Addition of Runoff to Post-Mining Predictive Simulation Rosemont Mine Model

Document ID: montgomery-addition-runoff-to-post-mining-predictive-simulation-2011

During post-submittal review of the Rosemont Mine model submitted in 2010, Montgomery & Associates (M&A) determined that precipitation runoff into the pit lake from the area above the spill level was not simulated in the LAK2 package. This area encompasses approximately 187 acres. Runoff from this area is estimated to be approximately 64 gallons per minute (gpm). Addition of this runoff will decrease projected groundwater drawdown impacts and increase projected lake stage. The model was revised to evaluate sensitivity of model projections to inclusion of the additional 64 gpm runoff inflow to the pit lake.