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DIVISION OF RECLAMATION, MINING AND SAFETY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866 -3567 <br />FAX: (303) 832 -8106 <br />September 28, 2011 <br />Kathleen G. Welt <br />Mountain Coal Company, LLC <br />P.O. Box 591 <br />Somerset, CO 81434 <br />Re: West Elk Mine <br />Technical Revison No. 127 (TR -127) <br />Revised RPE East Design to Include Colluvium and an Underdrain <br />Dear Ms. Welt: <br />Tom Kaldenbach <br />Environmental Protection Specialist <br />Also, please revise Drawing C -07A to show the underdrain as fully wrapped in geotextile. <br />Sincerely, <br />cc: Dan Hernandez, DRMS (emailed) <br />Office of <br />Mined Land Reclamation <br />STATE OF COLORADO <br />COLORADO <br />D I V I S I O N O F <br />RECLAMATION <br />MINING <br />—&— <br />SAFETY <br />Bit Ritter, Jr. <br />Governor <br />Mike King <br />Executive Director <br />Loretta E. Pineda <br />Director <br />The DRMS has completed a preliminary review of the above - referenced submittal (Exhibit 82) and has the <br />following comments. <br />1. In order to inhibit the development of a shear plane along the colluvium/refuse interface, please add <br />to the design in Section 4.0 benching of the colluvial surface. <br />2. Please remove the word " colluvium" from the second paragraph on page 26 in Section 4.8.2. <br />3. Please add to the observations to be included in inspection reports (second paragraph on page 26): <br />a. A description of the condition of colluvium exposed since the previous inspection report, <br />b. A statement regarding whether the condition of the colluvium was consistent with the <br />assumptions used in the stability analysis in Exhibit 82. <br />4. In order to reduce the migration of fine colluvial material into the underdrain, please replace the last <br />sentence of the third paragraph on page 19 (which begins "Filter rock will be placed.... ") with the <br />following sentences: <br />"Filter rock will be placed over the drainage rock. Woven geotextile will be wrapped around <br />the entire underdrain (drainage rock and filter rock)." <br />Office of <br />Denver • Grand Junction • Durango Active and Inactive Mines <br />