Mineral Resources and Ore Reserves updates

Rio Tinto PLC

19 February 2026

 

Notice to ASX/LSE                                                                                                                       

Mineral Resources and Ore Reserves updates

19 February 2026

Rio Tinto has today announced to the Australian Securities Exchange (ASX) changes in Mineral Resources and Ore Reserves to support its 2025 annual reporting[1], including: 

·      Increased Proved and Probable Ore Reserves and decreased Mineral Resources at the Rio Tinto Copper (RTC) Oyu Tolgoi Oyut open pit deposit in Mongolia.

·      A significant conversion of Mineral Resources to Ore Reserves at the Rio Tinto Copper Kennecott Bingham Canyon open pit deposit in Utah, USA, resulting in a material reduction in reported Mineral Resources.

·      An increase in reported Mineral Resources and Ore Reserves at the Rio Tinto Copper Kennecott Bingham Canyon underground deposit in Utah, USA.

·      Increased Ore Reserves and improved confidence with an associated decrease in Mineral Resources at the Rio Tinto Aluminium (RTA) Pacific Operations Amrun deposit in Queensland, Australia.

·      Increased Mineral Resources and revised classification for the Ore Reserves at Rio Tinto Borates (RTB) Boron deposit.

Supporting information for the changes in 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 2025 Annual Report, to be released to the market on 19 February 2026 (London time), which will set out in full Rio Tinto's Mineral Resources and Ore Reserves position as at 31 December 2025, and Rio Tinto's interests.  

Rio Tinto Copper - Oyu Tolgoi

Mineral Resources and Ore Reserves for the Oyu Tolgoi deposits[2] are presented in Table A and Table B. Proved Ore Reserves have increased by 17 million tonnes (Mt) and Probable Ore Reserves have increased by 63 Mt, for an overall increase in Ore Reserves of 80 Mt (8%). Within the Oyut open pit Proven Ore Reserves have increased by 17 Mt (7%) and Probable Ore Reserves have increased by 61 Mt (17%), for an overall increase of 79 Mt (14%).

There is no material change to Mineral Resources at the Property level. Within the Oyut open pit Measured and Indicated Mineral Resources have increased by 65 Mt (60%), while Inferred Mineral Resources have decreased by 125 Mt (39%) for an overall decrease of 60 Mt (14%).

The material change in both Oyut open pit Ore Reserves and Mineral Resources is largely driven by the Oyut block model update and resulting conversion of Inferred Mineral Resources into Indicated Mineral Resources and subsequently Ore Reserves through increased drilling density and geological confidence, with mining production depletions being the other minor contributing factor.  There has been no material change to other modifying factors, including mine design, governmental, tenure, environmental, cultural heritage or community factors and the methodology for determining Mineral Resources remains unchanged. Note the material variance is solely at the Oyut open pit level, and at Property level there no material change to Mineral Resources or Ore Reserves.

Rio Tinto Copper - Kennecott Bingham Canyon open pit

Mineral Resources and Ore Reserves for the Kennecott Bingham Canyon open pit deposit[3] are presented in Table C and Table D. Measured and Indicated Mineral Resources tonnes have decreased by 63 Mt and Inferred Mineral Resources have increased by 7 Mt for an overall decrease of 56 Mt (74%) as a result of the conversion to Ore Reserves.

Rio Tinto Copper - Kennecott Bingham Canyon underground

Mineral Resources and Ore Reserves for the Kennecott Bingham Canyon underground deposit[4] are presented in Table E and Table F. These Mineral Resources have increased by 32 Mt (122%) and Ore Reserves have increased by 4.0 Mt (85%). These updated Mineral Resources and Ore Reserves reflect increased confidence in the Mineral Resources due to the completion of orebody knowledge drilling, a lower cut-off grade that considers current mining costs, and ongoing experience mining the orebody.

