3rd April 2023
Anglesey Mining
plc
(“Anglesey” or
“the Company”)
Parys Mountain
Resource Update
Anglesey Mining plc (AIM:AYM), the UK minerals development
company, is pleased to announce an updated Mineral Resource
Estimate (“MRE”) for its 100% owned Parys Mountain Cu-Zn-Pb-Ag-Au
project located on the isle of Anglesey. The resource estimates for
the White Rock and Engine Zones
have been updated on the basis of 10 additional drill holes
completed in 2022 and a detailed review of the previous geological
interpretations.
- Measured resources are now reported at Parys Mountain for the
first time in the project’s history. The inclusion of 1.3Mt in the
highest confidence category of resource provides a very strong base
for the next round of mine optimisation work
- The combined MRE for the White
Rock and Engine Zones, now referred to as Morfa Du, have
been reported at 5.72Mt at 0.4% Cu, 2.30% Zn, 1.24% Pb, 28/t Ag and
0.3g/t Au, or 2.0% Copper Equivalent (“CuEq”) / 5.6% Zinc
Equivalent (“ZnEq”) – reported above a cut-off based on a Net
Smelter Revenue (“NSR”) of US$45.15/t, including 1.6Mt at 2.5% CuEq in the
Engine Zone
- The Morfa Du Zone has 5.3Mt (93%) of the resource now reporting
to the Measured and Indicated (“M&I”) categories (23% Measured
and 70% Indicated) and contains 213,000t of combined Zn/Pb/Cu,
4.8Moz silver and 48koz gold
- The overall MRE for Parys Mountain, including the Northern
Copper Zone which has not yet been updated, is reported at 16.1Mt
at 1.0% Cu, 1.3% Zn, 0.7% Pb, 15g/t Ag and 0.2g/t Au (1.9% CuEq or
5.3% ZnEq) containing 486,000t of combined Zn/Pb/Cu, 7.9Moz silver
and 86koz gold
- The Company will undertake a similar resource update process
for the large Northern Copper Zone including additional drilling,
which will be the first into this zone since 2008. As detailed in
the RNS dated 28 November 2022, the
company believes there is substantial upside to the existing
resource base of 9.4Mt, relative to the 1969 internal resource of
32.7Mt (which should not be considered compliant with any modern
JORC or NI43-101 methodologies)
- The updated MRE will provide the foundation for the
Pre-Feasibility Study, which will incorporate an optimised mine
design layout and results from recently commenced metallurgical
testwork
Jo Battershill, Chief
Executive of Anglesey Mining, commented: “It is very
pleasing to have finalised the updated Mineral Resource Estimate
for Parys Mountain, which for the first time includes significant
tonnes in the Measured category. This update was completed to
provide the most robust resource estimate going into the next steps
of the project’s evaluation. The geology and resources form the
basis for every other subsequent aspect in the evaluation phase,
from the mine design through to metallurgy and management of
tailings. The first inclusion of tonnes in the Measured category
demonstrates the increased level of confidence the team has in the
Parys Mountain project.”
“The grade-tonnage curve gives us a
high-level of confidence that a robust economic development is
achievable at Parys Mountain, especially given metallurgical
testwork has demonstrated the ore could be successfully up-graded
through pre-concentration methods that reject up to 40% of the
mined volumes.”
“One other benefit of this exercise
has been to highlight the outstanding exploration potential of the
project. Numerous zones have been identified where mineralisation
could potentially extend beyond the resource boundary. Many
drillholes contain ‘ore-grade’ hits that have not been included in
the estimate. One of these is the shaft pilot hole with
intersections including 5.8m at 2.6%
Cu and 3.0m at 3.0% Cu commencing
around 20m below the current base of
the Morris Shaft. We believe that once mining commences at Parys
Mountain the probability of finding more ore zones is very high, as
with all Volcanogenic Massive Sulphide deposits.”
Parys Mountain Mineral Resource
Estimate
The updated JORC compliant Mineral Resource Estimate (MRE) was
prepared by Micon International and stands at 16.08Mt at 0.98% Cu,
1.32% Zn, 0.71% Pb, 15g/t Ag and 0.17g/t Au (1.9% CuEq or 5.3%
ZnEq), as set out in the table below.
