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VI. HISTORIC RECORD STUDY AREA SOIIS <br />' Soils of the historic record study area are mapped as Absarokee-Work foams by the <br />Natural Resource Conservation Service (USDA, 1980). These soils are representative <br />of the gently sloping terraces and benches found above the North Fork of the Gunnison <br />' River drainage on sideslopes and tceslopes. The Absarokee loam is a moderately deep, <br />well-drained soil originating from sandstone parent material. [t ranges from 20 to 40 <br />inches in depth. Work foams are generally deeper than the Absarokee foams and may <br />' be present in eolian material as well as in-place decomposed sandstone parent material. <br />Both soils have surface layers which are foams approximately six inches thick. The <br />primary difference between these series is the depth of the subsoil horizon, the Work <br />' series having a clay layer twice as thick as the Absarokee series. Native vegetation <br />may include grasses, sagebrush, oakbrush, and serviceberry. These soils are primarily <br />used for grazing and wildlife habitat. <br />' Samples taken during the 1996 field season verify the prior mapping of these soil map <br />' units. Within the historic rewrd study area the soils varied little from south to north. <br />Both test pits revealed deep mineral soils (>74 inches), with little development of <br />surface organic horizons. Both soil samples were identified as Work loam. <br />Descriptions of the soil test pits are contained in the Appendix. <br />Table 3 presents the results of analyses on the three soil horizons obtained during <br />August 1996 sampling. The physical and chemical characteristics of the soil horizons <br />from the historic record study area are similar in character to soils from other locations <br />at the mine site and adjacent areas. Hydrogen ion concentrations (pH) of the historic <br />' record study area soils reflect a slightly acid condition, which is expected for soils <br />originally associated with oakbrush vegetation (oaks being known for their tannic acid <br />content). Electrical conductivity of the soil horizons is low, illustrating relatively low <br />' concentrations of soluble salts in these soils. This is also expected, given the arid <br />moisture regime and lack of significant retained soil moisture. Textures of the soil <br />horizons reflect their genesis, foams and clays reflecting parent materials of sandstone <br />' and shale. Low organic matter content is a reflection of slow decomposition occurring <br />in the arid environment. Concentrations of macronutrients (N, P, K) reflect conditions <br />' found at the majority of other soil types in the vicinity of the mine (Savage and Savage, <br />1996b, 1996c). Micronutrients detrimental to plant growth or livestock (Se, B, Mo) <br />are not present in significant quantities. <br />1 <br /> <br />' -12- <br />