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Mesaverde Group. This unit consists of interbedded sandstones, siltstones, <br /> shales, and coals. The unit is not thought to be of marine origin and, as a <br /> result, the sandstones and the coals are highly lenticular, discontinuous, and <br /> of limited lateral extent in outcrop_ This unit ranges up to 1,500 feet thick <br /> and outcrops throughout most of the five-year permit area. <br /> The Mesaverde Formation is unconformably overlain by the Tertiary Age Rudy or <br /> Wasatch Formation. This formation consists of red to buff-colored shales, red <br /> sandstones, and red to gray conglomerates. The sediments of this formation <br /> are weathered volcanic rocks. The Ohio Creek conglomerate is the basal unit <br /> within the formation and is 100 to 200 feet thick. <br /> The alluvium of the North Fork of the Gunnison River consists of Quaternary <br /> Age deposits of mixed coarse sand, cobbles and boulders. These coarse <br /> sediments are composed primarily of igneous and metamorphic rock types, and <br /> have their source area in ttte headwaters and upper reaches of the North Fork. <br /> This coarse alluvium is capped by finer sands and silts. The North Fork <br /> alluvium in the area of the Hawk's Nest, Bear, West Elk and Somerset Mines is <br /> fairly narrow in width and is between 50 and 70 feet thick. About a mile <br /> below the town of Somerset, Colorado, the width of alluvium increases while <br /> the thickness of alluvium decreases to about 35 feet. <br /> Since the three main minable seams (B, E, and F) on West Elk's property <br /> directly overlie one another, their structural characteristics are virtually <br /> identical. The F seam strikes north 60 degrees west and dips three: to five <br /> degrees northeast across the! lease block. In the Jumbo Mountain area, the B <br /> seam has an average dip of e1 .6 degrees in a north 25 degrees east direction. <br /> 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 <br /> seam workings. Fracture sets and cleat orientations of the E seam are also <br /> the same. The major clear direction in the nearby Bear and Somerset mines is <br /> from North 70 to 75 degrees east and is probably representative of the face <br /> cleat direction in the Jumbo Mountain area. <br /> Only minor faulting of limited vertical displacement has been observed in the <br /> Blue Ribbon, Bear, and Hawk's Nest Mines. However, in the Orchard Valley <br /> Mine, a fault with a displacement of 50 feet was encountered during mining. <br /> Drill hole data indicate the presence of other faults in the life-of-mine area <br /> with similar displacements. One major fault has been encountered in the <br /> Somerset Mine. The faults which have been encountered in existing mines tend <br /> to be high angle, normal faults. <br /> Climatological Information - Rules 2.4.8 <br /> Information regarding climate characteristics can be found in Section 2.04 .3 <br /> and 2.04.8 of west Elk's permit application. <br /> The mine site lies within the North Fork valley near Somerset, Colorado. At <br /> the mine site the valley is narrow and steep sided and follows a general <br /> east-west orientation. Considerable topographic variation across the mine <br /> site, and west central Colorado in general, results in marked fluctuation in <br /> seasonal and average precipitation and. temperature values for the entire area. <br /> The mountains of the Continental Divide provide an effective barrier to the <br /> movement of moisture-laden air that reaches the eastern slope of the Rocky <br /> Mountains from the Gulf of Mexico. Under this influence, two basic types of <br /> climate, semi-arid and undifferentiated highlands, are characteristic of the <br /> general area where the mine is situated. Temperatures can range below <br /> freezing in the winter, and the summer, with the exception of higher <br /> elevations, can be extremely warm. The precipitation that does fall, <br /> originates from the Pacific Ocean weather systems, and most frequently occurs <br /> in the winter. <br /> Average annual precipitation ranges from approximately ten inches along the <br /> North Fork of the Gunnison River and the lower portion of Minnesota Creek to <br /> as much as 24 inches on the flanks of Mount Gunnison. The majority of <br /> precipitation falls as snow during the winter months, while the sparse summer <br /> precipitation consists of '_solated thunderstorms. <br /> 8 <br />