Rio Tinto Aluminium Pacific Operations - Amrun

Mineral Resources and Ore Reserves for the RTA Pacific Operations, including the Amrun deposit[5], are presented in Table G and Table H. The updated Ore Reserves at Amrun reflects a material increase in Ore Reserves, and a material change in Ore Reserve classification. Proved Ore Reserves have increased by 258 Mt (55%), while Probable Ore Reserves have decreased by 161 Mt (31%), for a net increase of 123 Mt (13%), offset by 25 Mt depletion, to a total of 1,076 Mt.  The increase in Ore Reserves has resulted from a routine review of economic assumptions over the life of the mine, and updated orebody knowledge. The change in Ore Reserves classification reflects a higher level of confidence in the modifying factors resulting from increased confidence in the underlying Mineral Resources due to updated orebody knowledge. There has been no material change to other modifying factors, including governmental, tenure, environmental, cultural heritage or community factors. Mineral Resources exclusive of Ore Reserves have decreased by 94 Mt (13%) at Amrun due to the conversion of Mineral Resources to Ore Reserves, updated orebody knowledge and increased resource confidence.

Rio Tinto Borates - Boron

Mineral Resources and Ore Reserves for the RTB Boron Operations[6] are presented in Table I and Table J.  Mineral Resources have increased by 9.3 Mt saleable boric oxide (B₂O₃), reflecting an increase in the level of studies to process mineralised stockpiles. This provides reasonable prospects for eventual economic extraction of the additional material.

Total Ore Reserves (combined Proved and Probable) remain consistent with 2024, with mining depletion of 0.5 Mt B₂O₃ the only change. However, there has been a change in the classification methodology whereby a higher level of geotechnical study is now required for Proved Ore Reserves. Applying this change has converted 1.7 Mt B₂O₃ of Ore Reserves previously classified as Proved Ore Reserves to Probable Ore Reserves. There is no change to level of geotechnical information supporting the Ore Reserves, nor are there changes to any other modifying factors, including governmental, tenure, environmental, cultural heritage or community factors. The result of this change is that Proved Ore Reserves have decreased by 2.2 Mt B₂O₃ and Probable Ore Reserves have increased by 1.7 Mt B₂O₃.

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 19 February 2026 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 Person for the information in the Table 1 Release that relates to Oyu Tolgoi Mineral Resources is Ms Joanna Marshall MAusIMM.  The Competent Person for the information in the Table 1 Release that relates to Oyu Tolgoi Ore Reserves is Mr Nathan Robinson MAusIMM. 

3 The Competent Persons for the information in the Table 1 Release that relates to Kennecott Bingham Canyon open pit Mineral Resources is Mr Gerry Austin MAusIMM and Mr Pancho Rodriguez MAusIMM.  The Competent Person for the information in the Table 1 Release that relates to Kennecott Bingham Canyon open pit Ore Reserves is Mr Eric Hoffmann MAusIMM.

⁴ The Competent Person for the information in the Table 1 Release that relates to Kennecott Bingham Canyon underground Mineral Resources is Mr Ryan Hayes MAusIMM.  The Competent Person for the information in the Table 1 Release that relates to Kennecott Bingham Canyon underground Ore Reserves is Mr Charles McArthur MAusIMM.

⁵ The Competent Person for the information in the Table 1 Release that relates to RTA Pacific Operations Mineral Resources is Mr Angus C. McIntyre MAusIMM.  The Competent Person for the information in the Table 1 Release that relates to RTA Pacific Operations Ore Reserves is Mr William Saba MAusIMM.

⁶ The Competent Person for the information in the Table 1 Release that relates to RTB Boron Mineral Resources and Ore Reserves is Mr Brandon Griffiths who is a Registered Member of the Society for Mining, Metallurgy, and Exploration.

Table A          Rio Tinto Copper Oyu Tolgoi Mineral Resources as at 31 December 2025 

	Likely mining method1	Measured Mineral Resources as at 31 December 2025						Indicated Mineral Resources as at 31 December 2025						Total Measured and Indicated Mineral Resources as at 31 December 2025
		Tonnage	Grade					Tonnage		Grade				Tonnage		Grade
Copper		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
Oyu Tolgoi (Mongolia)2
- Heruga ETG	U/G	-		-	-	-	-	-	-		-	-	-	-	-		-	-	-
- Heruga OT	U/G	-		-	-	-	-	-	-		-	-	-	-	-		-	-	-
- Hugo Dummett North3	U/G	53		1.91	0.50	4.28	-	375	1.39		0.35	-	-	428	1.45		0.37	3.37	-
- Hugo Dummett North Extension	U/G	-		-	-	-	-	83	1.63		0.55	4.21	-	83	1.62		0.55	4.21	-
- Hugo Dummett South	U/G	-		-	-	-	-	-	-		-	-	-	-	-		-	-	-
- Oyut Open Pit	O/P	23		0.41	0.28	1.01	-	150	0.32		0.26	1.07	-	173	0.33		0.27	1.06	-
- Oyut Underground	U/G	12		0.46	0.85	1.24	-	88	0.38		0.55	1.22	-	100	0.39		0.58	1.22	-
Total		87		1.32	0.49	3.02	-	696	1.06		0.38	2.63	-	784	1.09		0.39	2.67	-