Parys Mountain
Resources, Combined March 2023 and January 2021 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
1.30 |
0.33 |
2.32 |
1.28 |
33 |
0.43 |
4.3 |
30.1 |
16.6 |
1.36 |
18.0 |
Indicated |
3.98 |
0.37 |
2.39 |
1.29 |
27 |
0.23 |
14.7 |
95.3 |
51.5 |
3.47 |
29.7 |
Inferred |
10.79 |
1.29 |
0.81 |
0.43 |
9 |
0.11 |
139.4 |
87.7 |
46.6 |
3.05 |
38.9 |
Total |
16.06 |
0.98 |
1.33 |
0.71 |
15 |
0.17 |
158 |
213 |
115 |
7.9 |
86 |
The previous global resource estimate for Parys Mountain
(reported in January 2021) was 16.9Mt
at 1.0% Cu, 1.5% Zn, 0.8% Pb, 17g/t Ag and 0.2g/t Au (2.0% CuEq or
5.6% ZnEq).
Morfa Du Mineral Resource Estimate
The updated MRE for the Morfa Du Zone, which contains the
White Rock and Engine Zone ore
shoots, comprises 5.72Mt at 0.36% Cu, 2.30% Zn, 1.24% Pb, 28/t Ag
and 0.28g/t Au (2.0% CuEq or 5.6% ZnEq), as set out in the table
below.
Morfa Du Zone
Resources, March 2023 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
1.30 |
0.33 |
2.32 |
1.28 |
33 |
0.43 |
4.3 |
30.4 |
16.7 |
1.38 |
18.3 |
Indicated |
3.98 |
0.37 |
2.39 |
1.29 |
27 |
0.23 |
14.7 |
95.3 |
51.4 |
3.44 |
29.7 |
Inferred |
0.45 |
0.40 |
1.41 |
0.65 |
25 |
0.25 |
1.8 |
6.4 |
2.9 |
0.36 |
3.6 |
Total |
5.72 |
0.36 |
2.30 |
1.24 |
28 |
0.28 |
20.4 |
131.7 |
70.9 |
5.17 |
51.3 |
Notes to table:
- Mineral Resources are based on JORC Code
definitions
- Operating costs for mining, processing and G&A were
modelled at US$45.15/t of mill
feed
- An Average Value operating cut-off of US$45.15/t has been applied
- Payability varies depending on metal (from 70% up to
97.5%)
- Metal prices used in the NSR and CuEq calculations were
based on US$3,350/t for Zn,
US$2,292/t for Pb, US$9,523/t for Cu, US$25.50oz for Ag and US$1850/oz for Au
- Recoveries used in the NSR were based on historical
metallurgical testwork and the 2,000t bulk sample processed in 1991
(80% to 82% for Zn, 48% to 80% for Cu, 68% to 78% for Pb, 72% for
Ag and 25% for Au to concentrate and 40% for Au to
gravity)
- Dilution allowance of 5% included
- CuEq – Copper equivalent was calculated using the formula
set out below:
- CuEq = (Cu grade % x Cu Recovery) + (Zn grade % x Zn
recovery % x (Zn price / Cu price)) + (Pb grade % x Pb recovery % x
(Pb price / Cu price)) + (Ag grade g/t / 31.103 x Ag recovery % x
(Ag price / Cu price)) + (Au grade g/t / 31.103 x Au recovery % x
(Au price / Cu price))
- It is the opinion of Anglesey Mining and the Competent
Persons that all elements and products included in the metal
equivalent formula have a reasonable potential to be recovered and
sold
- Density values were calculated using a linear regression of
density versus the combined Cu, Pb, and Zn grade
- Rows and columns may not add up exactly due to
rounding
On a like-for-like basis, the previous resource estimate of the
Morfa Du Zone was 6.9Mt at 0.44% Cu, 2.70% Zn, 1.40% Pb, 30g/t Ag
and 0.24g/t Au (2.2% CuEq or 6.2% ZnEq). The updated resource
included a robust review of the geology resulting in tighter
geological constraints being applied, which resulted in previous
zones of inferred material being removed. However, it is important
to note that these areas still represent key target zones for
future drilling.
