Method for gas drainage from high-position roadway coal seam containing shielded soft rock

Abstract

The invention discloses a method for gas drainage from a high-position roadway coal seam containing shielded soft rock. According to the method, before the coal seam is mined, a roadway is developed in a hard rock formation of the coal seam roof and is called a high-position roadway for short as being designed at the coal seam roof part. The well-developed roadway can be used for ensuring the stability of surrounding rock and enhancing the temporary support; then during the working surface mining, holes are drilled in the coal seam in the roadway of a working surface, and preliminary gas drainage is carried out; and finally, at the same time of the preliminary gas drainage, holes are drilled in the coal seam in the high-position roadway, self-drilling drill rods with a hollow structure are adopted in the drilling, small holes are processed in the sections where the self-drilling drill rods enter the coal seam, the self-drilling drill rods are kept in the drilling holes of the coal seam after drilling in the coal seam, and the gas drainage can be continuously carried out through the self-drilling drill rods. According to the method, the drainage is carried out in the high-position roadway, the characteristic of upward flow of gas is fit, and thus the drainage is convenient to realize. The hollow drill rods with holes are used for the drainage, the drilling holes can be prevented from being sealed by the shielded soft rock and further a good drainage effect is realized.

Description

technical field [0001] The invention belongs to the technical field of coal mining. Background technique [0002] Co-mining of coal and gas is one of the new topics in coal mining. [0003] At present, gas drainage is mainly carried out by drilling ordinary boreholes in the service roadway of the coal seam. In gas drainage, as the mining depth increases, the effect of gas drainage is closely related to rock structure and lithology. At present, the coal seam gas drainage effect on the soft rock roof is not good, mainly because the cracks in the soft rock layer are easy to close and have a shielding effect, and no effective gas drainage method has been found for the coal seam containing soft rock. [0004] Therefore, it is necessary to invent an effective drainage method for gas drainage under the conditions of multi-structure, large buried depth and soft rock formation. Contents of the invention [0005] The purpose of the invention is to propose a construction method wi...

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Problems solved by technology

[0005] The purpose of this invention is to propose a construction method with an ideal drainage effect in view of the current situation that the gas drainage effect of shielding soft rock is not ideal

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