Challenge. Evaluate hydrologic impacts and contributions of inflows into the mine resulting from proposed expansion to the world’s largest underground iron ore mine

Solution. Working under a 7-month timeframe, INTERA developed coupled groundwater and surface water models to evaluate the hydrologic impacts of the proposed expansion. Because of the sub-level caving mining method used, surface deformation is expected to expand along with future operations. Based on predicted future subsidence, input parameters for the groundwater model were varied over the life of the mine to account for both the expansion and changes in hydraulic properties over time. A system-level model was developed, using the GOLDSIM code, that integrates water balance information from surface water and groundwater models as well as the mine’s water use and management operations to simulate the complete water cycle in the vicinity of the mine. Collectively, the models provide estimates of the impacts to water resources from expanding mining operations and serve as important decision support tools for optimizing water management methods and processes.