	Inferred Mineral Resources as at 31 December 2025					Total Mineral Resources as at 31 December 2025						Rio Tinto interest	Total Mineral Resources as at 31 December 2024
	Tonnage	Grade				Tonnage		Grade					Tonnage		Grade
Copper	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
Oyu Tolgoi (Mongolia)2
- Heruga ETG	1,502	0.41	0.40	1.44	0.012	1,502	0.41		0.40	1.44	0.012	56.0	1,502	0.41		0.40	1.44	0.012
- Heruga OT	107	0.42	0.30	1.58	0.011	107	0.42		0.30	1.58	0.011	66.0	107	0.42		0.30	1.58	0.011
- Hugo Dummett North3	716	0.83	0.29	2.47	-	1,143	1.06		0.32	2.81	-	66.0	1,145	1.06		0.32	2.80	-
- Hugo Dummett North Extension	161	1.04	0.37	2.84	-	244	1.24		0.43	3.31	-	56.0	244	1.24		0.43	3.31	-
- Hugo Dummett South	731	0.83	0.07	1.87	-	731	0.83		0.07	1.87	-	66.0	731	0.83		0.07	1.87	-
- Oyut Open Pit	197	0.28	0.19	1.16	-	370	0.30		0.23	1.11	-	66.0	430	0.30		0.21	1.04	-
- Oyut Underground	117	0.42	0.40	1.15	-	217	0.40		0.48	1.18	-	66.0	203	0.40		0.49	1.23	-
Total	3,530	0.60	0.29	1.78	0.005	4,314	0.69		0.31	1.94	0.004		4,362	0.69		0.31	1.93	0.004

1.   Likely mining method: O/P = open pit/surface.

2.   Copper Mineral Resources are stated on a dry in situ weight basis.

3.   The Hugo Dummett North Mineral Resources include approximately 1.3 million tonnes of stockpiled material at a grade of 0.35% copper, 0.11 g/t gold and 0.85 g/t silver. 

Table B          Rio Tinto Copper Oyu Tolgoi Ore Reserves as at 31 December 2025 

	Type of mine1	Proved Ore Reserves as at 31 December 2025					Probable Ore Reserves as at 31 December 2025					Total Ore Reserves as at 31 December 2025
		Tonnage	Grade				Tonnage	Grade				Tonnage	Grade
Copper2		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
Oyu Tolgoi (Mongolia)
- Hugo Dummett North3	U/G	-	-	-	-	-	374	1.56	0.30	3.20	-	374	1.56	0.30	3.20	-
- Hugo Dummett North Extension	U/G	-	-	-	-	-	36	1.68	0.59	3.96	-	36	1.68	0.59	3.96	-
- Oyut Open Pit	O/P	241	0.54	0.39	-	-	409	0.38	0.26	1.10	-	650	0.44	0.31	1.15	-
- Oyut stockpiles	S/P	-	-	-	-	-	76	0.32	0.13	0.94	-	76	0.32	0.13	0.94	-
Total		241	0.54	0.39	-	-	895	0.92	0.28	2.08	-	1,136	0.84	0.30	1.90	-

	Average mill recovery %				Rio Tinto interest	Rio Tinto share recoverable metal				Total Ore Reserves as at 31 December 2024
										Tonnage		Grade
Copper2	Cu	Au	Ag	Mo	%	Mt Cu	Moz Au	Moz Ag	Mt Mo	Mt	% Cu	g/t Au	g/t Ag	% Mo
Oyu Tolgoi (Mongolia)
- Hugo Dummett North3	92	79	81	-	66.0	3.57	1.88	20.44	-	386	1.58	0.31	3.25	-
- Hugo Dummett North Extension	93	81	84	-	56.0	0.31	0.31	2.13	-	36	1.68	0.60	3.97	-
- Oyut Open Pit	76	67	55	-	66.0	1.43	2.84	8.69	-	571	0.46	0.32	1.22	-
- Oyut stockpiles	71	54	50	-	66.0	0.11	0.12	0.77	-	63	0.31	0.13	0.98	-
Total						5.42	5.14	32.04	-	1,056	0.90	0.31	2.04	-

