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identified in the Upper Coal Member: the D (Oliver) horizon, the E (Hawk's Nest) horizon, and <br /> the F horizon. The D horizon occurs directly above the massive sandstone of the Lower Coal <br /> Bearing Member and contains three seams. This horizon was mined in the Bowie #1 and#2 <br /> Mines. The E horizon occurs about 130 feet above the D horizon and contains two coal seams. <br /> This horizon has been mined at the Hawk's Nest Mine and was mined at the Blue Ribbon Mine. <br /> The West Elk Mine is mining the E Seam, but did not mine the E seam on Jumbo Mountain <br /> because this seam is split and comprised of several thin(< 5 ft.) coal benches which are <br /> separated by rock partings. The F horizon contains two coal seams and has been mined at the <br /> West Elk Mine. At the mine site, the coal is immediately overlain and underlain by shale. Coal <br /> seams of the F horizon do not exist to the north of the North Fork of the Gunnison River in <br /> thicknesses sufficient for mining. In the Jumbo Mountain area, the F Seam thins to less than five <br /> feet in thickness and is of limited aerial extent. Therefore, MCC does not plan to mine this seam <br /> in Jumbo Mountain. <br /> Overlying the Upper Coal Member is the Barren Member of the Mesaverde Formation. This unit <br /> consists of interbedded sandstones, siltstones, shales, and coals. The unit is not thought to be of <br /> marine origin and, as a result, the sandstones and the coals are highly lenticular, discontinuous, <br /> and of limited lateral extent in outcrop. This unit ranges up to 1,500 feet thick and outcrops <br /> throughout most of the permit area. <br /> The Ohio Creek Member is the uppermost member of the Mesaverde Group. This unit is <br /> approximately 700 feet thick and consists primarily of interbedded sandstone, mudstone, and <br /> shale. The sandstones range from a few feet to more than 100 feet in thickness and are generally <br /> lenticular in nature. Although typically fine to coarse grained, the sandstones may locally be <br /> conglomeratic. <br /> The Mesaverde Formation is unconformably overlain by the Tertiary Age Rudy or Wasatch <br /> Formation. This formation consists of red to buff colored shales, red sandstones, and red to gray <br /> conglomerates. The sediments of this formation are weathered volcanic rocks. <br /> Immediately south east of the permit boundary, igneous intrusives of Tertiary age form the <br /> laccolith of Mt. Gunnison. <br /> The alluvium of the North Fork of the Gunnison River consists of Quaternary Age deposits of <br /> mixed coarse sand, cobbles and boulders. These coarse sediments are composed primarily of <br /> igneous and metamorphic rock types, and have their source area in the headwaters and upper <br /> reaches of the North Fork. This coarse alluvium is capped by finer sands and silts. The North <br /> Fork alluvium in the area of the Hawk's Nest, Bear, West Elk and Elk Creek Mines is fairly <br /> narrow in width and is between 50 and 70 feet thick. About a mile below the town of Somerset, <br /> Colorado,the width of alluvium increases while the thickness of alluvium decreases to about 35 <br /> feet. <br /> Since the three main minable seams (B, E, and F) within the West Elk Mine's permit boundary <br /> directly overlie one another, their structural characteristics are virtually identical. The F Seam <br /> strikes north 60 degrees west and dips three to five degrees northeast across the lease blocks. In <br /> the Jumbo Mountain area, the B Seam has an average dip of 4.6 degrees in a north 25 degrees <br /> east direction. The major cleat orientation within the F and B Seams is north 70 degrees east. <br /> This face cleat is prominent and consistent throughout the existing F and B Seam workings. <br /> 17 <br />