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Evaporation of water standing in the pond may also cause an increase in TDS, <br />although the increase above background concentrations (1500-2000 mg/1) is not <br />expected to be large. <br />The Division has determined that probable hydrologic effects on surface water <br />identified above will not preclude use of the water below the point of discharge <br />from the mine. This conclusion is based on the small and infrequent flows <br />relative to the large amount of dilution available in receiving waters. The <br />quality of surface water is limited on site and the treatment systems should act <br />to mitigate any adverse effects on surface water. <br />Ground Water Effects <br />There are two potentially impacted ground water systems within and adjacent to <br />the King Coal operation: the Menefee Forntation and the Hay Gulch alluvial <br />system. <br />The probable hydrologic consequences of mining to the Menefee Formation are <br />negligible. The Menefee is essentially dry at the King Coal Mine. This has <br />been historically documented during past operations. Additionally, a drilling <br />program initiated in 1980 for the proposed Shalako Mine (about 1 mile northeast <br />of the King Coal Mine in Hay Gulch) confirmed that the coal and overburden <br />are essentially free of water. Perched aquifers, which may be located above the <br />mined seam, will be dewatered during the course of mining operations . The <br />perched aquifers above the mine are probably limited both in number and in <br />areal extent. There is no documented use of any of these aquifers, nor is there <br />any evidence to suggest that these aquifers supply base flow to any local steams <br />or springs. Therefore, impacts to perched aquifers, and the Menefee Forntation <br />as a whole, will be minimal. <br />The second ground water system identified near the permit area is [he Hay <br />Gulch alluvial aquifer. This aquifer system may be potentially affected by <br />surface runoff from the mine bench or discharge from the sediment pond <br />infiltrating into the alluvial body. This infiltration could cause localized <br />increases in total dissolved solids within the alluvium. The probability of this <br />occurring is minimal. The sediment control system at the King Coal Mine has <br />been designed to minimize impacts to the prevailing hydrologic balance at and <br />near the permit area. All surface rnnoff from the mine area will flow, via a <br />series of conveyance culverts and ditches, to the sediment ponds, which are <br />located on either side of the combination haul/access road adjacent to the <br />alluvial valley. The sediment ponds, which are adequately sized to contain the <br />nmoff from a ]0-year, 24-hour storm, will not discharge until a storm event of <br />this magnitude has been exceeded. National King Coal has committed to an <br />extensive water quality sampling plan, should the ponds discharge due to mine <br />portal discharges. The sampling plan should be an effective method of <br />determining the extent, if any, of impacts which are occurring to the alluvial <br />aquifer system. <br />l6 <br />