The estimation included the application of higher commodity
prices than those used in the 2021 MRE, which resulted in the
incorporation of lower grade material within the interpreted
mineralised zone. The test for Reasonable Prospect of Eventual
Economic Extraction (RPEEE) used higher operating cost estimates
than the 2021 MRE incorporating recent inflationary factors.
Details of these changes are provided in the notes to the
tables.
The following tables show the updated (2023) and previous (2021)
mineral resource estimates for White
Rock.
White Rock
Resources, March 2023 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
0.86 |
0.23 |
2.29 |
1.28 |
22 |
0.41 |
2.0 |
19.7 |
11.0 |
0.60 |
11.2 |
Indicated |
2.83 |
0.23 |
2.18 |
1.20 |
22 |
0.29 |
6.5 |
61.7 |
34.0 |
2.02 |
26.4 |
Inferred |
0.35 |
0.31 |
1.61 |
0.73 |
29 |
0.31 |
0.7 |
5.6 |
2.5 |
0.32 |
3.4 |
Total |
4.04 |
0.28 |
2.30 |
1.24 |
28 |
0.28 |
9.3 |
87.1 |
47.6 |
2.95 |
41.1 |
White Rock
Resources, January 2021 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
|
|
|
|
|
|
|
|
|
|
|
Indicated |
4.71 |
0.25 |
2.30 |
1.23 |
23 |
0.30 |
11.8 |
108.3 |
57.9 |
3.48 |
45.4 |
Inferred |
1.26 |
0.28 |
2.56 |
1.26 |
28 |
0.30 |
3.5 |
32.3 |
15.9 |
1.13 |
12.2 |
Total |
5.97 |
0.26 |
2.35 |
1.24 |
24 |
0.30 |
15.3 |
140.6 |
73.8 |
4.62 |
57.6 |
Lower tonnages are due to the tighter geological constraints
used in the interpretation and the higher costs estimates used in
the RPEEE.
The following tables show the updated (2023) and previous (2021)
individual mineral resource estimates for Engine Zone.
Engine Zone
Resources, March 2023 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
0.45 |
0.52 |
2.38 |
1.27 |
53 |
0.48 |
2.3 |
10.5 |
5.6 |
0.76 |
6.8 |
Indicated |
1.15 |
0.71 |
2.92 |
1.52 |
39 |
0.09 |
8.1 |
33.6 |
17.5 |
1.45 |
3.4 |
Inferred |
0.10 |
0.72 |
0.73 |
0.36 |
9 |
0.05 |
0.7 |
0.7 |
0.3 |
0.03 |
0.1 |
Total |
1.71 |
0.66 |
2.65 |
1.39 |
41 |
0.19 |
11.2 |
45.2 |
23.7 |
2.25 |
10.5 |
Engine Zone
Resources, January 2021 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
|
|
|
|
|
|
|
|
|
|
|
Indicated |
0.50 |
1.36 |
4.94 |
2.59 |
92 |
0.50 |
6.8 |
24.7 |
12.9 |
1.48 |
8.0 |
Inferred |
0.12 |
1.73 |
6.73 |
3.42 |
70 |
0.50 |
2.1 |
8.1 |
4.1 |
0.27 |
1.9 |
Total |
0.62 |
1.43 |
5.29 |
2.75 |
87 |
0.50 |
8.9 |
32.8 |
14.1 |
1.75 |
9.9 |
The increased tonnages and lower grades for Engine Zone has been
driven by the combination of extending the areas of modelled
mineralisation in the interpretation and the incorporation of
higher commodity prices.
Northern Copper Zone, Garth Daniel and Deep Engine Zone Mineral
Resource Estimates
The Northern Copper Zone, Deep Engine Zone and Garth Daniel Zone resource estimates were not
updated during this process and thereby remain unchanged.
