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VI. HISTORIC RECORD STUDY AREA SOIIS Soils of the historic record study area aze mapped as Absazokee-Work foams by the Natural Resource Conservation Service (USDA, 1980). These soils are representative of the gently sloping terraces and benches found above the North Fork of the Gunnison River drainage on sideslopes and tceslopes. The Absazokee loam is a moderately deep, well-drained soil originating from sandstone pazent material. It ranges from 20 to 40 inches in depth. Work foams are generally deeper than the Absarokee foams and may be present in eolian material as well as in-place decomposed sandstone parent material. Both soils have surface layers which aze foams approximately six inches thick. The primary difference between these series is the depth of the subsoil horizon, the Work series having a clay layer twice as thick as the Absazokee series. Native vegetation may include grasses, sagebrush, oakbrush, and serviceberry. These soils are primarily used for grazing and wildlife habitat. Samples taken during the 1996 field season verify the prior mapping of these soil map units. Within the historic record study azea the soils varied little from south to north. Both test pits revealed deep mineral soils (>74 inches), with little development of surface organic horizons. Both soil samples were identified as Work loam. Descriptions of the soil test pits are contained in the Appendix. Table 3 presents the results of analyses on the three soil horizons obtained during August 1996 sampling. The physical and chemical characteristics of the soil horizons from the historic record study area are similar in character to soils from other locations at the mine site and adjacent areas. Hydrogen ion concentrations (pH) of the historic _ record study azea soils reflect a slightly acid condition, which is expected for soils originally associated with oakbrush vegetation (oaks being known for their tannic acid content). Electrical conductivity of the soil horizons is low, illustrating relatively low concentrations of soluble salts in these soils. This is also expected, given the acid moisture regime and lack of significant retained soil moisture. Textures of the soil horizons reflect their genesis, foams and clays reflecting parent materials of sandstone and shale. Low organic matter content is a reflection of slow decomposition occurring in the grid environment. Concentrations of macronutrients (N, P, K} reflect conditions found at the majority of other soil types in the vicinity of the mine (Savage and Savage, 1996b, 199fx). Micronutrients detrimental to plant growth or livestock (Se, B, Mo) are not present in significant quantities. -12-