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<br />-34- <br />The permittee will be obtaining part of the required water supply from wells <br />completed in the White River alluvium as discussed earlier. Approximately 600 <br />gpm will be pumped from the aquifer to a head tank in the D-Portal Area. This <br />is less than one percent of the low flow of the White River. Therefore <br />impacts will not be significant. <br />Recharge of the ground water is not expected to be impacted significantly by <br />the proposed mining operation. Most of the recharge area for the Mesaverde <br />aquifers is outside of the mine plan area. It is possible that surface <br />fracturing resulting from subsidence could increase recharge to the Upper <br />Williams Fork. However, these cracks, if they occur, are expected to exist <br />for only a short period of time before they seal up. <br />Recharge of the White River Alluvium by bedrock aquifers is not considered to <br />be significant because of the low transmissivities of the aquifers. The <br />permittee has estimated that total discharge could be 1.3 gpm through bedrock <br />aquifers to the White River, which is less than a tenth of a percent of the <br />base flow of the river. Therefore, changes in the recharge capacity of the <br />bedrock aquifers is not expected to be a significant impact to the alluvial <br />aquifer. <br />The surface recharge capacity of the alluvial material in Scullion Gulch may <br />be reduced due to the construction of cuts and fills in the portal areas. <br />This disturbed area is small relative to the total area of Scullion Gulch and <br />therefore impacts are expected to be very minor. <br />Due to the presence of Kenney Reservoir, water withdrawal from the White River <br />alluvial aquifer will not cause measurable drawdown in the alluvium at the <br />well field site. The quantity of water which will be pumped is less than one <br />percent of the low flow of the river. <br />Subsidence from underground mine working could potentially impact both <br />Red Wash and Scullion Gulch. The effect on Red Wash is of greatest importance <br />because it drains approximately 122 square miles at the location where mining <br />will extend beneath it. Although predictions indicate that maximum vertical <br />subsidence could approach six feet, large crevasses or collapse of the surface <br />should not occur because there is approximately 600 to 1200 feet of overburden <br />above the coal seam in that area. Furthermore, the swelling of shales and <br />overburden from the caved roof should effectively fil] the open mine cavity. <br />An on-going monitoring program will be implemented to detect subsidence on the <br />first longwall panel and first room and pillar section to be mined during the <br />initial years of production. Predictions of probable disruption of the <br />hydrologic regime from subsidence will be based on an analysis of that data. <br />Tension cracks from subsidence may develop in formations directly underlying <br />Red Wash. It appears that these cracks may extend upward for several tens of <br />feet (oral communication with experts in this field; Page II. C-106b of the <br />permit application). These cracks will be of limited extent, therefore a <br />minimal amount of surface water will be siphoned into them. Furthermore, <br />sediment accumulating in the cracks, and clays in the overburden may <br />ultimate]y seal them off from surface inflow. <br />Impacts on Scullion Gulch are expected to be similar to those on Red Wash, <br />although maximum vertical after room and pillar mining is only predicted to be <br />one foot. The subsidence monitoring program previously mentioned will be used <br />