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COLORADO <br />,lI <br />Division of Reclamation, <br />Mining and Safety <br />Department of Natural Resources <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />Date: February 6, 2015 <br />To: Tyler O'Donnell, Division of Reclamation, Mining & Safety <br />From: Peter Hays, Division of Reclamation, Mining & Safety <br />Re: Fourth review of Slope Stability Analysis, Albert Frei & Sons Inc., Hatchery Pit, File No. <br />M- 2014 -043 <br />The Division of Reclamation, Mining and Safety (Division) staff has reviewed the stability <br />analysis response dated January 29, 2015. <br />Using Clover Technology's Galena v6.1 slope stability software, the Division conducted further <br />analysis of four critical slope area configurations and mining slope combinations for the <br />Hatchery Pit. Specific comments and requirements for each of the cross sections are provided <br />below. <br />South Section — Section B -B — 88th Ave <br />1. The Applicant's cross section was duplicated for verification. The safety factor produced by <br />Galena is lower (1.41) than the safety factor produced by the Applicant's model (1.44); <br />however the factor of safety is greater than the required safety factor of 1.3. Therefore, the <br />accuracy of the Applicant's analysis is confirmed. A copy of the Galena model is attached. <br />East Section — Section C -C — Monaco Street <br />2. The Applicant's cross section was duplicated for verification. The safety factor produced by <br />Galena is higher (1.72) than the safety factor produced by the Applicant's model (1.71). <br />Therefore, the accuracy of the Applicant's analysis is confirmed. A copy of the Galena <br />model is attached. <br />North Section — Section D -D — Haul Road <br />3. The Applicant's cross section was duplicated for verification. The safety factor produced by <br />Galena is significantly higher (1.74) than the safety factor produced by the Applicant's <br />model (1.38). Therefore, the accuracy of the Applicant's analysis is confirmed. A copy of <br />the Galena model is attached. <br />of Q)o <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http: / /mining.state.co.us I <br />John W. Hickenlooper, Governor I Mike King, Executive Director I Virginia Brannon, Director <br />