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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Department of Natural Resources <br />1313 Sherman St, Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 866-3567 <br />FAX: (303) 8328706 <br />9 December 2005 <br />Mr. Tay Tonozzi <br />Colowyo Coal Mine <br />5731 State Highway 13 <br />Meeker, CO 81641 <br />Re: Colowyo Mine C-1981-019 <br />Preliminary Adequacy Review -Technical Revision 62 <br />Deaz Mr. Tonozzi, <br />COLORADO <br />DIVISION O F <br />MIN sRALS <br />GEOLOGY <br />EFCLANATIOMNINNIG <br />SAEFTY•ECIFNCE <br />Bill Owens <br />Govmwr <br />Russell George <br />Exxutive Director <br />Ronald W. canary <br />Division Director <br />Natural Resource Trustee <br />The Division has received Colowyo Coal Company's 4 November 2005 submittal of <br />Technical Revision 62 - 2005 Midterm Review responses. The Division has the <br />following 11 adequacy questions. <br />During initial permitting of the Colowyo Mine in the eazly 1980's, the Division <br />had questioned whether the intensity of baseline soil sampling and mapping was <br />adequate to allow for sufficiently accurate estimates of available soil volumes for <br />operational and reclamation purposes. Operator azgued that data was adequate <br />(see page 2.04.9-16), but agreed to monitor soil balance and provide soil balance <br />reports on an annual basis, as a means of confirming the adequacy of the baseline <br />information. Appazently, the Division approved deletion of the annual soil <br />balance reporting in association with Permit Renewal RN-1, in 1987, based on <br />review of the monitoring data that had been provided. <br />Within this (TR-62) revision application, Operator is requesting to reduce the <br />topsoil replacement thickness from 18 inches to 8 inches, based on comparison of <br />surveyed soil stockpile volumes to disturbed acreage not yet topsoiled. The <br />evaluation indicates that topsoil in stockpile is sufficient to allow an average <br />replacement thickness of only 8.48 inches. <br />Please provide an explanation of the factors that resulted in the current <br />shortfall (as compared to original projections). Were original estimates of <br />soil availability inaccurate? Were inadequate "quality control" practices <br />employed to ensure and document that all suitable topsoil is salvaged from <br />the various soil types, and that an "approximately uniform" soil thickness is <br />Office of Office of Colorado <br />Mined Land Reclamation AcC~ve and Inactive Mines Geological Survey <br />