Gas extraction method during mining process and after mining of steep coal seam

Abstract

The invention belongs to the technical field of coal mine gas extraction, and discloses a gas extraction method during the mining process and after mining of a steep coal seam. The gas extraction method comprises the steps that two left and right drill fields are arranged in rock strata with a horizontal distance of more than 15 meters in the roof direction in a coal seam return air way; the length of a borehole between the drill fields overlaps by more than 20m; five boreholes are formed in each drilling field correspondingly, and the inclination angle and azimuth angle of each borehole are different; the boreholes are arranged in a five-hole pattern, and the diameter of the drill holes is Phi 70-130; sealing drilling is carried out, a hose is used for being connected into a mine negativepressure gas extraction system to facilitate detection of gas extraction flow rate, extraction negative pressure, extraction gas concentration and the like; and the boreholes are formed above an opencut of a working face with 10m away from the open cut, and gas extraction is carried out after a roof fissure zone develops to the corresponding position after the open cut is pushed forwards. According to the gas extraction method, the drilling construction efficiency is high, the construction speed can be accelerated by more than 60%, the gas extraction concentration can reach more than 80%, and the gas extraction efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of gas drainage in coal mines, and in particular relates to a gas drainage method during and after mining a large dip angle coal seam. Background technique [0002] At present, the existing technologies commonly used in the industry are as follows: mines mined in large-inclination coal seams, especially high-inclination high-gas and outburst mines, have "three highs and two lows" (higher inclination, high gas pressure, high gas content, and well type). low gas drainage efficiency) production geological characteristics. The method of gas drainage in the mining process of the coal mining face generally adopts the implementation of bedding fan-shaped drilling drainage, bedding parallel drilling drainage, cross-drilling drainage, etc. in the coal seam, but the amount of drilling engineering is large , a lot of manpower and material resources are invested, and a series of engineering problems such as low single-...

AI Technical Summary

Problems solved by technology

[0006] ②Large-diameter drilling requires a large construction site, and small and medium-sized mines do not have this condition because the section of the roadway is generally small;

[0007] ③ Large-diameter drilling rigs require an investment of more than tens of millions of yuan, and small and medium-sized mines do not have such a large capital investment

[0015] (1) Use fissure zones for gas drainage to realize real high-level borehole drainage technology, such as high-level and large-diameter borehole gas drainage technology, but it is difficult to apply in small and medium mines

[0016] (2) Increase the negative pressure of gas drainage. Practice shows that simply increasing the negative pressure is difficult to solve the problem of gas drainage

[0019] The significance of solving the above technical problems: it not only solves the problem of gas overrun in the upper corner of the coal seam mining process with a large dip angle, but also solves the problem of gas accumulation in the goaf after mining the coal seam face with a large dip angle A series of problems such as the drainage of pressure-relieving gas in the protected layer, minimizing the engineering quantity of gas drilling, and improving the efficiency of gas drainage

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