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In summary, the proposed steel-cased borehole involves the following steps: <br />1. Construction of a surface drill pad for the drilling equipment. <br />2. Drilling a nominal 12-3/4" to 14-3/4" OD surface hole and grouting in-place approximately <br />80' of 10" to 14" O.D. steel surface casing. <br />3. Drilling of a nominal 6-1/4" OD pilot hole to within 10' of the top of the surveyed entry. <br />4. Reaming of the nominal 6-1/4" OD pilot hole to a nominal 8-3/4" OD second pass to within <br />10' of the top of the surveyed entry. <br />5. Reaming of the nominal 8-3/4" OD second pass to a nominal 11" OD final pass to within 10' <br />of the top of the surveyed entry. <br />6. Alternative option - Drill a single pass nominal 11" OD hole to within 10' of the top of the <br />surveyed entry. <br />7. Installation of a nominal 8-5/8" OD thread and coupled steel casing to the bottom of the <br />drilled hole. <br />8. Grouting of the resulting annulus using a tremmie pipe and/or pressure displacement method <br />to within 6 feet of the surface. <br />9. All drilling activities would be temporarily stopped at this point until all persons are <br />evacuated from the mine. <br />10. Evacuation of persons from the mine before drilling is completed into the surveyed entry. <br />11. Completion of drilling of the nominal 7-7/8" OD hole into the surveyed entry while all <br />persons are evacuated from the mine. <br />12. After completion of the drilling and reaming into the surveyed entry, persons shall be <br />allowed back into the mine. <br />13. Removal of drilling rods from the borehole. <br />The target area of the East Mining District is inby the seals on the down slope approximately 50 <br />feet in elevation in the entries of the 6 Right gateroad. The drilling depth is approximately 432' <br />to the top of the entry. When drilling of the 6.25' pilot hole reaches a safe distance of <br />approximately 10' above the seam roof, the drilling string and pilot hole bit will be removed. A <br />nominal 8.75 and 11" diameter bit will then be installed on the drilling string and the hole will be <br />reamed to that same depth of approximately 10' above the seam roof and drilling will be <br />stopped. The proposed drilling location does not contain gobbed material and is up dip of the <br />angle of draw on the nearest longwall panel. In addition there is a significant sandstone layer <br />approximately 10' above the mine roof. <br />If circulation is lost during drilling, drilling will stop immediately. If this circulation loss <br />happens during initial pilot hole drilling, the mine will be evacuated before any further activity is <br />conducted by the drilling crew. After the mine is evacuated, the drilling string will be removed <br />from the hole and the bottom of the hole sealed with a cement grout. After the drill hole is <br />sealed, the mine shall go back to operation. The hole will then be safely reamed to a depth 10' <br />feet above the point where circulation was first lost. Prior to completing the drilling to the casing <br />depth, the mine will again be evacuated and remain evacuated until drilling and reaming is <br />completed to the casing depth. <br />If circulation is lost during the reaming process to the casing depth, and after the hole is initially <br />drilled to the 10' foot level above the seam, reaming will stop immediately. The mine will be <br />APPROVED <br />L:\MSHA SUBMITTED OR APPROVED PLANS\ThickenenUnderflow6Right\MSHA Cover Letter 6 Right Borehole 103 <br />DEC 16 2000 <br />