tailings storage.
Fifty-six representative rock samples and four tailings samples were collected for geochemical characterization. The 56 rock samples
represent in-place mine rock at the projected surface of the proposed pit shell and the rock to be mined. The rock samples are distributed
widely both horizontally and vertically across the proposed pit and surrounding the ore body, as shown on Figure 17.9.
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Figure
17.9: Mine rock sample spatial distribution (from Geochemical Solutions 2023)
The
four tailings samples were derived from bench-scale metallurgical (locked cycle) testing of representative ore samples. Bench scale process
water samples from the locked cycle testing were also submitted to an analytical laboratory for analysis.
Geochemical
analyses included:
| ● | Whole
rock characterization assesses the bulk geochemical composition of the waste rock, tailings,
and low-grade ore materials. |
| ● | Acid-base
accounting (ABA) determines the balance of acid-generating sulfide minerals and acid-neutralizing
minerals in the samples. |
| ● | Net
acid generation (NAG): This method uses hydrogen peroxide to oxidize the exposed sulfide
minerals in the samples. The oxidation provides a high-end estimate of the acidity that may
be produced through oxidative weathering of any exposed materials. It also allows the identification
of potential elemental release through oxidative weathering of mine materials. |
| ● | Meteoric
Water Mobility Procedure (MWMP): a single-pass column leach test used for non-acid generating
mine rock to assess the chemical quality of contact water. |
| ● | Humidity
cell testing (HCT) is a multi-week column weathering test that provides the test sample with
excess water and oxygen to facilitate rapid oxidation of sulfide minerals. Weekly column
rinses are analyzed for various parameters (such as pH, alkalinity, iron, and sulfate),
and a monthly rinse sample is analyzed for a range of regulated metals and metalloids. |
Geochemical
Solutions (2023) also evaluated the mineralogy and petrography of mine rock to better understand the controls on acid-generation potential
(AP) and neutralization potential (NP). Mineralogic analyses included:
| ● | Quantitative
mineralogy by x-ray diffraction (XRD). |
| ● | Optical
microscopic examination. |
| ● | Scanning
electron microscopy (SEM), using backscattered electron imaging. |
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The
ABA and NAG tests are considered static test procedures, while the subsequent MWMP and HCT tests are considered kinetic tests. Water
samples are obtained weekly from the testing apparatus to evaluate whether leaching is occurring and when it may be expected to start.
The HCTs were conducted over a 108-week period. Figure 17.10 summarizes the ABA results, and Figure 17.11 summarizes the HCT results.
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Figure
17.10: Results of ABA Tests (from Geochemical Solutions 2023)
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Figure
17.11: Results of Humidity Cell Tests (from Geochemical Solutions 2023)
Using
industry-standard methods, the characterization of the geochemical properties of Project mine rock and representative tailings
indicates the limited probability of the rocks and tailings producing ARD in contact water. ABA and NAG static testing results
indicated the presence of potentially acid producing mine rock and release of metals in 5 of the 56 samples, two located
approximately halfway up the west side of the projected pit surface and three with excavated waste rock. Some higher
sulfur-containing samples indicate the limited and local presence of PAG mine rock. However, little mine rock is mapped as having
elevated sulfur and increased ARD potential. Most of mine rock is characterized as NPAG, with an overall median Net Neutralization
Potential (NNP) of 24.5 short tons of CaCO3 per 1,000 tons of rock (tCaCO3/1,000t rock) and Neutralization Potential Ratio (NPR) of
33.3; rock with either NNP greater than 20 tCaCO3/1,000t rock or NPR greater than three is considered NPAG. The median NAG pH was
6.2; samples with NAG pH greater than 4.5 were classified as NPAG. Results from the NAG metal analysis showed that arsenic, cadmium,
copper, lead, and zinc were observed in five samples. However, HCT and MWMP
results show no low pH (acidic) water or metal release production, which resulted in NPAG classification, regardless of sulfur content.
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The
mineralogy of the mine rock affects the potential for the formation of ARD. Sulfide minerals appear primarily as small pyrite and chalcopyrite,
with trace percentages of other sulfides disseminated in the silicate matrix. Silicate minerals provide the bulk of NP. Based on the
extended HCT results, it appears that the rate of NP from silicate minerals is able to keep pace with the limited rate of acid production.
MWMP
leach testing of NPAG demonstrates low to no leaching of dissolved regulated metals. Leaching of total iron and manganese was
observed to produce concentrations that exceeded domestic use criteria but were consistent with ambient background groundwater
concentrations. In one instance domestic use criteria was exceeded for dissolved arsenic. One sample exceeded the agricultural use
criteria for total iron. MWMP results for representative tailings samples indicated that leached water from tailings were
consistently below domestic use criteria. HCT testing of rock samples, which spanned the range of sulfur concentrations results from
the ABA data, resulted in neutral to slightly alkaline pH conditions for up to 108 weeks of testing with metal release observed to
be negligible and low sulfate release rates. The four metallurgical testing tailings samples analyzed contain limited sulfide
sulfur; therefore, the representative tailings produced NPAG results.
Four
samples representative of process water were submitted for analysis. Arsenic concentrations in these samples routinely exceeded domestic
and agricultural use criteria, but not livestock use criteria. The remaining constituents were below regulatory criteria.
17.2 | REQUIREMENTS
AND PLANS FOR WASTE AND TAILINGS DISPOSAL, SITE MONITORING, AND WATER MANAGEMENT |
This
section is divided into three subsections as follows:
| ● | Waste
Rock and Tailings Management (Section 17.2.1) |
| ● | Site
Monitoring (Section 17.2.2) |
| ● | Water
Management (Section 17.2.3) |
This
section summarizes design and operational requirements during construction, mining, mineral processing, closure, and post-closure.
17.2.1 | Waste
Rock and Tailings Management |
Waste
rock and tailings generated during mining and mineral processing will be deposited in engineered facilities on the Project site.
The
waste rock consists of excavated overburden and rejected material from the pit containing insufficient concentrations of copper or
gold for economic mineral processing. Waste rock will have various on-site uses/destinations, including construction and capping of
haul roads and erosion control features, deposition
in the West and East Waste Rock facilities (WWRF and EWRF, respectively), and use as the TMF’s outer retention shell and buttress.
The waste rock facility design and construction are described in Section 15. This section focuses on the associated environmental management
controls.
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The
following environmental management controls will be incorporated:
| ● | Stability:
The WWRF and EWRF are designed to have a slope angle of 3H:1V, substantially flatter
than the rock’s angle of repose, inherently providing an acceptable safety factor for
geotechnical stability. These facilities will be constructed using 20 to 30-foot-thick lifts.
Construction will start from the lower ground surface elevations, moving upward and outward
a lift at a time, stepping back such that the final angle of the entire facility is 3H:1V. |
| ● | Water
management and seepage control: Each lift will have a running surface that drains precipitation
away from the dumping fronts for stability and to minimize percolation. The driving surface
will be compacted by the haul trucks. Runoff and seepage will be collected in detention ponds
constructed at the downstream toe of the two waste rock facilities. Overflow spillways will
be provided to prevent the overtopping of detention ponds during runoff events exceeding
the design storm event (Section 17.2.3). The water in the detention ponds will be pumped
out for use in dust control on-site or other production-related uses. Accumulated sediments
will be periodically removed from the ponds and disposed of in the TMF. |
| ● | ARD
control: Kinetic testing on waste rock resulted in non-potentially acid rock drainage
(ARD)/metal leaching (Section 17.1.4). The Project will implement a Material Testing Program
(MTP) to test blast hole cuttings to quantify Au, Cu, and Ag grades to differentiate between
ore and waste rock. Additionally, the waste rock blast hole cuttings will be subjected to
Net Acid Generation (NAG) pH testing to delineate non-potentially acid generating (NPAG)
and potentially acid generating (PAG) waste rock polygons. Waste rock will be considered
non-PAG (NPAG) if the NAG pH is greater than or equal to 4.5, per the Global Acid Rock Drainage
(GARD) Guide (INAP 2023). PAG waste rock will be routed to either the CLS lined TMF or temporarily
to the CLS lined Ore Stockpile. PAG waste rock that is placed within the Ore Stockpile will
be relocated to the pit after Year 8 of operations. NPAG waste rock will be placed in the
WWRF, EWRF, or the TMF rock buttresses or shell. A mine-bench scale 3-D database comprised
of NAG pH grades and coordinates will be maintained and used for short term and life of mine
planning. Results of the NAG pH analyses will be made available within 24 hours, transmitted
electronically to the ore control engineer to delineate NPAG and PAG waste rock polygons.
In the event of delayed assay results, the waste rock would either remain in the pit until
assays are received or handled as PAG. |
| ● | Reclamation:
The WWRF and EWRF will be reclaimed by topsoil covering and revegetation. The soil growth
medium component of the cover will limit infiltration, promoting vegetation growth, runoff,
and evapotranspiration. The soil growth medium layer thickness will be 12 inches. Geotechnical
site investigations indicate there is sufficient material located on the Project site suitable
for a soil cover that meets these requirements. The waste rock is expected to be suitable
for a base for the soil cover. Some waste rock processing will be required to produce a transition
zone between the rock and the soil growth medium cover material. Preliminary design of the
transition zone indicates a minimum two-foot-thick layer of well graded (coefficient of uniformity
greater than four) material with a maximum particle size of three inches. |
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The
tailings will be filtered to extract as much moisture as feasible prior to their deposition, maximizing their structural strength and
geotechnical stability, thereby avoiding the need for a tailings dam and the associated stability and seepage risks. Filtered tailings
also maximize the amount of water that can be recycled to mineral processing, reducing make-up water requirements and minimizing overall
water consumption (Section 17.2.3). The processed tailings will be hauled to and placed in the TMF until Year 8.25. After that, the remaining
tailings produced will be hauled to and placed in the open pit.
The
following environmental management controls will be incorporated into the TMF operation and maintenance plan:
| ● | Stability:
Tailings filtration produces tailings near their optimum moisture content for compaction,
maximizing their geotechnical strength and stability. Thus, the risk of slope failures and
spills is significantly reduced. The filtered tailings will be co-deposited with waste rock.
The waste rock retention shell will function as a buttress to stabilize the TMF. The TMF
outer surfaces will be monitored for movement, and piezometric pore pressure will be monitored
within the tailings mass for signs of potential decreased stability. |
| ● | Erosion
and sediment control: Grading of the TMF will be controlled to maintain the active crest
surface of the TMF with a gradient that slopes downhill to avoid pooling and infiltrating
water into the placed tailings. The general design of the TMF includes zonation, such that
a waste rock retention shell will be constructed concurrently with tailings placement. During
wet conditions, placement of tailings will be in the interior of the TMF, away from the perimeter.
Compaction will be performed as quickly as feasible following initial tailings deposition
using a smooth roller compactor to seal the surface, prevent fugitive dust, and promote runoff. |
| ● | Water
management and seepage control: Runoff and seepage from the TMF will be collected in
detention ponds. Overflow spillways will be provided to prevent overtopping of detention
ponds during runoff events exceeding the design storm event. A pond will be constructed upstream
of the TMF to capture runoff from the watershed to the west of the TMF. Overflow from this
pond will be conveyed through the TMF underdrain, overdrain, or both, depending on the stage
of the project. The water in the detention ponds will be pumped out for use in the process
plant and dust control on site. Accumulated sediments will be periodically removed from the
ponds and disposed of in the TMF. Seepage control of the TMF is provided by the seepage collection
drain installed above the TMF liner as discussed in Section 15.3.2. The drain will maintain
a low hydraulic head in the bottom of the tailings mass, to promote free drainage of the
tailings, and minimize tailings saturation. |
| ● | Dust
control: To minimize fugitive dust emissions from the TMF, compaction of the top of the
tailings surfaces will be performed as quickly as feasible following tailings deposition
and spreading by dozers using a smooth roller compactor to seal the surface. The waste rock
retention shells will be placed over the exposed tailings slopes once the final tailings
slope and elevation have been achieved. Speed limits will be imposed and enforced throughout
the Project site. Water will be sprayed on active surfaces to control fugitive dust emissions
as required. Use of soil binders and tackifiers or other approved dust suppressants may be
considered, depending on the effectiveness of the above measures. Erection of wind breaks
may also be considered as a backup solution, if required. |
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| ● | Off-specification
tailings management: The process plant will use a batch filtration process for drying the tailings. Bench-scale testing has been
performed on tailings samples to determine the type and size of filter press needed for the Mine to achieve the design moisture
content criteria of at
or below 14% metallurgical 2. It is expected that commercial-scale tailings filtration
equipment will generally meet the moisture content criteria. However, there may be variations in the ore feed (e.g., clay content) that
could affect the performance of the filters, requiring adjustments to be made. During the adjustment period, off-specification tailings
may result. In addition, as the plant transitions from one filtration unit to the other there may be upset conditions. The plant has
been designed to cater to these conditions, but for limited periods the moisture content specifications may not be achieved until adjustments
are made to the filtration units. Off-specification tailings may also occur during the initial commissioning of the filter presses as
the equipment is adjusted to field conditions. Off-specifications tailings delivered to the TMF will be air dried at the placement site
prior to roller compaction. Air drying will be enhanced by blading and/or discing the tailings surface into windrows on a regular basis
until a lower, workable moisture content is achieved. Monitoring and adjustments will be made, as necessary, to the filter presses to
regularly meet the specifications to allow hauling, placement, and surface rolling of the tailings. The moisture content of the delivered
tailings will be monitored and no tailings with moisture content exceeding the criteria will be disposed at the TMF. If wet conditions
cause excess moisture in the tailings, then placement may need to stop until suitable conditions can be restored. Monitoring and adjustments
will be made, as necessary, to the filter process to regularly meet the specifications. |
| ● | PAG
waste rock deposition in the TMF: PAG waste rock identified during the operational life
of the TMF will be placed on top of the CLS and within the interior of the waste rock retention
shell on the south side of the TMF, to isolate it from weathering effects and prevent it
from acting as a potential source of ARD and metal leaching. The PAG waste rock will be spread
to limit vertical accumulation in concentrated areas, which will limit contact with the limited
amount of infiltrating water migrating vertically through the waste rock. The CLS will prevent
seepage that may have come into contact with PAG materials from infiltrating into the groundwater. |
| ● | Monitoring
and inspection: An Operations, Maintenance and Surveillance (OMS) Plan will be prepared
and implemented for the TMF addressing requirements for the operation, safety, and environmental
performance of the facility, including a framework for identifying, evaluating, and reporting
significant observations. Specific monitoring and inspections related to the TMF will include: |
| ○ | Structural
stability assessment of the TMF and related water control structures, |
| ○ | Water
quality sampling at designated monitoring points, and |
| ○ | Piezometric
monitoring of water levels in the tailings mass. |
| ● | Reclamation: A
vegetated soil cover will be placed over the closed TMF to achieve a stable hydrologic configuration and minimize infiltration. The
cover will promote conveyance of stormwater; prevent surface water ponding; disperse rather than concentrate runoff; limit erosion
and channel scour; provide long-term erosional stability; and promote establishment of perennial, self-sustaining, native
vegetation. The soil growth medium component of the cover will limit infiltration, promoting vegetation growth, runoff, and
evapotranspiration. The soil growth medium layer thickness will generally be 12 inches. Geotechnical site investigations indicate
there is sufficient material located on the Project site suitable for a soil cover that meets these requirements. The waste rock
shell is expected to be suitable for a base for the soil cover. Some waste rock processing will be required to produce a transition
zone between the rock structural shell
and the soil growth medium cover material. Preliminary design of the transition zone indicates a minimum two-foot-thick layer of well
graded (coefficient of uniformity greater than four) material with a maximum particle size of three inches. Micro-topographical undulations
will be created in the TMF slope for wildlife habitat. The TMF will receive shrub-specific vegetation for wildlife on the south face.
