Challenge. Evaluate impacts on water resources from various alternatives for closing a large open pit at a mine site located inside a National Park and upstream of UNESCO world heritage wetlands.

Solution. INTERA’s modeling expertise was used to support the development and optimization of mine closure strategies. A major part of this work included developing and applying a groundwater flow and solute transport model to facilitate closure planning for one of the mine’s large open pits. The model was used to evaluate various pit closure scenarios based on predictions of potential solute loadings from the pit to nearby surface water resources. We also applied a systems assessment methodology to evaluate the effectiveness of a selected closure scenario in preventing tailings, which are being used to backfill the pit, from adversely impacting surface water and groundwater resources over the next 10,000 years. These tools played a key role in establishing support and obtaining approval from regulators and other stakeholders for the recommended closure strategy.