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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 two seams. To the north of the permit area, the <br />interburden between the "A" and "B" seams may thin out, resulting in a single, thicker "A" <br />seam. <br />Ground Water Hydrology (2.04.5 and 2.04.7) <br />The following four water -bearing stratigraphic units have been identified in the vicinity of the <br />permit area: the alluvium of Hay Gulch; the Cliff House Sandstone; Menefee formation <br />(sandstone and coal deposits); and Point Lookout Sandstone. All but the alluvium (recent <br />age) 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 north <br />side of Hay Gulch. The elevation of the water table varies seasonally, ranging from just above <br />the ground surface to a few feet below the surface. Ground water in the alluvium probably flows <br />downstream along Hay Gulch. Ground water in the Hay Gulch alluvium generally has a high <br />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 formation. Based on information from exploration drilling and several decades of <br />underground mining, this is generally an unsaturated formation. However, lenticular sandstones <br />in this formation have produced viable amounts of groundwater. <br />The Point Lookout Sandstone is approximately 400 feet total in 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 <br />by 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 II- 004, and <br />King II-008. <br />5 <br />