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• Length Slope Factor This parameter must be chosen very carefully to represent the pre-mining and post-mining conditions. Since the area was restored to approximate original contour, the same LS factor is used in both cases. No undisturbed areas above the disturbed areas are considered. The 6.24 acre area at the N#1 Mine is shown on the attached map. This area is best represented as a slope of 30% grade and a length of 300 feet. Using the enclosed Table 1 from the RUSLE reference, it is seen that the LS factor for these conditions is 8.68. This is used for both the pre and post- mining conditions. The slopes at all sites are relatively straight, therefore no adjustments to the LS factor due to concave or convex slopes are needed. C Management Factor For rangeland and pastureland, the "C" factor is directly related to the percent of the ground that is covered by vegetation and the type of vegetation that is present. The type of vegetation is important because herbaceous cover, grasses, will protect the soil better than trees or shrubs at the same vegetative cover levels. The enclosed Table 2, reproduced from the EPA (1977), shows how the "C" factor is related to the vegetation. According to all of the baseline data for vegetation in Chapter K of the permit, almost all of the pre-mining communities were mountain shrub or big sagebrush. The mountain shrub community consists of predominately oak and serviceberry with very little grass cover. The big sagebrush community consists of big sagebrush, rabbitbrush and minor grasses. Total graminoids comprised less than 12% cover. Total vegetative cover is 65.1%. Canopy cover for this community is approximately 55%. From the enclosed Table 2, using "w" for the type of cover and using 10°k cover that contacts the surface, the C factor for this community at shrub height of 0.5 meters is 0.26. With 2.0 meter shrubs, C = 0.34. These are averaged to get c = 0.30. Pre-Mining Average "C" _ .30