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<br />Mountain Coal Company <br />West Elk Mine <br />Exhibit 27 <br />Characteristics of West Elk Mine Soil Ivtapping Units <br />Consequently. any operations involving the reveeetation of disturbed, transported, and <br />relocated materials from these soils will need to be very carefully managed. Because of <br />their rather severe limitations as a result of their fine texture the soils of this unit are <br />considered to be only moderately good sources for seedbed materials. <br />The soils of mapping unit number 31 have wide shrink'swell ratios. total potential <br />extensibility of ~l0-inch sectior, ranges from about' to 5 inches. <br />In their natural state. these soils are not susceptible to much soil erosion unless native <br />vegetation has been destroyed or depleted. If cleared or disturbed they are very <br />susceptible to water erosion due to large amounts of runoff, and moderately susceptible <br />to wind erosion. <br />Minor evidence of mass movement on some of the steeper slopes is observed. The soils <br />of this unit have a moderate to high potential for such movement and any practice <br />involving the addition of large amounts of water on these soils will increase the <br />susceptibility for mass movement. <br />• Chemical Propgrties and Natural Fertility - These soils are moderately weathered, <br />maturely developed having genetic horizons of silicate clay accumulations (B2t horizons) <br />but normally lacking horizons of secondary carbonate accumulation. The soil solum (A <br />and B horizons) is neutral to mildly alkaline while the C horizon is neutral to moderately <br />alkaline and may contain some free carbonate. Under such conditions the cation <br />exchange complex (portion of the soil having an ability to hold and exchange cations) is <br />normally base saturated with calcium being the predominant cation, but there is not <br />enough free calcium and magnesium carbonate to seriously depress the availability of <br />other plant nutrients. Natural fertility levels aze high in the upper horizons of the soil <br />but gradually decrease with depth as organic content decreases. No evidence of <br />deficiencies of essential plant nutrients or of trace elements is observed. <br />Nitrogen supplies and availability aze closely associated with the amount and <br />decomposition of organic matter in the soil. Any practice that involves the loss of the <br />organic rich upper soil horizons. more rapid than normal decomposition of organic <br />matter, or the prevention of an annual return of organic plant remains could cause <br />temporary nitrogen deficiencies. Supplemental fertilization of disturbed areas that are <br />to be revegetated will insure the best and most vigorous seedling growths. <br />Map~ine Unit Number X31 -This mapping unit has the same description as mapping <br />unit number 3l. <br />• Classification of Major Components -The components listed below comprise the major <br />part of the mapping unit: <br />Exhibit 27-26 <br />