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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$106 <br />INTEROFFICE MEMORANDUM <br />DIVISION OF MINERALS AND GEOLOGY <br />TO: Dan Mathews <br />FROM: Mike Boulay X111 <br />DATE: October 24, 2005 <br />SUBJECT: McClane Canyon Mine (Permit No. C-1980-004) <br />Technical Revision No. 14 (TR-14) <br />COLORADO <br />DIVISION O F <br />MIN SRALS <br />GEOLOGY <br />REC LAMATION•ry1NING <br />SAFETY•SCIENCE <br />Bill Owens <br />Governor <br />Russell George <br />Executive Director <br />Ronald W. Cattany <br />Division Director <br />Natural Resource Tmstee <br />I have reviewed TR-14 for McClane Canyon Mine regarding changes in the drainage control <br />plan. The design for the new proposed culvert "P" is adequate. The culvert capacity was derived <br />from the Handbook of Steel Drainage & Highway Construction. I checked the design capacity <br />with the given peak discharge and other information provided in the revision and determine that a <br />48 inch culvert will be adequate for culvert "P". Central Appalachia Mining proposes to plug <br />and abandon culvert "F" in place. It would be preferable to remove and dispose the culvert, but <br />given the site conditions and problematic location of the culvert I am recommending that we <br />accept the proposal to plug the culvert and redirect the flow to the sediment pond. The operator <br />has included drainage basin D-5 above culvert "F" into the hydrologic pazameters and peak flow <br />calculations and indicates that the existing capacity of the sediment pond is adequate. <br />I have the following comment concerning performance bond liability. <br />The operator has indicated on the Application Form that there is no bond increase <br />associated with this revision. However, Central Appalachia Mining proposes a new 48- <br />inch culvert and proposes plugging and abandoning culvert "F" in place. The reclamation <br />cost estimate should be reviewed and adjusted if necessary. <br />C: Sandy Brown <br />Office of Office of Colorado <br />Mined Land Reclamation Active and Inactive Mines GEnlogical Survey <br />