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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) 832-8106 <br />June 2, 2003 <br />DIVISION OF <br />MINERALS <br />GEOLOGY <br />RECLAMATION <br />MINING•SAFETY <br />Elmer Bentley Bill oven: <br />Lorencito Coal Company, LLC Governor <br />20500 Highway 12 Greg E. Walther <br />Executive Director <br />Weston, CO 81091 Ronald W. Cattany <br />Division Director <br />RE: Excess Spoil Fill Inspections <br />Lorencito Canyon Mine, #C-96-084 <br />Mr. Bentley: <br />The Division of Minerals and Geology has completed review of the 4th quarter 2002 and <br />the 1st quarter 2003 excess spoil fill inspections for Fills 7, 8 and 9 at the Lorencito <br />Canyon Mine. Two issues or concerns resulted from this review. <br />1. Under the heading Sediment Control for all three excess spoil fill inspection <br />reports, the text states "All surface runoff from the fill areas is directed to this <br />sediment control facility" Please identify by name each specific sediment control <br />facility. <br />2. Each report contains a heading titled "Drainage Systems (Underdrains)". While <br />the underdraih is an important feature of each fill, after the drain is cover, the <br />presence of seepage from the drain becomes the only significant observation <br />during the inspection. No specific reference is made under this heading <br />regarding other surface drainage on each fill. The Division recommends another <br />heading be included in each report for surface drainage on, and above (in the <br />case of valley fills), each fill, directed towards function and condition of terraces <br />and downdrains. Experience has shown that these two constructed features are <br />the most likely candidates for future problems due to surtace runoff and <br />sedimentation. Proper drainage at terrace/downdrain intersections is critical to <br />prevention of erosion and damage to the body of the fill. Stability of the channel <br />lining in the Downdrains is also critical to stability of the body of the fill. <br />We have no further questions or concerns at this time. If you have any questions, <br />please call me. <br />Sin ly, <br />rham ~ <br />Environmental Protection Specialist II <br />