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with a dark colored surface horizon and subsoil clay accumulation. This soil has a thinner surface <br />horizon than either Cochetopa or Routt. Adjacent Binco profiles lack a mollic epipedon and argillic <br />horizon. <br />The recommended topsoil salvage depth is based solely on the thickness of the surface mollic epipedon <br />and adjacent, underlying transitional horizons. Topsoil salvage should typically be terminated at the top <br />of the argillic IBtI horizon. The upper portion of the argillic horizon in a few profiles is marginally <br />suitable due to acceptable saturation percentages, consistency, and organic matter contents. The <br />mean in situ suitable topsoil depth for 18 profiles is 20 inches (Appendix 9-51~ <br />The 12E map unit consists of 85 percent Buckskin with 5 percent Buckskin variant (moderately deepl, <br />4 percent Binco, 3 percent Cochetopa, and 3 percent Routt inclusions (Appendix 9-2, Table 1 j. A 1.5- <br />foot mean salvage depth was used for Map Units 12C, 12D, and 12E to calculate recoverable topsoil <br />volumes listed in Table 21-1 and Exhibit 9-1. This topsoil salvage depth figure accounts for inclusions <br />and topsoil loss during salvage due to brush clearing. <br />27A-Silas Loam. Silas loam soils occur on nearly level to gently sloping alluvial fans and valley <br />bottoms. This soil is deep, has a thick, dark colored surface horizon, and lacks significant <br />subsoil/substratum profile development. Adjacent soils are wetter (Venable) or lack a mollic epipedon <br />(Chapertonl~ <br />The recommended topsoil salvage depth is based on the thickness of the surface mollic epipedon and <br />the average depth to unsuitable, subsurface clay lenses. The mean in situ suitable topsoil depth for 4 <br />profiles is 43 inches (Appendix 9-BI. <br />The 27A map unit consists of 90 percent Silas with 5 percent Chaperton and 5 percent Venable <br />inclusions (Appendix 9-2, Table 11• A 3.5-foot mean salvage depth was used for this map unit to <br />calculate recoverable topsoil volumes listed in Table 21-1 and Exhibit 9-1. <br />33D-Lymanson Variant (shallow)-Teton Complex. This map unit is located on moderately steep <br />colluvial sideslopes in the northern portion of the mine area. The soil profiles have dark colored surface <br />and subsoil horizons which overlie a silty clay substratum. <br />15 Revised 4/24/91 <br />