Guimarães de Oliveira, B, Holanda, S, Malcher, S, Rossy, Y, Augusto, E & Assis, V 2026, 'Risk-based progressive mine closure in the Amazon', in AB Fourie, G Boggs, J Heyes & M Tibbett (eds), Mine Closure 2026: Proceedings of the 19th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-13, https://doi.org/10.36487/ACG_repo/2615_89
(https://papers.acg.uwa.edu.au/p/2615_89_Guimaraes/)
Abstract: Progressive mine closure in humid tropical environments presents significant challenges due to high rainfall, intense weathering and the potential for acid mine drainage (AMD) generation. These conditions require closure strategies that are responsive to site-specific risk and performance. This paper presents a risk-based framework for progressive mine closure, developed from site geochemical conditions and applied at a large open pit copper–gold operation in the eastern Amazon, Brazil. The approach integrates operational risk classification with long-term hydrogeochemical monitoring to differentiate waste rock facilities according to closure risk and performance. Monitoring results demonstrate clear geochemical distinctions between closure risk classes, supporting the use of proportional, performance-based closure strategies. The case study shows that a risk-driven approach can reduce uncertainty, optimise closure measures, and support defensible progressive relinquishment in high-rainfall tropical mining contexts.