Managing too little and too much water: Robust mine-water management strategies under variable climate and mine conditions

Mine-water managers need tools to guide robust management strategies that can address the challenges of climate-influenced water scarcity and unregulated discharge. We aimed to identify those factors driving the risks of insufficient water supply for mine production and unpermitted discharge of mine-affected water in a way that is robust to heterogeneity between extreme climatic variability and mine sites. Using 16 coal mines in the Bowen Basin of Queensland, Australia, as a case study, we combined a model of complex mine-water management systems (C-HSM) with global sensitivity analysis (eFAST) to identify influential mine-water management factors. Comprehensive model diagnostics for the 16 mine-water systems under three climate conditions revealed that the uncertainty of key mine-water management indicators, and the contributions of model input parameters differed substantially between climate conditions and mine sites. We then applied four criteria from decision theory into the total sensitivity effects produced by the eFAST method, and developed sensitivity indicators that were robust to heterogeneity between climates and mine sites. These sensitivity indicators provide mine-water managers with options to guide the development of effective management strategies and the collection of additional information based on their own risk preference. While our results indicate some general management strategies that will be robust under multiple conditions, we caution that mine-water managers' experience in dealing with challenges caused by too little and too much water cannot be blindly transplanted from one mine to another, or from one climate condition to another.