Rock outcroppings will also be constructed to enhance wildlife habitat. Post-mining, the TMF landforms will provide long vegetated south-facing
slopes with shrubbery to support local wildlife. |
2
Metallurgical water content is tailings moisture measured by total weight. Geotechnical water content is measured by dry weight.
A 14% tailings moisture metallurgical is equivalent to 16.3% geotechnical.
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As
described in Section 15, after the pit is fully excavated during Year 8, the pit will be backfilled with tailings produced during the
last two years of post-mining mineral processing up to an elevation of 6,630 feet amsl. Then, with a combination of blasting and earthmoving,
the pit rim will be dozed into the pit to create a 3H:1V final pit wall slope and final backfilled pit elevation of approximately 6,720
feet amsl.
Groundwater
and precipitation will flow into the pit backfill material and the groundwater level will slowly rise within the pit until it stabilizes
at about 6,717 feet elevation about 130 years after mining (Neirbo Hydrogeology 2023). As described above, geochemical testing of mine
rock and tailings indicates limited potential to produce ARD and/or metal release, therefore water contacting the pit wall rock and backfill
is not expected to result in detectable metal leaching. A pit lake is not expected to form because evaporation losses will keep the groundwater
level below the surface of the backfill. The pit is predicted to act as a hydraulic sink with no groundwater outflows.
The
scope of site monitoring activities during construction, mining, mineral processing, reclamation, and closure is derived from impact
and risk assessment, permit conditions of approval, and commitments made in the permit applications (Section 17.3). The following site
monitoring activities will be performed:
| ● | Meteorology:
The current meteorological monitoring program (Section 17.1) will continue through the
construction and operating phases of the mine. |
| ● | Air
quality: Continued ambient air quality monitoring will be conducted for PM10 emissions.
Opacity monitoring will be conducted at the crusher, screens, conveyor transfer points, and
other points of fugitive emissions. Water and chemical dust suppression use will be recorded,
including quantities and water truck operating hours. Emergency generator usage will be recorded. |
| ● | Surface
water: Monitoring of flow and water quality in streams, post-storm seeps, and at detention
ponds and associated channels and other engineered flow paths will be conducted per WYPDES
permit conditions (Section 17.3). |
| ● | Groundwater:
Monitoring of groundwater level and quality will be conducted. Additional groundwater
monitoring wells will be installed and periodically sampled. Some existing and planned monitoring
wells will be lost to mine development. Open pit dewatering water quality and flow rates
will be monitored during operations. |
| ● | Waste
rock ARD potential: Blast hole cuttings will be geochemically tested to classify the
rock as either PAG or NPAG for handling accordingly (Section 17.2.1). |
| ● | TMF
Operations, Maintenance and Surveillance (OMS) Plan: TMF performance monitoring and inspections
will be conducted, including structural stability, water quality sampling, and piezometric
monitoring of water levels in the tailings mass (Section 17.2.1). |
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| ● | Pit
wall stability: Survey monuments will be placed around the pit excavation to monitor
for movement. Ongoing geotechnical mapping and monitoring of the pit slope faces will be
conducted. Movement beyond that which would be expected from rock mass dilation and unloading
will trigger redesign or remedial measures. Piezometric water levels in the pit wall rock
will be monitored for signs of potential decreased stability. |
| ● | Noise
and vibrations: Ground vibration, air overpressure, flyrock distances, and dust and gas
emissions from blasting will be measured. |
| ● | Topsoil
stockpiles: Monitoring of wind and water erosion of stockpiles will be ongoing during
operations. |
| ● | Weed
growth: Operational areas, stockpiles and reclaimed areas will be monitored to limit
the spread of noxious weed species. |
| ● | Wildlife
monitoring: Operational areas will be inspected for the presence of listed and other
sensitive species (Section 17.1.1) prior to construction disturbance. |
| ● | Cultural
and paleontological finds: A chance finds procedure will be implemented to protect unknown
cultural or paleontological resources potentially encountered during initial construction
disturbance. |
| ● | Post-closure
monitoring: A post-closure monitoring plan will be implemented to verify that closure
objectives are met, including water quality, the closed facilities’ long-term physical
and chemical stability, and establishment of post-mining land use. |
The
CK Gold Project will operate in a net water deficit situation, given that the mean annual evapotranspiration exceeds the mean annual
precipitation (Section 17.1). The Project will implement water saving measures, as summarized below. Also described below are the Project’s
water balance, water supply source, and groundwater/surface water management design and monitoring approach.
17.2.3.1 | Water
Saving Measures |
The
Project will implement the following water saving measures to minimize its water consumption from off-site sources:
| ● | Tailings
filtration: Tailings generated in the flotation process will be filtered to an optimum
low moisture content to produce “dry stack” tailings, thereby minimizing water
consumption and avoiding the need for a tailings dam and the associated environmental and
safety risks. The tailings slurry produced by flotation initially containing about 65% water
(by weight) will first be thickened for initial water recovery. The water content of the
thickened underflow slurry will be reduced to about 45%, while the thickener overflow water
will be returned to the process for reuse. The thickened slurry will be pumped to storage
tanks ahead of a large pressure filtration plant comprising multiple large pressure filters
that further reduce the water content to <15% (typically 14%). The recovered water is
recycled back into the flotation process, instead of being disposed of in a tailings dam
where much of it would be lost to seepage and evaporation. |
| ● | Pit
dewatering recycling: Groundwater and precipitation inflow into the pit will be collected
in a sump and used for dust control on site, lowering the overall demand for water from external
sources. The Project’s rights to the pit inflow water are permitted (Section 17.3). |
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| ● | Surface
runoff and seepage recycling: Surface runoff and seepage from mine facilities, including
the waste rock facilities, TMF, and other facilities will be collected in detention ponds
and recycled for reuse as dust control or to meet process water demand. These water rights
have been permitted (Section 17.3). |
| ● | Irrigation
ditch: Water from an existing irrigation ditch (“Simmons No. 4 Ditch”) currently
supplying water to a hayfield at the proposed mineral processing plant location, fed during
the late spring/early summer months by the South Crow Creek Reservoir south of the Project
site, will be consumed by the Project during construction and operations, and restored to
its current use during the reclamation phase. |
| ● | On-site
potable water supply well: An on-site water supply well was permitted to supply potable
water for on-site staff consumption. |
| ● | Truck
wash water recycling: Used wash water will be collected at the truck wash facility, decanted
and reused for dust control on site. |
| ● | Dust
control water recycling: The fraction of water consumed in the pit and primary crusher
for dust control purposes that is left over after evaporation and infiltration will be collected
and recycled for dust control on site. |
The
Project’s total average water consumption is 562 gallons per minute (gpm). This number is the estimated total consumption, excluding
reductions in demand for water from off-site sources associated with the water saving measures described above. Consumption for mineral
processing, general operations, and dust control is as follows:
| ● | Process
plant: 475 gpm, based on a daily feed of 20,000 short tons of ore. The initial moisture
of the incoming ore to the primary crusher is estimated to be 3%. The metallurgical test
work identified the moistures of the two final products of ore processing, which are as follows:
concentrate (less than 1% of the total ore feed by weight) with remnant moisture by weight
of 10%; and tailings (99% of the total feed by weight) with 14% moisture. |
| ● | Truck
Wash: 3.5 gpm, based on the design of this facility that utilizes high efficiency (low
water consumption) nozzles and an average wash time of 25 minutes for each piece of equipment,
3-4 times a month for preventive and unplanned maintenance. Approximately 75% of
the water may be recycled back into the system. |
| ● | Primary
Crusher: 5.5 gpm, based on spray nozzles operating for 60 seconds each time a truck dumps
in the crusher dump hopper, at a rate of 40 gpm. For a 100-ton truck there are 200 loads
in a day dumped into the crusher dump hopper. |
| ● | Dust
Control: The various consumptions below are estimated by making assumptions on the frequency
and supply capacity of spraying on a daily basis: |
| ○ | Pit
dust control spraying on the shot rock loading faces: 10 gpm, groundwater seepage and precipitation
collected in the pit sump. |
| ○ | Waste
Rock Facilities dust control spraying at the dumping locations: 5 gpm, sourced from precipitation
runoff collected in the detention ponds and the water storage tank as needed. |
| ○ | Dust
control spraying at the newly spread tailings on the TMF surface: 14.1 gpm, sourced from
precipitation runoff collected in the detention ponds and the water storage tank as needed. |
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| ○ | Temporary
haul roads dust control spraying: 37.5 gpm, sourced from precipitation runoff collected in
the sedimentation ponds and the water storage tank as needed. No water will be applied for
dust suppression on the roads outside of the pit and the access road. These roads will be
periodically sprayed/treated with dust suppression agents, such as magnesium chloride or
other dust suppressant solution. |
| ● | Staff:
4.5 gpm, based on a maximum of 260 staff present each shift and an average consumption of
25 gallons per day per person. |
A
schematic of the Project water balance is shown on Figure 17.12.
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Figure
17.12: Water Balance
Tierra
Group developed a site-wide water balance for the CK Gold Project to maximize the reuse of contact and non-contact water within the site’s
watershed (Tierra Group, 2025c). The water balance assumes that the meteoric precipitation that falls on Project facilities will generally
be collected by the detention ponds and pumped back to TMF-1 for reuse as dust suppression or to meet the process water demand. A system
of pumps and pipelines will deliver the surface water collected in the detention ponds around site to TMF-1. The pumping system is conservatively
designed to convey the design storm volume reporting to each pond within 30 days, or the maximum monthly volume calculated from the water
balance, whichever is greater.
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17.2.3.4 | Water
Supply Source |
Under
an agreement with the Ferguson Ranch, the surrounding landowner, a water exploration program has successfully identified a nearby source
in the Red Canyon approximately 1-mile north of the project. The Red Canyon water will be less costly to develop and less costly to purchase
under the agreement with the Ferguson Ranch and adjustments to the identified “source and yield” specified in the two main
project permits (ISC and MOP) will be made to reflect the Red Canyon water supply once final development has been completed. Regardless
of the source, water purchased will be used to make up the water deficit. Local consultants conducted preliminary engineering to confirm
feasibility and costs associated with the Red Canyon supply. Following studies by TGI water generated from pit dewatering, surface runoff,
and waste rock and tailings seepage will be recycled for use in mineral processing and/or dust suppression, reducing the volume of make-up
water.
The
Project will pump water from the Red Canyon well field to the Project water tank.
As
a water supply back up, the Project negotiated a water supply agreement with the Cheyenne Board of Public Utilities (BOPU). BOPU the
Lone Tree Creek (LTC) well field south of the Project and south of the I-80. BOPU also operates the South Crow Creek Reservoir and water
supply pipelines that pass through and are near the Project. Should the BOPU water source be adopted, water will flow through the South
Crow Creek pipeline where water will be transferred up to the water storage tank. Figure 17.13 shows the approximate alignment of the
supply line.
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Figure
17.13: New Water Source and Approximate Alignment to Fresh Water Tank
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As
shown on Figure 17.14, a water line will tap into the South Crow Creek pipeline and transmit water to the Project’s proposed on-site
water storage tank. A pumping system may be installed at the water line tap to pump water to the Project’s storage tank. The pumping
system will have variable frequency drives and are required to maintain a constant water supply to the tank and to the process plant.
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Figure
17.14: Proposed Water Transmission Infrastructure (from Trihydro 2023)
17.2.3.5 | Groundwater
Management |
The
open pit formed by mining will collect precipitation and groundwater inflow. Based on groundwater modeling performed by Neirbo Hydrogeology
(2023), pit inflow is expected to be diffuse and limited due to the overall low permeability and low water storage capacity of the surrounding
rock. Faults and fracture zones will yield little water and will drain rapidly due to limited spatial extents.
The
annual pit bottom elevation starts at 6,900 feet AMSL in year 1 and progresses to 6,120 feet at the end of mining. Passive open pit dewatering
begins when pit advancement reaches the water table. Predicted pit inflow during the first year is 6 gpm. As the pit advances pit inflows
are predicted to be less than 15 gpm. This water will be recycled on site during the operations phase, as described above.
Pit
dewatering during mining will result in a groundwater level decline (drawdown) relative to the pre-mining level. Drawdown will also
result from changes in groundwater recharge due to changes in precipitation infiltration caused by changes in the Project
site’s ground surface. The groundwater model differentiates
between mine-induced groundwater drawdown and groundwater level changes caused by non-Project groundwater pumping and seasonal and annual
precipitation variation. Based on Project groundwater monitoring from 2020 to 2022, Project induced drawdown would need to exceed 10
feet to be distinguishable from natural and other non-Project variation.
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The
modeled mine-induced drawdown decreases rapidly with distance away from the pit, as shown on Figure 17.7. The 5-foot drawdown contour
is predicted to remain completely within the Project boundary at except for a small jut along the western edge (Figure 17.8). The drawdown
extent is limited mainly due to the low permeability of the rock.
The
nearest domestic wells are approximately 2,000 feet from the predicted 5-feet drawdown area. At this distance, any mine induced drawdown
would likely not be discernable from natural variation and groundwater-level changes induced by the domestic wells themselves.
After
mining, the backfilled pit will slowly fill with water as precipitation and groundwater flows in. The backfill materials consist of tailings
and rock dozed from the pit rim. As described in Section 17.1.4, geochemical testing of mine rock and tailings using industry standard
methods on representative samples (Geochemical Solutions 2024) indicates limited probability to produce ARD and/or metal release to water.
Groundwater quality is not expected to significantly deteriorate due to contact with pit wall rock, waste rock, or tailings.
The
backfill surface elevation is modeled at 6,720 feet and the groundwater level is predicted to stabilize at 6,717 feet after about 130
years. The pit is roughly conical in shape, so the rate of water level rise slows as the pit volume increases with increasing elevation.
Evaporation is modeled to start when the water level is within 5 feet beneath the backfill surface. Evaporation losses depress the groundwater
level and prevent water from daylighting and forming a permanent pit lake. Water may temporarily pond in the pit following large precipitation
events, but evaporation losses will gradually lower the water level to below the surface of the backfill. This depressed water level
creates a hydraulic sink with lower groundwater levels immediately adjacent to the pit and no groundwater outflow from the pit. Therefore,
any unforeseen water quality deterioration would be contained within the pit zone.
During
the post-mining period, drawdown is predicted to propagate slowly and remain near the pit. Drawdown greater than 5 feet is predicted
to generally extend a small distance outside the Project boundary, except for the northeast corner, at peak drawdown, 150 years after
mining (Figure 17.8).
Groundwater
monitoring wells around the Project site, including up- and down-gradient of mine facilities, will be sampled quarterly during the first
year of mining operations. The data will be reported to the Wyoming DEQ-LQD in the Annual Reports and if the data is similar to baseline
data, a request to reduce the frequency of sampling to semi-annually will be made. Actual groundwater drawdown and quality data will
be recorded to confirm the modeling predictions or identify any deviations from the predictions that would trigger remedial action.
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17.2.3.6 | Surface
Water Management |
The
proposed Project facilities will be limited to ephemeral drainages that are not capable of hosting aquatic life. Two water courses traversing
the Mine Area (Figure 17.3) have been designated Waters of the United States, and are described in Section 17.1.1:
| ● | North
tributary of Middle Crow Creek |
Project
disturbance will remain outside of these water courses and associated adjacent wetlands. The Neirbo Hydrogeology (2023) groundwater flow
model predicts reductions in streamflow in these streams of only one percent or less due to mine-induced groundwater drawdown.
