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EFCI Southfield Mine — 2012 Annual Hydrology Report April 18, 2013 <br />due to continuing drought conditions at that time along with the elimination of former inflow or <br />seep locations due to retreat mining Review of historic mine inflow water quality monitoring <br />results documented in previous AHR's indicates only minor variances in inflow water quality over <br />time. <br />2.2 Mine Water Handling, Consumptive Use, and Discharge <br />During active operations, mine dewatering systems in the mine captured most mine water inflow <br />near their sources from where it was pumped downhill to the mined -out and abandoned west and <br />north areas of the mine. Dewatering activities were discontinued after September 2001. Mine <br />inflows are anticipated to continue within the sealed mine workings and water will accumulate in <br />the lowest portions of the mined -out workings, gradually rising into other mined -out areas, until a <br />dynamic equilibrium is reached between mine water inflows and recharge of localized groundwater <br />systems. Monitor well MW -NW was established in 2003, by approved conversion of a former mine <br />dewatering well into a monitoring well, in order to detect water accumulating in the Southfield <br />mine workings (see Section 3.1, Groundwater monitoring results). No water has been observed at <br />this well through the period of this report. <br />During the period of this report, consumptive water use occurred only from pond evaporation. Pond <br />4 and Pond 5 at the mine site held limited water during early fall from a storm event, as described in <br />Section 3.3, Surface Water Monitoring Results. Based on the size and duration of pooled water in <br />each pond, the total 2012 pond evaporation is estimated at 0.131 acre -feet. This quantity is <br />significantly less as compared to previous years. Lower water quantities were held in the mine <br />ponds due to small and infrequent storm events during the reporting period, two mine site ponds <br />were reclaimed, and there was a likely decrease in surface runoff from reclaimed areas having <br />mature vegetation establishment. <br />The source of water for any intended consumptive uses would likely be obtained from the towns of <br />Florence or Rockvale and hauled by truck. No water was trucked to the site or pumped from the <br />Corley Well during 2012, and it is anticipated that future consumptive water use will be limited to <br />pond evaporation from the remaining four sedimentation ponds (Mine Site ponds 4 and 5; Loadout <br />ponds L1 and L2). Total consumptive use for 2012 is based solely on pond evaporation estimated <br />at 0.131 acre -feet, shown on Table 1, Water Balance and Consumptive Use Summary. <br />The water balance shown on Table 1 compares water source withdrawals (consumptive use) with <br />discharge quantities. Withdrawals previously included any excess mine water pumped from the <br />mine and all water withdrawn from wells. No water was pumped from the mine or withdrawn from <br />wells during 2012. Consumptive use during the reporting period was therefor only due to pond <br />evaporation. No pond water was discharged through the NPDES outfalls, shown on Table 2, to the <br />stream system during the reporting period. <br />2012 AHR text doc <br />Page 2 <br />