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co <br /> 9 <br /> o DEPARTMENT OF NATURAL RESOURCES <br /> k * David H.Getches,Executive Director <br /> Mrs * MINED LAND RECLAMATION DIVISION <br /> 1876 DAVID C.SHELTON, Director <br /> Richard D.Lamm <br /> Governor <br /> DATE: May 20, 1985 <br /> TO: Candace Thompson <br /> FROM: Jim Pendleton <br /> RE: Mid-Contine t Resour is Tunnel Sealing Plan (C-017-81) <br /> I reviewed Mid-Continent Resource, Inc. ' s tunnel sealing plan, prepared for <br /> the Rock Tunnel at the Coal Basin Mine. This plan was submitted in compliance <br /> with stipulation No. 4 of the permanent program mining permit for the Coal <br /> Basin Mines. <br /> The proposed plan calls for concrete seals to be constructed above and below <br /> the Cozette, Rollins, and Middle sandstones, as well as at the tunnel <br /> portals. Conceptually, the plan appears appropriate and workable. Prior to <br /> approval , however, I will require additional information as follows. <br /> (1 ) The operator should present a specific keyway depth to be used to <br /> prevent leakage around the seals. I believe at least 24 inches of <br /> penetration into solid bedrock should be accomplished in order to <br /> assure proper sealing. The plan currently contains no specific <br /> statement regarding this design detail . <br /> (2) The operator should submit groundwater head and concrete seal design <br /> calculations, in order to support the planned dimensions and <br /> anchorage specifications. <br /> With the addition of these details the design should be approvable. <br /> JAP/ddt <br /> cc: Brian Munson <br /> 0564F <br /> 423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203 Tel. (303) 866-3567 <br />