1.     Type of Mine: O/P = open pit/surface, S/P = stockpile, U/G = underground. 

2.     Copper Ore Reserves are reported as dry mill feed tonnes.

3.     The Hugo Dummett North Ore Reserves include approximately 1.9 million tonnes of stockpiled material at a grade of 0.48% copper, 0.14 g/t gold and 1.18 g/t silver.

Table C          Rio Tinto Copper Kennecott Bingham Canyon open pit Mineral Resources as at 31 December 2025 

Likely mining method(1)

Measured Mineral Resources

Indicated Mineral Resources

Total Measured and Indicated Mineral

as at 31 December 2025

as at 31 December 2025

Resources as at 31 December 2025

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

Kennecott (US)

- Bingham Open Pit (3)

O/P

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

Inferred Mineral Resources

Total Mineral Resources

Rio Tinto interest

Total Mineral Resources

as at 31 December 2025

as at 31 December 2025

as at 31 December 2024

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

Kennecott (US)

- Bingham Open Pit (3)

20

0.13

0.30

2.91

0.008

20

0.13

0.30

2.91

0.008

100.0

76

0.37

0.18

2.65

0.017

1.     Likely mining method: O/P = open pit/surface.

2.     Copper Mineral Resources are stated on a dry in situ weight basis.

Table D          Rio Tinto Copper Kennecott Bingham Canyon open pit Ore Reserves as at 31 December 2025 

Type of mine(1)

Proved Ore Reserves as at 31 December 2025

Probable Ore Reserves as at 31 December 2025

Total Ore Reserves as at 31 December 2025

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

Kennecott (US)

- Bingham Open Pit(3)

O/P

442

0.38

0.18

1.98

0.034

288

0.34

0.19

1.93

0.025

730

0.36

0.18

1.96

0.030

	Average mill recovery %				Rio Tinto interest	Rio Tinto share  recoverable metal				Total Ore Reserves as at 31 December 2024
										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
Kennecott (US)
- Bingham Open Pit(3)	88	68	71	65	100.0	2.35	2.90	32.68	0.14	777	0.36	0.18	1.97	3.34

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 Reserve molybdenum grades interpolated from exploration drilling assays have been factored based on a long reconciliation history to blast hole and mill samples.

Table E          Rio Tinto Copper Kennecott Bingham Canyon underground Mineral Resources as at 31 December 2025 

	Likely mining method(1)	Measured Mineral Resources					Indicated Mineral Resources					Total Measured and Indicated Mineral
		as at 31 December 2025					as at 31 December 2025					Resources as at 31 December 2025
		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
Kennecott (US) - Underground Skarns
- Lower Commercial Skarn	U/G	0.9	1.49	0.62	9.70	0.027	7.2	1.51	0.62	9.53	0.021	8.1	1.51	0.62	9.55	0.022
- North Rim Skarn	U/G	-	-	-	-	-	25	2.06	0.96	12.89	0.008	25	2.06	0.96	12.89	0.008
Total Underground Skarns		0.9	1.49	0.62	9.70	0.027	32	1.94	0.88	12.14	0.011	33	1.93	0.88	12.08	0.011

	Inferred Mineral Resources					Total Mineral Resources					Rio Tinto interest	Total Mineral Resources
	as at 31 December 2025					as at 31 December 2025						as at 31 December 2024
	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
Kennecott (US) - Underground Skarns
- Lower Commercial Skarn	4.5	1.33	0.99	9.15	0.020	13	1.45	0.75	9.41	0.021	100.0	7.5	1.89	0.85	11.26	0.015
- North Rim Skarn	20	2.15	0.82	13.27	0.009	45	2.10	0.90	13.05	0.008	100.0	18	2.92	1.11	15.77	0.007
Total Underground Skarns	24	2.00	0.85	12.51	0.044	58	1.96	0.87	12.26	0.011		26	2.62	1.04	14.47	0.009

