Developing tailings storage facility closure criteria for a mine in Africa

Authors: Aheto-Tsegah, D; Morapi, T Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2515_02

Cite As:
Aheto-Tsegah, D & Morapi, T 2025, 'Developing tailings storage facility closure criteria for a mine in Africa', in S Knutsson, AB Fourie & M Tibbett (eds), Mine Closure 2025: Proceedings of the 18th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-15, https://doi.org/10.36487/ACG_repo/2515_02



Abstract:
According to The World Bank (2021), the failure rate of tailings storage facilities (TSFs) averages one to two a year worldwide. The release of material from a TSF in the case of failure could result in some of the most significant environmental impacts in mining. The resulting consequence of the failure does not change whether this is during the mining operational or closure phases. One could argue that the post-closure phase perhaps presents a higher risk, if not assessed critically, since the closed TSF will exist over a long-term period compared to the operational phase of a TSF, which ordinarily lasts less than 30 years. Bearing this in mind, there is a strong focus on TSF closures globally to ensure that decommissioned and closed TSFs are physically, chemically and ecologically safe, and able to provide beneficial uses for surrounding communities. Meeting this overall objective requires the development of plans and criteria to minimise the negative impacts, against which the success of the TSF closure activities can be measured. The term closure criteria or success criteria are described by the International Council on Mining and Metals (ICMM) as “quantitative indicators of successful closure activities” (ICMM 2021). Development of such closure criteria requires the input of the various stakeholders including the regulator, communities and the mine operators. The closure criteria, if achieved, ensure there is no human or environmental harm during TSF closure and post-closure activities. Using examples in Africa, this paper focuses on risks posed by TSFs in general, the considerations in setting TSF closure objectives, and guidance on how to successfully develop closure criteria that are comprehensive, achievable, site-specific and, more importantly, meet global sustainability goals in TSF management. For the mine in Ghana, agroforestry was selected as the end land use. The closure criteria towards this were developed using governing rules such as national regulations and the Global Industry Standard on Tailings Management as a foundation, further refined with other key considerations including the socio-economic needs of the surrounding communities and the climatic conditions. Furthermore, trial plots for assessing the feasibility of planting directly into the tailings were used to further refine the closure criteria to ensure the success of the closure plan.

Keywords: tailings storage facilities, closure criteria, closure objectives, closure risks

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