Notice to
ASX/LSE
Mineral Resources and Ore Reserves updates
21 February 2024
Rio Tinto has today announced to the
Australian Securities Exchange (ASX) changes in Mineral Resources
and Ore Reserves to support its 2023 annual
reporting[1],
including:
· Decreased Mineral Resources at the Rio Tinto Kennecott (RTK)
Bingham Canyon open pit deposit in Utah, United States of
America.
· Increased Ore Reserves and associated decreased Mineral
Resources at the Rio Tinto Aluminium (RTA) Pacific Operations Amrun
deposit in Queensland, Australia.
· Revised classification for the Ore Reserves at the
Iron Ore Company of Canada (IOC)
operations in Newfoundland and Labrador,
Canada.
Supporting information relating to
the changes of Mineral Resources and Ore Reserves is set out in the
Table 1 Release and its appendices. This release provides a summary
of those changes. Mineral Resources and Ore Reserves are
quoted in this release on a 100 percent basis. Mineral Resources
are reported in addition to Ore Reserves. The figures used to
calculate Mineral Resources and Ore Reserves are often more precise
than the rounded numbers shown in the tables, hence small
differences may result if the calculations are repeated using the
tabulated figures.
These changes will be included in
Rio Tinto's 2023 Annual Report, to be released to the market on 21
February 2024, which will set out in full Rio Tinto's Mineral
Resources and Ore Reserves position as at 31 December 2023, and Rio
Tinto's interests.
Rio
Tinto Kennecott
Mineral Resources and Ore Reserves
for the RTK Bingham Canyon open pit are presented in
Table A and
Table B[2]. Mineral Resources tonnes have
decreased by 21 Mt (22%) as a result of the conversion of the East
Wall Extension to Ore Reserves and removal of an opportunity to
steepen the South Wall due to geotechnical concerns and changes to
economic assumptions. There is an associated increase in Ore
Reserves as a result of the East Wall conversion, which has been
offset by depletion.
Rio
Tinto Aluminium Pacific Operations - Amrun
Mineral Resources and Ore Reserves
for the RTA Amrun deposit are presented in Table C and Table D[3]. Mineral
Resources exclusive of Ore Reserves have decreased by 55 Mt (7%) at
Amrun due to conversion of Mineral Resources to Ore Reserves
resulting from a routine review of price assumptions over the life
of the mine, and updated orebody knowledge.
Ore Reserves have increased by 149
Mt (19%) at Amrun. The increase in Ore Reserves is associated with
a routine review of price assumptions over the life of the mine,
and updated orebody knowledge. There has been no material
change to other modifying factors, including governmental, tenure,
environmental, cultural heritage, community or
operational.
Iron Ore Company of Canada
Mineral Resources and Ore Reserves
for IOC are presented in Table E
and Table
F[4]. The
classification of the Ore Reserves has changed as a result
of reclassification of a significant
proportion of the Proved Ore Reserves to Probable Ore Reserves. The
change reflects a lower level of confidence in the modifying
factors in areas supported by older data which does not have
recovery and grind energy geometallurgical data.
Table A
Rio Tinto Kennecott Copper Bingham Canyon open pit Mineral
Resources as at 31 December 2023
|
|
Likely
mining
method(1)
|
Measured Mineral Resources
|
Indicated Mineral
Resources
|
Total Measured and Indicated
Mineral
|
|
|
as at 31 December 2023
|
|
|
as at 31 December 2023
|
|
Resources as at 31 December
2023
|
|
|
Tonnage
|
Grade
|
|
|
|
Tonnage
|
Grade
|
|
|
|
Tonnage
|
Grade
|
|
|
|
|
Copper(2)
|
|
Mt
|
%
Cu
|
g/t
Au
|
g/t
Ag
|
%
Mo
|
Mt
|
%
Cu
|
g/t
Au
|
g/t
Ag
|
%
Mo
|
Mt
|
%
Cu
|
g/t
Au
|
g/t
Ag
|
%
Mo
|
|
Bingham Canyon (US)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- Bingham Open
Pit(3)
|
O/P
|
38
|
0.47
|
0.15
|
2.47
|
0.020
|
22
|
0.39
|
0.16
|
2.66
|
0.016
|
59
|
0.44
|
0.15
|
2.54
|
0.018
|
|
|
Inferred Mineral Resources
|
Total Mineral Resources
|
Rio Tinto
interest
|
Total Mineral Resources
|
|
|
|
|
as at 31 December 2023
|
|
|
as
at 31 December 2023
|
as at 31 December 2022
|
|
|
Tonnage
|
Grade
|
|
|
|
Tonnage
|
Grade
|
|
|
|
|
Tonnage
|
Grade
|
|
|
|
|
Copper(2)
|
Mt
|
%
Cu
|
g/t
Au
|
g/t
Ag
|
%
Mo
|
Mt
|
% Cu
|
g/t Au
|
g/t Ag
|
% Mo
|
%
|
Mt
|
%
Cu
|
g/t
Au
|
g/t
Ag
|
%
Mo
|
|
Bingham Canyon (US)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- Bingham Open
Pit(3)
|
12
|
0.26
|
0.20
|
2.56
|
0.005
|
72
|
0.41
|
0.16
|
2.55
|
0.016
|
100.0
|
93
|
0.43
|
0.15
|
2.24
|
0.016
|
1. Likely mining method:
O/P = open pit/surface.
