2012-05-03_REPORT - C1981014 (2)

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EFCI Southfield Mine — 2011 Annual Hydrology Report April 25, 2012 2.2 Mine Water Handling, Consumptive Use, and Discharge During active operations, mine dewatering systems in the mine captured most mine water inflow near their sources from where it was pumped downhill to the mined -out and abandoned west and north areas of the mine. Dewatering activities were discontinued after September 2001. Mine inflows are anticipated to continue within the sealed mine workings and water will accumulate in the lowest portions of the mined -out workings, gradually rising into other mined -out areas, until a dynamic equilibrium is reached between mine water inflows and recharge of localized groundwater systems. The monitor well MW -NW was established in 2003, at the location of a former mine dewatering well, in order to detect water accumulating in the Southfield mine workings (see Section 3.1, Groundwater monitoring results). No water has been observed at this well through the period of this report. During the period of this report, consumptive water use occurred only from pond evaporation. Pond 4 and Pond 5 at the mine site intermittently held small pools, estimated to be less than a foot deep from storm events during the spring and summer months. Based on the size and duration of pooled water in each pond, the total 2011 pond evaporation is estimated at 0.004 acre -feet. This quantity is significantly less as compared to previous years. Lower water quantities were held in the mine ponds due to small and infrequent storm events during the reporting period, and there was a likely decrease in surface runoff from reclaimed areas having mature vegetation establishment. The source of water for any intended consumptive uses would be from the towns of Florence or Rockvale, hauled by truck. No water was trucked to the site or pumped from the Corley Well during 2011, and it is anticipated that future consumptive water use will be limited to pond evaporation from the remaining four sedimentation ponds (Ponds 4, 5, L1, and L2). Total consumptive use for 2011 is therefore estimated at 0.004 acre -feet, as indicated on Table 1, Water Balance and Consumptive - Use Summary. The water balance shown on Table 1 compares water source withdrawals (consumptive use) with discharge quantities. Withdrawals previously included any excess mine water pumped from the mine and all water withdrawn from wells. No water was pumped from the mine or withdrawn from wells during 2011. Consumptive use during the reporting period was therefor only due to pond evaporation. No pond water was discharged through any of the NPDES outfalls, shown on Table 2, to the stream system during the reporting period. 2011 AHR text doc Page 2