Rosemont Pit Backfill Simulation
At the request of Rosemont Copper, Montgomery & Associates (M&A) evaluated waste rock backfilling of the Rosemont pit using the Rosemont pit-dewatering groundwater flow model. For this evaluation, the final backfill surface is assumed to not rise above the equilibrium pit lake elevation, which maintains the pit as a hydraulic sink due to lake evaporation. Backfill of the pit void reduces post-mining groundwater inflow to the pit. Projected results for the 1,000-year post-mining period indicate the decreased groundwater inflow due to pit backfilling resulted in negligibly less groundwater level drawdown compared to the base simulation without backfill.