Laserfiche WebLink
<br />Mountain Coal Company <br />West Elk Mine <br />Exhibit 27 <br />Characteristics of West Elk Mine Soil Mapping Units <br />Normally the soils of this unit are not subject to serious Hood hazards. although streams <br />may flood occasionally. In their natural state. these spilt are not susceptible to <br />accelerated soil erosion unless native vegetative cover has been destroyed or depleted. <br />When disturbed and cleared these soils are moderately susceptible to both wind and water <br />erosion. <br />No tendency toward mass movement was noted within areas mapped as mapping unit <br />number X38 and the potential for such movement is iow. <br />Chemical Pro~rties and Natural Fertility -These are moderately weathered. mature soils <br />having genetic horizonation including horizons of silicate clay accumulation, but lacking <br />horizons of calcium carbonate accumulation. Soil reaction ranges from sliehtly acid to <br />mildly alkaline. Under these conditions the cation exchange complex (portion of the soil <br />having the ability to hold and exchange cations) is base saturated or nearly so with <br />calcium being the dominant cation. Thus, there is no deficiency of bases but there is no <br />excess of calcium or magnesium carbonate to depress the availability of other plant <br />nutrients. Detrimental accumulation of sodium or other soluble salt was not observed <br />in these soils. <br />• It is characteristic of the type of soil development found in areas of mapping unit number <br />X38 to have thick, strongly weathered and partly leached surface horizons (A'_ horizons). <br />These horizons are very light colored due to a lack of organic matter and part of their <br />original content of clay has been removed. The type of vegetative cover (conifer) <br />growing on these soils yields very low annual returns of readily decomposable organic <br />matter and favors acid-forming microbiological life in the organic mulch that overlies the <br />mineral portion of the soil. While these processes are not as advanced as in the <br />Spodosolic soil groups (Podzols), they have exerted some intluence on the genesis of the <br />soils of this group. <br />Consequently, natural fertility levels in the upper horizons of the soils of this group are <br />below average for the area. While they are adequate for present stands of timber and <br />deep root systems, some program of fertilization including potassium, nitrogen, and <br />phosphorus would prove beneficial to revegetation activities involving these soils. Soil <br />analysis indicated a borderline deficiency of potassium in these soils (see Exhibit 26). <br />Mappine Unit Number 200: Land Type: Rockland. Sandstone, and Shale - t\fapping unit <br />number 200 is a land type in which the soil pattern is extremely variable from area to <br />area. Typically this unit is used to describe the steep and very steeply sloping <br />escarpment-like borders of mesas, but may also occur on the crests and shoulders of <br />ridges and hills. Its soil pattern is the same as that described for mapping unit number <br />I, except that the areas have a significant amount of bare rock outcrop. Rock is usually <br />ledge sandstone but areas of raw shale are included as µe11. Rock outcrops constitute <br />about 25 to 90 percent of delineated areas. <br />Exhibit 27-32 <br />