Company: RTNTF
Filing Date: 2025-02-20
Form Type: 20-F
Source: 0001628280-25-006642
Chunk: 441

Company: RIO TINTO LTD
Filing Date: 2025-02-20
Form: 20-F
Chunk 441
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 in Mineral Reserves. 3. Jadar equivalent dry in situ Mineral Resources comprise of 85 million tonnes at 16.1% B 2 O 3 (Indicated) and 58.0 million tonnes at 12.0% B 2 O 3 (Inferred). 4. Jadar Mineral Resources valuations are based on commodity prices of US$19.439/t for lithium carbonate and US$1,495/t for boric acid. These prices were sourced from CRU. 5. Diamond and lithium Mineral Resources are stated as dry in situ tonnes. 6. Diavik Mineral Resources valuations are based on a 3-year trailing average price of US$106.12/ct. 7. Lithium brine Mineral Resources are reported in situ and both inclusive and exclusive of Mineral Reserves. It should be noted that for other commodities Rio Tinto normally reports Mineral Resources exclusive of Mineral Reserves, but such methodology is not considered appropriate for lithium brines. However the SEC SK-1300 reporting requirements require Mineral Resources to be reported exclusive of Mineral Reserves and as such this methodology is also presented. The exclusive Mineral Resources volumes are calculated by subtracting the extracted Measured volumes from the in situ Measured volumes and the extracted Indicated volumes from the in situ Indicated volumes. Inferred volumes are not modified. The exclusive Mineral Resources grades were calculated by back-calculating the average lithium grade after mining based on the lithium mass after mining and the total brine volume prior to mining (to account for zones with dilute concentrations in the total brine volume). It is noted that the average lithium grade after mining is highly uncertain due to the dynamic nature of the brine system. 8. Rincon Mineral Resources lithium metal and LCE tonnages are in situ values assuming 100% recovery as per standard brine reporting practices. To obtain the equivalent tonnage for LCE, the estimated mass of lithium was multiplied by a factor that is based on the atomic weights of each element in lithium carbonate to obtain the final compound weight. The factor used was 5.322785 to obtain LCE mass from lithium mass. 9. Rincon Mineral Resources valuations are based on a lithium carbonate price of US$19,439/t. This price was sourced from CRU.

| Annual Report on Form 20-F 2024 | 299 | riotinto.com |

Production, Mineral Reserves, Mineral Resources and operations | Mineral Resources

| Total Measured and