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Erosivity Index R <br /> The R factor is mapped by USDA NRCS, and represents a combination of the rainfall intensity and <br /> duration, which are recognized as major factors in dislodging soil particles. The value of the R factor <br /> for the Colowyo Mine area is 19. <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 Moffat County,Colorado shows the following mapped <br /> soils in the Phase II bond release block, along with corresponding K factors. <br /> Pre-Mining K Factor for Colowyo Mine <br /> Weighted <br /> Symbol Soil K Factor Acres % K Factor <br /> Phase II Bond Release Block <br /> ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................... <br /> 5 CamP.... ass Ps fine sand loam 3 to 12 percent slopes 0.24 0.5 0.2% 0.00 <br /> ..................................................................... .................................................Y.................................................... .................................... ................................................................................................................................................................................................................................... <br /> 26 ass Cam sP....P fine sand loam, 12 to 25 ercent slo es 0.24 7.1 2.4% 0.01 <br /> ............................... <br /> ...................................... .................................................Y..........................................................P....................................P.............................................................................................................................................................................................................................. <br /> 37 Cocheto a loam 12 to 25 percent slopes 0.28 58.5 19.9% 0.06 <br /> ..................................................................................P.............................................................P....................................P.......................................................................................................................................................................................................................................................................... <br /> 38 Cocheto a loam,25 to 65 percent slopes 0.28 36.6 12.4% 0.03 <br /> ..................................................................................P............................................................... ....................................P......................................................................................................................................................................................................................................................................... <br /> 77 Forelle loam 3 to 12 ercent slopes 0.28 0.9 0.3% 0.00 <br /> .................................................................................................................................P....................................P............................................................................................................................................................................................................................................................................................ <br /> 113 Kemmerer-Yamo complex,5 to 30 Percent slopes 0.32 2.5 0.8% 0.00 <br /> .................................................................................................................................... ............................................ ....... ............................................................................................................................................................................................................ <br /> 135 MoraP os loam, P P <br /> 12 to 25 percent slopes 0.32 93.1 31.6% 0.10 <br /> ....................................................................... ................................................................. .................................... ................................................................................................................................................................................................................................................................................ <br /> 206 Ustorthents,fri id-Borolls complex, 25 to 75 percent slopes 1 0.1 1 95.5 1 32.4% 0.03 <br /> Summary 294.6 1 100% 0.23 <br /> *Acreage does not reflect removing channels. <br /> Lenath Slope Factor LS <br /> The LS factor accounts for uninterrupted slope lengths and slope steepness. Representative slope <br /> lines were draped onto the pre-mining and post-mining topography in AutoCAD to provide slope lengths <br /> and gradients. The table below presents the LS Factors calculated for each slope using RUSLE 1.06c. <br /> LS Factor for Colow o Mine <br /> Pre-Mining Post-Mining <br /> Sloe 1 Slope 2 Slope 3 Sloe 1 Slope 2 Slope 3 <br /> Gradient (%) 33.3 10.8 11.1 16.5 7.5 21.0 <br /> Length ft 582 666 377 582 666 377 <br /> LS-Factor 11.600 2.544 2.236 4.670 1.474 5.526 <br /> 10 <br />