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-35- <br /> The mining activities will not have an adverse effect on the quantity of <br /> surface water within or outside the permit area. i'Ylid-Continent has a <br /> water right to withdraw water from Coal Creek up to 7.48 cfs. This is <br /> the only withdrawal of water from within the permit area. Through <br /> Pumping water from the mines, the flow in Coal Creek is increased on the <br /> average by 3.75 cfs, thus the net effect of withdrawal is to deplete <br /> 3.73 cfs, which is approximately one percent of the average low flow in <br /> the Crystal River. Most of the water will be withdrawn from the Coal <br /> Creek drainage during the summer months for dust suppression. Since the <br /> flow in the summer months is greater than average, the Crystal River will <br /> be depleted by less than one percent during the summer. Therefore, the <br /> proposed operation will not significantly affect the quantity of surface <br /> water in the hydrologic regime outside the permit area. <br /> Probable Hydroloqic Consequences - Ground Water <br /> The impacts incurred by ground water resources as a result of the <br /> proposed mining operations are expected to be insignificant. However, <br /> several slight changes in the hydrologic system are expected. First, the <br /> coal seams and immediately adjacent strata will be dewatered in the <br /> vicinity of the mining operations. Second, the water quality of alluvial <br /> ground water located adjacent to the several mine-waste piles may become <br /> slightly degraded. ' Third, slight mixing of ground waters from previously <br /> unconnected aquifers may occur as a result of the proposed rock tunnel . <br /> None of these potential impacts are expected to cause material damage to <br /> ground waters in the Coal Basin area. Each is discussed in greater <br /> detail below. <br /> As a part of normal operating procedures, the applicant must handle water <br /> that develops in the mine workings. This water is handled in one of the <br /> following ways: <br /> I . it will be used during the mining process, <br /> 2. it will be allowed to migrate downdip either in the coal or the <br /> underlying sandstone units, or <br /> 3. it will be pumped from the mine at a rate of 40 to 300 gpm. <br /> 3asea on mine pump records (see Table III-E-2 of the permit application) , <br /> the amount of water pumped from the workings increases during the spring <br /> and significantly decreases during the late fall and winter. This mine <br /> dewatering process should lower water levels in the two coal seams being <br /> mined and the Rollins and ��iddle sandstones. Based on the exoected lcw <br /> transmissivities. it i sunlik lv that the drawdowns would extend more <br /> than a vile from th ga of r M.6_,oerk-ings. Since the mine is <br /> located near an outcrop area, it is unlikely that these strata are fully <br /> saturated anyway. The low pumping rates required to oewater the mine <br /> wor'ings is evidence of this. ,also, the fact that the punning rates <br /> dramatically increase during the spring season inoicates variable degrees <br /> of aquifer saturation throughout -a' given year, <br />