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SG-1 Upper Sylvester Gulch pond <br /> NSSA North Soil Storage Area pond <br /> RPE ponds Refuse pile expansion area <br /> With the exception of pond SG-1, all sedimentation ponds discharge <br /> directly into the North Fork of the Gunnison River. The mine operation <br /> has obtained the appropriate NPDES permits for the discharges. Effluent <br /> quality for the sedimentation ponds has been monitored and will continue <br /> to be monitored to determine permit compliance. With the exception of <br /> occasional WET test failures for microorganisms, and isolated <br /> exceedances of suspended solids discharge limitations, the mine has not <br /> had recurring problems complying with surface water quality standards. <br /> The NPDES permit allows for a discharge of 10,000 gpd, based on a <br /> 30-day average, from MCC's sanitary waste water treatment plant. The <br /> potential impact of discharge of waste water effluent would be greatest <br /> when the dilution ratio for effluent is smallest. <br /> After mining is completed at the West Elk Mine, the underground <br /> workings may flood to a point where mine water discharges to the <br /> surface either through a perpetual drain that MCC may construct at the <br /> down-dip end of the workings next to State Highway 133, or as seepage <br /> from the coal outcrop on the hillside south of the highway(if the drain is <br /> not constructed). The maximum discharge is predicted to be around 100 <br /> gpm. The discharge would likely be relatively high in dissolved solids <br /> (on the order of 1,500 to 5,000 mg/l total dissolved solids). The <br /> maximum 100 gpm discharge would be diluted to near premining quality <br /> by water in the North Fork of the Gunnison River, where flow is always <br /> more than 4,500 gpm and total dissolved solids are less than 200 mg/l. <br /> MCC predicts the quantity of its water use will not adversely affect the <br /> hydrologic balance. Snowmelt provides most surface water flow in the <br /> permit area. Mining activities will not have a significant effect on <br /> snowmelt runoff. Overland runoff passes over disturbed areas within the <br /> permit area to one of the eight sedimentation ponds, mentioned <br /> previously in this section. This water may be discharged to the North <br /> Fork or stored when water rights are in priority. <br /> During Water Year 1982, MCC's conditional right to withdraw water <br /> from the North Fork was deemed absolute. When this water right is in <br /> priority, water can be pumped from the intake point to the 10 acre-foot <br /> freshwater pond. This water right is expected to be out of priority from <br /> July to September. Average withdrawals from the North Fork of the <br /> Gunnison are not expected to exceed 400,000 gallons per day(gpd) and <br /> are likely to be on the order of 200,000 gpd. The freshwater pond is <br /> filled during spring runoff and kept full until water rights are out of <br /> priority. The water is either treated to meet potable and sanitary water <br /> requirements, used and then treated as sanitary waste water, or is <br /> withdrawn for dust suppression in the mine and becomes mine water. <br /> 47 <br />