1.     Likely mining method: U/G = underground.

2.     Copper Mineral Resources are stated on a dry in situ weight basis.

Table F          Rio Tinto Copper Kennecott Bingham Canyon underground Ore Reserves as at 31 December 2025 

	Type of mine(1)	Proved Ore Reserves as at 31 December 2025					Probable Ore Reserves as at 31 December 2025					Total Ore Reserves as at 31 December 2025
		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
Kennecott (US) - Underground Skarns
- Lower Commercial Skarn	U/G	0.8	1.68	0.59	9.83	0.042	1.2	1.46	0.47	7.23	0.040	2.0	1.54	0.52	8.25	0.040
- North Rim Skarn	U/G	-	-	-	-	-	6.6	2.25	1.29	15.59	0.007	6.6	2.25	1.29	15.59	0.007
Total Underground Skarns		0.8	1.68	0.59	9.83	0.042	7.8	2.13	1.16	14.28	0.012	8.6	2.08	1.11	13.86	0.014

	Average mill recovery %				Rio Tinto interest	Rio Tinto share  recoverable metal				Total Ore Reserves as at 31 December 2024
										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
Kennecott (US) -    Underground Skarns
- Lower Commercial Skarn	90	71	76	71	100.0	0.03	0.02	0.40	0.000	1.7	1.89	0.71		10.01		0.044
- North Rim Skarn	93	69	64	45	100.0	0.14	0.19	2.13	0.001	3.0	2.39	1.77		16.66		0.010
Total Underground Skarns						0.17	0.21	2.54	0.001	4.7	2.21	1.39		14.30		0.022

1.     Type of Mine: U/G = underground. 

2.     Copper Ore Reserves are reported as dry mill feed tonnes.

Table G         Rio Tinto Aluminium Pacific Operations Mineral Resources as at 31 December 2025 

	Likely mining method(1)	Measured Mineral Resources			Indicated Mineral Resources			Total Measured and Indicated Mineral
		as at 31 December 2025			as at 31 December 2025			Resources as at 31 December 2025
		Tonnage	Grade		Tonnage	Grade		Tonnage	Grade
Bauxite		Mt	% Al2O3	% SiO2	Mt	% Al2O3	% SiO2	Mt	% Al2O3	% SiO2
Rio Tinto Aluminium (Australia)
- Amrun(2)	O/P	143	48.9	11.7	276	49.6	12.0	419	49.4	11.9
- East Weipa and Andoom(2)	O/P	32	48.0	9.0	-	-	-	32	48.0	9.0
- Gove(3)	O/P	9	47.6	8.8	0.1	49.0	7.6	9	47.6	8.8
- North of Weipa(3)	O/P	-	-	-	212	51.9	11.3	212	51.9	11.3
Total (Australia)		183	48.7	11.1	488	50.6	11.7	671	50.1	11.5

	Inferred Mineral Resources			Total Mineral Resources			Rio Tinto interest	Total Mineral Resources
	as at 31 December 2025			as at 31 December 2025				as at 31 December 2024
	Tonnage	Grade		Tonnage	Grade			Tonnage	Grade
Bauxite	Mt	% Al2O3	% SiO2	Mt	% Al2O3	% SiO2	%	Mt	% Al2O3	% SiO2
Rio Tinto Aluminium (Australia)
- Amrun(2)	234	51.4	12.4	653	50.1	12.1	100.0	747	50.1	12.0
- East Weipa and Andoom(2)	-	-	-	32	48.0	9.0	100.0	36	48.0	8.9
- Gove(3)	-	-	-	9	47.6	8.8	100.0	10	47.7	9.0
- North of Weipa(3)	1,179	51.8	11.3	1,391	51.9	11.4	100.0	1,451	51.9	11.4
Total (Australia)	1,412	51.7	11.5	2,083	51.2	11.5		2,244	51.3	11.6

1.   Likely mining method: O/P = open pit/surface.

2.   Bauxite Mineral Resources for Amrun and East Weipa and Andoom are stated as dry product tonnes and total alumina and silica grades.

3.   Bauxite Mineral Resources for Gove and North of Weipa are stated as dry crude tonnes and total alumina and silica grades.