Mine
construction, operation, and reclamation activities involving excavation and grading could potentially cause surface soil erosion and
sedimentation of adjacent streams. Mitigation measures that will be implemented to avoid these potential impacts include the following:
| ● | Phased
clearing and grubbing of vegetation in areas closely preceding planned excavation and grading
activities, minimizing the aerial extent and duration of surface soil exposure. |
| ● | Stockpiling
of topsoil for use in covering and reseeding (reclamation) of disturbed areas. |
| ● | Implementing
surface reclamation activities as soon as feasible after disturbance to minimize the duration
of exposed soil surfaces, including concurrently with mining operations to the extent feasible. |
| ● | Compaction
of exposed soil surfaces to minimize erosion and sediment transport. |
| ● | Deployment
of erosion control materials on exposed sloped soil surfaces to minimize erosion and sediment
transport. |
| ● | Directing
and capturing surface runoff from Project disturbed areas via surface channels discharging
into detention ponds. |
Surface
water flow and quality will be monitored. Water quantity and quality in the detention ponds will also be monitored as required by the
WYPDES permit (Section 17.3).
Surface
runoff (contact water) from the Project facilities will be collected in channels and detention ponds and recycled on-site as described
above (Tierra Group, 2025c). Diversion ditches will be constructed to reduce the volume of stormwater run-on to the Project site from
undisturbed areas outside of the Project boundary and to direct contact water runoff into the detention ponds. Ditches will be armored
with riprap where the slope/flow velocity requires it to protect against erosion. Riprap drops and pipe drops will be constructed at
the end of the diversion ditches to convey the water to a detention pond. Energy dissipators will be constructed at the end of the pipe
drops to prevent erosion.
Detention
ponds will be constructed to collect contact water runoff from the mine facilities. Additional ponds will be constructed in the process
plant area for contact water collection and for emergency containment of process water (Figure 17.15). Generally, there is a detention
pond located at the downstream end of the waste rock, Ore Stockpile, and TMF within draw bottoms to collect contact water and prevent
routine discharges outside of the Project site. Water that collects in the detention ponds will be pumped to TMF-1 for use as on-site
dust control and process demands. Most of the ponds are permitted by the Wyoming State Engineer’s Office (SEO). TMF-1, TMF-2a,
TMF-2b, and TMF-3 have been revised since the original permit submittal and the permits will need to be updated with the SEO.
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Figure
17.15: Project Site Layout
The
ponds will consist of an embankment that is less than 20 feet tall and have a capacity that is less than 35 acre-feet each, maintaining
a dam classification of non-jurisdictional. The embankments will be constructed from available soil at each pond’s location and/or
excess material from other construction operations. The embankment soil will be compacted to 90% of standard Proctor dry density. The
prevalent on-site silty clays with sand and gravel are suitable for embankment construction. The embankment crest will be a minimum of
12 feet wide. The upstream slope will be no steeper than 3H:1V, and the downstream slope no steeper than 2.5H:1V. The ponds will be lined
with a CLS, consisting of 60-mil HDPE liner. Overflow spillways will be provided to prevent overtopping of detention ponds during runoff
events exceeding the design storm event. Ponds are designed to contain either the 10-year, 24-hour storm event (EWRF-1, WWRF-1, WWRF-2,
WWRF-3, TMF-2A, TMF-2B, TMF-3) or the 100-year 24-hour storm event (TMF-1, Ore-1, Mill Site, South Mill, Admin, South Creek)while the
spillways are designed to pass flow for the 100-year, 24-hour event.
17.3 | REQUIRED
PERMITS AND STATUS |
The
Project occupies state-owned and private land. Construction and operation of the mine requires various permits issued at the state and
local levels. Some limited federal permitting is involved. Below is a list of the most significant agencies and associated permits. The
major required permits have been obtained, as described in the sections that follow.
| ● | US
Army Corps of Engineers: Approved Jurisdictional Determination (Section 17.3.1) |
| ● | US
Environmental Protection Agency: Public Water Supply Permit (Section 17.3.2) |
| ● | Wyoming
Office of State Lands and Investments: Mining Lease (Section 17.3.3) |
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| ● | Wyoming
Department of Environmental Quality: |
| ■ | Exploration
Permit (Section 17.3.4) |
| ■ | Mine
Operating Permit (Section 17.3.5) |
| ○ | Air
Quality Division: Air Quality Permit to Construct and Operate (Section 17.3.6) |
| ○ | Industrial
Siting Division: Industrial Siting Permit (Section 17.3.7) |
| ○ | Water
Quality Division (Section 17.3.8) |
| ■ | Wyoming
Pollutant Discharge Elimination System (WYPDES) Permit |
| ■ | Stormwater
Pollution Prevention Plan and Notices of Intent and Termination under the Large Construction
General Permit (for Construction) and Industrial General Permit (for Operation) |
| ■ | Permit
to Construct Water Supply and Wastewater Facilities |
| ■ | Operator
Certification for Drinking Water System |
| ● | State
Engineer’s Office: Permits for Water Use and Water Related Facilities (Section
17.3.9) |
| ● | State
Historical Preservation Office (Section 17.3.10) |
| ● | State
Fire Marshall (Section 17.3.11) |
| ● | Laramie
County (Section 17.3.12) |
17.3.1 | Approved
Jurisdictional Determination |
In
February 2021 the US Army Corps of Engineers (USACE) Omaha District, Wyoming Regulatory Office, issued an Approved Jurisdictional Determination
(AJD) covering the CK Gold Project site. Under this AJD, the following two surface water bodies and associated wetlands in the Project
area are considered Waters of the United States and subject to USACE jurisdiction and permitting for discharging of dredged or fill materials:
| ● | North
tributary of Middle Crow Creek |
There
are no plans for Project infrastructure that would lead to deposition of dredge or fill material in the above surface waters on the Project
site, therefore no further USACE permitting is anticipated to be required. In April 2024 the USACE issued a confirmatory letter in this
regard. The AJD is valid for five years from the date of issue. If the start of Project construction were to be delayed beyond this period
(February 2026), a new AJD would need to be applied for. The legal definition of Waters of the US is subject to change in the meantime,
and subsequent AJD could potentially incorporate different surface water bodies.
17.3.2 | Public
Water Supply Permit |
USEPA
Region 8 implements the Safe Drinking Water Act in Wyoming (the only state that has not taken over this responsibility itself). The
Act covers public water systems with 15 or more service connections or that serve 25 or more persons for at least 60 days per year.
The Project plans to supply its personnel with potable water from an on-site well and is therefore subject to this requirement. This
permit has not yet been applied for. Prior to supplying potable water, an application will be filed with the USEPA Region 8.
The Project will be required to monitor the quality of the supplied water and report the results to the USEPA.
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Exploration
activities conducted by the Project to date have been permitted by the Wyoming Department of Environmental Quality, Land Quality Division
(DEQ-LQD), which has primary jurisdiction over mining projects in Wyoming. The Project has posted bonds to guarantee the reclamation
of surface disturbance caused by the development of exploration drill pads, test pits and some roads. All such surface disturbance has
been reclaimed, including revegetation. Bond release for exploration disturbance is currently still pending the reestablishment of revegetated
areas.
17.3.4 | Mine
Operating Permit |
The
Project received its Mine Operating Permit (MOP) from the DEQ-LQD in May 2024. The MOP process began in October 2020 with a “Pre-Application
Meeting” and a resulting Action Plan defining the information, environmental studies, and operational and closure plans required
as part of the MOP application.
The
MOP application package included the following main components:
| 1. | Adjudication
File: Signed application forms; landowner consent and list of landowners of record; tabulation
of lands within the Project Permit Area; and associated maps and aerial photos. Reclamation
bonding and proof of public notification are added to the Adjudication File after the public
noticing and technical review. |
| 2. | Baseline
Studies: Land use, history, archeology, paleontology, climatology, topography, geology,
hydrology, soils, vegetation, wildlife, and wetlands (Section 17.1.1). |
| 3. | Mine
Plan: General description of mining operation, mining method and schedule, mining hydrology,
waste disposal, public nuisance and safety measures, and mineral processing and tailings
management. |
| 4. | Reclamation
Plan: Post-mining land use; land contouring plan; surface preparation; topsoil and/or
subsoil placement; revegetation; hydrologic restoration; infrastructure and processing facility
decommissioning, stabilization and reclamation; reclamation schedule; reclamation cost estimate;
and public nuisance and safety measures. The reclamation cost estimate is based on the cost
that would be incurred if the DEQ-LQD were to hire contractors to reclaim the mine and facilities.
Reclamation bonding can take the form of an irrevocable letter of credit, self-bond, or collateral
bond (including federally insured certificates of deposit, cash, government securities or
real property). The bond amount is determined by the DEQ-LQD approved Reclamation Plan and
associated cost estimate. |
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The
initial MOP application package was submitted to the DEQ-LQD in September 2022. The first public notice took place in November 2022,
following the issuance of DEQ-LQD’s completeness review of the permit application. After the agency’s subsequent technical
review, the Project submitted an amended application in January 2024 addressing public and agency comments, and a second public notice
was issued. In May 2024 DEQ-LQD formally approved the MOP and issued the associated License to Mine. The following conditions of approval
were attached to the license, which have been fully satisfied by the Project:
| 1. | Construction
and mining may start after posting and approval of the $5,010,000 reclamation bond, covering
reclamation of the first year’s planned site disturbance. |
| 2. | Water
discharge activities are authorized after issuance of the WYPDES permit by DEQ Water Quality
Division. |
| 3. | Construction
and mining may start after issuance of the Air Quality Permit by DEQ Air Quality Division. |
The
foregoing permit conditions are in addition to the Project commitments made in the MOP application package, namely the technical provisions
in the Mine Plan and Reclamation Plan.
Additionally,
the permit requires submittal to DEQ-LQD of an annual report within 30 days prior to the permit issuance anniversary date. Project requested
changes to the approved MOP Mine Plan or Reclamation Plan would be highlighted in the annual report. The annual report is followed by
a site inspection conducted by DEQ-LQD. A reclamation bond increase must be posted each year covering the next year’s planned site
disturbance, minus any credit due for completed reclamation of previous site disturbance.
17.3.5 | Air
Quality Permit to Construct and Operate |
The
Project received its Air Quality Permit to Construct from the DEQ’s Air Quality Division (DEQ-AQD) in November 2024, following
a public hearing held the month before during which no comments were received. The permit will expire if construction is not started
by November 2026. The Project must notify DEQ-AQD of the anticipated date of mine startup between 30 and 60 days prior, and obtain the
Air Quality Permit to Operate within three months after the start of mining operations (generally a simple formality, absent significant
Project changes). The permit conditions of approval include specific requirements for:
| ● | A
variety of dust suppression and wind erosion control measures during construction, mining
and mineral processing; |
| ● | Limiting
opacity of fugitive emissions; |
| ● | Avoiding
exceeding ambient air quality standards and reporting exceedances; |
| ● | Air
quality and meteorological monitoring and reporting; |
| ● | Limiting
use of the emergency generator (grid power will be relied upon during normal conditions); |
| ● | Limiting
the size and specifications of the mobile equipment fleet as specified in the permit application;
and |
| ● | Limiting
blasting operations. |
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This
permitting process consisted of a New Source Review, including the development and submittal of the Project’s air emission inventory
and dispersion modeling. The Project is classified as a Minor Source and falls under the DEQ-AQD’s requirements for general air
quality permitting to construct and minor source permitting to operate. Title V of the Clean Air Act does not apply.
17.3.6 | Industrial
Siting Permit |
The
Industrial Siting Permit (ISP) requirement is triggered by an overall project construction cost estimate amount threshold which changes
each year. When the Project’s ISP application was submitted to the DEQ - Industrial Siting Division (ISD) in February 2023, the
construction cost estimate threshold triggering the ISP requirement was approximately $254 million. The state’s intent with this
requirement is to plan for and mitigate potentially significant environmental and socioeconomic community impacts arising from a temporary
influx of construction workers.
The
Project’s ISP application was approved in June 2023 via a written Order by the Industrial Siting Council (ISC). The ISC was convened
by the DEQ-ISD to review and rule on the Project’s ISP application. The ISP application package included a project description,
socioeconomic and environmental impact assessment, and management plan. Associated technical studies were focused primarily on Project
induced noise and traffic, as well as socioeconomic impacts. Other types of environmental impacts were assessed as part of the MOP process
described above. The socioeconomic impacts were generally assessed as positive in the ISP application.
The
impact assessment study area covered portions of Laramie County and the adjacent Albany County to the west (the Project is wholly located
within Laramie County). The Project notified and consulted with these county governments and other local government agencies. Following
submittal of the permit application, public notifications were issued and public informational meetings held in the cities of Cheyenne
and Laramie (the respective county seats) in December 2022. Various agencies provided written feedback to the Project and the DEQ-ISD,
mainly consisting of requests, recommendations, and notification of their applicable requirements. The ISC presided over a public hearing
held in May 2023, during which the Project’s representative answered questions under oath.
The
ISC’s June 2023 permit approval Order includes a provision to award “unmitigated impact assistance funds” of approximately
$408,000 to Laramie County and $726,000 to the City of Cheyenne. These awards will be funded by the state from increased state tax receipts
associated with anticipated Project related procurement of materials within the state. According to the ISC’s Order, “these
funds are to compensate for unmitigated impacts to the affected counties, cities, and towns in the area primarily affected.”
The
ISP will expire if Project construction does not start by June 2026. Permit conditions of approval include:
| ● | Obtaining
and adhering to conditions of the other required state and local permits. |
| ● | Notifying
the DEQ-ISD in advance of proposed Project changes in “scope, purpose, size, or schedule,”
and filing of an evaluation of Project changes potentially resulting in significant environmental
and social impacts not evaluated in the ISP, before such changes are implemented. |
| ● | Developing
a written plan and program for achieving compliance with the permit conditions and commitments
made in the permit application, including identification of a compliance coordinator. |
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Detail
procedures for local hiring in the compliance plan and file job postings with the local Workforce Center.
| ● | Performing
additional mitigation measures beyond those committed to in the ISP, if certain unforeseen
adverse environmental or social impacts are caused by the Project. |
| ● | Additional
notifications as follows: |
| ○ | to
the DEQ-ISD of the start date of construction and when “physical components of the
facility are 90 percent complete;” and |
| ○ | public
notification via local newspaper ad when the “facility is nearing completion.” |
| ● | Submitting
annual reports through the first year of mining operations documenting: |
| ○ | efforts
to comply with the permit conditions and commitments made in the permit application; |
| ○ | construction
completion status relative to the approved schedule, and schedule revisions; |
| ○ | summary
of construction, reclamation and other activities to be conducted the following year; and |
| ○ | demonstration
of compliance with permit conditions. |
| ● | Implementing
a monthly monitoring program and quarterly results reporting to DEQ-ISD of: |
| ○ | average
and peak numbers of employees of the Project owner, contractors and subcontractors; |
| ○ | employee
city and state residency while hired and employed; |
| ○ | number
of new students enrolled by grade level and school district related to Project employees; |
| ○ | Wyoming
resident vs non-resident mix; and |
| ○ | updated
construction schedule. |
| ● | Notification
in advance of changes in the construction workforce schedule triggering a 15% or more exceedance
of the committed peak workforce number, or changes in the committed lodging plan. |
| ● | Submitting
to the DEQ-ISD at least 30 days prior to the start of construction, the following documents: |
| ○ | “Spill
Prevention, Control, and Countermeasure (SPCC) Plan which additionally adheres to the recommendations
of the DEQ’s Water Quality Division for the Fuel Depot/Truck Shop and Truck Wash Building,
Standard Operating Procedures and Spill Kit, and Water Recycling;” |
| ○ | The
signed Wyoming Game & Fish Department (WGFD) monitoring plan; and |
| ○ | Class
III Cultural Resources Survey. |
The
foregoing permit conditions are in addition to the Project commitments made in the ISP application package.