Northern Copper Zone
Resources, January 2021 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
|
|
|
|
|
|
|
|
|
|
|
Indicated |
|
|
|
|
|
|
|
|
|
|
|
Inferred |
9.38 |
1.27 |
0.38 |
0.24 |
5 |
0.1 |
120.1 |
35.6 |
22.5 |
1.5 |
30.2 |
Total |
9.38 |
1.27 |
0.38 |
0.24 |
5 |
0.1 |
120.1 |
35.6 |
22.5 |
1.5 |
30.2 |
Garth Daniel Zone
Resources, January 2021 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
|
|
|
|
|
|
|
|
|
|
|
Indicated |
|
|
|
|
|
|
|
|
|
|
|
Inferred |
0.34 |
1.89 |
5.78 |
2.76 |
66 |
0.1 |
6.4 |
19.7 |
9.4 |
0.7 |
1.1 |
Total |
0.34 |
1.89 |
5.78 |
2.76 |
66 |
0.1 |
6.4 |
19.7 |
9.4 |
0.7 |
1.1 |
Deep Engine Zone
Resources, January 2021 |
Classification |
Tonnes
(Mt) |
Grades |
Contained
Metal |
Cu |
Zn |
Pb |
Ag |
Au |
Cu |
Zn |
Pb |
Ag |
Au |
(%) |
(%) |
(%) |
(g/t) |
(g/t) |
(kt) |
(kt) |
(kt) |
(Moz) |
(koz) |
Measured |
|
|
|
|
|
|
|
|
|
|
|
Indicated |
|
|
|
|
|
|
|
|
|
|
|
Inferred |
0.62 |
1.95 |
4.21 |
1.90 |
23 |
0.2 |
12.1 |
26.1 |
11.8 |
0.5 |
4.0 |
Total |
0.62 |
1.95 |
4.21 |
1.90 |
23 |
0.2 |
12.1 |
26.1 |
11.8 |
0.5 |
4.0 |
Notes to table:
- Mineral Resources are based on JORC Code
definitions
- Operating costs for mining, processing and G&A were
modelled at US$39.08/t of mill
feed
- An NSR operating cut-off of US$48/t has been applied
- Payability of 72% applied
- Metal prices used in the NSR and CuEq calculations were
based on US$2756/t for Zn,
US$2,205/t for Pb, US$5512/t for Cu, US$17.50oz for Ag and US$1275/oz for Au
- Recoveries used in the NSR were based on historical
metallurgical testwork and the 2,000t bulk sample processed in 1991
(80% to 82% for Zn, 48% to 80% for Cu, 68% to 78% for Pb, 72% for
Ag and 25% for Au to concentrate and 40% for Au to
gravity)
- No allowance was made for dilution
- CuEq – Copper equivalent was calculated using the formula
set out below:
- CuEq = (Cu grade % x Cu Recovery) + (Zn grade % x Zn
recovery % x (Zn price / Cu price)) + (Pb grade % x Pb recovery % x
(Pb price / Cu price)) + (Ag grade g/t / 31.103 x Ag recovery % x
(Ag price / Cu price)) + (Au grade g/t / 31.103 x Au recovery % x
(Au price / Cu price))
- It is the opinion of Anglesey Mining and the Competent
Persons that all elements and products included in the metal
equivalent formula have a reasonable potential to be recovered and
sold
- Density values were calculated using a linear regression of
density versus the combined Cu, Pb, and Zn grade
- Rows and columns may not add up exactly due to
rounding
Next Steps
From a mineral resource perspective, the Company will embark on
a similar remodelling and estimation process for the Northern
Copper Zone, Garth Daniel Zone and
Deep Engine Zone over the course of 2023.
Based on the review of the Northern Copper Zone (released in
November 2022), management believes
there is potential to significantly increase the current modelled
mineralisation envelope with some additional drilling to confirm
some of the historical intersections and infill to lift the level
of confidence. As highlighted in the November update, the current
resource estimate of 9.4Mt is significantly lower than the
internally generated historical resource of 32.7Mt from 1970.
Recent work also suggests the potential to extend the high-grade
Garth Daniel shoot both up and down
dip and along strike – perhaps connecting with the remaining
eastern leg of the Deep Engine Zone.
