Key technology for safe and efficient uncovering for long distance strong outburst coal seam in incline
Compared with ordinary cross-cut uncovering coal,long-distance coal uncovering in incline has high risk and difficulty.In order to ensure that the main incline of Libi Coal Mine will safely and efficiently pass through the outburst coal seam,the technical difficulties for long-distance coal uncovering of incline are analyzed,and safety measures for uncovering outburst coal seam are proposed,based on the geological exploration results,support design and measured gas parameters of No.3 seam in coal uncovering area.By using pilot hole layout layout,a comprehensive enhanced extraction technology system of"six in one",such as increasing the hole depth with large aperture,multiple"enlargement",casing down,high negative pressure,gas lift reverse circulation slag cleaning,and curing intercept extracting,has been put forward,which significantly improves the construction quality of drilling,solves the problem of efficient extraction from long distance strong outburst coal seam in inclines,and effectively controls gas emission after explosion.The method of vertical uncovering strong outburst coal seam at one time in inclines is adopted,which significantly increases the range of uncovering coal at one time.The problem of roof and structure forming control of roadway in seam is solved by using the method of dense hole slotting along the contour of inclines.It takes 36 days by uncovering No.3 coal seam and 3meters vertical distance passing through coal seam.The maximum gas concentration in working face after blasting is 0.68%,and the maximum air return gas is 0.36%during coal uncovering.The operation ensures safe uncovering and provides an important reference for long-distance coal uncovering in similar coal seams.
pilot hole layoutmultiple enlargementgas blockage extractionvertical drilling and blastingdense hole slotting
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