2012-10-01_REVISION - M1977305 (14)

Home Browse Search

Exhibit I Soils Information LP -21 Mine Permit Amendment M -1977 -305 The major soil types found in the region of the LP -21 Mine as defined by the United States Department of Agriculture, Web Soil Survey (WSS) are: 1. 17 -Barx- Progresso complex 2. 23- Bodot, dry -Ustic Torriorthents complex 3. 45- Gladel- Bond -Rock outcrop complex, 1 to 50 percent slopes 4. 73- Paradox fine sandy loam, 1 to 4 percent slopes 5. 76- Pinon - Bowdish -Rock outcrop complex 6. 87 -Rock outcrop 7. 88 -Rock outcrop - Orthents complex A complete description of each soil type, as well as general locations of each type within the LP -21 permit area, is included in the WSS report and map below. The main surface disturbance will be located in the Bodot, dry -Ustic Torriorthents complex (Soil map unit 23) and Rock outcrop - Orthents complex (Soil map unit 88). The Bodot, dry -Ustic Torriorthents complex component is on terraces, structural benches and landslides. The parent material consists of residuum weathered from sandstones and shales. Depth to a root restrictive layer, bedrock, is 10 to 80 inches. The natural drainage class is well drained and water movement in the most restrictive layer is moderately low. The Rock outcrop - Orthents complex is described as "warm, shallow, well- drained, sloping to steep soils and rock outcrops on breaks and canyons." A typical landscape is characterized by the deep sandstone canyons with steep slopes (from 25 % - 100 %) and long narrow valleys. The dominant parent material for these soils is sandstone with some shale and alluvium. This mapping unit can be divided into three general components. Rock outcrops account for about 45% of the unit. These are largely of sandstone, with some small shale outcrops. About half of the unit (49 %) is in shallow (20 inches or less) stony soils, generally, with a light colored, loamy surface layer. Mixed alluvial soils of the Dolores and San Miguel River bottoms account for about six percent of the mapping unit. The dominant ground cover associated with this mapping is pinon-juniper. At higher elevations oak brush, serviceberry, and grass are more prevalent, while willows and cottonwoods may be found along the narrow valley. For a full discussion of associated vegetation see Exhibit J - Vegetation Information.