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King Coal Mine (C-1981-035) MT-9 <br /> Basin, which extends southward into New Mexico. The Hogback monocline forms the boundary <br /> between the Four Corners platform and the San Juan basin. <br /> Sedimentary rocks of the Upper Cretaceous Mesaverde Group are exposed throughout the area. The <br /> Lower Cretaceous Mancos shale forms the valley five miles to the north, through which U.S. Highway <br /> 160 has been constructed. The Mesaverde Group sits stratigraphically atop the Mancos shale, and is <br /> composed of three major units (in ascending order): the Point Lookout Sandstone, the coal-bearing <br /> Menefee Formation, and the Cliff House sandstone. The general dip of the strata is to the south, <br /> ranging from 2 to 11 degrees. Locally, the Point Lookout is approximately 400 feet thick, the <br /> Menefee is 300 feet in thickness, and the Cliff House unit averages 350 feet. A stratigraphic section is <br /> provided in Appendix 4 of the PAP. <br /> Topography in the area consists of gently south-sloping upland surfaces, bisected by steep-sided <br /> drainages which generally flow to the south-southwest. Within the permit area, the Cliff House forms <br /> the top surface of the upland areas and is exposed, with the Menefee in some instances, in the sides <br /> of the drainages. The deeper Point Lookout unit is not exposed within the permit area. Quaternary <br /> sediments, both alluvial and colluvial, are present in the valley bottoms, and minor landslides have <br /> been mapped on the valley slopes. <br /> Of the two mineable coal seams exposed in the permit area, only the upper seam (Peacock, or "A") of <br /> the Menefee formation was developed at the King I Mine and is currently being developed at the King <br /> 11 Mine. Thickness of the upper seam ranges from less than 48 inches to more than 76 inches. The <br /> upper seam lies approximately 22 feet below the base of the Cliff House sandstone, and has 100 to <br /> 400 feet of overburden throughout much of the permit area. <br /> The lower ("B") coal seam is well exposed at the Burnwell Mine, located adjacent to the King I Mine. <br /> Operations began there in the 1940s, but the mine has long been abandoned and was never <br /> permitted under SMCRA. The lower coal seam of the Menefee Formation has an average thickness of <br /> 48 inches. This seam lies approximately 80 feet below the upper seam, with inter-bedded sandstone <br /> and shale between the two seams. To the north of the permit area, the interburden between the "A" <br /> and "B" seams may thin out, resulting in a single, thicker "A" seam. <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; the Cliff House Sandstone; Menefee Formation (sandstone and coal <br /> deposits); and Point Lookout Sandstone. All but the alluvium (recent age) are Cretaceous units. <br /> The Hay Gulch alluvium consists of unconsolidated and poorly consolidated gravel, sand, silt, and clay <br /> that was deposited by stream flow in Hay Gulch during the last several thousand years. The alluvium <br /> is several tens of feet thick and approximately 1,000 feet wide. GCC has monitored the Hay Gulch <br /> alluvium for more than 30 years in a monitoring well (the Wiltse well) next to the King I Mine. <br /> Ground water in the alluvium is unconfined. The alluvium is recharged by snowmelt and <br /> Page 5 of 11 <br />