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AWES, LLC <br /> 4 Fort Coiiins, Colorado, USA <br /> March 11,2020 <br /> State of Colorado <br /> Division of Reclamation, Mining and Safety <br /> 1313 Sherman Street, Rm 215 <br /> Denver,CO 80203 <br /> Attn: Mr. Peter Hays <br /> RE: Response to Adequacy Review <br /> AWES Revised Pit 122 Slope Analysis <br /> File#M-2015-033 <br /> Dear Mr. Hays: <br /> This letter and attachments are in response to your adequacy review comments in a letter to Varra <br /> Companies,Inc.,dated March 9,2020.Your letter is provided as Attachment A for reference. <br /> Your comment regarding the profile#3 analysis as being mislabeled was correct and that profile analysis has <br /> been relabeled as profile#4. In addition, profiles#2 and#3 have been analyzed for stability.As you are aware <br /> direct shear testing was performed on sand and gravel samples obtained from Tract A of Pit 122. Sand with <br /> gravel is the dominant soil type in Tract A. Soil properties used in our analyses are provided in Table 1. <br /> Table 1—Soil Strength Properties <br /> Material Wet Unit Weight Saturated Unit Cohesive Friction <br /> (Ibs/cu ft.) Weight Intercept(PSF) Angle <br /> (Ibs/cu ft.) <br /> Overburden <br /> Clay* 114 126 150 28 <br /> j Sand,with <br /> gravel 118** 131** 0 44.6** <br /> Bedrock* 124 134 500 22 <br /> Note: * Unit weight values(table values)reported by DRMS <br /> ** Unit weight values reported by Engineering Analytics data <br /> Computer generated summaries for stability analyses (profiles 1-5 and worst case) are presented in <br /> Attachment B. A review of Attachment B shows that predicted safety factors for all profiles varied between <br /> 1.33(profile#4)and 1.99(profile#5). <br /> Collins, l"1 80524 <br /> i ourt, Fort olli �u _ <br />