With the completion of the updated MRE for the White Rock and Engine Zones, now referred to
as Morfa Du, the Company will now focus on upgrading the 2021 PEA
to a Pre-Feasibility Study. This process will include the following
aspects:
- Re-optimise the underground development with initial focus on
the Morfa Du Zone
- Include results of ongoing metallurgical testwork into the
preliminary engineering designs, with a particular focus on
selecting the preferred pre-concentration method
- Preliminary engineering designs for the proposed dry-stack
tailings management facility
- Preliminary engineering designs for the process plant;
and,
- Updating the site infrastructure plans including decline portal
location, temporary mining waste storage location and supply of
utilities
The outputs of a Pre-Feasibility Study would be expected to
include selection of the final mining and processing methods to
take forward into a Feasibility Study and declaration of a mining
reserve. It would also be expected to identify any potential
requirements for additional resource, geotechnical and
metallurgical drilling.
The ongoing Environmental Impact and Social Assessment
activities and planning consent process will progress concurrently
with the PFS.
MORFA DU MINERAL
RESOURCE UPDATE
APPENDIX
Parys Mountain Geology and
Mineralisation
Lenses of massive Zn-Pb-Cu sulphides at the Parys Mountain
deposit in Anglesey, in North West
Wales, occur at and near the contact between Ordovician
shales and overlying rhyolites. The rhyolites have been dated as
Lower Silurian (Parrish 1999) and have a thickness of a few hundred
metres. These are subsequently overlain by Lower Silurian shales.
The rhyolites and shales strike north-easterly for 2 km to 3 km and
dip to the north.
Minor basalts are present, but there are no intermediate rocks.
Cu-bearing stockwork veins occur in the upper portion of the
Ordovician shales, and Cu-bearing mineralisation was mined from the
Lower Silurian shales in the 18th century. Precambrian basement
rocks are present to the south and north of Parys Mountain.
A commonly accepted model to explain the field relationships at
Parys Mountain invokes a large synclinal structure with an
east-west axis and a northern limb, which is overturned to the
south. This limb comprises the Northern shales, the Northern
rhyolites, and part of the Central shales. The Northern shales
contain overturned graded sandstone beds. In addition, they contain
Ordovician acritarchs, which in at least one area become younger to
the south.
The property scale synclinal axis is inferred to run for the
most part through the Central shales, which show common evidence of
folding and thrusting on a variety of scales. To the west, the
Central shales pinch out, such that the Northern and Southern
rhyolites merge. West of this thick rhyolite sequence, the
northeast striking Penymynydd fault is present.
The mineralisation of Parys Mountain extends for roughly 3 km,
striking NNE to SSW in a band 1 km wide. It is associated with an
ancient volcanic event (late Ordovician circa 480 Ma) involving the
extrusion of mostly silica rich rhyolites and dacite lavas with ash
ejection.
These deposits grade laterally into the shallow water volcanic
sediments which include siliceous sinter and cherts and also host
intrusive rhyolites and later dolerites. This volcanic sequence
overlies the Parys shales and is in turn overlain by later Silurian
shales. These beds appear to have been compressed into a steep
trough shaped structure striking NE to SW and tilted over to the
SE. The axis is exposed at the ends of the Great Opencast. The
region is also traversed by the steep NNW to SSE striking cross
faults and to the north there are older Precambrian schists of the
Mona complex, brought up by the Carmel head and Corwas thrust
faults.
The primary mineralisation is comprised of pyrite
(FeS2) which can be seen in the slump structures in the
exposures at the centre of the Great Opencast, indicating formation
on the sea floor. This was followed by a phase dominated by
chalcopyrite (CuFeS2) and then by one dominated by the
intimate mixture of sphalerite (ZnS) and galena (PbS) with only
minor chalcopyrite. This is known locally as "Bluestone".
The mineralisation is believed to have formed from exhalations
on the sea floor analogous to the black smokers seen in other
oceans today. The ore deposit is thus thought to be of the "Kuroko"
type and as such is unique in Britain.
A secondary phase remobilisation occurred during the later
Caledonian metamorphism and has been dated to be 360 Ma.
Parys Mountain Modelling and Grade
Interpolation
Since the previous resource estimation process in 2021, a
further campaign of infill drilling has been carried out focusing
on the White Rock and Engine Zone.
This campaign included 10 drillholes being completed between
December 2021 and May 2022. Of the 10 holes completed, 8 showed
significant mineralised intervals which have added further
datapoints for the new Mineral Resource model.
