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lower coal seam of the Menefee has an average thickness of 48 inches. This seam lies approximately <br />80 feet below the upper seam with inter-bedded sandstone and shale between the two seams. <br />Ground Water Hydrology <br />The following four water-bearing stratigraphic units have been identified in the vicinity of the permit <br />area: the alluvium of Hay Gulch (poorly consolidated stream gravel, sand, silt, and clay of Recent <br />age), the Cliffhouse Sandstone (Cretaceous marine barrier baz complex), the Menefee Formation <br />(Cretaceous fluvial sandstone and coal swamp deposits), and the Point Lookout Sandstone <br />(Cretaceous marine beach and bar deposits). Figure 1 shows the hydrostratigraphic setting. <br />The Hay Gulch alluvium consists of unconsolidated and poorly consolidated gravel, sand, silt, and <br />clay that was deposited by stream flow in Hay Gulch during the last several thousand yeazs. The <br />alluvium is several tens of feet thick and is approximately 1,000 feet wide. NKC has monitored the <br />Hay Gulch alluvium for more than 20 yeazs in a monitoring well (the Wiltze well) next to the King <br />Coal Mine. Ground water in the alluvium is unconfined. The alluvium is recharged by snowmelt <br />and precipitation, and by seepage from the Menefee Formation subcrop along the north side of Hay <br />Gulch. The elevation of the water table vanes seasonally, ranging from just above the ground surface <br />to a few feet below the surface. Ground water in the alluvium probably flows downstream along Hay <br />Gulch. NKC's annual hydrology reports show ground water in the Hay Gulch alluvium is a <br />magnesium-calcium-sulfate type of water that has a high concentration of total dissolved solids <br />(TDS). TDS concentrations consistently are more than 1,500 mg/1, rendering the water unsuitable <br />for domestic and irrigation purposes, but mazginally suitable for stock watering. Sulfate <br />concentrations are greater than 600 mg/1. Sulfate concentrations greater than 250 mg/1 can cause <br />weight-loss in livestock. There aze no known private wells completed in the Hay Gulch alluvium <br />near the permit area, other than the mine's own well. <br />The Cliffhouse Sandstone is afine-grained sandstone that was deposited in a barrier bar <br />complex along a marine shoreline. The Cliffhouse is more than 200 feet thick. NKC's mine <br />workings directly underlie the Cliffhouse in the Menefee Formation. Water supply wells that <br />are located within one mile of the permit area and are probably completed in the Cliffhouse <br />Sandstone include the V. Paulek and G. Paulek wells. <br />The Menefee Formation is afine-grained interbedded sequence of sandstone, siltstone, mudstone, <br />and coal that was deposited on an alluvial plain. Environments ranged from fluvial channel deposits <br />to coal swamps. The Menefee is more than 200 feet thick. NKC mines coal from the top of the <br />Menefee. The Grush well is a water supply well that is located within one mile of the permit area <br />and is probably completed in the Menefee Formation. <br />The Point Lookout Sandstone is afine-grained sequence of sandstone and mudstone that was <br />deposited along a marine shoreline in beach and baz environments. The Point Lookout is more than <br />250 feet thick. It lies more than 200 feet stratigraphically below NKC's coal mine workings. The <br />Point Lookout is not widely used as a source of ground water along the flanks of the San Juan Basin <br />due to low well yields and high dissolved solids content of the water. Water supply wells that are <br />located within one mile of the permit area and are probably completed in the Point Lookout <br />Sandstone include the Haugen, Funk, Beyer, and Etheridge wells. <br />5 <br />