2. Copper Mineral Resources are reported on a dry in situ weight
basis.
3. Bingham Canyon Open Pit Mineral Resources molybdenum grades
interpolated from exploration drilling assays have been factored
based on a long reconciliation history to blast hole and mill
samples.
Table B
Rio Tinto Kennecott Copper Bingham Canyon open pit Ore Reserves as
at 31 December 2023
|
|
Type
of
mine(1)
|
Proved Ore Reserves
|
Probable Ore Reserves
|
|
|
Total Ore Reserves
|
|
|
as at 31 December 2023
|
|
|
as at 31 December 2023
|
|
as
at 31 December 2023
|
|
|
|
Tonnage
|
Grade
|
|
|
|
Tonnage
|
Grade
|
|
|
|
Tonnage
|
Grade
|
|
|
|
|
Copper(2)
|
|
Mt
|
%
Cu
|
g/t
Au
|
g/t
Ag
|
%
Mo
|
Mt
|
%
Cu
|
g/t
Au
|
g/t
Ag
|
%
Mo
|
Mt
|
% Cu
|
g/t Au
|
g/t Ag
|
% Mo
|
|
Bingham Canyon (US)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- Bingham Open
Pit(3)
|
O/P
|
470
|
0.37
|
0.18
|
1.98
|
0.038
|
360
|
0.36
|
0.18
|
1.98
|
0.028
|
829
|
0.37
|
0.18
|
1.98
|
0.033
|
|
|
Average mill recovery %
|
Rio Tinto
interest
|
Rio
Tinto share
|
|
|
|
Total Ore Reserves
|
|
|
|
recoverable metal
|
|
|
as at 31 December 2022
|
|
|
|
|
|
|
|
|
Tonnage
|
Grade
|
|
|
|
|
Copper(2)
|
Cu
|
Au
|
Ag
|
Mo
|
%
|
Mt Cu
|
Moz Au
|
Moz Ag
|
Mt Mo
|
|
Mt
|
%
Cu
|
g/t
Au
|
g/t
Ag
|
%
Mo
|
|
Bingham Canyon (US)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
- Bingham Open
Pit(3)
|
89
|
69
|
71
|
63
|
100.0
|
2.681
|
3.257
|
37.686
|
0.176
|
|
880
|
0.38
|
0.18
|
1.97
|
0.033
|
1. Type of Mine:
O/P = open pit/surface.
2. Copper Ore Reserves
are reported as dry mill feed tonnes.
3. Bingham Canyon Open
Pit Ore Reserves molybdenum grades interpolated from exploration
drilling assays have been factored based on a long reconciliation
history to blast hole and mill samples.
