Yolk coal rock formation downward hole pumping and mining pressure relief mash gas construction method

Abstract

The invention relates to a method for drainaging pressure relief gas construction by a downward borehole in soft coal seam and strata, characterized in that a downward cross-seam borehole is arranged on the roadway segment retained for next sublevel on the mining face of a protecting layer, and the lower covered protecting coal seam is gas pre-drainaged through the downward cross-seam borehole. The construction of the downward cross-seam borehole comprises the following steps: a borehole enlarging segment is formed downwards from the bottom plate of the coal seam of the roadway segment retained for next sublevel, the borehole protection is finished in the inner sleeve in the middle lower part of the borehole enlarging segment, slurry is injected between the outer wall of the inner sleeve and a rock to from a borehole sealing segment, and the further construction of the downward cross-seam borehole is carried out in the inner sleeve. According to the invention, the pressure relief gas of the protecting layer namely the lower covered coal seam is maximally drainaged when the protecting layer is mined, the mining effect of the protecting layer is improved, and the safe stoping of the mining face is ensured.

Description

technical field [0001] The invention relates to a construction method for gas drainage and pressure relief in the mining process of coal seam groups, more specifically to a construction method for gas drainage and pressure relief in the mining process of low air permeability, high gas, outburst and soft coal seams. Background technique [0002] The control of gas disasters is a major problem in the process of coal mining. Most of the mines mining coal seam groups at home and abroad adopt mining protective layers. When exploiting the protective layer, it is necessary to carry out gas pre-extraction on the protected layer. The gas pre-extraction is mainly to drill through the layer, and for the lower protective layer without or without the construction floor roadway, it is necessary to construct the drilled hole through the layer. Pre-draw. Otherwise, on the one hand, the protected layer will not be fully relieved after the protective layer is mined; Ventilation will still c...

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Problems solved by technology

[0004] In order to avoid the shortcomings of the above-mentioned prior art, the present invention provides a construction method for extracting pressure-relieving gas from downward boreholes in soft coal rock strata, so as to solve the problem of excessive gas flow in the return air lane of the coal mining face, and realize During the mining process of the protective layer, the gas pre-drainage is carried out on the protected coal seam of the underlying roadway without floor, so as to increase the gas concentration of the extraction, so as to improve the utilization rate of resources and ensure the efficient and safe mining of the coal mining face

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