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thereby increasing the time to flood the mine workings. The permittee has <br />proposed backfilling of the portals and construction of bulkheads upon <br />closure of the mine, minimizing the possibility for discharge. <br />A large coal refuse disposal area exists in the northern section of the mine <br />permit area. Drillhole data indicate that there is no ground water within 44 <br />feet of the ground surface in the coal refuse disposal area, and recharge to <br />ground water in the Mesaverde Group is minimal. Infiltration of water <br />through the refuse piles will be minimized by covering the compacted refuse <br />with 30 inches of the best available nontoxic material. Impacts to the ground <br />water system are not expected to be significant due to the relatively <br />impermeable nature of the refuse and the low water table. <br />The development and reclamation of the cuts and fills in the portal areas <br />should have no impact on the bedrock aquifer system. Recharge of the <br />aquifers does not occur in these areas due to surface water control systems, <br />which makes possible degradation of the ground water by infiltrating waters <br />is unlikely. The fill material itself is generally of suitable quality as a topsoil <br />substitute except for SAR values which are up to twice as high as defined in <br />the Wyoming Guidelines for suitability. As water flows through the fill, total <br />dissolved solids may increase due to soluble salts; however, this occurs <br />naturally within the existing ground water region. The fill does not contain <br />materials that create a toxic leachate. Water that infiltrates the fill may reach <br />Scullion Gulch. However, due to the small area of disturbance relative to the <br />entire drainage basin for Scullion Gulch, this will be a very minor <br />contribution of flow in the creek. <br />The permittee will be obtaining part of the required water supply from the <br />White River Lagoon, as discussed earlier. Approximately 552 ac. ft. per year <br />(601 gpm) will be pumped from the lagoon to a head tank in the D -Portal <br />area. This is less than one percent of the low flow of the White River. <br />Therefore, impacts will not be significant. <br />Recharge of the ground water is not expected to be impacted significantly by <br />the proposed mining operation. The majority of the recharge area for the <br />Mesaverde aquifers is outside of the mine plan area. It is possible that <br />surface fracturing resulting from subsidence could increase recharge to the <br />Upper Williams Fork. However, these cracks, if they occur, are expected to <br />exist for only a short period of time before naturally sealing. <br />Recharge of the White River alluvium by bedrock aquifers is not considered <br />to be significant because of the low transmissivities of the aquifers. The <br />permittee has estimated that total discharge could be 1.3 gpm through <br />bedrock aquifers to the White River, which is less than a tenth of a percent of <br />the base flow of the river. Therefore, the expected change in the recharge <br />capacity of the bedrock aquifers would not be a significant impact to the <br />35 <br />