Table C
Rio Tinto Aluminium Pacific Operations Mineral Resources as at 31
December 2023
|
|
Likely
mining
method(1)
|
Measured Mineral Resources
|
Indicated Mineral
Resources
|
Total Measured and Indicated
Mineral
|
|
|
as at 31 December 2023
|
as at 31 December 2023
|
Resources as at 31 December
2023
|
|
|
Tonnage
|
Grade
|
|
Tonnage
|
Grade
|
|
Tonnage
|
Grade
|
|
|
Bauxite
|
|
Mt
|
%
Al2O3
|
%
SiO2
|
Mt
|
%
Al2O3
|
%
SiO2
|
Mt
|
%
Al2O3
|
%
SiO2
|
|
Rio Tinto Aluminium
(Australia)(2)
|
|
|
|
|
|
|
|
|
|
|
|
- Amrun
|
O/P
|
115
|
49.2
|
11.7
|
388
|
49.7
|
11.7
|
504
|
49.6
|
11.7
|
|
- East Weipa and Andoom
|
O/P
|
43
|
49.9
|
8.8
|
-
|
-
|
-
|
43
|
49.9
|
8.8
|
|
- Gove
|
O/P
|
9
|
48.1
|
8.9
|
0.4
|
47.8
|
8.9
|
9
|
48.1
|
8.9
|
|
- North of Weipa
|
O/P
|
-
|
-
|
-
|
202
|
52.0
|
11.1
|
202
|
52.0
|
11.1
|
|
Total (Australia)
|
|
167
|
49.3
|
10.8
|
591
|
50.5
|
11.5
|
759
|
50.2
|
11.4
|
|
|
Inferred Mineral Resources
|
Total Mineral Resources
|
Rio
Tinto
interest
|
Total Mineral Resources
|
|
|
as at 31 December 2023
|
as
at 31 December 2023
|
as at 31 December 2022
|
|
|
Tonnage
|
Grade
|
|
Tonnage
|
Grade
|
|
|
Tonnage
|
Grade
|
|
|
Bauxite
|
Mt
|
%
Al2O3
|
%
SiO2
|
Mt
|
%
Al2O3
|
%
SiO2
|
%
|
Mt
|
%
Al2O3
|
%
SiO2
|
|
Rio Tinto Aluminium
(Australia)(2)
|
|
|
|
|
|
|
|
|
|
|
|
- Amrun
|
285
|
51.7
|
12.1
|
788
|
50.4
|
11.9
|
100.0
|
843
|
50.6
|
11.8
|
|
- East Weipa and Andoom
|
-
|
-
|
-
|
43
|
49.9
|
8.8
|
100.0
|
53
|
49.3
|
8.5
|
|
- Gove
|
0.01
|
46.9
|
8.1
|
9
|
48.1
|
8.9
|
100.0
|
13
|
48.3
|
9.0
|
|
- North of Weipa
|
1,248
|
51.8
|
11.4
|
1,451
|
51.9
|
11.4
|
100.0
|
1,330
|
52.0
|
11.6
|
|
Total (Australia)
|
1,533
|
51.8
|
11.5
|
2,291
|
51.3
|
11.5
|
|
2,240
|
51.4
|
11.6
|
1. Likely mining method:
O/P = open pit/surface.
2. Rio Tinto Aluminium
bauxite Mineral Resources are stated as dry product tonnes and
total alumina and silica grades.
Table D
Rio Tinto Aluminium Pacific Operations Ore Reserves as at 31
December 2023
|
|
Type
of
mine(1)
|
Proved Ore Reserves
|
Probable Ore Reserves
|
Total Ore Reserves
|
|
|
as at 31 December 2023
|
as at 31 December 2023
|
as
at 31 December 2023
|
|
|
Tonnage
|
Grade
|
|
Tonnage
|
Grade
|
|
Tonnage
|
Grade
|
|
|
Bauxite(2)
|
|
Mt
|
%
Al2O3
|
%
SiO2
|
Mt
|
%
Al2O3
|
%
SiO2
|
Mt
|
% Al2O3
|
% SiO2
|
|
Rio Tinto Aluminium
(Australia)(3)
|
|
|
|
|
|
|
|
|
|
|
|
- Amrun
|
O/P
|
263
|
53.9
|
9.2
|
688
|
54.5
|
9.0
|
950
|
54.3
|
9.1
|
|
- East Weipa and Andoom
|
O/P
|
69
|
50.5
|
7.9
|
3
|
49.5
|
8.7
|
72
|
50.5
|
8.0
|
|
- Gove
|
O/P
|
57
|
50.2
|
6.4
|
0.7
|
50.5
|
5.0
|
58
|
50.2
|
6.4
|
|
Total (Australia)
|
|
388
|
52.8
|
8.6
|
692
|
54.4
|
9.0
|
1,080
|
53.8
|
8.8
|
|
|
Rio Tinto interest
|
Rio
Tinto share recoverable mineral
|
|
Total Ore Reserves as at 31 December
2022
|
|
|
|
|
Tonnage
|
Grade
|
|
|
Bauxite(2)
|
%
|
Mt
|
|
Mt
|
%
Al2O3
|
%
SiO2
|
|
Rio Tinto Aluminium
(Australia)(3)
|
|
|
|
|
|
|
|
- Amrun
|
100.0
|
950
|
|
801
|
54.6
|
8.9
|
|
- East Weipa and Andoom
|
100.0
|
72
|
|
59
|
51.7
|
7.1
|
|
- Gove
|
100.0
|
58
|
|
56
|
50.5
|
5.8
|
|
Total (Australia)
|
100.0
|
1,080
|
|
916
|
54.2
|
8.6
|
1. Type of
Mine: O/P = open pit/surface.