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17.3.7 | Water
Quality Division Permits |
The
DEQ - Water Quality Division (WQD) issues several permits applicable to the CK Gold Project as summarized below.
Wyoming
Pollutant Discharge Elimination System (WYPDES) Permit
A
WYPDES Permit regulating potential Project water discharges from 12 outfalls was issued by the WDEQ-WQD in May 2024. The outfalls consist
of controlled discharge points from stormwater runoff and seepage detention ponds located on the Project site (Section 17.2.3). The Project’s
WYPDES permit number is WY0997003 and the permit expires in April 2029.
The
permit imposes effluent limits in terms of concentrations of various metals (total and dissolved), pH, and total suspended solids. Daily
effluent flow measurements are required, along with monthly chemical quality sampling, and quarterly reporting of results. Other requirements
include:
| ● | Notification
of changes resulting in classification as a new source or changes in the nature, or increase
in quantity, of pollutants discharged. Also, notification of noncompliance or potential noncompliance
within 24 hours. |
| ● | Proper
operation and maintenance of water treatment and control facilities. Bypasses of treatment
facilities are prohibited except for essential maintenance and if effluent limits are not
exceeded, or if a bypass was unavoidable to prevent loss of life, personal injury or severe
property damage. Noncompliance with effluent limits may be excused during upset conditions
if the water treatment and control facilities are properly designed and operated. |
| ● | Taking
reasonable steps to minimize adverse impacts on receiving waters due to noncompliance. |
Stormwater
Pollution Prevention Plan (SWPPP) and Notices of Intent (NOI) and Termination
A
Stormwater Pollution Prevention Plan (SWPPP) and Notice of Intent (NOI) must be submitted and approved by the DEQ-WQD prior to the start
of construction. This is still pending. Stormwater discharges from the Project site during the construction phase are expected to be
approved by the DEQ-WQD under the Large Construction General Permit (LCGP). Upon completion of the construction phase, the Project must
file a Notice of Termination of the stormwater discharges approved under the LCGP. Before the start of mining operations, another SWPPP
and NOI must be submitted to WQD for approval of stormwater discharges from the project site during the operations phase under the Industrial
General Permit (IGP). Permit decisions by the DEQ-WQD for both the LCGP and IGP can generally be expected within 30 days of submittal
of complete SWPPPs and associated notices.
Permit
to Construct Water Supply and Wastewater Facilities
Construction
of the Project’s water supply and wastewater infrastructure will require a DEQ-WQD permit. The permit application must include
plans, specifications, design data and potentially an environmental monitoring plan. This permit application is still pending. A permit
decision can generally be expected in 60 days.
Operator
Certification for Drinking Water System
The
Project must obtain an operator certificate from the DEQ-WQD to operate the water treatment and distribution system of potable water
serving Project site personnel and visitors. This is still pending. The certificate must be renewed every three years.
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17.3.8 | State
Engineer’s Office Permits for Water Use and Related Facilities |
The
Wyoming State Engineer’s Office (SEO) issues permits to appropriate water for beneficial use, as well as permits to construct and
operate water related infrastructure such as wells, mine dewatering systems and reservoirs. Between August 2022 and October 2023, the
SEO issued 13 permits for water detention and storage ponds on the Project site. Three of these permits will need to be updated and one
additional pond will need to be permitted with the SEO as a result of changes made to the water management plan as noted in Section 17.2.3.
Additionally, in November 2022 the SEO granted permits for the planned groundwater abstraction from the pit sump and from a water supply
well on the Project site.
17.3.9 | State
Historical Preservation Office |
The
Wyoming State Historical Preservation Office (SHPO) requires a Cultural Resource Clearance if cultural resources are encountered within
the Project site. A Class I cultural resource review was completed in June 2021, and a Class III field survey was conducted in September
2024. In the event that cultural or paleontological resources are encountered during construction or mining operations, activities must
be halted at the find location and the DEQ-LQD and SHPO must be contacted within five days of discovery. If a resource is encountered
on State land (Section 36), the OSLI must also be notified. Agency approval would be required to resume work at the find location.
17.3.10 | State
Fire Marshal Permits |
An
electrical plan and above ground fuel storage tank plan must be submitted to the State Fire Marshall for approval in accordance with
the National Electrical Code. This is pending.
A
fire protection system plan must be submitted in accordance with the Wyoming Department of Fire Protection and Electrical Safety. The
State of Wyoming has adopted the International Codes, including the International Fire Code. Additionally, the fire protection system
plan must meet the Laramie County Rural Fire Protection Development Rules and the Mining Safety and Health Administration (MSHA) regulations.
This is also pending.
Fire
hazard in the CK Gold Project area is generally low. The pit, stockpiles, and mine facilities will be stripped of vegetation and topsoil
prior to disturbance during development and mining. Mine site water trucks will be available for fire suppression. Mobile equipment must
have fire extinguishers per MSHA regulations.
17.3.11 | Laramie
County Permits |
Laramie
County will require a permit for the Project access road intersection or approach to County Road 210. The County may also require a Road
Use Agreement. These permits are still pending. A traffic study was conducted as part of the ISP, establishing baseline traffic volumes
and modeling Project related traffic volume increases on local roads. Work on public roadways will also require coordination and review
by the Wyoming Department of Transportation (WYDOT).
The
County may require permits for the various buildings to be constructed on the Project site. These permits have not yet been processed.
The Project may be subject to inspections by the County Building Department.
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17.4 | LOCAL
INDIVIDUALS AND GROUPS |
In
addition to the permitting requirements and associated interaction with the relevant federal, state and local government agencies as
summarized in the previous section, development of the CK Gold Project will require certain agreements with private local entities as
follows:
| ● | Ferguson
Ranch: land use rights and easements for access road and power line. Irrigation ditch
temporary water rights and water supply well. |
| ● | Black
Hills Energy, subsidiary of Black Hills Corporation: power supply agreement. |
| ● | Financing
and contracting: Subject to Project financing and satisfactory contracting arrangements. |
U.S.
Gold has also reached out and provided Project information to various additional local public and private entities which may be affected
by and/or interested in the project, as follows:
| ● | Laramie
County: host county potentially affected by Project environmental and socioeconomic impacts
(employment, procurement, tax revenue, worker influx, traffic, etc.). |
| ● | City
of Cheyenne: potentially affected by Project environmental and socioeconomic impacts,
and supplier of water to the Project. |
| ● | Neighboring
residents and property owners west of the Project site: potentially affected by Project
environmental impacts. |
| ● | Wyoming
State Parks: the Project site is near Curt Gowdy State Park. |
| ● | Wyoming
Game and Fish Department: the Project site occupies mule deer winter range. |
| ● | US
Fish and Wildlife Service: the Project site potentially hosts federally listed species. |
| ● | Wyoming
School Boards Association: the state-owned section of the Project site is held in trust
specifically to benefit Wyoming public schools. |
| ● | University
of Wyoming: the Geology Department has collaborated on the Project’s mineral exploration
activities. |
| ● | Granite
Canyon Quarry: nearby producer of construction aggregates. |
| ● | Sutherland
and King Ranches: neighboring cattle ranches. |
| ● | Wyoming
Mining Association: statewide trade association representing and advocating for mining. |
| ● | Wyoming
Taxpayers Association: trade association representing taxpayers, including large mineral
taxpayers. |
| ● | Cheyenne
Area Chamber of Commerce: local business organization. |
| ● | Cheyenne
LEADS: economic development organization for the city of Cheynne and Laramie County,
Wyoming. |
The
Project is not located adjacent to any indigenous, Native American, or Bureau of Indian Affairs lands.
The
Project has submitted a Reclamation Plan as part of the MOP application (Section 17.3). The closure objective is to reclaim the site
to enable the resumption of its current use of cattle grazing, mule deer winter range, and other wildlife grazing. A reclamation cost
estimate has been developed and submitted to the state as part of the reclamation bonding process. The reclamation plan is summarized
as follows.
Topsoil
will be removed from disturbed surfaces during the mine construction and operating phases and stockpiled on site for subsequent use
as cover soil and revegetation during site reclamation. Concurrent reclamation
will be practiced during the life of mine to reclaim portions of the Project site as soon as feasible prior to the end of mining, securing
corresponding early releases in bonding obligations. Cattle grazing will continue as feasible during mining on Project areas not directly
affected by mine operations.
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At
the end of mineral processing operations, the mineral processing plant and support structures and facilities will be dismantled or demolished
down to their foundations, with the latter left in place under a layer of revegetated cover soil. Materials and equipment will be salvaged
or disposed of off-site. Process vessels and fuel and reagent tanks will be cleaned prior to salvaging or disposal, and any contents
and residues will be managed and disposed of according to the applicable regulations. Certain structures or facilities may be left in
place if requested by the landowners.
Quarries,
borrow pits, yards, pads, drainage channels and impoundments will be regraded and revegetated. Roadways will be similarly reclaimed,
except for segments to remain operational for post-closure monitoring purposes or at landowners’ request. Wells will be abandoned
and plugged unless the landowners wish to retain them.
The
waste rock and tailings facilities’ final reclaimed slopes will be 3H:1V or flatter. Micro-topographical undulations will be created
on the TMF slope to promote revegetation and to support wildlife habitat. The TMF will receive shrub-specific vegetation on the south
face to support mule deer and other wildlife. Rock outcroppings will also be constructed to enhance wildlife habitat.
Regraded
surfaces will generally be covered with topsoil and revegetated using approved seed mixes. A transition material of crushed rock will
be used to limit topsoil from being lost into TMF or waste rock facility rock voids. While the new vegetation grows, erosion control
best practices will be implemented to protect against soil erosion. In certain areas of natural rock outcrop, the final exposed surface
may be bare rock instead of vegetation.
Precipitation
falling on the reclaimed areas will flow into natural drainages and infiltrate into the ground. Based on geochemical study results (Section
17.1.4), the waste rock and tailings are not expected to be acid generating, and seepage from these facilities is expected to meet applicable
water quality standards. Seepage will be allowed to flow from the toes of the waste rock and tailings facilities into established natural
drainages in a controlled manner that prevents erosion and sediment transport.
After
the pit is fully excavated during Year 8, the pit will be backfilled with tailings produced during the last two years of post-mining
mineral processing up to an elevation of 6,630 feet amsl. Then, with a combination of blasting and earthmoving, the pit rim will be dozed
into the pit to create a 3H:1V final pit wall slope and final backfilled pit elevation of approximately 6,720 feet amsl.
Groundwater
and precipitation will flow into the pit backfill material and the groundwater level will slowly rise within the pit until it stabilizes
at about 6,717 feet elevation about 130 years after mining (Neirbo Hydrogeology 2023). Geochemical testing of mine rock and tailings
indicates limited potential to produce ARD and/or metal release, therefore water contacting the pit wall rock and backfill is not expected
to result in detectable metal leaching. A pit lake is not expected to form because evaporation losses will keep the groundwater level
below the surface of the backfill. The pit is predicted to act as a hydraulic sink with no groundwater outflows.
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To
help increase the local area’s long-term water storage capacity, discussions have begun with BOPU about the possibility of converting
the post-mining open pit into a water storage reservoir. Upon completion of reclamation, water could be transferred from external sources
to the new reservoir to help meet the local area’s water storage needs.
A
post-closure monitoring plan will be implemented to verify that closure objectives are met, including the physical and chemical stability
of the closed facilities.
Environmental
compliance to date has been applicable to mineral exploration and other site investigation pre-mining activities, including management
of surface disturbance, drilling, water use and discharge, reclamation of drill pads and roads, and associated bonding. Environmental
management of these activities appears to have been good. The CK Gold project has a positive, collaborative relationship with the Office
of State Lands and Investments, the Department of Environmental Quality, and the affected private landowner.
Another
area of current focus is community engagement, including reaching out to and negotiating with the various private and public entities
with whom the Project seeks agreements to enable further Project development. Current community engagement efforts also extend to other
affected and interested local groups (Section 17.4).
Prior
to the start of construction of the mine facilities, a Project Environmental Management System (EMS) will be developed and implemented
consisting of a series of site-specific standards, plans and procedures governing the environmental management of the specific Project
activities causing potential environmental impacts during construction, operations, closure and post-closure. The plans and procedures
will identify management measures designed to avoid, mitigate or compensate for such impacts. The EMS will address the physical, natural
biological and human community environmental components of the Project site and surroundings, including potentially affected local individuals
and groups. The final engineering design of the Project, the environmental baseline studies (Section 17.1), the environmental impact
and risk assessment, and the permit conditions of approval (Section 17.3), collectively form the basis for developing the Project EMS.
17.7 | COMMITMENTS
TO LOCAL PROCUREMENT OR HIRING |
The
CK Gold Project’s policy is to prioritize procurement and hiring from within the State of Wyoming to the extent feasible.
To
date, the Project has found and utilized excellent local and in-state providers for the following services:
| ● | Environmental
baseline studies |
| ● | Preparation
of permit applications |
| ● | Geological
field work and logging |
| ● | Revegetation
and reclamation |
| ● | Miscellaneous
site works and preparation in support of drilling and test pit activities |
| ● | Hydrological
and hydrogeological studies and engineering design |
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| ● | Environmental
laboratory testing of water and rock samples |
| ● | Geotechnical
site investigation and laboratory testing |
| ● | Rock
quality testing for aggregate |
| ● | Socioeconomic
impact assessment |
As
development of the Project moves forward, U.S. Gold will continue to prioritize local procurement of competitively available goods and
services, and local hiring of qualified personnel.
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18.0 | Capital
and Operating Costs |
18.1 | Capital
Cost Estimate |
Capital
costs are categorized as either initial capital or sustaining capital. Initial capital costs are expended in the year before production
begins, Year -2 and Year -1. Sustaining costs are expended starting in Year 1.
The
capital cost estimate is built up by cost centers as defined by the project’s WBS for Area designations as well as by prime commodity
accounts. Inputs to the capital cost are derived from various sources including unit rates provided by contractors, equipment and material
quotations, in-house historical data, published databases, factors and estimators’ judgment (allowances). A growth allowance of
5% has been added to mechanical equipment costs. This is intended to account for incomplete criteria, the preliminary nature of specifications,
and overall quotation inaccuracies.
Contingency
is assessed by considering the quality of scope definition, quantification, and pricing within the estimate. Each component is assigned
a percentage based on the judgment of the project team to capture uncertainty or incompleteness of costs. Specific consideration used
in determining percentages include estimate allowances and factors, design maturity, project proximity relative to labor and material
markets, existing infrastructure, quality of vendor and contractor quotations, regulatory environment, and comparative costs and contingencies
from similar projects. The capital cost estimates have an accuracy of 20% to +25%.
