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<br />4. Site Description (Exhibits 1, J, &IC) <br />Soils, Vegetation, and Climate <br />The proposed mine site is on a very steep hillside with a western facing aspect ranging from <br />about 7,800 to 8,400 ft above sea level. The average slope across the various rock slides is 27" <br />(2H:1 V), and there is no soil cover present. 7-he average slopes on the outcrop areas above the <br />slides ranges from 75" (iH:3.5V) to 30". There is soil and vegetative cover on areas adjacent to <br />the rock slides and outcrops, but the slides and outcrops are bare of vegetation. The soil adjacent <br />to the rock slides and outcrops is mapped by the Soil Conservation Service as Nagitsy channery <br />loam (Soil Survey of Rio Blanco County Area, May 1982). It is a typical soil unit for <br />mountainsides, ridges, and hills in the area (see enclosed soils map). The native vegetation <br />growing on the Nagitsy soil is mainly shrubs and grasses. The average annual precipitaticn is 18 <br />to 22 inches, the average annual air temperature is 37 to 39 degrees F, and the average frost free <br />period is 45 to 75 days. <br />The Nagitsy soil is moderately deep and well drained. It formed in residuum and colluvium <br />derived fi'om sandstone and shale bedrock. The upper part of the surface layer is typically very <br />dark grayish brown channecy loam about 7 inches thick. The lower par[ is dark grayish brown <br />channery loam up to I G inches thick. The subsoil is brown very channery loam 10 inches thick. <br />Rock fragments make up 15 to 35 % of the A horizon and 35 to 65 % of the deeper section. <br />Hard sandstone is generally present at depths ranging from 20 to 40 inches. A closely related soil <br />unit present in the area is the Torriorthents rock outcrop complex. The unit consists of thin well <br />drained soils and rock outcrops with slopes ranging from 35 to 90 %. The rock slides and <br />outcrops to be mined are considered a subunit of the Torriorthents. Livestock grazing and <br />wildlife utilization on the Torriorthents are limited by loose rock, sparse vegetation, and steep <br />slopes. <br />The permeability of the Nagitsy soil is moderate and so is the available water capacity. Effective <br />rooting depth is 20 to 40 inches. Runoff is medium, and the hazard of water erosion is slight to <br />7 <br />