2. Bauxite
Ore Reserves are stated as recoverable Ore Reserves of marketable
product after accounting for all mining and processing losses. Mill
recoveries are therefore not shown.
3.
Australian bauxite Ore Reserves are stated as dry tonnes and total
alumina and silica grade.
Table E
Iron Ore Company of Canada Mineral Resources as at 31 December
2023
|
|
Likely
mining
method(1)
|
Measured Mineral Resources
|
Indicated Mineral
Resources
|
Total Measured and Indicated
Mineral
|
|
|
as at 31 December 2023
|
|
|
as at 31 December 2023
|
|
Resources as at 31 December
2023
|
|
|
Tonnage
|
Grade
|
|
|
|
Tonnage
|
Grade
|
|
|
|
Tonnage
|
Grade
|
|
|
|
|
Iron
ore(2)
|
|
Mt
|
%
Fe
|
%
SiO2
|
%
Al2O3
|
%
P
|
Mt
|
%
Fe
|
%
SiO2
|
%
Al2O3
|
%
P
|
Mt
|
%
Fe
|
%
SiO2
|
%
Al2O3
|
%
P
|
|
Iron Ore Company of Canada
(Canada)(3)
|
O/P
|
171
|
40.8
|
35.8
|
0.2
|
0.02
|
720
|
38.5
|
37.1
|
0.2
|
0.03
|
891
|
38.9
|
36.9
|
0.2
|
0.03
|
|
|
Inferred Mineral Resources
|
Total Mineral Resources
|
Rio Tinto
interest
|
Total Mineral Resources
|
|
|
|
|
as at 31 December 2023
|
|
|
as
at 31 December 2023
|
as at 31 December 2022
|
|
|
Tonnage
|
Grade
|
|
|
|
Tonnage
|
Grade
|
|
|
|
|
Tonnage
|
Grade
|
|
|
|
|
Iron
ore(2)
|
Mt
|
%
Fe
|
%
SiO2
|
%
Al2O3
|
%
P
|
Mt
|
% Fe
|
%
SiO2
|
%
Al2O3
|
% P
|
%
|
Mt
|
%
Fe
|
%
SiO2
|
%
Al2O3
|
%
P
|
|
Iron Ore Company of Canada
(Canada)(3)
|
751
|
38.2
|
35.7
|
0.2
|
0.03
|
1,641
|
38.6
|
36.3
|
0.2
|
0.03
|
58.7
|
1,666
|
38.7
|
37.4
|
0.2
|
0.03
|
1. Likely
mining method: O/P = open pit/surface.
2. Iron ore
Mineral Resources are stated on a dry in situ weight
basis.
3. The
reported Mineral Resources have the potential to produce marketable
product (57% pellets and 43% concentrate for sale at a natural
moisture content of 2%) comprising 73 million tonnes at 65% iron
2.7% silica (Measured), 301 million tonnes at 65% iron 2.7% silica
(Indicated) and 308 million tonnes at 65% iron 2.7% silica
(Inferred) using process recovery factors derived from current IOC
concentrating and pellet operations. LOI is not determined for
resource drilling samples, so no estimate of % LOI is available for
Mineral Resources.
