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- 4/ - <br />1 <br />' 2.04.7(1) Ground Water Information <br />The "D" coal seam at Sunlight Mine is a minor aquifer that is recharged by <br />Fourmile Creek where the coal strata crosses the streambed, slightly upstream of the <br />~' mine site. Static water level in the mine is approximately 100 feet below the stream <br />,, level (Table H,5). It is unlikely that the coal seam is recharged from the larger <br />' aquifers (sandstones) above since the dip is extremely steep and the coal aquifer is <br />overlain by shale. <br />it is likely that the sandstone aquifers are also recharged by the stream during the <br />'' high flow season. During low flow, the flow direction may reverse, with the aquifers <br />contributing to the stream base flow. The hydraulic head in the coal seam is <br />' artificially lowered by pumping and the direction of flow does not change during low <br />flaw season. - <br />The amount of water in the coal seam is small as evidenced by the pumping rates <br />' at the mine. The maximum pumping rate required is about 30 gallons per minute (gpm) <br />when mining operations have been shut down for 2 to 3 days. During the week, a rate <br />of about 15 gpm is required to maintain the water level below operations for the <br />present production level of 200 tons per month. The Sunlight Aline operation probably <br />-' augments the flow in Fourmile Creek an insignificant amount. In high flow season, the <br />mine discharge is less that 0.1 percent of the flow. In low season the mine discharge <br />`, is less than five percent of the flow. <br />_.' Water quality analysis (Table H.6) of the mine discharge indicates water that is <br /> extremely hard with a moderately high level of dissolved solids. However, there is no <br />-' evidence i n this analysis of toxic ity. Arsenic, boron, lead, and mercury levels are <br /> below the detectable limit. The wate r is mildly acidic, pH of 6.7, although samples <br />' k t <br />di <br />i <br />t th min <br /> were ta <br />en om s <br />an <br />ng wa <br />n <br />er e e. <br /> <br />~~ <br />s <br />-' <br />29 <br /> <br />