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thickness of 48 inches. This seam lies approximately 80 feet below the upper seam with inter- <br />bedded sandstone and shale between the seams. On an average, the upper seam lies 100 to 400 <br />feet below the surface of the mesa above Hay Gulch. <br />The King Coal operation has predominately mined the upper coal seam from the Menefee during <br />the course of its operations. <br />Ground Water Hydrology <br />Two aquifers have been identified within the area potentially affected by the King Coal operation: <br />the Hay Gulch alluvial aquifer; and, the Point Lookout Sandstone. <br />The Hay Gulch alluvial aquifer, which is adjacent to the operation, averages 20 feet in depth and <br />had a cross sectional area of 25,200 squaze feet, with an estimated transmissivity of 70,400 gallons <br />per day per foot (gpd/fr.). The water table surface in this alluvial aquifer varies with season from <br />above ground surface to about 3 feet below the surface. The direction of flow in this unconfined <br />system is downstream, parallel to the strike of Hay Gulch. Recharge to the alluvium is from <br />snowmelt and precipitation infiltration, and from the Menefee Formation contact along the north <br />side of Hay gulch. Sampling of this alluvial water by National King Coal indicates that the water <br />is high in total dissolved solids. The poor quality of the water makes it unsuitable for domestic <br />and irrigation purposes, but usable for stock watering. <br />An analysis of the probable effects of mining to this aquifer indicate that very little effects would <br />be noted . Future operations in the Upper Menefee coal seam are not expected to disrupt aquifers, <br />streams, waters systems, or the small watershed up slope of the mine site. Hydrologic data <br />obtained from existing workings, core drill holes, and other research studies show that the mining <br />operations have had only a mild impact on the water sources of Hay Gulch. The mine is not <br />located in a major groundwater recharge area. Research has shown this portion of the basin has <br />had very little ground water development. Most of the wells in the general azea have been <br />completed in the unconsolidated alluvial gravels and terrace deposited of the La Plata river and <br />its tributaries (including Hay Gulch), or in consolidated aquifers further south (down dip) in the <br />basin. The Point Lookout Sandstone aquifer, nearly 275 feet below the mine floor, to date has <br />been unaffected by mining operations. <br />With the exception of a very brief period in early 1986, all mine workings have been dry. All <br />coal within the permit area lies above the potentiometric surface of Hay Gulch therefore it is not <br />expected there will be any hydrologic consequences due to mining. <br />Ground water use in the vicinity of the mine is limited. Within aone-mile radius of the facilities <br />area, one spring and three water wells have been identified. <br />The Huntington Springs is located on the north side of Hay Gulch west of the La Plata No. 1 Mine <br />area (File No. C-87-072). This spring, which may issue from either the lower Menefee Formation <br />or the Hay Gulch alluvium, has been adjudicated for a water right. La Plata Coal Corporation <br />5 <br />