Table
18.1: Initial Capital Costs |
Item |
Cost
(Millions) |
Total
Initial Capital |
276.42
|
Total
Direct Costs |
189.44
|
Aggregate
Production |
0.00 |
Site
Infrastructure |
4.68 |
Mine
& Mine Facilities |
19.49 |
Mass
Earthwork |
5.70 |
Concrete |
11.51 |
Steel |
8.24 |
Buildings |
27.95 |
Mechanical |
68.80 |
Piping |
9.83 |
Electrical
& Instrumentation |
27.69 |
Tailings
Storage Facility |
5.54 |
Total
Indirect Costs |
41.52
|
Owner’s
Cost |
9.54
|
Contingency |
35.92
|
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Table
18.2: Sustaining Capital Costs |
Item |
Cost
(Millions) |
|
Phase
1 |
Phase
2 |
Total
Sustaining Capital |
6.72 |
8.29 |
Water
Infrastructure |
0.08 |
0.08 |
Ex-Pit
Roads |
0.02 |
0.02 |
Mineralized
Material Facility |
1.02 |
0.00 |
Waste
Rock Tailings Co-Disposal Facility |
4.30 |
6.64 |
Site
Earthworks/Grading |
0.19 |
0.19 |
Contingency |
1.11 |
1.37 |
18.2 | Operating
Cost Estimate |
Estimation
of operating costs for the Project is performed within the economic model for the Project on an annual basis. The operating cost estimate
is based on the Project and material schedule. The components of the operating cost are based on the project schedule, equipment sizing
and productivity, labor estimates, and unit costs for supply items. Inputs to the operating cost are based on vendor quotes, private
and commercially available cost models, and actual and factored unit costs from similar mining operations. The operating cost estimates
have an accuracy of +/- 25%.
Table
18.3 shows a summary of the operating costs at the CK Gold Project categorized by general area over the duration of the Project, or life
of mine (ROM). Error! Reference source not found. provides additional detail to the cost categories on an annual basis.
Table
18.3: Project Operating Cost Summary |
|
Total
LOM |
Avg
Annual |
$/ton |
($millions) |
($millions) |
processed |
Total
Project Operating Costs |
$1,026.10 |
$101.29 |
$14.01 |
Mining
Cost |
$277.81 |
$27.42 |
$3.79 |
Process
Cost |
$517.84 |
$51.12 |
$7.07 |
Tailings
Haulage |
$124.22 |
$12.26 |
$1.70 |
Site
G&A |
$106.22 |
$10.49 |
$1.45 |
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Table
18.4: Annual Operating Costs |
Years |
Total |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
Total
Project Costs (Millions $) |
$1,026.1 |
$108.6 |
$114.1 |
$112.6 |
$115.4 |
$113.6 |
$105.8 |
$102.9 |
$90.7 |
$77.0 |
$75.6 |
$9.7 |
Mining
Cost |
$277.8 |
$36.9 |
$36.3 |
$35.5 |
$38.2 |
$36.6 |
$32.0 |
$28.4 |
$17.4 |
$8.0 |
$7.8 |
$0.8 |
Drill
& Blast |
$105.2 |
$14.7 |
$14.9 |
$15.0 |
$14.9 |
$14.7 |
$13.3 |
$12.3 |
$5.4 |
$0.0 |
$0.0 |
$0.0 |
Load
& Haul |
$113.3 |
$14.5 |
$13.4 |
$12.8 |
$15.9 |
$14.3 |
$13.5 |
$10.6 |
$7.3 |
$5.1 |
$5.1 |
$0.8 |
Grade
Control |
$17.6 |
$2.4 |
$2.6 |
$2.3 |
$2.1 |
$2.2 |
$2.1 |
$2.4 |
$1.6 |
$0.0 |
$0.0 |
$0.0 |
Voids |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
Soils
Removal |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
Pit
Closure |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
Mine
General |
$34.8 |
$4.6 |
$4.6 |
$4.6 |
$4.6 |
$4.6 |
$2.3 |
$2.3 |
$2.3 |
$2.3 |
$2.3 |
$0.0 |
Mine
Maintenance |
$7.0 |
$0.8 |
$0.8 |
$0.8 |
$0.8 |
$0.8 |
$0.8 |
$0.8 |
$0.8 |
$0.5 |
$0.4 |
$0.0 |
Process
Cost |
$517.8 |
$48.5 |
$51.4 |
$51.4 |
$51.4 |
$51.4 |
$51.4 |
$51.4 |
$51.4 |
$51.4 |
$51.4 |
$6.7 |
Labor
|
$95.8 |
$9.5 |
$9.5 |
$9.5 |
$9.5 |
$9.5 |
$9.5 |
$9.5 |
$9.5 |
$9.5 |
$9.5 |
$1.2 |
Fixed
Power |
$43.8 |
$4.3 |
$4.3 |
$4.3 |
$4.3 |
$4.3 |
$4.3 |
$4.3 |
$4.3 |
$4.3 |
$4.3 |
$0.6 |
Variable
Power |
$129.6 |
$11.6 |
$12.9 |
$12.9 |
$12.9 |
$12.9 |
$12.9 |
$12.9 |
$12.9 |
$12.9 |
$12.9 |
$1.7 |
Maintenance
|
$26.6 |
$2.6 |
$2.6 |
$2.6 |
$2.6 |
$2.6 |
$2.6 |
$2.6 |
$2.6 |
$2.6 |
$2.6 |
$0.3 |
Reagents |
$48.8 |
$4.4 |
$4.9 |
$4.9 |
$4.9 |
$4.9 |
$4.9 |
$4.9 |
$4.9 |
$4.9 |
$4.9 |
$0.6 |
Grind
Media |
$107.2 |
$9.6 |
$10.7 |
$10.7 |
$10.7 |
$10.7 |
$10.7 |
$10.7 |
$10.7 |
$10.7 |
$10.7 |
$1.4 |
Water |
$7.0 |
$0.6 |
$0.7 |
$0.7 |
$0.7 |
$0.7 |
$0.7 |
$0.7 |
$0.7 |
$0.7 |
$0.7 |
$0.1 |
Consumables |
$40.5 |
$4.0 |
$4.0 |
$4.0 |
$4.0 |
$4.0 |
$4.0 |
$4.0 |
$4.0 |
$4.0 |
$4.0 |
$0.5 |
Laboratory |
$18.6 |
$1.8 |
$1.8 |
$1.8 |
$1.8 |
$1.8 |
$1.8 |
$1.8 |
$1.8 |
$1.8 |
$1.8 |
$0.2 |
Site
G&A |
$106.2 |
$10.6 |
$10.6 |
$10.7 |
$10.8 |
$10.8 |
$10.8 |
$10.9 |
$10.9 |
$10.0 |
$9.2 |
$0.9 |
G&A |
$106.2 |
$10.6 |
$10.6 |
$10.7 |
$10.8 |
$10.8 |
$10.8 |
$10.9 |
$10.9 |
$10.0 |
$9.2 |
$0.9 |
Tailings
Haulage |
$124.2 |
$12.6 |
$15.9 |
$15.0 |
$15.0 |
$14.8 |
$11.7 |
$12.2 |
$10.9 |
$7.6 |
$7.1 |
$1.4 |
Tailings
Haulage |
$124.2 |
$12.6 |
$15.9 |
$15.0 |
$15.0 |
$14.8 |
$11.7 |
$12.2 |
$10.9 |
$7.6 |
$7.1 |
$1.4 |
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234 |
Table
18.5 and Error! Reference source not found. shows additional detail on the project operating costs for mining and processing categories.
Table
18.5: Mining Costs LOM Summary |
|
Total
LOM |
Avg
Annual |
$/ton |
$/ton |
($millions) |
($millions) |
processed |
Mined |
Total
Mining Costs |
$277.8 |
$27.4 |
$3.79 |
$1.97 |
Drill
& Blast |
$105.2 |
$10.38 |
$1.44 |
$0.74 |
Load
& Haul |
$113.3 |
$11.18 |
$1.55 |
$0.80 |
Grade
Control |
$17.6 |
$1.74 |
$0.24 |
$0.12 |
Voids |
$0.0 |
$0.00 |
$0.00 |
$0.00 |
Soils
Removal |
$0.0 |
$0.00 |
$0.00 |
$0.00 |
Pit
Closure |
$0.0 |
$0.00 |
$0.00 |
$0.00 |
Mine
General |
$34.8 |
$3.43 |
$0.47 |
$0.25 |
Mine
Maintenance |
$7.0 |
$0.69 |
$0.10 |
$0.05 |
Table
18.6: Process Operating Costs LOM Summary |
|
Total
LOM |
Avg
Annual |
$/ton |
($millions) |
($millions) |
Processed |
Total
Process Costs |
$517.84 |
$51.12 |
$7.07 |
Labor
|
$95.79 |
$9.46 |
$1.31 |
Fixed
Power |
$43.80 |
$4.32 |
$0.60 |
Variable
Power |
$129.55 |
$12.79 |
$1.77 |
Maintenance
|
$26.59 |
$2.62 |
$0.36 |
Reagents |
$48.84 |
$4.82 |
$0.67 |
Grind
Media |
$107.22 |
$10.58 |
$1.46 |
Water |
$6.97 |
$0.69 |
$0.10 |
Consumables |
$40.49 |
$4.00 |
$0.55 |
Laboratory |
$18.59 |
$1.84 |
$0.25 |
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235 |
The
economic analysis of the CK Gold Project is reliant on the project schedule, mine schedule, capital, and operating costs discussed in
the previous sections of this report. This economic analysis excludes Inferred Resources, and the positive economic outcome is used to
delineate a Mineral Reserve for the Project. The economic parameters used are believed to be reasonable for the type of project. All
figures shown represent constant Q1 2025 US Dollars.
Certain
information and statements contained in this section and in the Report are “forward looking” in nature. Forward-looking statements
include, but are not limited to, statements with respect to the economic and study parameters of the Project; Mineral Resource estimates;
the cost and timing of any development of the Project; the proposed mine plan and mining methods; dilution and extraction recoveries;
processing method and rates and production rates; projected metallurgical recovery rates; infrastructure requirements; capital, operating
and sustaining cost estimates; the projected life of mine and other expected attributes of the Project; the net present value (NPV) and
internal rate of return (IRR after-tax) and payback period of capital; capital; future metal prices; the timing of the environmental
assessment process; changes to the Project configuration that may be requested as a result of stakeholder or government input to the
environmental assessment process; government regulations and permitting timelines; estimates of reclamation obligations; requirements
for additional capital; environmental risks; and general business and economic conditions.
All
forward-looking statements in this Report are necessarily based on opinions and estimates made as of the date such statements are made
and are subject to important risk factors and uncertainties, many of which cannot be controlled or predicted. Material assumptions regarding
forward-looking statements are discussed in this Report, where applicable. In addition to, and subject to, such specific assumptions
discussed in more detail elsewhere in this Report, the forward-looking statements in this Report are subject to the following assumptions:
| ● | There
being no significant disruptions affecting the development and operation of the Project. |
| ● | The
availability of certain consumables and services and the prices for power and other key supplies
being approximately consistent with assumptions in the Report. |
| ● | Labor
and materials costs being approximately consistent with the assumptions in the Report. |
| ● | Permitting
and arrangements with stakeholders being consistent with current expectations as outlined
in the Report. |
| ● | All
environmental approvals, required permits, licenses and authorizations will be obtained from
the relevant governments and other relevant stakeholders. |
| ● | Certain
tax rates, including the allocation of certain tax attributes, being applicable to the Project. |
| ● | The
availability of financing for the planned development activities. |
| ● | The
timelines for exploration and development activities on the Project. |
| ● | Assumptions
made in Mineral Resource estimate and the financial analysis based on that estimate, including,
but not limited to, geological interpretation, grades, commodity price assumptions, extraction
and mining recovery rates, hydrological and hydrogeological assumptions, capital and operating
cost estimates, and general marketing, political, business, and economic conditions. |
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236 |
The
production schedules and financial analysis annualized cash flow table are presented with conceptual years shown. Years shown in these
tables are for illustrative purposes only. If additional mining, technical, and engineering studies are conducted, these may alter the
Project assumptions as discussed in this Report and may result in changes to the calendar timelines presented.
The
economic model is a series of annual cashflows through the life of the Project modeled in a spreadsheet. The annual cashflow has three
primary components; income (discussed in this section) and operating and capital costs, in Section 18.
The
discounted cash flow analysis was performed on a stand-alone project basis with quarterly cash flows for years -3 through year 3 and
annual cash flows after year 4. The economic evaluation used a real discount rate of 5% and was performed at commencement of construction
using Q1 2025, US dollars.
All
costs prior to the start of construction are considered as “sunk costs” and not considered in the economic analysis.
This
economic analysis is a direct result of the capital cost estimate and is therefore considered to have the same level of accuracy minus
20% to plus 25%.
Table
19.1: Economic Model Parameters |
Description |
Values |
Construction
Period (years) |
2.5 |
Economic
Life |
10.13 |
Discount
Rate |
5% |
Contingency
Capital Costs |
15% |
Production
Inputs |
Gold
Recovery (%) |
67% |
Copper
Recovery (%) |
80% |
Silver
Recovery (%) |
68% |
Mineral
Pricing |
Gold
Price ($/oz) |
$2,100 |
Copper
Price ($/lb) |
$4.10 |
Silver
Price ($/oz) |
$27.00 |
Cost
Criteria |
Leverage |
100%
Equity |
Royalties |
State
of Wyoming Office of State Lands |
2.1% |
Taxes
|
|
Federal
Tax |
21.0% |
Ad
Valorem Production Tax |
6.7% |
Ad
Valorem Property Tax |
6.7% |
Wyoming
Severance Tax |
2.0% |
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237 |
The
total capital cost is estimated at $316.4 million, including $272.8 million during preproduction, $16.6 million for sustaining capital,
and $27 million in initial working capital over the life of the mine. Working capital is recovered over the life of the mine. Note that
the preproduction capital does not match Section 18. Some of the initial capital is withheld as retention payments in Year 1 Quarter
1 and captured as sustaining capital. Table 19.2 summarizes the capital cost over the life of the mine.
Table
19.2: Life of Mine Capital Cost Summary |
Description
|
Cost
US$M |
Site
Infrastructure |
$4.7 |
Mine
& Mine Facilities |
$19.5 |
Earthwork |
$5.7 |
Concrete |
$11.5 |
Steel |
$8.2 |
Buildings |
$28.0 |
Mechanical |
$68.8 |
Piping |
$9.8 |
Electrical |
$23.1 |
Instrumentation |
$4.6 |
Tailings
Storage Facility |
$5.5 |
Process
Facilities Construction Indirects |
$6.8 |
Process
Facilities Construction Equipment |
$3.2 |
3rd
Party QA/QC |
$0.5 |
Pre-Operations
Support |
$0.9 |
Process
Facilities Spare Parts |
$1.4 |
Initial
Fills |
$0.7 |
Freight |
$7.2 |
Contingency |
$35.9 |
Retention
Payments |
-$3.6 |
Total
Preproduction Capital |
$272.8 |
Sustaining
Capital - Mining |
$2.2 |
Capital
Cost Retention Payments |
$3.6 |
Sustaining
Capital - TMF Infrastructure |
$8.0 |
Sustaining
Capital - Ore Stockpile |
$2.9 |
Total
Sustaining Capital |
$16.6 |
Working
Capital (initial) |
$27.0 |
Total
LOM Capital |
$316.4 |
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238 |
The
LOM operating cost is estimated at $1,026.1 million, or $922.3 per equivalent ounces of gold processed, as summarized in Table 19.3.
