Management of mine sites after closure

Authors: Bocking, KA; Kam, SN; Welch, DE; Williams, DA Download Paper

DOI https://doi.org/10.36487/ACG_repo/908_17

Cite As:
Bocking, KA, Kam, SN, Welch, DE & Williams, DA 2009, 'Management of mine sites after closure', in AB Fourie & M Tibbett (eds), Mine Closure 2009: Proceedings of the Fourth International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 245-252, https://doi.org/10.36487/ACG_repo/908_17



Abstract:
The ideal outcome for mine closure measures is a walk-away scenario, with all hazards and liabilities resolved and with the land returned to beneficial use. Unfortunately, in the majority of cases, this ideal is not practicably attainable. After a mining company makes large capital expenditures and completes its agreed closure measures, it may still have ongoing obligations, liabilities and risks. These could include: post- closure inspections and reporting, routine care and maintenance, and in some cases, ongoing treatment of effluent. In addition, there may also be residual hazards to the public, safety concerns related to, for example, unstable crown pillars or open pit slopes as well as a risk of failures due to long return period events, such as floods and earthquakes. Uncertainties will also remain regarding the performance of the long-term closure measures. There may also be unresolved liabilities requiring financial reporting and costs associated with ongoing beneficial use of the land. If, alternatively, the mining lease is returned to the government, there may be a requirement for a lump sum payment to cover future costs associated with the unresolved liabilities. It is possible to estimate the aggregate cost of these unresolved post-closure liabilities using risk modelling. The risk cost could then form the basis for the following alternative approaches for managing mining properties after closure: • Retaining the property and establishing internal funding to pay for future costs and risks. • Returning the mining lease to the government, with a payment to cover the future costs and residual risks. • Transferring the ownership to a special purpose company and purchasing insurance against the residual liabilities on the property. • Transferring some of the assets to a local community or government with some arrangement to cover costs of future maintenance and risks.

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