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Gulch and construction will entail the development of large cuts and fills to <br />provide for flat working areas. Both entries are cut through rock and slope <br />down toward the-D-seam. <br />In the northern sections of the mine plan area, a large coal refuse disposal <br />area is proposed. There is no ground water within 44 feet of the ground sur- <br />face in the disposal area, and recharge to ground water in the Mesa Verde For- <br />mation is minimal. Infiltration of water through the refuse pile will be <br />minimized by covering the refuse with four feet of the best available nontoxic <br />material from the refuse site which will be removed prior to refuse disposal. <br />Impacts to the ground water system are not expected to be significant. For <br />further information on the Refuse Pile see the Miscellaneous Section, (Coal <br />Refuse Disposal) of this TEA. <br />Subsidence effects include fracturing of the material overlying the coal for a <br />distance of 30 to 40 feet due to caving of the roof material and surface subsi- <br />dence and possible development of tension cracks on the surface due to <br />differential settling. Groundwater inflows during mining are expected to be <br />minimal: 5 to 10 gpm. Water that does flow into the mine will be used for <br />dust suppression. Due to the low transmissivities of the aquifers, if caving <br />should create a hydraulic connection from the mine to an aquifer within 30 to <br />40 feet of the coal, the additional inflow will be minimal. In fractured <br />areas, increased flows of 100 to 300 gpm may be encountered fora short period <br />of time. These flows will diminish as equilibrium is reestablished. It is not <br />probable that fracturing from the surface to the mine will occur as a result of <br />subsidence and cause the flow of surface water to the mine. <br />Subsequent to completion of mining, the ground water will slowly reestablish <br />its premining water levels. Due to the caving of the roof materials into the <br />mine, an area of increased permeability will exist within the mine which will <br />act as a "sump area" until equilibrium is established. However, due to the <br />small quantity of water in the aquifers being discharged to the White River and <br />its tributaries, the lack of ground water usage in the area, and the poor <br />quality of ground water, potential impacts to f1 ow i n the White River wil l be <br />very minor. <br />4 <br />