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4.2 Mining Simulation Mining conditions were modeled to show the potential impacts that dewatering could have on surcounding wells. The mining conditions model was run to match the proposed mining phases as presented in Table 8 and Figure 8. A model run was done for each phase of mining to evaluate the effects of dewatering. Constant head nodes approximately equal to the bedrock elevation within the mined area were applied to each phase to reflect dewatering. Table 8 Mining Scenario Phase Property/Site Wiant/Gurule Villano SAW Yokaoji M1 Dewater Farm Farm Farm M2 Reclaimed Dewater N 1/2 Farm Farm Reclaimed Reclaim N 112, Farm Farm M3 Dewater S 1/2 Reclaimed Reclaimed Dewater X33, Farm S Farm Md Reclaimed Reclaimed Reclaim N 1/3, Farm MS Dewater S 113 Reclaimed Reclaimed Reclaimed N Z3, Dewater M6 Dewater S 1/3 Notes: 1. Dewatering occurs in conjunction with mining. 2. Input parameters used to calibrate the steady-state model were maintained dudng the mining scenado simulafion. 3. Dewatedng was modeled using constant heads. 4. SAW is Sasaki, Adams, Wafada properties For example, a run done for Phase M1 would be modeled with: l) the Wiant and Gurule piece being dewatering and 2) the rest of the site being farmed. A run for each phase in Table 8 was performed and the results are reported in Table 9. The model indicates that the dewatering phases of the mining operation could result in fluctuating water levels in some wells close to the areas being dewatered. The northern margin of fluctuation is WCR 10'/z and the southern margin is WCR 4'/:with an approximate affected radius for all phases of 4,700 feet. Table 9 reports the approximate fluctuations in the existing groundwater levels due to dewatering during each mining phase. The resulting water levels during each phase of mining are reported in Table 9 below. Report - SW TKO Water Storage Project - 8 - February