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• Mountain Coal Company Exhibit '7 West Elk Mine Characteristics of West Elk Mine Soil Mapping Units Physical Properties - Soils of mapping unit number I are young soils in which natural soil structure is only weakly developed. and wha[ structure is present can be easily destroyed. A majority of the components of this mapping unit. therefore, are not well adapted to disturbance and development of new seedbeds. Most of these soils are subject to excessive compaction it traversed b_v heavy machinery and to irreversible puddling if manipulated when the moisture of the soils are near field capacity. Fine textured components (soils with more than 35 percent clay) are parncularly susceptible to these effects. Soils of mapping unit number I are very susceptible to water erosion and moderately susceptible to wind erosion. They contribute runoff and silt during rains that can be detrimental to lower lying areas. Chemical Properties and Natural Fertility - Normally there are no serious chemical limitations to the use of the soils of mapping unit number 1. While most of the components are calcareous throughout, calcium carbonate does not occur in concentrations high enough to seriously affect nutrient availability. • All of the soils of mapping unit number 1 have lower than normal natural fertility levels of the general area. Nitrogen and phosphorus are low even in the A horizons and available supplies decrease with depth. Potassium is not known to be deficient, nor are there any known deficiencies in trace elements. The soils of this mapping unit are poorly weathered soils and have little or no natural reserve of plant nutrients. In consequence, they are unable to regenerate adequate levels of fertility after disturbance. Disturbed areas in which revegetation is to be attempted should have a supplemental fertilizer program. Mapping Unit Number 4 - Moderately deep (20 to 40 inches to bedrock) and deep (more than 40 inches to bedrock) light colored, medium to moderately fine textured (18 percent to 35 percent clay) undeveloped soils having no soil horizonation other than a slightly darkened surface horizon and weak and inconsistent horizons of secondary carbonate accumulation (Torriorthents) or weakly developed soils having slightly darkened surface horizons, brighter colored subsurface horizons of weak to moderate structure and weak horizons of secondary carbonate accumulation (Camborthids) occurring in parts of the study area where the mean summer soil temperature (June, July, and August averages measured at 20 inches) is 59°F or warmer. Classification of Major Com~nents -The components listed below comprise the major • part of the mapping unit: Exhibit 27-2