Gas drainage method on working face of thin coal seam with low gas permeability

Abstract

The invention provides a gas drainage method on a working face of a thin coal seam with low gas permeability. The working face is divided into an adjacent mining roadway evaluation unit, an adjacent cutting hole roadway evaluation unit and a working face middle evaluation unit; different bedding gas extraction drill arrangement methods are adopted for different evaluation units, finally bedding gas extraction drills are connected with gas extraction pipelines, coal-seam gas in each evaluation unit in the working face is extracted under the action of negative pressure, gas inspection drills areconstructed in each evaluation unit, the gas extraction effect is inspected, the method better solves the problem that gas extraction is substandard due to the fact that the gas extraction drills areeasily inclined to a top plate or a bottom plate due to the thin coal seam, poor air permeability and large length of the working face, the effective utilization ratio of the gas extraction drills isincreased, the target rate of gas extraction of the coal seam in the middle of the working face is increased, and safe mining of the working surface is ensured.

Description

Technical field [0001] The invention relates to the technical field of coal mining, in particular to a method for gas drainage in a thin coal seam face with low air permeability. Background technique [0002] Coal and gas outburst is one of the major disasters facing coal mine safety production. With the increase in the intensity and depth of coal mining in my country, the danger of coal and gas outburst disasters is becoming more and more serious, which has a serious negative impact on the image of the coal industry. [0003] The coal resources in southern my country are dominated by thin coal seams, with high gas content and poor coal seam permeability. It takes a long time for the working face to meet the standard and it is difficult to extract. On the one hand, the reason is that the relatively short extraction time of the open cut area of ​​the face is also On the one hand, it is difficult to guarantee the construction quality of bedding gas drainage drilling in the middle area...

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Problems solved by technology

[0003] Coal resources in southern my country are dominated by thin coal seams with high gas content and poor gas permeability. It takes a long time for the mining face to reach the standard, and the extraction is difficult. On the one hand, the reason is that the extraction time in the cut-out area of ​​the working face is relatively short, and on the other hand On the one hand, it is difficult to guarantee the quality of borehole construction for bedding gas drainage in the central area of ​​the working face

[0004] In the past, for the gas drainage of low-permeability thin coal seam recovery working face, usually before the working face recovery, the mining roadway on both sides and the cut-out roadway are used to drill holes along the coal body of the working face for gas drainage, but this method is difficult to ensure the gas drainage of the working face. The effect of gas drainage in the central part, especially for low-permeability thin coal seam working faces, due to the difficulty of gas flow in the coal seam, gas drainage is more difficult. The phenomenon of deviation to the roof or floor rock formations further reduces the effect of bedding gas drainage boreholes, which in turn leads to poor coal seam gas drainage effects in the middle of the working face, and often causes gas to exceed the limit in the working face during mining. , and even induce coal and gas outburst disasters in severe cases

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