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Table 1• DRMS Model Parameters <br /> <br />Soil Type .Effective <br />Friction Angle <br />01 (degrees) Effective <br />Cohesion <br />c' (PSI) Saturated Unit <br />Weight <br />%W c <br />Overburden 28 50 126 <br />Gravel 35 0 137 <br />Weathered Bedrock 14 0 142 <br />Bedrock 28 100 142 <br />In our opinion, the parameters for weathered bedrock are very conservative based on the conditions <br />typically encountered in the project area. <br />In accordance with the DBMS guidelines, we analyzed a vertical highwall section. The vertical section <br />corresponds to a steep highwall mining scenario where the highwall inclination is approximately 0.5:1 <br />(horizontal to vertical). The depth to bedrock varied from 311/2 to 51 feet across the project site. <br />Table 2 below summarizes the results of our analysis. The analysis was performed using the DRMS <br />parameters shown in Table 1. The factor of safety required by the DRMS for temporary mine slopes <br />and reservoir embankments are provided for comparison. Output graphics for each of the analyses are <br />attached. <br />Table 2! Highwall Setback DRMS AnalVAS Results <br /> Setback Calculated Required Factor <br />Model Distance (feet) Factor of of Safety <br /> <br />Adjacent to Brighton Road 50 1.17 1.0 <br />Adjacent to Spier Property 45 1.14 1.0 <br />Near McCann Ditch 65* 1.08 1.0 <br />*the above setback distance is from the existing ditch <br />The required setback distance provided in Table 2 is calculated from the crest of the mine highwall to <br />the potential failure surface intersection with the existing ground surface. If the McCann ditch is to be <br />relocated we recommend that a new setback distance is analyzed in the future based on the design of the <br />relocation. <br />P10377 Hart EnAmmentnl maky Ickes Stab&y Aoalysis\Stabddy ExhIMB-mley Lake Stability ExhibiLdoc <br />Bromley Lakes <br />DRMS 112 Permit <br />Page SE2 of SE2