Mine closure plans developed at a conceptual stage rely on assumptions due to limited site-specific data, introducing uncertainty in the design and effectiveness of proposed closure measures. This paper presents a quantitative prioritization framework applied to an internal risk assessment exercise on a conceptual mine closure plan, using the Failure Mode and Effects Analysis (FMEA) methodology established in the Integrated Mine Closure Good Practice Guide (ICMM, 2025).
For each risk, uncertainties and information gaps were identified, and targeted technical studies were assigned to address them. The framework ranks 11 proposed technical studies based on three indicators derived from the risk register: risk coverage, total risk reduction, and coverage of high-level risks. All indicators were normalized and combined as a weighted score, enabling an objective comparison across the study portfolio.
Results identify hydrogeological characterization and water quality monitoring as the top-priority study, followed by geochemical characterization of mine waste, predictive hydrogeological and geochemical modeling, water balance and hydrological design, and geotechnical stability analysis as the top five.
A sensitivity analysis across 66 weighting scenarios confirms the robustness of these rankings. The methodology offers a practical, data-driven tool for guiding the staged implementation of technical studies over the life, supporting better-informed and risk-validated closure planning decisions.
