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III. SYLVESTER GULCH FACILITIES AREA SOIIS: <br />HLSTORIC DESCRIPTIONS P-ND MAPPING RESULTS <br />The proposed Sylvester Gulch Facilities Area originates immediately south of the <br />Lower Refuse Pile and extends approumately one mile south along Sylvester Gulch. <br />The SGFA is comprised of a lineaz transportation corridor (initial 3500 feet), with <br />extended surface facilities development for approximately 2000 additional feet south of <br />the transportation corridor. The proposed surface facilities development will include <br />surface support facilities and underground mine access. Development of the surface <br />facilities and transportation comdor will require disturbance of the Sylvester Gulch <br />drainage bottom, tce and sideslopes. Construction of the surface facilities will occur in <br />phases. <br />Sylvester Gulch is an ephemeral drainage trending north-south with a drainage area of <br />4.25 square miles. The drainage has a maximum elevation of 8290 feet and a <br />minimum elevation of 6070 feet. Channel length is 3.4 miles with an average gradient <br />of 12 percent. Sylvester Gulch drains the west flanks of the West Flatiron and empties <br />into the North Fork of the Gunnison River north of State Highway 133, immediately <br />east of the mine entrance road. There are four significant branches comprising <br />Sylvester Gulch. The drainage is sharply incised with steep tceslopes adjacent to a <br />narrow drainage bottom. The drainage bottom ranges from three feet at its narrowest <br />point to nearly 200 feet wide in areas with depositional terraces or at the confluence of <br />drainage branches. <br />Topography of the Sylvester Gulch drainage is best described as steep, rocky sideslopes <br />with occasional terraces above the drainage bottom formed by surficial mass movement <br />or alluvial deposition. Outcrops of sedimentary bedrock aze common above the <br />drainage bottom along the sideslopes. <br />Soils of the Sylvester Gulch drainage reflect young soils with little horizon <br />development. Since slopes are steep, annual precipitation low, and vegetation <br />characterized by woody species of montane and zeric conditions, soils do not have <br />significantly developed organic horizons. The deepest and most well developed soils in <br />the Sylvester Gulch drainage are found on terraces above the drainage bottom which <br />have benefited from deposition of fine material from surface water flow events and/or <br />surficial deposition originating with downslope surficial creep from sideslopes. <br />Several general soil surveys of the mine permit and adjacent area have been conducted <br />commencing in 1976 with the original environmental studies for the initial permitting <br />of the West Elk Mine. Subsequent surveys and mapping occurred in 1980 with a more <br />• detailed sampling and description of the soils to be disturbed during the construction of <br />mine facilities. Additionally, the NRCS mapped private and Bureau of Land <br />Management (BLM) lands within the SGFA, while the USFS surveyed and mapped <br />-5- <br />