Secondary hole sealing method for underground coal mine gas drainage drill hole

Abstract

The invention discloses a secondary hole sealing method for an underground coal mine gas drainage drill hole. The secondary hole sealing method comprises the following steps that (1) a bag type grouting hole sealing device and a two-blocking one-injecting hole sealing process are adopted for implementing first-time hole sealing and continuous drainage; (2) during gas drainage, a low-concentration gas drainage drill hole is selected, and a connected gas drainage pipeline is disconnected; (3) a sealing steel pipe is connected with a compressed air self-rotating drill bit and then inserted into a first-time hole sealing pipe, a high-pressure air supply pipeline is connected, and coal slag in the hole sealing pipe and the drill hole is cleaned through the compressed air self-rotating drill bit and high-pressure air blowing; (4) the sealing steel pipe is withdrawn, and a second-time hole sealing device is plugged into the first-time hole sealing pipe to a designed position; (5) grouting is conducted on the second-time hole sealing device for implementing secondary hole sealing; and (6) a hole sealing pipe of the second-time hole sealing device is connected into the gas drainage pipeline for gas drainage. According to the secondary hole sealing method for the underground coal mine gas drainage drill hole, the application engineering cost is low, the process is relatively simple, the drainage efficiency is fully improved, the drainage time is shortened, and gas disasters are eliminated to the maximum extent.

Description

technical field [0001] The invention belongs to the technical field of coal mine safety production, and in particular relates to a method for secondary sealing of underground gas drainage boreholes in coal mines. Background technique [0002] As a large economic country, my country has abundant reserves of coal resources. With the continuous mining of coal, shallow coal seams have been exhausted, and the depth of coal mining has gradually increased. With the increase of mining depth, the stress of the coal seam increases, the gas content in the deep coal seam is higher, and the coal and gas outburst disasters become more and more serious. The phenomenon of high gas and high outburst in coal seams always restricts the progress of coal mine mining and easily leads to mineral disasters. In order to realize high-efficiency mining of coal seams, the relationship between coal and gas should be dealt with, to avoid coal and gas outburst disasters, and to achieve safe production. ...

AI Technical Summary

Problems solved by technology

[0011] 2. Existing gas drainage secondary sealing method

[0013] Existing problems: When drilling along the bedding, the drilling tool is disturbed, the coal body on the hole wall is broken, and the drilling stability is poor

The construction process of the sealing structure is relatively complicated. In view of the soft and broken coal wall of the drilled hole and the development of coal seam cracks, the expansion cement is used to seal the hole in the polyurethane sealing section. The length of the sealing section is relatively large, and the amount of grouting material used is large. The cost of grouting is high and the economy is poor

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