Table
19.3: Summary of Operating Costs |
Description
|
Total
LOM |
Annual
Average |
Per
Eq Oz Au |
|
US$M |
US$M |
$
/ oz Au Eq |
Production
Mining |
$277.8 |
$27.4 |
$249.72 |
Labor
|
$95.79 |
$9.5 |
$86.10 |
Fixed
Power |
$43.80 |
$4.3 |
$39.37 |
Variable
Power |
$129.55 |
$12.8 |
$116.45 |
Maintenance
|
$26.59 |
$2.6 |
$23.90 |
Reagents |
$48.84 |
$4.8 |
$43.90 |
Grind
Media |
$107.22 |
$10.6 |
$96.38 |
Water |
$6.97 |
$0.7 |
$6.26 |
Consumables |
$40.49 |
$4.0 |
$36.39 |
Laboratory |
$18.59 |
$1.84 |
$16.71 |
Tailings
Haulage |
$124.22 |
$12.26 |
$111.66 |
G&A
|
$106.22 |
$10.5 |
$95.48 |
Total
|
$1,026.1 |
$101.3 |
$922.3 |
19.5 | Taxes,
Royalties, Depreciation and Depletion |
The
CK Gold Project is subject to a production royalty of 2.1% on the gross sales value of the product sold, less deductions for costs incurred
for processing, refining, transportation, and related costs. This royalty is paid to the Office of State Lands and Investments, State
of Wyoming. Note that the typical value of this royalty is 5% in Wyoming; however, US Gold has received an exception from the Office
of State Lands. The concentrate value, less applicable deductions, is multiplied by 2.1% to yield the royalty payment. The Project’s
net income value already considers the royalty payment.
In
addition to royalites, Wyoming imposes both an Ad Valorem Production and Ad Valorem Property Tax. Production taxes are assessed at 6.7%
and calculated using the proportionate profits methodology. This methodology is a ratio defined as (direct mining costs) / (total direct
costs) less administration costs. The gross sales value of product sold, less deductions for costs incurred for processing, refining,
transportation, and royalties is multiplied by the ratio described above and 6.7% to yield the Ad Valorem Production tax. The ad valorem
property tax also applies to the real and tangible assets. In this situation the real property is owned by the State. The tangible assets
including plant and equipment will be owned by U.S. Gold Corp and would be subject to the tax. The fair market value of the assets less
depreciation is multiplied by the assessment ratio, (in this case 11.5% for industrial property). This becomes the taxable value which
is then multiplied by the mills levied which has been estimated at 6.7%, or 67 mills.
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239 |
Wyoming
also imposes a 2% severance tax calculated using the proportionate profits methodology described above. The gross sales value of the
product sold, less deductions for costs incurred for processing, refining, transportation, and royalties, is multiplied by the (direct
mining costs)/(total direct costs) less administration costs and 2% to yield the Severance tax.
A
Federal tax rate of 21% is assessed on taxable income. Federally taxable income is gross revenue less operating costs, sustaining capital,
depreciation, depletion, property taxes, state severance taxes, and tax losses carried forward.
Deprecation
of project capital infrastructure costs for the purpose of federal tax calculation is based on a units of production depletion model.
Equipment depreciation is over a period of 7 years. Depletion for federal tax purposes is calculated by using percentage depletion method.
For this property the depletion percentage is 15% of the gross revenue less royalties, not to exceed 50% of the taxable income.
A
summary of the royalties and taxes is provided in Table 19.4.
Table
19.4:Summary of Royalties & Taxes |
Description
|
Annual
Average
US$M |
Per
Ton Produced
$/oz
Au |
Royalties |
State
of Wyoming Office of State Lands |
$4.3 |
$39.13 |
Taxes |
Federal
Tax |
$5.8 |
$52.60 |
Ad
Valorem Production Tax |
$4.2 |
$38.27 |
Ad
Valorem Property Tax |
$2.2 |
$20.25 |
Wyoming
Severance Tax |
$1.3 |
$11.42 |
Total
|
$17.8 |
$161.68 |
19.6 | Cashflow
Forecasts and Annual Production Forecasts |
The
results of the economic analysis are provided in Table 19.5 and Table 19.6.
Table
19.5: Economic Model Results |
Key
Project Indicators |
Value
US$M |
Pre
Tax Economics |
|
IRR |
36.0% |
Cash
Flow (Undiscounted) |
$693.2 |
NPV
5% Discount Rate |
$459.2 |
Payback
(years) |
1.7 |
1st
3 Years Net Profit (Avg) |
$153.5 |
After
Tax Results |
|
IRR |
29.5% |
Cash
Flow (Undiscounted) |
$556.9 |
NPV
5% Discount Rate |
$355.9 |
Payback
(years) |
2.1 |
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240 |
Table
19.6: Project Details |
Key
Project Indicator |
Value |
Gold
Ounces Sold (000's) |
663 |
Copper
Sold (Million Lbs.) |
196 |
AuEq
Ounces Sold (000's) |
1,069 |
1st
3 years Avg AuEq Production (000’s) |
138 |
Initial
Capital ($ Million) |
$272.8 |
Sustaining
Capital ($ Million) |
$16.6 |
Avg.
Cash Cost of Production ($/oz AuEq) |
$922.0 |
All
in Sustaining Cost ($/oz AuEq) |
$937.0 |
Income
from concentrate sales is based on the metal grades stored within the resource model and associated with material scheduled for the concentrator
during the time period. Concentrator recovery factors are applied to the in-situ, contained metal to yield a total metal contained in
the concentrate. Smelter terms were provided by Trafigura and Glencore, with Glencore offering more attractive terms which were applied
in the economic model. The total income from metal sales, smelter terms, transportation costs, and royalty payments are subtracted to
yield net project income. Table 19.7 shows a summary of metal production and revenue projections for the Project. Table 19.8 shows the
cash flow summary for the Project.
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241 |
Table
19.7: Metal Projections |
$
Values in Millions |
Total
|
Year
-3 |
Year
-2 |
Year
-1 |
Year
1 |
Year
2 |
Year
3 |
Year
4 |
Year
5 |
Year
6 |
Year
7 |
Year
8 |
Year
9 |
Year
10 |
Year
11 |
|
Metal
in Concentrate |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Gold
(000's oz) |
679.5 |
|
|
|
110.8 |
102.8 |
73.2 |
72.6 |
72.6 |
61.1 |
63.4 |
60.1 |
28.4 |
31.4 |
3.1 |
|
Copper
(Millions lbs) |
208.3 |
|
|
|
18.8 |
25.8 |
23.6 |
22.2 |
21.7 |
21.6 |
24.3 |
23.1 |
13.9 |
11.4 |
1.8 |
|
Silver
(000's oz) |
2039.5 |
|
|
|
287.3 |
271.5 |
198.8 |
221.1 |
178.3 |
173.5 |
165.6 |
166.1 |
173.9 |
181.2 |
22.4 |
|
Metal
Sold |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Gold
(000's oz) |
662.6 |
|
|
|
108.0 |
100.3 |
71.4 |
70.8 |
70.8 |
59.6 |
61.8 |
58.6 |
27.7 |
30.6 |
3.0 |
|
Copper
(Millions lbs) |
195.4 |
|
|
|
17.8 |
24.2 |
22.1 |
20.9 |
20.3 |
20.3 |
22.7 |
21.5 |
13.0 |
10.7 |
1.8 |
|
Silver
(000's oz) |
1835.6 |
|
|
|
258.5 |
244.3 |
178.9 |
199.0 |
160.5 |
156.1 |
149.1 |
149.5 |
156.5 |
163.1 |
20.1 |
|
Refiner
Receipts |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Gold |
$1,391.4 |
|
|
|
$226.8 |
$210.6 |
$149.9 |
$148.7 |
$148.7 |
$125.1 |
$129.9 |
$123.1 |
$58.2 |
$64.2 |
$6.3 |
|
Copper |
$801.3 |
|
|
|
$73.0 |
$99.3 |
$90.5 |
$85.9 |
$83.4 |
$83.3 |
$93.1 |
$88.3 |
$53.3 |
$43.9 |
$7.2 |
|
Silver |
$49.6 |
|
|
|
$7.0 |
$6.6 |
$4.8 |
$5.4 |
$4.3 |
$4.2 |
$4.0 |
$4.0 |
$4.2 |
$4.4 |
$0.5 |
|
Deductions |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Transportation
Costs |
$108.2 |
|
|
|
$9.1 |
$13.6 |
$12.5 |
$11.2 |
$11.4 |
$11.4 |
$12.9 |
$12.3 |
$7.4 |
$5.6 |
$0.8 |
|
Treatment/Refining |
$60.9 |
|
|
|
$5.5 |
$7.7 |
$6.9 |
$6.4 |
$6.4 |
$6.3 |
$7.1 |
$6.7 |
$4.1 |
$3.2 |
$0.5 |
|
Royalty |
$43.5 |
|
|
|
$6.1 |
$6.2 |
$4.7 |
$4.7 |
$4.6 |
$4.1 |
$4.3 |
$4.1 |
$2.2 |
$2.2 |
$0.3 |
|
Total
Revenue |
$2,029.6 |
|
|
|
$286.0 |
$289.0 |
$221.1 |
$217.7 |
$214.0 |
$190.8 |
$202.6 |
$192.3 |
$102.1 |
$101.6 |
$12.4 |
|
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242 |
Table
19.8: Cash Flow Projections |
$
Values in Millions |
Total |
Year
-3 |
Year
-2 |
Year
-1 |
Year
1 |
Year
2 |
Year
3 |
Year
4 |
Year
5 |
Year
6 |
Year
7 |
Year
8 |
Year
9 |
Year
10 |
Year
11 |
Year
12 |
Total
Revenue |
$2,029.6 |
$0.0 |
$0.0 |
$0.0 |
$286.0 |
$289.0 |
$221.1 |
$217.7 |
$214.0 |
$190.8 |
$202.6 |
$192.3 |
$102.1 |
$101.6 |
$12.4 |
$0.0 |
Operating
Costs |
$1,026.1 |
$0.0 |
$0.0 |
$0.0 |
$108.6 |
$114.1 |
$112.6 |
$115.4 |
$113.6 |
$105.8 |
$102.9 |
$90.7 |
$77.0 |
$75.6 |
$9.7 |
$0.0 |
Net
Profit Before Tax |
$1,003.5 |
$0.0 |
$0.0 |
$0.0 |
$177.3 |
$174.9 |
$108.4 |
$102.3 |
$100.5 |
$85.0 |
$99.7 |
$101.6 |
$25.1 |
$26.0 |
$2.7 |
$0.0 |
|
Capital
Costs |
$272.8 |
$16.8 |
$104.4 |
$151.7 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
Sustaining
Capital |
$16.6 |
$0.0 |
$0.0 |
$0.0 |
$5.4 |
$2.9 |
$3.8 |
$0.0 |
$0.0 |
$4.6 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
$0.0 |
Working
Capital |
$0.0 |
$0.0 |
$0.0 |
$27.0 |
$1.3 |
-$0.3 |
$0.9 |
-$0.5 |
-$1.9 |
-$0.7 |
-$3.1 |
-$3.4 |
-$0.4 |
-$16.5 |
-$2.4 |
$0.0 |
Closure
Bond & Closure Costs |
$20.8 |
$0.0 |
$0.0 |
$0.0 |
$2.3 |
$1.8 |
$1.1 |
$1.0 |
$0.2 |
$0.8 |
$1.2 |
$0.5 |
-$3.2 |
-$0.9 |
$13.0 |
$3.2 |
|
Before
Tax Cash Flow |
$693.2 |
-$16.8 |
-$104.4 |
-$178.6 |
$168.4 |
$170.5 |
$102.7 |
$101.8 |
$102.2 |
$80.3 |
$101.6 |
$104.6 |
$28.7 |
$43.4 |
-$7.8 |
-$3.2 |
Cumulative
Before Tax Cash Flow |
$693.2 |
-$16.8 |
-$121.2 |
-$299.8 |
-$131.4 |
$39.0 |
$141.7 |
$243.5 |
$345.7 |
$426.0 |
$527.6 |
$632.2 |
$660.9 |
$704.2 |
$696.4 |
$693.2 |
|
After-Tax
Cash Flow |
$556.9 |
-$16.8 |
-$104.4 |
-$178.6 |
$147.0 |
$139.1 |
$84.4 |
$87.9 |
$89.0 |
$70.2 |
$89.6 |
$90.9 |
$27.5 |
$42.3 |
-$7.9 |
-$3.2 |
Cumulative
After-Tax Cash Flow |
$556.9 |
-$16.8 |
-$121.2 |
-$299.8 |
-$152.8 |
-$13.8 |
$70.6 |
$158.5 |
$247.5 |
$317.7 |
$407.3 |
$498.2 |
$525.7 |
$568.0 |
$560.1 |
$556.9 |
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243 |
Sensitivity
Analysis was performed on the parameters, capital cost, operating cost, and metal price. The following figures, Figure 19.1 through Figure
19.4, show the sensitivity of the project NPV and IRR, respectively, to key changes in project parameters on both a pre-tax and post-tax
basis.

Figure
19.1: Pre-Tax NPV Sensitivity
 |
244 |

Figure
19.2: Pre-Tax IRR Sensitivity
 |
245 |

Figure
19.3: Post Tax NPV Sensitivity
 |
246 |

Figure
19.4: Post Tax NPV Sensitivity
A
sensitivity analysis on metals pricing indicates additional potential for this Project at higher metals pricing, Table 19.9. Additionally,
the sensitivity indicates the robustness of the Project with positive economic outcomes at reduced metals pricing.
Table
19.9: Metal Price Sensitivity |
Metal
Pricing |
Pre-Tax
|
Post-Tax |
Gold
Price |
Copper
Price |
NPV |
IRR |
Payback
|
NPV |
IRR |
Payback
|
Au/oz |
Cu/lb |
$M |
% |
Years |
$M |
% |
Years |
$1,300 |
3.80 |
$35 |
8.1% |
5.55 |
($13) |
3.8% |
6.98 |
$1,700 |
3.90 |
$240 |
23.0% |
2.71 |
$177 |
18.4% |
3.44 |
$2,100 |
4.10 |
$459 |
36.0% |
1.73 |
$356 |
29.5% |
2.12 |
$2,500 |
4.30 |
$678 |
47.6% |
1.37 |
$532 |
39.4% |
1.63 |
$3,000 |
4.50 |
$945 |
60.4% |
1.10 |
$745 |
50.3% |
1.31 |
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247 |
The
text of this Section remains substantially unchanged from the Gustavson Associates report, “S-K 1300 Technical Report Summary CK
Gold Project”, dated Dec. 1, 2021.
There
is no information from adjacent properties that is material to the CK Gold Project. There are no adjacent properties requiring any disclosure.
The area is a historical mining district, however the QPs are not aware of any mineral exploration occurring on adjacent properties.
The proximity and similarities of these historic copper-gold deposits does not, on its own, indicate the CK Gold Project should be similarly
mineralized.
Approximately
two miles to the south of the property is an aggregate quarry that has no material impact to the Project.
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248 |
21.0 | Other
Relevant Data and Information |
In
addition to metal concentrate sales from operations, there is also potential to sell granite/granodiorite waste rock to local construction
companies as feed material for aggregate production. The material considered for aggregate feedstock has been sampled from existing exploration
holes and is representative of the rock selected for aggregate production and rail ballast. Analysis shows that the material is suitable
for aggregate production. Production parameters are shown in Section 21.2.
21.2 | Aggregate
Market Study |
The
U.S. Gold CK Gold Property is located in southeast Wyoming approximately 18 miles east of Cheyenne in the southern Laramie Mountains.
The area is attractive for the quarrying of granite for use as construction aggregate. In the state of Wyoming there are currently three
permitted operating granite quarries. These three quarries are located within four miles of the project site location. On average, in
recent years, the two operational pits in the area produced a total of approximately 2.9 million tons of granite annually. Having conducted
extensive testing on the rock quality under the supervision of Mountain Plains Consulting and associates, aggregate specialists, a study
was commissioned by Burgex and completed in August 2024.
