Company: RTNTF
Filing Date: 2025-02-20
Form Type: 20-F
Source: 0001628280-25-006642
Chunk: 347

Company: RIO TINTO LTD
Filing Date: 2025-02-20
Form: 20-F
Chunk 347
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closure while the operation as a whole is in production.–The length of any post-closure monitoring period. This will depend on the specific site requirements and the availability of alternativecommercial arrangements; some expenditure can continue into perpetuity. The Rio Tinto Kennecott closure and environmentalremediation provision includes an allowance for ongoing monitoring and remediation costs, including groundwater treatment, ofapproximatelyUS$0.7billion.–The probability weighting of possible closure scenarios. The most significant impact of probability weighting is at the Pilbara operations (IronOre) relating to infrastructure, and incorporates the expectation that some infrastructure will be retained by the relevant State authorities postclosure. The assignment of probabilities to this scenario reduces the closure provision byUS$0.5billion.–Appropriate sources on which to base the calculation of the discount rate. The discount rate, by nature, is subjective and thereforesensitivities are shown below for how the provision balance, which at31 December 2024wasUS$15,731million, would change ifdiscounted at alternative discount rates.There is significant estimation uncertainty in the calculation of the provision and cost estimates can vary in response to manyfactors including:–changes to the relevant legal or local/national government requirements and any other commitments made to stakeholders–review of remediation and relinquishment options–additional remediation requirements identified during the rehabilitation–the emergence of new restoration techniques–precipitation rates and climate change–change in foreign exchange rates–change in the expected closure date–change in the discount rate.Experience gained at other mine or production sites may also change expected methods or costs of closure, although elements of therestoration and rehabilitation can be unique to each site. Generally, there is relatively limited restoration and rehabilitation activity andhistorical precedent elsewhere in the Group, or in the industry as a whole, against which to benchmark cost estimates.The expected timing of expenditure can also change for other reasons, for example because of changes to expectations relating to OreReserves and Mineral Resources, production rates, renewal of operating licences or economic conditions.Changes in closure cost estimates at the Group’s ongoing operations could result in a material adjustment to assets and liabilities in the next12 months and would also impact the depreciation and the unwinding of discount in future years.Changes to closure cost estimates for closed operations, and changes to environmental cost estimates at any operation, could cause amaterial adjustment to the income statement and closure liability. We do not consider that there is significant risk of a change in estimates forthese liabilities causing a material adjustment to