Assessing the impacts of artisanal and small-scale mining on rehabilitated land

Authors: Wanenge, MT; Mashiyi, N Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2515_25

Cite As:
Wanenge, MT & Mashiyi, N 2025, 'Assessing the impacts of artisanal and small-scale mining on rehabilitated land', 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. 1-12, https://doi.org/10.36487/ACG_repo/2515_25



Abstract:
Progressive rehabilitation is vital for successful mine closure and reducing long-term liabilities (International Council on Mining and Metals [ICMM] 2025). It helps demonstrate the success and sustainability of the closure plans, which is vital in getting the buy-in of stakeholders, especially regulators and the host communities. The Siguiri Gold mine in north-eastern Guinea, a region historically tied to artisanal and small-scale mining (ASM), managed to rehabilitate about 50% of its 25 waste rock dumps between 2015 and 2019. However, after gold prices rose in 2015, ASM activities surged, leading to extensive damage to rehabilitated areas and forcing the mine to halt rehabilitation in 2020. Since then, the mine has taken steps to mitigate the ASM impact and explore other more sustainable closure alternatives for the dumps. In 2022 internal studies, including fieldwork and mapping, estimated that 30% of the rehabilitated areas had been damaged by ASM activities. However, following the recommendations of that study, in 2024 the mine commissioned a more detailed, independent assessment. The project aimed to map ASM damage, remodel landforms and estimate the extent of repairs required. Using topographical devices, geospatial technology and field surveys, the assessment re-mapped the site and quantified the extent of damage. The 2024 study estimated that the damage was about three times higher by cost and area than the 2022 initial estimate. The 2022 assessment only considered disturbed hectares, while the 2024 study accounted for landform and topography changes. Remodelling requires cutting undisturbed areas to fill disturbed ones, resulting in a larger impact than initially expected. Time-series mapping from 2014 onwards also helped track ASM disturbances and vegetation regrowth. Key lessons include recognising that ASM impacts should be assessed from a landform perspective (3D) and not just areas disturbed (2D), and that mapping alone can be misleading due to vegetation regrowth. In regions with historical ASM activity, alternative land use options should be explored, and government support is crucial for success.

Keywords: artisanal and small-scale mining, progressive rehabilitation, disturbance, closure estimate

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