The
aggregates industry business cycle reacts to levels of activity within commercial and residential construction markets, in public infrastructure
projects, as well as other types of construction. Local demand for aggregate is driven by use in infrastructure projects in the Cheyenne
metropolitan area. Due to projected low population growth in Wyoming and shortfalls in tax revenue available from the energy sector,
demand for aggregate for road and construction projects in southeast Wyoming may be very limited and be met with significant established
competition by the currently permitted quarries. The greatest demand for aggregate from the site would be to the south in Colorado along
the Northern Front Range where there are multiple metropolitan districts that are in an active phase of population and economic growth.
Significant increases in population and employment have been forecasted to varying degrees within the multi-county 100 mile stretch of
Interstate-25 (I-25) that links Cheyenne, Wyoming to these high growth areas in Colorado. The proximity of the Project site to northern
Colorado’s Front Range urban corridor provides a geographically favorable conduit for materials that could be produced in a more
advantageous tax and regulatory climate for operators.
Interviews
with key operators active in the construction industry, specifically concrete and asphalt producers, were conducted to better understand
the potential demand from the Project. Demand for hard rock, such as the subject granite, that meets specifications for transportation
projects is high in urban areas such as the Front Range. In these areas competing land uses can make it difficult for operators to obtain
a land position sufficient for long-term aggregate production. Two construction companies expressed immediate interest in obtaining aggregate
materials from the Project. Based on their estimates, it is reasonable to project that the Project could supply 250,000 st of granite
aggregate feedstock the first year of production mining and could ramp up to 1,000,000 st of feedstock annually after the third mining
production season.
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249 |
An
estimate of the price that could be obtained for the stockpiled granite feedstock material at the project site was developed based on
information in the public domain and information provided via interviews with market participants. Major cost components were considered
in processing the stockpiled material into a usable end product. This was necessary to determine at what price competing products from
other sites can be sold in the market since the subject granite must remain cost-competitive with other local supply sources near Cheyenne.
The main cost centers consist of the following: 1) crushing, screening, stockpiling; 2) loading and scaling; 3) hauling to take off point.
Prices for delivered products in Cheyenne were used as the benchmark for the price analysis. Based on the data analyzed in the Burgex
Study (August 2024), the price for the average granite materials produced at the mine gate would be anticipated to be $25.23 per ton.
Costs to process the stockpiled material at the site are estimated to be $11.88 per ton, see Burgex Study Case C, the Contractor Case
Table 21.1. Comparing the average price to the average cost indicates the material could sell with a margin of $13.12 per ton from the
Project site. Prices correlate well with information obtained locally related to sales prices from nearby quarry operations.
Table
21.1: Aggregate Cost Buildup |
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250 |
22.0 | Interpretation
and Conclusions |
The
results of the CK Gold Pre-Feasibility Study indicate that the property contains a Mineral Resource, and a significant portion of that
Mineral Resource converts to a Mineral Reserve. The Project has a positive economic outcome given the data, parameters, and estimates
outlined in the TRS. Furthermore, there are significant opportunities to pursue beyond the project’s focus on the recovery of copper,
gold and silver, The potential of the rock set aside to uncover metal containing ore also holds the potential to be an additional source
of revenue. While there is a positive economic outcome at the stated metal prices, improvement in metal prices offer opportunity and
decreases would have to be substantial for the project to make a loss. Additionally, the potential of the revenue from non-metal bearing
rock further protects the viability of the project should metal prices fall precipitously.
22.1.1 | Metallurgical
Program |
Previous
test work at SGS in 2008-2010 and at prior facilities concluded that flotation would be the most appropriate flowsheet to recover copper,
gold, and silver into a high value concentrate. The work at KCA (Reno, USA) and Base Metals Laboratory (Kamloops, Canada) has confirmed
this. The most recent test work program concluded at BML in September 2022 and the overall body of testwork is now judged to be of suitable
depth and quality to act as a valid reference for the Pre-Feasibility Study process design.
Three
composites, each 200-300 kg, were prepared for test work, namely a High-Grade Oxide composite (from Hole 4), an Oxide Composite from
holes 1-3 plus 5-7, and a Sulfide composite from holes 1-7. Between the oxide and sulfide zones is a narrow band of "mixed"
material. As this only represented a small component of the drill core it was included in the sulfide composite. However, as results
subsequently showed, the impact was significant. The mineralogy indicated 10-15% of the copper minerals in this "sulfide" composite
were not sulfide. A second sulfide composite was prepared from core more remote from the mixed zone and tested at BML in July 2021. This
resulted in significantly better copper, gold, and silver recoveries, as shown in Section 10.
Sub-samples
of core from each composite were provided to Hazen Research in Denver for comminution test work. This showed the material to be of medium
hardness but relatively competent. This supports the selection of a SAG-Ball-Pebble crusher grinding circuit. A primary grind P80
of 90 µm appears to be close to optimal.
Open
circuit flotation of the High-Grade Composite was successful at KCA, providing high (for an "oxide") recoveries of copper (55%),
gold (69%) and silver (40%) to a 25% Cu flotation concentrate. Locked Cycle Tests at BML confirmed these results.
Flotation
of the Oxide Composite proved to be more challenging. The mineralogy of this composite showed an abundance of copper minerals, such as
chrysocolla, that are non-floating. None the less, flotation was moderately successful in that open circuit rougher and cleaner tests
produced a low-grade but high value copper concentrate, 10-15% Cu, that contained over 150 gpt gold and 100 gpt silver. This material
constitutes about 6-8% of the deposit. The mine plan could see this material treated on a campaign basis or combined with sulfide. Locked
Cycle Tests at BML produced concentrates with 7.9%Cu, over 250 gpt Au, over 200 gpt Ag and a gold recovery of 60%.
 |
251 |
The
sulfide zone constitutes the majority of the deposit. LCTs on two sulfide composites gave high recoveries of copper (82-88%) and gold
(67-74%) to a 21-25% Cu, 76 gpt Au, 82 gpt Ag concentrate. Silver recovery was 59%.
The
mineralogy showed that some non-sulfide copper minerals were present in the first sulfide composite, and this had a negative impact on
the flotation recoveries. As a result, seven variability samples were selected for test work in the PFS phase. In addition, seven variability
oxide samples were tested. These tests were summarized in Table 10.29. With less non- sulfide copper, the copper recovery was over 80%.
Gold and silver recoveries showed significant variation. The test data to date does not show any correlation between metallurgical performance
and the regrind P80 in the range 20-40 µm. Finer regrind needs to be investigated as well as flotation test work on
two new low grade composites before the issue of an FS.
Rougher
tests investigated the primary grind P80 over a range of 50-150u. This and earlier work had concluded the optimum to be between
85u and 100u and most of the testwork has been carried out in that range.
Economic
Risk
There
is no guarantee that metal prices will continue to support adequate revenues to cover the cost of mining and processing. Additionally,
the consumer items, manpower, energy, water, capital equipment could potentially increase to the point that profitable operations would
be jeopardized. At appropriate stages the company will investigate securing off-take agreements and contracts for cost items that will
protect the viability of the Project in the long-term. Economic risk can be reduced through pursuing additional revenues from potential
non-metal rock sales.
Resource
Risk
While
the resource has been extensively drilled and tested and the nature of the mineralization consistent and well understood, there is a
risk that the contained metal in the resource may have been misestimated, that the metallurgical performance is not fully representative
of the whole rock mass, and the reported values may not be extracted.
Metallurgy
& Processing Risk
In
general terms, the Project can be classified as low risk, as it uses a conventional, well-proven process flowsheet with no unusual and/or
developmental equipment. The market for a clean copper/gold flotation concentrate is global and relatively stable (subject to macroeconomic/global
trends).
Although
a metallurgical benefit is likely, the Project has purposely avoided using cyanide to recover additional gold as this approach helps
to maintain a responsible social and environmental footprint. Power consumption is low relative to other processing routes (e.g., Hydrometallurgical)
and water consumption has been minimized through the application of relatively complex and expensive dewatering technology prior to tailings
storage.
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252 |
However,
some metallurgical/process risks remain:
| ● | Head
Grades of composites used for SGS, KCA, and some BML testwork programs have tended to be
higher grade than the PFS reserve mineralization grades. To address this, a short program
of work was appended to the program, to provide additional low-grade data points. These are
incorporated into the metallurgical models for the FS. |
| ● | Additional
variability test work using spatially diverse low-grade composites would help to reinforce
the metallurgical models. |
| ● | The
comminution database is relatively small compared to more complex geometallurgical projects.
However, ore hardness is not excessive and results to date have been in a relatively narrow
range, indicating straightforward grinding performance. A simple jaw crusher + SAG mill circuit
offers a low-capital cost option for comminution, but more SAG mill sizing data would be
preferable. Additional SMC and Drop weight testing is recommended. |
Future
flotation test work should include various combinations of sulfide-oxide ore types. Separate campaigns for oxide and mixed zone material,
particularly the high-grade oxide may be required.
The
tailing filtration plant is a large, capital-intensive area of the flowsheet. The sizing of such machinery is critical to the project
success and as such, more detailed analysis is recommended, perhaps in conjunction with a preferred vendor. Several vendors supply suitable
pressure filtration equipment although sizes do vary. Confirmatory testwork at a vendor’s facility would be a helpful de-risking
exercise.
The
selection and sizing of the jaw crusher, mills, flotation equipment and tailings filters will be the subject of detailed optimization
discussions with vendors during the Feasibility and Detailed Engineering phases.
Operations
Risk
There
are many potential operational risks ranging from the inability to hire, train and retain workers, and professionals necessary to conduct
operations, to poor management and exceptional weather events or climate change that could negatively impact operations. While similar
operations are conducted in the vicinity and there is no reason to believe these risk factors cannot be eliminated, they still exist.
However, there are many working open pit mining and processing operations currently exist in more remote and extreme environmental conditions.
The
Red Canyon water source is currently in exploration. The first pilot well drilled delivered promising water volume at a reasonable drill
depth. All agreements are in place for water usage and Right of Way. The second well drilled at production size did not hit the water
source at the same depth as the pilot well due to hole deviation. Another well has been drilled from a new collar and this well encountered
a significant transmissive sand layer in excess of 250-ft and work continues so water quality and pump tests can be completed. The Red
Canyon water source location is more favorable than other sources previously considered, but there is a risk of access to the volume
of water required until the well field testing is completed.
Environmental
Risk
Environmental
risks include:
| ● | Community
relations: Neighboring residents and landowners could have concerns about real or perceived
negative environmental impacts such as traffic, noise, dust emissions, and visual effects.
Other stakeholders could have similar concerns due to the proximity of the Project to the
Curt Gowdy
state park. The Project’s stakeholder engagement has focused on impact assessment (as part of the Industrial Siting permitting
process), local project benefits, and impact mitigation measures. |
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253 |
| ● | Permitting:
Timelines for receiving water permits from the Wyoming Department of Environmental Quality
could be longer than expected due to potential public opposition and legal challenges from
activist organizations. |
| ● | Many
of the Project’s surface water management ponds are sized for 10-year or 100-year storm
events. The current permitting does not allow for discharge of water from these ponds without
testing and proof that water chemistry is at a quality that can be discharged. Additional
consideration of surface water management needs to be addressed in following phases. Those
options could be proactive treatment options, strategic increase in the size of certain ponds
to allow for additional storage, additional pumping capacity to account for extreme precipitation
events, or reviewing process water balancing to ensure storage space is available when needed. |
| ● | Regulatory:
Changes in regulations, including potentially the definition of Waters of the US and possible
changes in regulation of dust emissions, could affect project design and permitting. These
risks would be mitigated by starting construction prior to the expiration in February 2026
of the current US Army Corps of Engineers’ Approved Jurisdictional Determination of
Waters of the US, and by proceeding with the air quality permitting under the current regulations. |
22.3 | Significant
Opportunities |
Resource
Expansion
U.S.
Gold has focused on the value proposition surrounding the known resource as a prime motivator to create value for its shareholders. The
company realizes that additional mineralization continues at depth, evidenced by exploration holes bottoming out in economic grades,
as well as opportunities to expand the existing resource to the southeast. Outreach to the University of Wyoming and reliance on experts
is aimed at a better understanding of the origins and genesis of the resource. Pursuing such information and prudent expenditures toward
exploration as company valuation increases or revenue streams allow will allow resource expansion to be pursued.
Metallurgy
& Processing
Flotation
test work continued through 2024. Some further improvement and optimization may still be possible for the oxide and mixed material types.
Cyanide
leaching of the high-grade flotation tailings gave high extraction of gold and silver. This, together with possible leaching of scavenger
concentrates and cleaner tailings may represent a future opportunity. However, the use of cyanide is a potentially controversial topic
within the local community and may trigger additional regulatory reviews and increased facility costs. Cyanide alternatives for metal
recovery could also be investigated, however the company has not chosen to pursue non-mainstream technologies up to this point.
Filtration
of tailing slurry is an expensive and operationally complex area of the plant. A detailed study of this area, together with examination
of alternate dewatering strategies would be very beneficial to the Project.
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254 |
The
process plant layout was improved as part of this PFS, with a more compact plant (and building) layout as a result. However, further
costs can likely be saved through additional value engineering.
Several
new flotation technologies, such as Jameson cells are currently being tested by U.S. Gold and will be evaluated in the Feasibility Study.
Aggregate
Production
Work
to date has established that the non-mineralized rock is almost certainly in large part an excellent source of aggregate. Additionally,
a market study (Section 21.1) suggests that the local demand could accommodate an additional source of supply and this has been confirmed
anecdotally by a series of inquiries and from potential consumers to U.S. Gold. This is further supported by the August 2024 Burgex study
that summarized work by aggregate specialists and conducted a market study. There is a sound rationale that further value can be obtained
from what would otherwise be waste material at the Project, which has already undergone the cost of mining as part of the gold and copper
mining operations. Beyond the potential to increase the revenue from the rock mined and sold as aggregate or aggregate feedstock, there
are benefits to reducing the waste stored at site, such as the reduced footprint of areas to be reclaimed.
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255 |
Reduction
in Closure Costs
To
help increase the local area’s long-term water storage capacity, discussions have begun with the Cheyenne Board of Public Utilities
about converting the post-mining open pit into a water storage reservoir. The hydrogeological and geochemical study results to date indicate
that the pit wall permeability will be low enough overall to contain water with no significant leakage, and the pit wall rock will be
geochemically stable enough to preserve water quality to applicable standards. Assuming the ongoing environmental studies confirm these
findings, U.S. Gold intends to put forth the concept of converting the pit to a water storage reservoir as the preferred closure concept.
At the end of mining, water could be transferred from external sources to the new reservoir to meet the local area’s water storage
needs. If further studies identify significant obstacles to this pit closure concept, alternative pit closure concepts can be evaluated,
or the current closure plan can be implemented. A post-closure monitoring plan will be implemented to verify that closure objectives
are met, including the physical and chemical stability of the closed facilities.
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256 |
The
project economics reviewed in Section 19 show this project is robust enough to advance to feasibility stage. The recommendations listed
below would further advance the understanding of the property and provide the necessary rigor.
To
further assess the viability of the Project and to feed into a more accurate and comprehensive assessment, plans for an EPCM strategy,
construction, and operations to support project development should be created. The development of a detailed owner’s team for development,
contracting strategy and transitional plan to operations should be identified.
23.2.1 | Deposit
Understanding |
As
indicated in Section 6 additional drilling should be performed to solidify understanding of the Copper King fault and mineral deposit
model. However, the density of drilling and the distribution of metal values suggest a high level of confidence in the stated reserves.
