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The outcrop of the coal seam is at 10, 000 feet and the seam <br /> drops downdip into the mountain at 12 degrees. The coal seam is <br /> under 3,000 feet of cover under Huntsman Ridge and some 2,000 <br /> feet below the Muddy Creek valley to the west of Coal Basin. The <br /> affected aquifers have a very low permeability. There are no <br /> known users of ground water from the Mesaverde Group aquifers <br /> within a two-mile radius from the edge of the mine. Therefore, <br /> no impacts to ground water use should result from the dewatering <br /> of the mine workings. When mining in Coal Basin is terminated, <br /> the water levels in the aquifers will rise to the pre-mining <br /> ground water levels in 12 to. 24 months. This was the case with <br /> Nos. 4 and 5 mines. <br /> The present measured.mine discharge rates vary seasonly <br /> between 40 to 360 GPM per operating mine. These flows may <br /> increase as the mines move farther down the dip of the strata. <br /> Past experience has shown this not to be significant as in No. 1 <br /> mine which is some 7, 000 feet downdip at present (6/86) . The <br /> flow has increased very little (10 to 20%+) from 4 ,000 feet down <br /> slope. In 1980 the total peak flow from all five mines was <br /> approximately 1,000 GPM. Today (1986) the total peak flow from <br /> Nos 2 and 2 mines is approximately 1,000 GPM. Note: It is suspected <br /> that No. 3 mine as it fills is applying some pressure on the <br /> aquifers adjacent to No. 1 mine, thus increasing the flow in the <br /> longer slopes of No. 1 mine. <br /> To give some perspective to the amount of water produced, <br /> • the U. S. Steel Somerset mine peak pumping rate in 1985 was <br /> 20, 000 GPM. <br /> 50 <br /> II <br />