Reimagining mine closure

Authors: Werner, P Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2315_072

Cite As:
Werner, P 2023, 'Reimagining mine closure', in B Abbasi, J Parshley, A Fourie & M Tibbett (eds), Mine Closure 2023: Proceedings of the 16th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, https://doi.org/10.36487/ACG_repo/2315_072



Abstract:
The legacy of mining in the U.S.A. is littered with environmental hazards and a crushing public financial burden as many closed mine sites carry residual environmental risk long after mining has ended. The 2020 report to Congress on Abandoned Hard Rock Mines (GAO-20-238) carries some alarming statistics on the state of abandoned mines on public lands and the potential liabilities they pose to the environment, public health and safety, and the American taxpayer. In short, approximately USD 3B has been spent by federal agencies on abandoned mine work between 2008 and 2017, with annual expenditures running close to USD 300M. Future costs for managing abandoned mine sites will run billions more. Many of these abandoned sites pre-date modern mining regulations when little to no reclamation was required; however, for current and future mining operations, we have the tools to prevent, or at least minimize, the financial burden from their default and abandonment. Most current federal mining regulations require a reclamation performance bond whose purpose is to place the responsibility for reclamation on the operator. Federal regulations, however, fall short of anticipating how a reclaimed landscape may perform over time. The public, including investors, are demanding responsible land stewardship from mining companies, and the ESG movement has provoked an awareness of the burden and impacts, both short-term and long-term, from these mining operations. To remain competitive, mining companies must address how to resolve the long-term impacts of their operations and pivot from doing the bare minimum that the regulations require. Enlightened mine closure in the 21st century must include long-term care and maintenance provisions to avoid further system failures. Responsible closure planning requires a shift away from an approach based on engineering time and towards one acknowledging that many closed mine facilities may need to remain functional far into the future. Identifying the reclaimed mine features most susceptible to failure is not always apparent, and evaluating how this residual risk may manifest itself requires a thoughtful and transparent approach. Arriving at a reasonable cost for reclamation, and more importantly, any attendant long-term care and maintenance requirements, can be difficult as this type of exercise requires one to make projections of future needs based on incomplete information. What follows is a reimagination of how we should approach future mine reclamation that is predicated on the premise that mining creates new landforms, some with significant residual risk, that will evolve over time in tandem with the surrounding landscape. The current federal mining regulations fail to account for this temporal reality, and our natural inclination towards optimism bias when it comes to evaluating potential risks makes the current approach to mine reclamation susceptible to failure. Simple risk analysis tools can aid in identifying how these artificial landforms may perform over time and help in crafting care and maintenance solutions to ensure ongoing reclamation performance. Utilizing the time value of money, long-term care and maintenance funds can be established that will minimize the future financial burden from closed mine sites.

Keywords: geomorphology, landform evolution, optimism bias, risk management, DCF analysis

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