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IX. Assessment of Probable Hydrol <br />Hvdroloaic Imoacts - Rules 2. <br />Probable Hydrologic Consequences <br />c Consequences of Mining and Cumulative <br />c ~ ., .,a o m c Iot/,.~ <br />The probable hydrologic consequences section of this findings document <br />addresses the effects that the Coal Gulch Mine will have on the ground and <br />surface water systems within and adjacent to the proposed mine area. The <br />information used in this assessment is found in Sections 2.04 and 2.05 of the <br />permit application. <br />Ground Water <br />In Section V, Ground Water Hydrology, the Division identified six potential <br />aquifer systems present within and adjacent to the permit area: <br />1. Lightner Creek alluvial aquifer <br />2. Discontinuous colluvial flow systems in Coal Gulch and tributaries <br />3. Localized subsidence related systems <br />4. Minor coal seam aquifers <br />5, Perched aquifers in the Menefee Formation, above and below the "A" seam <br />6. Regional aquifers of the Cliff House Sandstone and Point Lookout <br />Sandstone/lower Menefee Formation. <br />The effects of mining on each of these systems will be examined. <br />Lightner Creek, with it's associated alluvial aquifer, will not be impacted by <br />mining. Kline operations will be conducted approximately 400 feet <br />higher (topographically) than the elevation of the alluvium, therefore, <br />depletion of the aquifer will not occur. No surface activities will take <br />place on the Lightner Creek side of the drainage, so there will be no <br />diminution of water quality due to increases in sediment or chemical <br />parameters . <br />colluvial slumps in Coal Gulch and it's tributaries comprise a discontinuous <br />aquifer system which contributes water to the stream. These slumps contribute <br />enough water to the stream to sustain flow into the late spring. The effects <br />of mining on the colluvial system will be dependent upon subsidence activity. <br />Subsidence fracturing may produce cracks in the bedrock on which the coluvium <br />rests. This fracturing could induce flow from the colluvium to the mine, thus <br />depriving the stream of "base flow". The possibility of dewatering the <br />colluvial system is most likely in the first tributary drainage upstream of <br />the proposed portal. Coal Gulch itself should be far enough removed from <br />mining so that fracturing will not intercept slumps there. <br />