1986-12-11_PERMIT FILE - C1981017

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-28- have been previously mined, and the "C" and "0" seams are currently being mined in the Sunlight Mine. Three commercially minable coals of the Lower Bowie Shale submember ("A", "B", and "C" seams) are located in the area of the North Thompson Creek Mines. The North Thompson Creek No. 1 Mine is currently mining the "A" seam. The inactive No. 2 Mine was within the "B" seam. In the area of the Coal Basin Mines, there are two minable seams, the "A" and "B" seams. The "B" seam is being mined at the Coal Basin No. 1 , 3, 4 and 5 Mines. The two seams are separated by 0 to 39 feet of interburden. The Upper Bowie Shale submember overlies the Middle Sandstone submember. This submember contains the Dutch Creek or Middle bed seam, which is mined only at the Coal Basin No. 2 Mine. The Middle and Upper Sandstone submembers are deltaic beach front sandstones. These sandstones are fine to medium-grained and poor to moderately well sorted. The Upper sandstone member is slightly coarser in texture. The Paonia member is about 600 feet thick in the area of the mines, and consists of interbedded sandstone, siltstone, shale and coal beds. The sandstones of this member are more lenticular and discontinuous, and their deposition represents a more terrestrial origin than the sandstones of the Bowie member. There are six irregularly distributed coal seams within the general area of the mines. These seams are, in ascending order, the Placita, the Sunshine, the Anderson, the Lake Ridge, the Thompson, and the Stony Ridge seams. The North Thompson Creek No. 3 Mine is located in the Anderson seam. This is the only active mine in a Paonia member coal . In addition to these minable seams, the Paonia member contains several thin, lenticular seams. The Upper Barren member consists of between 2,000 and 2,500 feet of lenticular sandstones and gray shales. The lenticular sandstones represent terrestrial stream channel deposits. The Tertiary Age Wasatch Formation - Ohio Creek conglomerate, unconformably overlies the Mesaverde Group. This formation outcrops west of the permit areas of the mines. The Wasatch consists of up to 5,800 feet of interbedded claystone, siltstone, sandstone, and conglomerate. The Ohio Creek conglomerate consists of about 400 feet of sandstone and conglomerate unconformably overlying the Mesaverde Group. The sedimentary strata in the southern end of the Grand Hogback Monocline have been injected by igneous dikes, sills, and a laccolith. The coal beds in the Coal Basin Mines have been naturally coked as a result of this igneous activity. Unconsolidated Pleistocene gravel deposits occur as glacial remnants capping some of the ridge tops. The alluvia of the tributaries to the roaring Fork River (e.g., Fourmile Creek, Thompson Creek, and Coal Creek) are generally thin, intermittent and, for the most part, restricted to the immediate stream channels. The most extensive alluvium occurs at the confluence of two or more tributaries.