Company: RTNTF
Filing Date: 2025-02-20
Form Type: 20-F
Source: 0001628280-25-006642
Chunk: 525

Company: RIO TINTO LTD
Filing Date: 2025-02-20
Form: 20-F
Chunk 525
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 Mineral Reserves The table on pages 282 - 283 sets out the amount, grade, cut-off grade, price and metallurgical recovery of the Escondida Property’s Proven and Probable Mineral Reserves for the year ended 31 December 2024. Compared to the year ended 31 December 2023, there was less than a 1% increase in Mineral Reserves as at 31 December 2024 due to net impact of depletion offset by increases in mine and processing costs. Material assumptions in the estimation of Mineral Reserves for Escondida are: – The resource model reflects the continuity and complexity of the deposit with the confidence stated in the classification. – Variable cut-off grade strategy that maximises throughput for the concentrator, smelter and refinery. – The point of reference for Mineral Reserves is mine gate. – Escondida Mineral Reserves cut-off criteria used are for Oxide ≥ 0.20% soluble Cu. For Sulphide ≥ 0.30% Cu and where greater than the variable cut-off of the concentrator. Sulphide ore is processed in the concentrator plants as a result of an optimised mine plan with consideration of technical and economic parameters in order to maximise net present value. For Sulphide Leach ≥ 0.25% Cu and 70% or less of copper contained in chalcopyrite and lower than variable cut-off grade. Sulphide leach ore is processed in the leaching plant as an alternative to the concentrator process. – Escondida metallurgical recoveries for Oxide 54%; Sulphide Leach 41%; Sulphide 42% for material processed by leaching or 85% for material processed via the concentrator. – Commodity prices, operating and capital costs. For more information regarding the material assumptions for the Mineral Reserves estimates for Escondida, see Section 12 of Escondida Technical Report Summary filed as exhibit 96.2 to the 2022 Form 20-F . Exploration A total of 2,732km of exploration drilling has been completed (up until December 2023), distributed across 5,978 drill holes for Escondida and distributed across 2,891 drill holes for Escondida Norte. The main objective of the exploration programs implemented at Escondida has been the exploration of new deposits, as well as to improve mineral resources classification to support the annual planning cycle. The results of these programs serve as the basis to support planning and growth