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• <br />Mountain Coal Company <br />West Elk Mine <br />Exhibit 27 <br />Characteristics of West Elk Mine Soil Mapping Units <br />Physical Properties -The soils of mapping unit number X3~ are weakly developed below <br />the surface horizons (A horizons) and have only weak grades of nautral structure. The <br />unfavorable surface conditions are counteracted by the medium-coarse texture which <br />insures good permeability. Any manipulation of these soils will not greatly affect the <br />quality of seedbed material. Compacted areas can usually be rectitied by conventional <br />tillage methods. <br />Shrink swell ratios of this unit are very low. Tonal potential extensibility ranges from <br />0 to 0.8 inch fora 30-inch section. There is no esidence of mass movement and <br />potentta] for thts movement is low. <br />Flat-topped mesa-like areas in the northeastern part of the mine area have extensive aeeas <br />of this soil mapping unit. Shading patterns of aerial photographs result from the <br />formation of dunes or drifts around stands of oakbrush and juniper. This is considered <br />the wind-eroded phase of mapping unit number X25. <br />Since the area is vulnerable to high winds, reclamation will be started promptly after <br />mining to provide adequate protection. <br />• Chemical Properties and Natural Fertility -These soils are weakly weathered and <br />immature with no genetic horizonation other than a dazk surface horizon (A horizon}. <br />They are non-calcareous throughout and neutral to mildly alkaline in reaction. Thus <br />although the cation exchange complex (portion of the soil capable of holding and <br />exchanging cations) is base saturated, with calcium as the principal cation. there is no <br />excess of calcium or magnesium as free carbonate to depress the availability of other <br />essential plant nutrients. <br />No field evidence of deficiencies in essential plant nutrients or trace elements was noted; <br />however, the soil analysis indicated a borderline phosphorus deticiency (see Exhibit'_6). <br />Temporary deficiencies of nitrogen may occur in early spring months because these soils <br />occur above 7,800 feet and soil temperatures warm slowly. This is a common <br />phenomenon in many soils of high elevation and is temporary. Reclamation procedures <br />may require supplemental nitrogen and phosphorus to insure vigorous seedling growth <br />in the early spring months. <br />Mapping Unit Number 26 - Moderately deep (20 to 40 inches to bedrock) and deep <br />(more than 40 inches to bedrock), dark colored, medium to moderately fine textured (18 <br />to 35 percent clay), soils having immature soil horizonations consisting of darkened <br />surface horizons (A horizons) and in places brighter colored subsurface (B_ horizonsl of <br />weak to moderate structure, occurring in parts of the studs area where the mean summer <br />soil temperature (June. July, and August mean temperature measured at ~0 inches) is <br />• 59°F or warmer. <br />Exhibit 27-17 <br />