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PeabodH <br />Twentymile Coal Company <br />October 31, 2009 <br />Mr. Allyn C. Davis <br />MSHA Coal District 9 <br />Denver Federal Center <br />6a' and Kipling <br />2"d Street, Building #25. E-16 <br />Denver, CO 80225 <br />7Ris SS-A ie? <br />N D IEC C?[1VC <br />N?V 0 Z2009 D <br /> <br />USDOL - MSHA- CMS&H <br />DISTRICT 9 <br />29515 Routt County Road #27 <br />Oak Creek, Colorado 80487 <br />970.879.3800 <br />Re: Twentymile Coal Company - Foidel Creek Mine (MSHA ID No. 05-03836) <br />6 Right - Thickener Underflow Bore Hole <br />Dear Mr. Davis: <br />Twentymile Coal Company (TCC) submits for review a drilling plan to install a cased borehole <br />into the sealed portion of the underground workings. The completed installation will be a <br />nominal 8-5/8" OD cased borehole extending from the surface approximately 432 feet into the <br />sealed mine workings of the East Mining District (EMD). The borehole will provide a passage <br />for the thickener underflow from the washplant to be pumped into the EMD. <br />The 6 Right Thickener Borehole will be located on the surface near the intersection of Routt <br />County Road #27 and Routt County Road #33. The location is shown in the drawing labeled <br />6RT Thickener Borehole Location and in the "Drill Rig Site Layout" drawing included in this <br />package. The hole will be located within a 10' radius of the location show on the drawing. <br />The proposed borehole will require the preparation of a drill pad for the rig to set on while <br />drilling. Once prepared, the drilling contractor will auger and grout a nominal 10" to 14" inch <br />diameter by 80' long conductor casing into place. The drill rig will then set on this conductor <br />casing and drill a nominal 6-1/4" OD first pass pilot hole, a nominal 8-3/4" OD second pass <br />reamed hole, and a nominal 11" OD final pass reamed hole to 10 feet above the surveyed mine <br />roof. Depending on the rig used, a single pass, 11" OD hole may be drilled in lieu of the 6-1/4" <br />and 8-3/4" OD pilot hole and second pass. A nominal 8-5/8" OD thread and coupled steel casing <br />will then be installed in nominal 40 foot joint lengths to the bottom of the drilled hole. The <br />resulting annulus will be fully grouted with the use of a tremmie pipe and/or pressure <br />displacement method to within 6 feet of the surface. Following grouting and evacuation of men <br />from the mine, the drill rig will ream the remaining 10 feet of the hole to a nominal 7-7/8" <br />diameter to connect the borehole and the mine workings of the EMD. <br />The drilling will be accomplished with a Midway 2000 rotary mud drill rig, a Gardner-Denver <br />GD 14W rotary air/mud system or an Atlas Copco RD 20 drilling unit with auxiliary equipment. <br />APPROVED <br />L:XMSHA SUBMITTED OR APPROVED PLANS\ThickenenUnderflow6Right\MSHA Cover Letter 6 Right Borehole 10 109A <br />DEC 1 6 2009 <br />CMSH