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STATE OF COLORADO <br />DIVISION OF MINERALS AND GEOLOGY <br />Departmeni of Natural Resources <br />1373 Sherman St., Room 215 <br />Denver, Colorado 80203 <br />Phone: (303) 86G3567 <br />FAX: (303) 832.8106 <br />INTEROFFICE MEMORANDUM <br />TO: Jim Burnell <br />FROM: Mike Boulay MB <br />DATE: May 2, 2005 <br />SUBJECT: West Elk Mine C-80-007, Methane Drainage Project Panels 16-24 <br />COLORADO <br />D 1 V[ S I O N O F <br />MIN SRALS <br />GEOLOGY <br />0.ECLAMATION•NINING <br />EAf ETY•ECIENCE <br />Bill Owens <br />Governor <br />Russell George <br />Executive Director <br />Ronald W. Cattany <br />Division Director <br />Natural Resource Trustee <br />At your request, I have reviewed MCC's 2005 Annual Operating Plan for methane drainage well <br />(MDW) drilling and abandonment. The drill hole plugging method is in compliance with our recent <br />guidance document: Installation, Operation, and Abandonment of Coal Mine Methane <br />Drainage/Monitoring Wells in Colorado. Specifically, MCC's plan is compliant with our closure <br />recommendation presented in the guidance document (filly feet of cement plug be placed at the <br />lowest point inside the solid casing, above the perforated interval of the well). I did note a couple of <br />differences from last years submittal. Last yeaz MCC submitted both a Typical MDW Well Design <br />and a Proposed Drill Hole Plugging diagram for our review prior to initiating the drilling program. <br />The 2005 plan did not contain a Proposed Drill Hole Plugging Diagram. Last yeazs plan also <br />specifically indicated that MCC would fill the remainder of the hole with a suitable media. This <br />yeazs plan states that from the point above the 50 foot cement plug, ..."the hole maybe plugged to <br />within 5 foot of the casing cut-off point with approved materials. The top five feet of the well below <br />the sub-surface casing cut-offpoint (3 feet below surface) will be plugged with a cement cap". This <br />is important for two reasons. First our rules specifically require that drill holes completed in aquifers <br />shall be sealed using cement or other suitable sealant by placing the sealant in the hole from the <br />bottom to within 10 feet of the surface. Second, our rules require a surface plug be placed in all <br />cases as follows: The operator shall place a suitable plug 10 feet below the ground surface to support <br />a cement plug or other media approved by the Division to within three feet of the ground surface. If <br />the hole is not plugged to within 5 foot of the casing cut-off point with approved materials, then their <br />surface plug methodology is incorrect. <br />Office of Office of Colorado <br />Mined land Reclamation Active and Inactive Mines Geological Survey <br />