Chosen samples from these drillholes were also the subject of
specific gravity analysis (water immersion method), giving
additional density data for the mineralised intervals to be
utilised in the updated Mineral Resource model.
After updating the Parys Mountain drillhole database to include
the 2022 drillholes, cross sections were generated through the
White Rock and Engine Zones at
50m spacings utilising the Leapfrog
Geo software package. Each assay within the drillhole database was
assigned a raw-insitu-value, calculated using the trailing 3-yr
average commodity prices. From this, the company selected a cut-off
of US$45 to generate the ‘mineralised
envelope’. The cross sections were then used to confirm previous
interpretative work or updated based on new information.
The sectional interpretations were then geo-referenced into
their correct position within the Leapfrog model, which allowed for
the interpretations to be digitised using polylines. These
polylines were then used to form a mesh, which was used as the
extents of the new Mineral Resource model.
Further analysis was also completed on the existing assay
database used in the previous resource model, which found some
inconsistencies with historic drilling data. These inconsistencies
are detailed here:
- PM126 had no assay data included in the database, however,
assays were available between 99.07 - 102.83m and were subsequently included
- PM122 was given an incorrect collar location, dip and azimuth.
These were corrected within the database
- AMC5 assay data for the interval 278.3 - 285.7m should have read 278.3 - 278.9m. This was corrected in the database
- A53 assay data for the interval 561.8 - 566.6m was identified as being included as an
average across the interval. The database was corrected with the
addition of the individual assays for each sample length
- CZ13 assay data had been input incorrectly with a transposition
error. This was corrected in the database
- Elevations of some collars had minor inconsistencies with the
LiDAR topography data for the area. All hole coordinates were
verified by historic maps, then pinned to the LiDAR data to give
their accurate elevation.
Interpretation of the data and previous model has resulted in
the Engine Zone increasing in size and dip extent. Drilling clearly
shows the addition of a new western ‘limb’ within the Engine Zone
mineralisation. Re-evaluation of the historical project data
suggests that drilling included in Deep Engine Zone (A51A, PM109),
and holes within the same vicinity as Deep Engine Zone (PM108, A48,
PM113, PM107) are likely to be extensions of the Engine Zone.
However, additional drilling would be required to confirm and
expand the resource at depth.
Similarly, White Rock has been
extended down-dip to encompass the mineralised intervals of A51,
A51A and the bottom mineralised interval of PM113, none of which
had previously been included in any of the previous resource
models.
For the Morfa Du Zone resource update, five elements were
modelled - Cu, Zn, Pb, Ag and Au. The higher-grade populations were
separately interpreted and wireframed. All the domains were
interpreted on a section-by-section basis and were used to generate
solid ‘3D’ wireframes. The same methodology was applied for the
individual high-grade populations by commodity.
Within the broader mineralised envelope, wireframes were
constructed for the Engine Zone and White
Rock ore bodies based on assay grades, lithological logs,
and deposit-scale geological information. High- and low-grade
domain wireframes were modelled for Ag, Au, Cu, Pb, and Zn within
the two separate ore bodies.
Drill hole assay data was composited at 2.0m intervals. Exploratory data analysis was
performed for each domain to validate geostatistical stationarity,
identify the nature of the contacts between domains, and to inform
outlier management.
Normal score variograms were modelled for Ag, Au, Cu, Pb, and Zn
in the Engine Zone and White Rock
ore bodies. Data from high- and low-grade domains were combined to
ensure sufficient pairs of samples for robust variogram modelling.
The modelled variograms show similar ranges and principal
directions for the most strongly correlated elements (Ag, Cu, Pb,
and Zn) and are orientated parallel to the respective ore body.
