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STATE OF COLORADO <br />DIVISION OF RECLAMATION, MINING AND SAFETY <br />Department of Natural Resources <br />1313 Sherman St., Room 215 <br />Colorado 80203 <br />Denver COLORADO <br />, D <br />DIVI E S I ON OF <br />F <br />Phone: (303) 866-3567 RECLAMATION <br />FAX: (303) 832-8106 MINING <br /> <br /> SAFETY <br />September 14, 2009 <br /> Bill Ritter, Jr. <br />Ms. Kathleen G. Welt Governor <br />Mountain Coal Company LLC Harris D. Sherman <br /> Executive Director <br />Box 591 <br />P <br />O <br />. <br />. Ronald W. Cattany <br />Somerset, CO 81434 Division Director <br /> Natural Resource Trustee <br />Re: West Elk Mine (Permit C-1980-007) <br />Technical Revision 118 <br />Dear Ms. Welt: <br />Comments regarding geotechnical aspects of the submittal are provided below. Numbering <br />follows in sequence with the comments in our letter of September 3, 2009. <br />6. Please review the assumptions made regarding the cohesion value for Colluvial Soils, and re- <br />run the stability program to verify that colluvial soils with lower cohesion values will not <br />adversely affect the overall stability of the Lower Refuse Pile with the addition of the <br />proposed Preparation Plant Facility. <br />7. Moisture-density compaction testing was conducted during construction of the Lower Refuse <br />Pile. The in-place unit weights so measured were substantially greater than the design values <br />reported in Exhibit 51 of the permit. Please re-calculate the anticipated stability of the LRP <br />using appropriate material characteristics, as they were measured and reported during <br />construction of the pile. <br />Please contact Marcia Talvitie if you have questions about these two comments. <br />Sincerely, <br /> <br />Tom Kaldenbach <br />Environmental Protection Specialist <br />cc (via email): Marcia Talvitie, CDRMS <br />Dan Hernandez, CDRMS <br />Office of Office of <br />Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines