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5.0 Model Simulation and Results <br />Model Scenarios <br />Mining and reclamation at the site is anticipated to occur for approximately 20 years; <br />however, the rate of mining and overall life of the mine is dependent upon demand and <br />market conditions. In order to assess potential magnitude and extent of groundwater <br />drawdowns, simulations of the mining phase where performed for a period of 15 years, as <br />follows: <br />• Phase IA: Years 1-15 <br />• Phases 1 B and 1 C: Years 4- 7 <br />• Phase 2: Years 8 -11 <br />• Phases 3 through 5: Years 12 -15 <br />Given uncertainties in the timing of the various mine phases, sensitivity analyses <br />included model runs assuming longer periods of mining to ensure that potential effects <br />were fully assessed. <br />Dewatering of the mine site was simulated by setting drain elevations near the base of the <br />aquifer at cells along the perimeter of each mining phase identified in the mine plan <br />(Exhibit D). The simulated drawdowns resulting from dewatering at the end of each of <br />the above periods of mining were calculated by subtracting the heads generated at the end <br />of the dewatering period from the initial heads simulated in the calibration phase (Figures <br />4, 5, 6, and 7). <br />A post-mining model simulation was conducted to assess potential combined effects of <br />reclamation activities of all mine cells (Mine Phases 1 - 5) on the shallow alluvial aquifer. <br />Mined areas were modeled as either as a pond or as reclaimed (filled) with mine spoils <br />according to the reclamation plan (Exhibit F). Excavations modeled as ponds were <br />simulated with a hydraulic conductivity of 100 cm/sec to reflect the high transmissivity <br />of the water body. Mined areas reclaimed with mine spoils were simulated with a <br />hydraulic conductivity of 1x10-4cm/sec to reflect the transmissivity of the silt and clay- <br />rich material to be used to fill the former mine excavation(s). Post-mine simulations <br />were conducted for a 10-year period to simulate steady state conditions after reclamation <br />activities are completed. The effects on groundwater elevations from the post-mining <br />EnviroGroup Limited 9