A rotated block model dipping 50° to the North was constructed
with a parent block size of 8.0m (X),
8.0m (Y) and 4.0m (Z) with a sub-block size of 2.0m (X), 2.0m (Y)
and 2.0m (Z). The Ag, Au, Cu, Pb, and
Zn grades for each domain were interpolated using ordinary kriging
in 3 passes with hard boundaries. The orientation and anisotropy of
the search ellipse was kept constant for the most strongly
correlated elements (Ag, Cu, Pb, and Zn) and was related to the
general orientation and range of the modelled variograms. For
increasing estimation pass number, the size of the search ellipse
was increased, and the minimum number of samples was decreased to
ensure all blocks were interpolated. The maximum number of samples
was calibrated to match the expected grade tonnage curve at the
scale of future mining, this was to ensure that there was not
excessive smoothing of the estimate. Top caps were applied to
extreme values and for high-grade outlier values restricted search
neighbourhoods were used. The restricted neighbourhoods ensured
that high-grade outlier values only informed blocks in close
proximity to the composite data, limiting the smearing of
high-grade data.
In order to assure the quality of the estimate, the block model
was validated using statistical comparison, visual inspection and
swath plot analysis.
The density values were calculated using a linear regression of
density versus the combined Cu, Pb, and Zn grade.
Parys Mountain Classification and
Reporting
Clause 20 of the JORC (2012) Code requires that all reports of
Mineral Resources must have Reasonable Prospects for Eventual
Economic Extraction (RPEEE), regardless of the classification of
the resource. The Parys Mountain deposit has reasonable prospects
for eventual economic extraction on the following basis:
- Metallurgical test work by multiple consultants has confirmed
that the Parys Mountain mineralisation is amenable to flotation
processes;
- The cut-off grade adopted for reporting (US$45.15/t NSR) is considered reasonable given
the Mineral Resource will most likely be exploited by underground
mining methods and processed using flotation techniques
- Operating costs for mining, processing and G&A were
modelled at US$45.15/t of mill feed;
and,
- Minerals Resources were constrained by optimised stope
shapes
The Preliminary Economic Assessment (PEA) completed in 2021
demonstrated that the deposit potentially has a positive net
present value (NPV), and that the mineralised zone is potentially
mineable using underground methods under the given economic
scenario and parameters. The PEA did not estimate Ore Reserves for
the deposit. The deposit appears to have reasonable prospects of
eventual economic extraction under a realistic set of criteria.
The Parys Mountain Mineral Resource has been classified based on
the guidelines specified in the JORC Code. The classification level
is based upon an assessment of geological understanding of the
deposit, geological and mineralisation continuity, drill hole
spacing, QA/QC results, search and interpolation parameters and an
analysis of available density information. The MRE is reported by
classification in the tables above, and are constrained by
5.0m (height) x 5.0m (width) x 20.0m (level interval) stope shapes dumped at an
angle of 50° to the North above an NSR cut-off of US$45/t.
Competent Person
The information in this announcement which relates to the
updated resource estimate for the Parys Mountain deposit has been
approved by Mrs. Liz de Klerk,
M.Sc., Pr.Sci.Nat., MIMMM who is a professional registered with the
South African Council for Natural Scientific Professionals
(SACNASP) and independent consultant to the Company. Mrs. de Klerk
is the Senior Geologist & Managing Director of Micon
International Co Limited and has over 20 continuous years of
exploration and mining experience in a variety of mineral deposit
styles. Mrs. de Klerk has sufficient experience which is relevant
to the style of exploration, mineralisation and type of deposit
under consideration and to the activity which she is undertaking to
qualify as a Competent Person as defined in the 2012 Edition of the
"Australasian Code for reporting of Exploration Results,
Exploration Targets, Mineral Resources and Ore Reserves" (JORC
Code). Mrs. de Klerk is also a "Qualified Person" as defined in the
"Note for Mining and Oil & Gas Companies" which form part of
the AIM Rules for Companies. Mrs. de Klerk has reviewed and
consented to the inclusion in the announcement of the information
in the form and context in which it appears.
