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�/ © COLORADO <br />Division of Reclamation, <br />® Mining and Safety <br />Department of Natural Resources <br />1313 Sherman Street, Room 215 <br />Denver. CO 80203 <br />MEMORANDUM <br />Date: July 10, 2020 <br />To: Robin Reilley; Division of Reclamation, Mining & Safety <br />From: Peter Hays; Division of Reclamation, Mining & Safety <br />Re: Trapper Mine; C-1981-010; Permit Revision No. 10 (PR10); <br />I and J Pit Spoil Pile Geotechnical Review Memo <br />The Division of Reclamation, Mining and Safety (Division/DRMS) has reviewed Evaluation of l- <br />and J -Pit Spoil Pile Stability report by Agapito Associates, Inc. dated May 26, 2019 for the <br />Trapper Mine Permit Revision No. 10 (PR -10). <br />1. Pursuant to Rule 4.09.1(4), please explain the process to remove all vegetation and organic <br />materials from the disposal areas and how topsoil will be removed, segregated and stored <br />or replaced under Rule 4.06. <br />2. Pursuant to Rule 4.09.1(7), please explain how the spoil piles will be covered with topsoil or <br />substitute material in accordance with Rule 4.06. <br />3. In the Conclusion and Recommendations section of the report, the Operator states the spoil <br />piles will be constructed in small lifts (20-40 feet) to allow for better compaction of the spoil <br />particles. Pursuant to Rule 4.09.1(7), please explain how the spoil piles will be concurrently <br />compacted to ensure mass stability and prevent mass movement. <br />4. Please provide the Rockscience Inc. slope stability analysis data for the Agapito Associates, <br />Inc. geotechnical evaluation of the I and J Pits Spoil Piles to allow the Division to duplicate <br />the analysis with Clover Technology's Galena software for verification purposes. Please <br />include the profile geometries and the material properties used in the stability analysis, <br />preferably in paper and electronic forms. <br />If you have any questions, please contact me at peter.hays@state.co.us or (303) 866-3567 Ext. <br />8124. <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 https://colorado.gov/drms <br />Jared S. Polis, Governor I Dan Gibbs, Executive Director I Virginia Brannon, Director <br />