Pressure relief gas directional drilling and blocking extraction method for mining adjacent layers in close-range coal seam group

Abstract

The invention relates to a pressure relief gas directional drilling and blocking extraction method for mining adjacent layers in a close-range coal seam group. An upper coal seam is a first mining layer, when the upper coal seam is mined, and pressure relief gas in a central coal seam is blocked and extracted by directional drilling in an upper bottom plate; when the central coal seam is mined, gas in a mined-out area of the upper coal seam and the pressure relief gas which is mined in the central coal seam are blocked and extracted by directional drilling in the upper bottom plate, and the pressure relief gas in a lower coal seam is blocked and extracted by directional drilling in a lower bottom plate; when the lower coal seam is mined, gas in a mined-out area of the central coal seam andthe pressure relief gas which is mined in the lower coal seam are blocked and extracted by directional drilling in the lower bottom plate. The pressure relief gas directional drilling and blocking extraction method solves the problems that in the mining process of the close-range coal seam group, the pressure relief gas in the adjacent layers mutually pours into each other, thereby causing the gas in a coal mining working face and the mined-out area easily exceed the limit, difficult to manage and the like. The pressure relief gas directional drilling and blocking extraction method has the advantages of long effective hole length, multi-purpose use of one hole, high extraction efficiency, low treatment cost and the like, and realizes safe and efficient mining of the close-range coal seamgroup.

Description

technical field [0001] The invention relates to an underground gas drainage method in a coal mine, which belongs to the technical field of coal mining, in particular to a method for directional drilling blocking and drainage of gas in adjacent layers of coal seam group mining for near-distance coal seam group mining. Background technique [0002] my country's coal seam geological occurrence conditions are complex, and close-distance coal seam groups are widely developed, forming a theoretical system of short-distance coal seam group pressure relief gas drainage technology that mines the upper protective layer first, and then mines the lower adjacent layers. [0003] However, in the mining process of the upper protective layer of the close-distance coal seam group, the floor damage depth is often greater than the interlayer spacing between adjacent coal seams, and the lower adjacent layers are affected by mining, resulting in doubled gas permeability of the coal seam, and a la...

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Problems solved by technology

[0006] The purpose of the present invention is to solve the problem that when the coal seam group is mined in a short distance, the pressure-relief gas in adjacent layers pours into each other, causing the gas in the coal mining face and goaf to easily exc

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