2012-01-06_PERMIT FILE - C1982057 (16)

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None of the soils exhibited levels of boron or selenium which are potentially toxic to plant ~~ growth, nor were there elevated levels of molybdenum, copper, or zinc. • Calcium carbonate equivalent content ranges from less than 1 to 16 percent. Calcium carbonate levels are lowest in the leached surface layers of all soils and generally lawyer in the soils derived from sandstone or siltstone within the mine area. The clay and clay loam textured soils have higher calcium carbonate percentages and often have an accumulation of lirne and gypsum in the subsoil. Acid base potential values show an excess neutralizing potential of 5 to 20 tons calcium carbonate per 1000 tons of soil. One soil, Spicerton Variant, showed a deficiency of greater than 5 tons of calcium carbonate which is below the recommended suitability level shown in Table 9-2. Particle size analyses show silt- and clay-size fractions to be dominant over sand values. This correlates well with the particle si;:e family classes presented in Table 9-4. Soils in the: study area typically have sand, silt, and clay values ranging from 15 to 40 percent, 25 to 55 percent, and 20 to 60 percent, respectively. Suitability of Soils for Topsoiling. An evaluation of each soil series and soil series veuiant's suitability as a topsoil resource is provided in Appendix 9-6, Evaluation of Topsoil Suitability. Each sail type was evaluated by individual sampled or described horizon for significant physical and chemical parameters presented previously in Table 9-2. The range of characteristics for each soil type (presented in Appendix 9-3) was also evaluated. A summary of restrictive features for each sampled pedon, as well as recommended topsoil salvage depths for each representative sampled or describer profile is also included in Appendix 9-6. Results of the 1997 Seneca II-W South Extension Area soil survey indicate no changes to the original topsoil suitability evaluation for soils in the south area. Reference to the additional 43 soil descriptions has been added to the appropriate soil series and map unit information presented in Appendix 9-3. Menbar Isample sites HG1 and HG3, map unit 52A) and Hunchback Isample site HG3, map unit 156) soils in Hubberson Gulch will not be disturbed by mining and therefore were not evaluated for topsoil suitability. All soils, except Spicerton variant, have suitable characteristics for reaction (pH), salinity IEC1, sodium adsorption ratio (SARI, and carbonates. The major restrictive physical limitation to topsoil salvage is the high clay content associated with the fine, montmorillonitic soil families (Aaberg, Abor, Binco, Buckskin, Bulkley, Cochetopa, Morapos, Routt, and Spicerton variant seriesl. A significant secondary limitation for the soils which occur on ridgeline or steep and very steep convex sideslope landscape positions is the high rock fragment content and very 26 Revise~f 9/98