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• Mountain Coal Company West Elk Mine Exhibit 27 Characteristics of West Elk Mine Soil Mapping Units A. TVpic Cryoboralf (Gray wooded soils>. 1. Fine-loam, mixed family. (Lick Series) (Tongue River Series) Extent and Major .-yreas of Occurrence - Ivtapping unit number X33 has a small total acreage and is found in the areas of highest elevation in the southeastern part of the mine area. Characteristic Toooeraohv -These soils occur on moderately to steeply sloping mountain and hillsides usually on north facing slopes. Slopes range from about 4 to 60 percent. Physical Properties -The soils of mapping unit number X38 are mature soils having distinct genetic soil horizonation including thick, light colored, A2 horizons with weak and unstable platy structure. The horizon of silicate clay accumulation usually lies at some depth but has moderate and stable structure. This would be a very unfavorable type of soil horizonation if it were not for the A2 horizon which is normally moderately coarse textured. This allows for good aeration and permeability of the soil since sand grains provide considerable pore space. The B2t horizons of these soils have medium to moderately fine texture and good stable soil structure. They can be disturbed without serious loss of physical properties for seedbed material if properh~ managed. Both the A2 and Bit horizons are subject to packing if traversed by heavy machinery and to irreversible puddling if handled wet. The A2 horizon under such conditions can be reversed and good physical soil properties renewed by conventional tillage procedures. The B2t horizon on the other hand can only be worked over a moderate range of soil moisture without serious loss of favorable physical properties for seedbeds. Any use of the soils of this unit for materials for new seedbeds probably will be accom- plished by a mixture of the A2 and B2t horizons. The result will be a matrix of sandy loam or sandy clay loam in which clods of clay loam are embedded. Such a mixture would have physical properties intermediate between those described for the two horizons separately and would still be physically capable of being used as seedbeds. The soils of this unit are listed as moderate for use in new seedbeds due to anticipated poor fertility levels rather than physical limitations. The soils of this unit have low shrink/swell ratios, with a difference in volume changing • ability between the upper and lower soil horizons. Assuming an upper 20 inches of loam to clay loam, the potential total extensibility of a ~l0-inch section is about 0.4 to 1.4 inches. Exhibit 27-31