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~ III IIIIIIIIIIIII'll <br />999 <br />Mountain Coal Company <br />West Elk Mine <br />Post Office Box 597 <br />Somerset, Colorado 91434 <br />Telephone 3039215075 <br />Fax 303 92955.95 <br />March 11, 1994 <br />Ms. Christine Johnston <br />Colorado Division of Minerals and Geology <br />Office of Mined Land Reclamation <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />RECEI~/r~ <br />P~IAR 1 ~ 1994. <br /> <br />Re: Mountain Coal Company (MCC), West Elk Mine, Permit No. C-80-007, Minor <br />Revision No. 114, Water System Improvement Project <br />Dear Ms. Johnston: <br />Enclosed are the responses to your Preliminary Adequacy Review of March 7, 1994, for <br />the subject minor revision. Note the dimensions of the support block footers have been <br />revised. A sketch of the piping supports and thrust blocks is enclosed for your <br />convenience. <br />1) The existing mine water line and potable water line shall remain in place. These lines <br />are not removed in the scope of this project. <br />2) The purpose of thrust blocks is to brace the pipelines against any water hammer <br />forces (shock forces caused by change of direction of moving water) that may occur. <br />Thrust blocks are placed where there is a major change of direction in the pipeline. <br />Thrust blocks are to be framed and poured in place. A sketch of a typical thrust block <br />is attached. <br />3) Where the pipelines are not buried or held by bridge or belt structure, pipelines <br />shall be supported upon precast concrete block foundations (footers). The <br />pipeline is supported by existing belt structure from the substation road to the mine <br />portals. The concrete block footers serve to lift the pipe off of the ground and provide <br />stability against movement. A sketch of a typical surface pipe support is attached. <br />4) The size of the block footers is approximately 24" x 12" x 6", 0.037 cu.yd. This <br />volume does not account for a pipe trough in the block. A sketch of a typical surface <br />pipe support is attached. <br /> <br />