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Erosivity Index R <br />The R factor was mapped by USDA NRCS, and represents a combination of the rainfall intensity <br />and duration, which are recognized as major factors in dislodging soil particles. The value of the R <br />factor used for the West Elk Mine area was 33.3. <br />Soil Erodibility Factor K <br />The K factor is an empirical factor with values published by USDA NRCS for mapped soils <br />throughout the United States. The Soil Survey of Gunnison County, Colorado shows the following <br />mapped soils in the Phase II bond release blocks, along with corresponding K factors. For these <br />reclaimed features with the small nature of the disturbance, where soil was pushed aside and <br />replaced, an average K factor of 0.23 was used to represent pre -mining and post -mining conditions. <br />K Factor for West Elk Mine <br />Phase II Bond Release Block Sols <br />Symbol <br />K Factor <br />Broad Can n -Scout family compin 5 do 25 rcent sl2n <br />111 <br />0.37 <br />Coberl -Falcon da complq& 0 to 15 rcent slo s <br />124 <br />0.28 <br />C hre is -C borolls-Rubble land com ex15 to 90 rcent slo s <br />130 <br />0.02 <br />Haploborolls-Ustochre is -Rock outicro com a 40 to 99 iLercent slo s <br />153 <br />0.10 <br />Ha ack-M ins-Nutras comoeN 5 to 40 rcent slopes <br />155 <br />0.37 <br />Herm-F hes-Kolob family com le 25 to 40 rcent d2eLs <br />158 <br />0.15 <br />Shawa-Sandia famil Kolob family com ex5 to 40 rcent slo <br />185 <br />0.24 <br />Taterhea Pa s ila comon 5 to 40 rcent slo s <br />188 <br />0.28 <br />Taterhea Pa s 'la comMS 40 to 65 rcent slo s <br />189 <br />0.28 <br />Weto -W com e 5 to 65 Nrcent sloM <br />200 <br />0.15 <br />F hes-F hes cool-Fughes, very stony, cool compley, 5 to 25 percent slopes <br />GR6 <br />1 0.32 <br />Averagel <br />1 0.23 <br />Length Slope Factor LS <br />The LS factor accounts for uninterrupted slope lengths and slope steepness. Representative <br />slope lines were draped onto topography in ArcGIS to provide slope lengths and gradients. Lands <br />were returned to approximate pre -mining topography so pre -mining and post -mining LS Factors were <br />the same. The table below presents the LS Factors calculated for each slope using RUSLE 1.06c. <br />11 <br />