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Wesf EIk Mrne <br />• Mass Movement <br />Some soils on steep slopes of the West Elk Mine study area are subject to some mass movement. <br />However, these soils aze not associated with the location of surface facility foundations. Such <br />movement is difficult to predict, however, and usually is triggered by some changes in <br />groundwater movement. <br />It should be emphasized that the following soil units have the potential for mass movement. <br />Moreover, not all areas mapped as a given unit have the identical potential. Thus unit 31 on a five <br />percent slope may be very stable whereas the same unit on a 30 percent slope may have a <br />considerable potential to slide. <br />From the standpoint of soil character alone, the soils of units 5, 17, 30, X30, 31, X31, and X32 <br />have the greatest potential for mass movement. Units 30 and X30 have the lowest potential and <br />have been listed primarily because in some landscapes they tend to be finer textured in the lower <br />solum and C horizon than would be anticipated by their family classification which is based on a <br />weighted average of the B2t horizon. <br />Soil Productive <br />In their natural undisturbed state, most of the soils of the area are suitable for growing natural <br />• vegetation. Natural fertility decreases with depth in most soils of the area and is not adequate for <br />vigorous growth in the lower solum and C horizons. Even though natural fertility seems to be <br />adequate in the upper horizons of many soils, it is believed that some supplemental fertilization <br />should be applied to all seedbeds to insure the best possible growth during early states of <br />reclamation. <br />The soils of the area have moderate to strong grades of natural soil structure. The preservation of <br />as much of the soils' original structure as is possible during the disturbance, transportation and <br />redistribution of these earths is considered an important management goal in all of the soils and is <br />extremely important in the use of some of the finer textured ones. <br />The productivity and capability of each mapping unit to support a variety of uses can be related <br />directly to that soil's suitability as a topsoil material. Table 23 and the mapping unit descriptions <br />provide such information for each unit. <br />Quantitative Soil Anal <br />Table 23 is a breakdown of the soil occurring on the survey area and an assessment of their <br />topsoiling suitability, stripping depth, and general limitations. Average topsoil stripping depths aze <br />based on the depth of material appearing suitable for topsoiling material when holes were augered <br />during mapping. <br />• <br />2.04-133 1/94 PRO5; 8/9471271; Revised Jun. 1995 PRfM <br />