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Hubberson Gulch. IV. Topsoil Soil resource information is provided in Tab 9, Volume 5 of the permit application. Information on topsoil handling, maintenance and testing is contained in Tab 21, Volume 13. The PR-1 submittal extensively reorganized the soils sections of the application and updated the soil baseline information to reflect 1990 survey of portions of the north mine area which had not previously been surveyed. Baseline data had been collected for the South Extension Area covered in PR-2, and in 1997 SCC conducted a topsoil depth verification survey to confirm the topsoil resource information collected previously. This information is also included in Tab 9. The permit area is occupied by three soil orders; Mollisols, Entisols, and Aridisols. The presence of these three orders is characteristic of the soils found in steep, semi-arid regions of Northwestern Colorado. These orders represent soils that grade from recently developed soils with minimum horizon development to more developed soils with well developed diagnostic horizons. Specific soil types within these orders occur on predominantly three types of parent material-land form combinations, namely: 1) upper side slopes, ridges, and swales of sandstone residuum; 2) toe slopes, side slopes, rounded ridge tops of shale residuum and colluvium; and 3) toe slopes, side slopes, ridges, and escarpments of sandstone and shale. Among the 22 soil types occurring within the permit area, major topsoil salvage limitations include clay textures, high coarse fragment con[ent, steep slopes, shallow bedrock, salini[y, and alkalini[y. Seneca Coal Company strips topsoil in single lifts once the woody vegetation which would interfere with handling of the topsoil has been removed, pursuant to 4.06.2(1). Topsoil will be redistributed immediately on regraded areas when possible or stockpiled in designated storage areas pursuant to 4.06.1(2). The amount [o be stockpiled depends on pit advance, season of the year, and reclamation activities taking place at the time of salvage. Stockpiled topsoil is placed in stable areas and protected from wind and water erosion by planting of aquick-growing vegetative cover. Single lift stripping mixes different soil horizons and thereby dilutes heavy clay concentrations encountered in various subsoils. Although soil survey information and soil handling plans contained in the PR-1 application were detailed and comprehensive, several issues of concern were raised during the adequacy review. The Division questioned what field characteristics would be used to define appropriate salvage depths and requested justification for complete or partial salvage variances proposed for a number of soil map units. Seneca provided appropriate detail in regard [o field salvage depth determinations. Generally, in shale derived soils dominated by western wheatgrass/alkali sagebrush vegetation, a 6 inch depth will be salvaged. In sandstone derived soils dominated by mixed brush vegetation, salvage will be terminated Seneca II-W Findings Document 33 June I5, 2001 Permit Renewal No. 3