Table H          Rio Tinto Aluminium Pacific Operations Ore Reserves as at 31 December 2025

	Type of mine(1)	Proved Ore Reserves			Probable Ore Reserves			Total Ore Reserves
		as at 31 December 2025			as at 31 December 2025			as at 31 December 2025
		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	724	54.1	9.0	351	54.5	9.4	1,076	54.2	9.1
- East Weipa and Andoom	O/P	44	50.3	8.4	1	49.5	9.9	45	50.3	8.4
- Gove	O/P	35	50.1	6.7	5	49.9	6.9	40	50.1	6.7
Total (Australia)		803	53.7	8.8	357	54.4	9.4	1,161	53.9	9.0

	Rio Tinto interest	Rio Tinto share recoverable mineral		Total Ore Reserves as at 31 December 2024
				Tonnage	Grade
Bauxite(2)	%	Mt		Mt	% Al2O3	% SiO2
Rio Tinto Aluminium (Australia)(3)
- Amrun	100.0	1,076		978	54.4	9.0
- East Weipa and Andoom	100.0	45		56	50.5	8.1
- Gove	100.0	40		48	50.0	6.4
Total (Australia)	100.0	1,161		1,083	54.0	8.8

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 I           Rio Tinto Borates Boron Mineral Resources as at 31 December 2025 

	Likely mining method1	Measured Mineral Resources	Indicated Mineral Resources	Total Measured and Indicated Mineral
		as at 31 December 2025	as at 31 December 2025	Resources as at 31 December 2025
		Tonnage	Tonnage	Tonnage
Borates		Mt	Mt	Mt
Boron (US)2	O/P	2.4	1.1	3.5

	Inferred Mineral Resources	Total Mineral Resources	Rio Tinto interest	Total Mineral Resources
	as at 31 December 2025	as at 31 December 2025		as at 31 December 2024
	Tonnage	Tonnage		Tonnage
Borates	Mt	Mt	%	Mt
Boron (US)2	5.8	9.3	100.0	-

1.     Likely mining method: O/P = open pit/surface.

2.     Boron Mineral Resources are reported as dry mineable B₂O₃ tonnes incorporating a mining recovery, rather than marketable product as in Ore Reserves.

Table J          Rio Tinto Borates Boron Operations Ore Reserves as at 31 December 2025 

	Type of mine1	Proved Ore Reserves	Probable Ore Reserves	Total Ore Reserves
		as at 31 December 2025	as at 31 December 2025	as at 31 December 2025
		Tonnage	Tonnage	Tonnage
Borates		Mt	Mt	Mt
Boron (US)2	O/P	5.0	7.0	12.0

	Rio Tinto interest	Rio Tinto share marketable product		Total Ore Reserves as at 31 December 2024
				Tonnage
Borates	%	Mt		Mt
Boron (US)2	100.0	12.0		12.6

1.     Type of Mine: O/P = open pit/surface. 

2.     Ore Reserves of borates are expressed in terms of marketable product (B₂O₃) tonnes after all mining and processing losses. Mill recoveries are therefore not shown.

Contacts

Please direct all enquiries to [e-mail]

Media Relations, United Kingdom Matthew Klar  M [phone]  David Outhwaite M [phone]	Media Relations, Australia Matt Chambers M [phone] Alyesha Anderson M [phone] Rachel Pupazzoni M [phone] Bruce Tobin   M [phone]	Media Relations, Canada Simon Letendre M [phone] Malika Cherry M [phone] Vanessa Damha M [phone] Media Relations, US & Latin America Jesse Riseborough  M [phone]
Investor Relations, United Kingdom Rachel Arellano M [phone] David Ovington M [phone] Laura Brooks   M [phone]  Weiwei Hu   M [phone]	Investor Relations, Australia Tom Gallop M [phone] Eddie Gan-Och  M [phone]
Rio Tinto plc 6 St James's Square London SW1Y 4AD United Kingdom T [phone] Registered in England No. 719885	Rio Tinto Limited Level 43, 120 Collins Street Melbourne 3000 Australia T [phone] Registered in Australia ABN 96 004 458 404

This announcement is authorised for release to the market by Andy Hodges, Rio Tinto's Group Company Secretary.

riotinto.com

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