Table F
Iron Ore Company of Canada Ore Reserves as at 31 December
2023
|
|
Type
of
mine(1)
|
Proved Ore reserves
|
Probable Ore Reserves
|
Total Ore Reserves
|
|
|
as at 31 December 2023
|
as at 31 December 2023
|
as
at 31 December 2023
|
|
|
Tonnage
|
Grade
|
|
Tonnage
|
Grade
|
|
Tonnage
|
Grade
|
|
|
Iron
ore(2)
|
|
Mt
|
%
Fe
|
%
SiO2
|
Mt
|
%
Fe
|
%
SiO2
|
Mt
|
% Fe
|
%
SiO2
|
|
Iron Ore Company of Canada
(Canada)(3)
|
O/P
|
149
|
65.0
|
2.8
|
275
|
65.0
|
2.8
|
423
|
65.0
|
2.8
|
|
|
Rio
Tinto
interest
|
Rio
Tinto share
|
|
Total Ore Reserves
|
|
|
marketable product
|
|
as at 31 December 2022
|
|
|
|
|
Tonnage
|
Grade
|
|
|
Iron
ore(2)
|
%
|
Mt
|
|
Mt
|
%
Fe
|
%
SiO2
|
|
Iron Ore Company of Canada
(Canada)(3)
|
58.7
|
249
|
|
453
|
65.0
|
3.0
|
1. Type of Mine: O/P =
open pit/surface.
2. Ore Reserves of iron
ore are shown as recoverable Ore Reserves of marketable product
after accounting for all mining and processing losses. Mill
recoveries are therefore not shown.
3. Iron Ore Company of
Canada Ore Reserves are reported as marketable product (57% pellets
and 43% concentrate for sale) at a natural moisture content of 2%.
The marketable product is derived from mined material comprising
357 million dry tonnes at 38% iron, 36% silica, 0.23% alumina,
0.022% phosphorus (Proved) and 651 million dry tonnes at 38% iron,
35% silica, 0.19% alumina, 0.023% phosphorus (Probable) using
process recovery factors derived from current IOC concentrating and
pellet operations. No meaningful relationship has been established
between the product and feed grades of alumina and phosphorus, so
these grades cannot be reported for Ore Reserves. Saleable product
is produced to meet silica grade specifications, so the Ore
Reserves silica grade is the targeted silica grade for the
currently anticipated long-term product mix. Loss on Ignition (LOI)
is not determined for resource drilling samples, so no estimate of
% LOI is available for Ore Reserves.
[1] These Mineral
Resources and Ore Reserves were reported in accordance with the
Australasian Code for Reporting of Exploration Results, Mineral
Resources and Ore Reserves, 2012 (JORC Code) and the ASX Listing
Rules in a release to the ASX dated 21 February 2024 titled "Ore
Reserve and Mineral Resource updates: supporting information and
Table 1 checklists" (Table 1 Release). Rio Tinto confirms that it
is not aware of any new information or data that materially affects
the information included in the Table 1 Release, that all material
assumptions and technical parameters underpinning the estimates in
the Table 1 Release continue to apply and have not materially
changed, and that the form and context in which the Competent
Persons' findings are presented have not been materially
modified.
[2] The Competent
Persons responsible for the information in the Table 1 Release that
relates to Rio Tinto Kennecott Mineral Resources were Pancho
Rodriguez and Ana Chiquini, who are Members of the Australasian
Institute of Mining and Metallurgy (MAusIMM). The Competent Person
responsible for the information in the Table 1 Release that relates
to Rio Tinto Kennecott Ore Reserves is Brady Pett
(MAusIMM).
[3] The Competent
Person responsible for the information in the Table 1 Release that
relates to Rio Tinto Aluminium Pacific Operations Mineral Resources
is Angus Mc Intyre (MAusIMM). The Competent Person responsible for
the information in the Table 1 Release that relates to Rio Tinto
Aluminium Pacific Operations Ore Reserves is William Saba
(MAusIMM).
[4] The Competent
Persons responsible for the information in the Table 1 Release that
relates to Iron Ore Company of Canada Mineral Resources were Ramsey
Way, Mervin McDonald and Beverly Power, who are Members of
Professional Engineers and Geoscientists of Newfoundland and
Labrador. The Competent Persons responsible for the information in
the Table 1 Release that relates to Iron Ore Company of Canada Ore
Reserves were Rodney Williams and Stéphane Roche, who are Members
of Professional Engineers and Geoscientists of Newfoundland and
Labrador.