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(sandstone and coal deposits); and Point Lookout Sandstone. All but the alluvium (recent age) <br />are Cretaceous units. <br />The Hay Gulch alluvium consists of unconsolidated and poorly consolidated gravel, sand, silt, <br />and clay that was deposited by stream flow in Hay Gulch during the last several thousand years. <br />The alluvium is several tens of feet thick and approximately 1,000 feet wide. GCC has monitored <br />the Hay Gulch alluvium for more than 30 years in a monitoring well (the Wiltse well) next to the <br />King I Mine. Ground water in the alluvium is unconfined. The alluvium is recharged by <br />snowmelt and precipitation, and by seepage from the Menefee Formation subcrop along the <br />north side of Hay Gulch. The elevation of the water table varies seasonally, ranging from just <br />above the ground surface to a few feet below the surface. Ground water in the alluvium probably <br />flows downstream along Hay Gulch. Ground water in the Hay Gulch alluvium generally has a <br />high concentration of total dissolved solids (TDS) and sulfate. <br />The Cliff House Sandstone is a fine-grained marine sandstone, and is more than 200 feet thick. <br />The mine workings lie approximately 22 feet below the Cliff House (in the Menefee Formation). <br />Based on information from exploration drilling, this is an unsaturated formation in the vicinity of <br />the King Coal Mine. <br />The Menefee Formation is a fine-grained interbedded sequence of sandstone, siltstone, <br />mudstone, and coal, and is more than 200 feet thick. The operator mines coal from the top of the <br />Menefee. Based on information from exploration drilling and several decades of underground <br />mining, this is generally an unsaturated formation. However, lenticular sandstones in this <br />formation have produced viable amounts of groundwater. <br />The Point Lookout Sandstone is approximately 400 feet in total thickness. The upper unit of the <br />Point Lookout is a massive, medium -grained sandstone approximately 100 feet thick, while the <br />lower member is made up of thin sandstone beds with interbedded shale. Stratigraphically, the <br />Point Lookout lies more than 200 feet below the King Coal Mine workings. Water has been <br />encountered in this formation in places, and the water quality has been characterized as good by <br />a professional geologist. <br />The only natural springs located within one mile of the King I and II Mines are the Huntington <br />Springs, located on the north side of Hay Gulch, west of the reclaimed La Plata No. 1 Mine (File <br />No. C-1987-072). This spring may flow from either the lower Menefee Formation or the Hay <br />Gulch alluvium. The Huntington Springs are beyond the area of influence of the King I and II <br />Mines. <br />Additional information on ground water hydrology can be found in the permit application in <br />Sections 2.04.7, 2.05.3 and 2.05.6 and on Maps King I-004, King I-008, King I1— 004, and King <br />II -008. <br />Surface Water Hydrology (4.05 and 4.07) <br />There are no perennial streams within the King Coal permit area. The surface facilities of the <br />King I and II Mines are located in ephemeral drainages that are tributary to Hay Gulch. Hay <br />Gulch does not have a stream channel in the vicinity of the permit area. Historically, surface <br />flow in Hay Gulch has been diverted into the irrigation ditch on the north side of the Gulch. This <br />ditch carries water that has been diverted from the La Plata River. Hay Gulch is a tributary of <br />7 <br />