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Revised 1/11/2016 <br />Soil Erodibility(K) <br />Page 2 <br />Section 3.03.1 <br />K factor in RUSLE represents the soil erodibility and is an integration of the impacts of rainfall and <br />runoff on soil loss for a given soil. No adjustment for K in either the reclaimed condition or the <br />non -mined condition for the effects of rock fragments is warranted, as a detailed analysis of soil <br />texture and rock percentage by weight would be necessary. For this analysis, a K value was selected <br />based on the representative soil at the mine site as presented in the permit application. <br />K = 0.32 (Soil Type-Kim-Cascajo complex) <br />Length Slope Factor (LS) <br />The LS factor accounts for the effects of topography on soil erosion and are determined by the <br />dimensionless factors L (hillslope length) and S (hillslope-gradient), which together account for both <br />rill and interrill erosion impacts. The equation for determining the LS factor is: <br />For slopes < 9% <br />LS = (L /72.6)' x (10.8 x sin(S) + 0.03) <br />For slopes > 9% <br />LS=(L/72.6)m x (16.8 x sin(S) — 0.5) <br />Where: L = Slope length <br />S = Slope angle <br />m = 0.3 for slopes< 3% <br />0.4 for slopes = 4% <br />0.5 for slopes > 5% and < 10% <br />0.6 for slopes> 10% <br />The slope length and slope angles for the non -mined and reclaimed conditions were determined <br />from the Map 13 and Map 29 respectively. The LS factor for each slope length and angle were <br />determined and then averaged. <br />Len (ft) <br />Slope (%) <br />LS Factor <br />220 <br />11% <br />2.60 <br />270 <br />3% <br />.52 <br />400 <br />13% <br />4.64 <br />160 <br />1 3% <br />.45 <br />The average LS is 2.05. <br />Cover Management Factor (C) <br />The cover management factor represents the effects of cover above the ground, ground cover (litter), <br />root mass, incorporated residue, surface roughness, and soil moisture on soil erosion. No <br />adjustments were made for root mass, incorporated residue, surface roughness, or soil moisture. The <br />C factors for the non -mined and reclaimed conditions were determined using information from the <br />vegetation study done by IME in 2013 and 2014 for final bond release. The non -mined area is <br />represented by averaging the sum of the values for plant cover and litter cover in 2013 and 2014 <br />taken from the Loadout reference area. The post mine, or reclaimed condition, was determined <br />