Glossary of Technical Terms
"Ag" |
chemical symbol for silver |
|
"Au" |
chemical symbol for gold |
|
"Cu" |
the chemical symbol for copper |
|
“CuEq” |
copper equivalent |
|
"cut-off" |
the lowest grade value that is
included in a Resource statement. It must comply with JORC
requirement 19: "reasonable prospects for eventual economic
extraction" the lowest grade, or quality, of mineralised material
that qualifies as economically mineable and available in a given
deposit. It may be defined on the basis of economic evaluation, or
on physical or chemical attributes that define an acceptable
product specification |
|
"grade" |
relative quantity or the percentage
of ore mineral or metal content in an ore body |
|
"g/t" |
grammes per tonne, equivalent to
parts per million |
|
"Inferred Resource" |
that part of a Mineral Resource for
which tonnage, grade and mineral content can be estimated with a
low level of confidence. It is inferred from geological evidence
and assumed but not verified geological and/or grade continuity. It
is based on information gathered through appropriate techniques
from locations such as outcrops, trenches, pits, workings and drill
holes which may be limited or of uncertain quality and
reliability |
|
"Indicated Resource" |
that part of a Mineral Resource for
which tonnage, densities, shape, physical characteristics, grade
and mineral content can be estimated with a reasonable level of
confidence. It is based on exploration, sampling and testing
information gathered through appropriate techniques from locations
such as outcrops, trenches, pits, workings and drill holes. The
locations are too widely or inappropriately spaced to confirm
geological and/or grade continuity but are spaced closely enough
for continuity to be assumed |
|
"JORC" |
The Australasian Joint Ore Reserves
Committee Code for Reporting of Exploration Results, Mineral
Resources and Ore Reserves 2012 (the "JORC Code" or "the Code").
The Code sets out minimum standards, recommendations and guidelines
for Public Reporting in Australasia of Exploration Results, Mineral
Resources and Ore Reserves |
|
"Measured
Resource" |
that part of a Mineral Resource for
which tonnage, densities, shape, physical characteristics, grade
and mineral content can be estimated with a high level of
confidence. It is based on detailed and reliable exploration,
sampling and testing information gathered through appropriate
techniques from locations such as outcrops, trenches, pits,
workings and drill holes. The locations are spaced closely enough
to confirm geological and grade continuity |
|
"Mineral Resource" |
a concentration or occurrence of
material of intrinsic economic interest in or on the Earth's crust
in such form, quality and quantity that there are reasonable
prospects for eventual economic extraction. The location, quantity,
grade, geological characteristics and continuity of a Mineral
Resource are known, estimated or interpreted from specific
geological evidence and knowledge. Mineral Resources are
sub-divided, in order of increasing geological confidence, into
Inferred, Indicated and Measured categories when reporting under
JORC |
|
“MRE” |
mineral resource
estimate |
"Mt" |
million tonnes |
“NSR” |
net smelter revenue |
"oz" |
troy ounce (= 31.103477
grammes) |
"Pb" |
the chemical symbol for
lead |
“PEA” |
preliminary economic
assessment |
"t" |
tonne (= 1 million
grammes) |
"Zn" |
the chemical symbol for
zinc |
“ZnEq” |
zinc equivalent |
A PDF version of this annoucement with additional diagrams can
be viewed or downloaded via the following
link: https://www.angleseymining.co.uk/wp-content/uploads/2023/04/Parys_Mountain_Resource_Update.pdf
About Anglesey Mining plc
Anglesey Mining is traded on the AIM market of the London Stock
Exchange and currently has 295,220,548 ordinary shares on
issue.
Anglesey is developing its 100% owned Parys Mountain
Cu-Zn-Pb-Ag-Au deposit in North
Wales, UK with a reported resource of 5.3 million tonnes at
over 4.0% combined base metals in the Measured and Indicated
categories and 10.8 million tonnes at over 2.5% combined base
metals in the Inferred category.
Anglesey also holds an almost 50% interest in the Grängesberg Iron
project in Sweden, together with
management rights and a right of first refusal to increase its
interest to 100%. Anglesey also holds 12% of Labrador Iron
Mines Holdings Limited, which through its 52% owned subsidiaries,
is engaged in the exploration and development of direct shipping
iron ore deposits in Labrador and
Quebec.
For further information, please
contact:
Anglesey Mining plc
Jo Battershill, Chief Executive –
Tel: +44 (0)7540 366000
John Kearney, Chairman – Tel: +1
416 362 6686
Davy
Nominated Adviser & Joint
Corporate Broker
Brian Garrahy / Daragh O’Reilly –
Tel: +353 1 679 6363
WH Ireland
Joint Corporate Broker
Katy Mitchell / Harry Ansell – Tel: +44 (0) 207 220 1666
LEI: 213800X8BO8EK2B4HQ71