23.2.2 | Future
Metallurgical Test Work |
The
geometallurgical models prepared for the Pre-Feasibility Study highlight recovery relationships with head grade and oxidation level.
Additional variability testing, together with larger scale work on lower grade samples would be useful.
There
is some test work evidence that suggests a finer regrind might be beneficial and this may be worthy of investigation in the Feasibility
Study.
Specialty
test work with the vendors of tailings and concentrate filtration, including the oxide and sulfide components.
Specific
test work on the mixed ore zone.
There
are indications that treatment of tailings to enhance gold recovery could be considered but such additional treatment could come with
significant environmental concern, and it is recommended that while the opportunity be assessed, the current flowsheet be maintained.
23.2.4 | Design
And Engineering |
Additional
discrete studies should be pursued prior to feasibility to improve and validate capital costs, pursue any potential improvements in process
costs or increased recovery. Samuel Engineering would recommend:
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257 |
| ● | Performing
coarse ore floatation test work which, if positive, could reduce operating costs and capital
costs. |
| ● | Complete
a Blasting and Run of mine material hardness, abrasion, and sizing study to confirm primary
crushing equipment sizing and type, and perhaps improve the downstream comminution circuit |
| ● | Complete
the test work on the Jameson cell processing option as a possible recovery improvement option |
During
the feasibility study additional engineering and should be performed to:
| ● | Update
engineering design completion and materials quantities to support S-K 1300 Feasibility Study
SME Reporting Guidelines |
| ● | Further
optimize site layouts and associated civil costs |
| ● | Revisit
building construction concepts (alternatives like lightweight steel/fabric materials) to
further reduce costs |
| ● | Final
optimization of general arrangements with final (ready to purchase) equipment selections |
| ● | Improve
the bulk material estimate by proving quantity take offs for major piping and electrical
runs, |
| ● | Process
area benches should be reviewed to balance site earthworks and potentially reduce civil construction
costs |
| ● | Update
major equipment specifications and pricing making them ‘Ready for Purchase’ at
the end of feasibility |
| ● | Complete
more design definition effort on the fresh water and surface water system to find ways of
reducing capital |
| ● | Finalize
concentrate off-take agreements (MOU) and consider alternative concentrate transport options
to smelter |
23.3 | Environmental,
Permitting, and Social |
Following
is a summary of the Environmental, Social, and Permitting recommendations:
| ● | Continue
activities needed to obtain the required state and local permits. |
| ● | Continue
project information disclosure and consultation with local stakeholders, especially focusing
on project impact assessment, local project benefits, and impact mitigation measures. |
| ● | Conclude
the power supply agreement. |
| ● | Identify
and secure a potential alternative backup water supply source. |
| ● | Additional
hydrogeologic assessment will need to be performed to determine potential impacts of the
Red Canyon well source. |
| ● | Continue
engagement with the City of Cheyenne regarding the potential post-mining conversion of the
pit to a water storage reservoir serving the city. |
| ● | Develop
and implement a Project Environmental Management System (EMS) consisting of site-specific
plans and procedures governing the environmental management of project activities causing
potential environmental impacts during construction, operations, closure and post-closure. |
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258 |
| ● | Alquimia
Engineers, Process Design Criteria, May 2021. |
| ● | Alquimia
Engineers, Flowsheets and Mass Balances, May 2021. |
| ● | Alquimia
Engineers, General arrangement Drawings, May 2021. |
| ● | Alquimia
Engineers, Main Equipment List, April 2021. |
| ● | Alquimia
Engineers, Capital Cost Estimate, July 2021. |
| ● | Alquimia
Engineers, Comminution Simulations. March 2021. |
| ● | Alquimia
Engineers, Process Conception Technical Memorandum, April 2021. |
| ● | Base
Metals Laboratory Report, BL-0789, August 2021. |
| ● | Base
Metals Laboratory Report, BL-0835/0882, March 15, 2022. |
| ● | Base
Metals Laboratory Report, BL-0980, August 2022. |
| ● | Base
Metals Laboratory Report, BL-1066, September 2022. |
| ● | FLSmidth
Mineralogy, 2021. |
| ● | Hazen,
Comminution Test work, April 2021. |
| ● | KCA
Metallurgical Test work Report, July 2021. |
| ● | Operating
Cost Estimate, John Wells, July 2021. |
| ● | Pocock
Industrial Inc Test work Report, (Solid-Liquids Separation ), March 2021. |
| ● | SGS
Testwork, Ref 11868-001 (2009) |
| ● | SGS
Testwork, Ref 11868-002 (2010) |
| ● | Summary
of Previous Test work. |
| ● | Trade-off
study for primary grind. |
| ● | “Environmental
and Permitting Report for CK Gold Pre-Feasibility Study” Report Date: July 2021. |
| ● | “Recommended
Prefeasibility-Level Geotechnical Slope Designs for the Copper King Open Pit. Piteau Associates
July 13, 2021. |
| ● | Mine
Development Associates (MDA) “Updated Technical Report and Preliminary Economic Assessment,
Copper King Project” December 5, 2017 |
| ● | Nevin,
A. E., 1973 (May 30), Interim Report, Copper King property, Laramie County, Wyoming: Henrietta
Mines Ltd. company report: Wyoming State Geological Society mineral files, 16 p. |
| ● | Tietz,
P., and Prenn, N., 2012 (August 24), Technical report on the Copper King Project, Laramie
County, Wyoming: Report prepared for Strathmore Minerals Corp. by Mine Development Associates,
133 p. |
| ● | Aleinikoff,
J.N., 1983. U–Th–Pb systematics of zircon inclusions in rock-forming minerals:
a study of armoring against isotopic loss using the Sherman granite of Colorado–Wyoming,
USA; Contributions to Mineralogy and Petrology 83, p. 259–269. |
| ● | Brady,
R.T., 1949. Geology of the east flank of the Laramie Range in the vicinity of Federal and
Hecla, Laramie County, Wyoming; M.A. Thesis, University of Wyoming, Laramie, 412 p. |
| ● | Edwards,
B.R., and Frost, C.D. 2000. An overview of the petrology and geochemistry of the Sherman
batholith, southeastern Wyoming: Identifying multiple sources of Mesoproterozoic magmatism;
Rocky Mountain Geology; 35 (1): Fig.1, p. 35. |
| ● | Frost,
C.D., Frost, B.R., Chamberlain, K.R. & Edwards, B.R., 1999. Petrogenesis of the 1.43
Ga Sherman batholith, SE Wyoming, USA: a reduced, rapakivi-type anorogenic granite; J. Petrol.
40, p. 1771-1802. |
| ● | Frost
C. D., Frost B. R., 1997. Reduced rapakivi-type granites: the tholeiite connection; Geology,
1997, vol. 25, p. 647-650. |
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259 |
| ● | Hausel,
W.D., 1989. The geology of Wyoming’s precious metal lode and placer deposits; Wyoming
State Geological Survey Bulletin 68, 248 p. |
| ● | Hausel,
W.D., 1992. Form, distribution, and geology of gold, platinum, palladium, and silver in Wyoming;
Geological Survey of Wyoming Reprint No. 51, 18 p. |
| ● | Hausel,
W.D., 1997. Copper, lead, zinc, molybdenum, and associated metal deposits of Wyoming: Wyoming
State Geological Survey Bulletin 70, 229 p. |
| ● | Hausel,
W.D., and Jones, S., 1982. Geological reconnaissance report of metallic deposits for in situ
and heap leach extraction research possibilities; Geological Survey of Wyoming Open File
Report 82-4, 51 p. |
| ● | Hausel,
W.D., 2012. Copper King Mine, Silver Crown District, Wyoming (Preliminary Report); internal
report prepared for Strathmore Resources, 19 p. |
| ● | Houston,
R.S. and Marlatt, G., 1997. Proterozoic geology of the Granite village area, Albany and Laramie
counties, Wyoming, compared with that of the Sierra Madre and Medicine Bow mountains of southeastern
Wyoming: U.S. Geological Survey Bulletin 2159, 25 p. |
| ● | Karlstrom,
K. E. & Houston, R. S., 1984. The Cheyenne belt: analysis of a Proterozoic suture in
southern Wyoming; Precambrian Research 25, p. 415–446. |
| ● | Klein,
T., 1974. Geology and mineral deposits of the Silver Crown District, Laramie County, Wyoming;
Geological Survey of Wyoming Preliminary Report No. 14, 27 p. |
| ● | McGraw,
R.B., 1954. Geology in the vicinity of the Copper King Mine, Laramie County, Wyoming; M.A.
Thesis, University of Wyoming, Laramie, 52 p. |
| ● | Mountain
Lake Resources Inc., 1997. Resource Evaluation and Exploration Potential, C.K. Gold-Copper
Deposit, Laramie County, Wyoming; Mountain Lake Resources internal report, 24 p. |
| ● | Reed,
J.C., Jr., Bickford, M.E., Premo, W.R., Aleinikoff, J.N., and Pallister, J.S., 1987. Evolution
of the early Proterozoic Colorado province--Constraints from U-Pb geochronology; Geology,
v. 15, p. 861-865. |
| ● | Reed,
J.C., Jr., Bickford, M.E., and Tweto, O., 1993. Proterozoic accretionary terranes of Colorado
and southern Wyoming; in Reed, J.C., Jr., and 7 others, Precambrian--Conterminous U.S., Boulder,
Colorado, Geological Society of America, The Geology of North America, v. C-2, p. 211-228. |
| ● | Sims,
P.K., Finn, C.A., and Rystrom, V.L., 2001. Preliminary Precambrian basement map showing geologic-geophysical
domains, Wyoming; U.S. Geological Survey Open File-Report 2001-199, 9 p. |
| ● | Tweto,
O., 1987. Rock units of the Precambrian basement in Colorado; U.S. Geological Survey Professional
Paper 1321-A, 54 p. |
| ● | Zielinski,
R. A., Peterman, Z. E., Stuckless, J. S., Rosholt, J. N. and Nkomo, I. T., 1981. The chemical
and isotopic record of rock–water interaction in the Sherman granite, Wyoming and Colorado;
Contributions to Mineralogy and Petrology 78, p. 209–219. |
| ● | Berger,
B.R., Ayuso, R.A., Wynn, J.C., and Seal, R.R., 2008. Preliminary model of porphyry copper
deposits; U.S. Geological Survey Open-File Report 2008–1321, 55 p. |
| ● | Carson,
D. J. T., 1998. Mineralogical study of samples from Copper King prospect, Wyoming; Unpublished
report, 7 p. |
| ● | Fossen,
H., 2016. Structural Geology; Cambridge University Press, 524 p. |
| ● | Hausel,
W.D., 1997. Copper, lead, zinc, molybdenum, and associated metal deposits of Wyoming; Wyoming
State Geological Survey Bulletin 70, 229 p. |
| ● | Hausel,
W.D., 2012. Copper King Mine, Silver Crown District, Wyoming (Preliminary Report); Internal
report prepared for Strathmore Resources, 19 p. |
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260 |
| ● | John,
D.A., Ayuso, R.A., Barton, M.D., Blakely, R.J., Bodnar, R.J., Dilles, J.H., Gray, Floyd,
Graybeal, F.T., Mars, J.C., McPhee, D.K., Seal, R.R., Taylor, R.D., and Vikre, P.G., 2010.
Porphyry copper deposit model, chap. B of Mineral deposit models for resource assessment;
U.S. Geological Survey Scientific Investigations Report 2010–5070–B, 169 p. |
| ● | Klein,
T., 1974. Geology and mineral deposits of the Silver Crown District, Laramie County, Wyoming;
Geological Survey of Wyoming Preliminary Report No. 14, 27 p. |
| ● | Bartos,
T., Diehl, S., Hallberg, L., and Webster, D. 2014. “Geologic and Hydrogeologic Characteristics
of the Ogallala Formation and White River Group, Belvoir Ranch near Cheyenne, Laramie County,
Wyoming” USGS Scientific Investigations Report 2013-5242. |
| ● | Geochemical
Solutions, 2022. Geochemical Characterization of CK Gold Mine Rock and Tailings, Report No.
1083.10.1, 6 December 2023. |
| ● | Hausel,
W., 2019. Gold at the Copper King Gold-Copper Mine near Cheyenne, Wyoming Blog. Available
from: The Gem Hunter: (http://copperking.blogspot.com/). |
| ● | Neirbo
Hydrogeology, 2023. CK Gold Project Hydrogeologic Characterization and Groundwater Flow Model. |
| ● | Tierra
Group International, Ltd., 2025a. Dry Stack TMF Stacking Plan. Technical Memorandum. 05 February
2025. |
| ● | Tierra
Group International, Ltd., 2025b. Dry Stack TMF Stability Analyses. Technical Memorandum.
05 February 2025. |
| ● | Tierra
Group International, Ltd., 2025c. CK Gold Mine Site-Wide Water Management Report. 05 February
2025. |
| ● | Trihydro,
2020. Aquatic Resources Inventory, CK Gold Project, 4 November 2020. |
| ● | Trihydro,
2022. Subsurface Exploration Report, CK Gold Project, 3 May 2022. |
| ● | Trihydro,
2023. CK Gold Mine Transmission Line, Laramie County, Wyoming, December 2023. |
| ● | Western
Archaeological Services, 2021. Class I Cultural Resource Data Review for the Proposed U.S.
Gold Corp CK Gold Project, 15 June 2021. |
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261 |
25.0 | Reliance
on information provided by registrant |
Table
25.1 provides a detailed list of information U.S. Gold (Registrant) provides for matters discussed in this Technical Report Summary (TRS).
Table
25.1: Information provided by U.S. Gold |
Category |
TRS
Section |
Reliance |
Legal
Matters |
Section
3 Property Description and Location |
Information
and documentation regarding mineral titles, surface land agreements, current permitting status, royalties, and other agreements provided
by U.S. Gold |
General
Information |
Section
4 Accessibility, Climate, Local Resources, Infrastructure and Physiography |
Physical
information about the Project was provided by U.S. Gold. Information consisted of consultant reports, and correspondence with U.S.
Gold. |
General
Information |
Section
5 History |
Historical
data provided by U.S. Gold, primarily previous Technical Reports |
Technical
Information |
Section
6 – Geological Setting, Mineralization, and Deposit |
Various
public and consultant reports. Dworian MSc thesis. |
Technical
Information |
Section
7 – Exploration |
Historical
project reports and exploration data |
Section
8 |
Sample
Preparation, Analysis, and Security |
Consultant
reports, Hard Rock Mining Annual reports. |
Technical
Information |
Section
13.2 Geotechnical |
“Recommended
Prefeasibility - Level Geotechnical Slope Designs for the Copper King Open Pit” Authored by Piteau Associates and provided
by U.S. Gold. |
Technical
Information |
Section
13.2 Hydrology |
Neirbo
Hydrology Report provided by U.S. Gold. Dahlgren Water Supply and Yield Analysis Report for the CK Gold Deposit. |
Technical
Information |
Section
15 |
PFS
level site plan and facility design and report by Trihydro and TGI. Mine operating permit application, Industrial Siting, WYPDES
and air permits. |
Economic
Information |
Section
16 |
Marketing
memo prepared by Andy Holloway and Mike Mason. Confidential concentrate sale term sheet. |
Environmental
Matters |
Section
17 |
Pre-permitting
work done provided by U.S. Gold. Mine operating permit application, Industrial Siting, WYPDES and air permits. |
Commitments
to local groups and individuals |
Section
17 |
Pre-permitting
work done provided by U.S. Gold. Mine operating permit application, Industrial Siting, WYPDES and air permits. |
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US Gold (NASDAQ:USAU)
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