Secondary hole sealing method capable of improving coal bed drilling firedamp sucking concentration

Abstract

The invention relates to a secondary hole sealing method for improving the gas drainage concentration of a coal seam drill hole, which is particularly suitable for gas drainage in places like an extracting face, a cross-cut coal place, a coal drift and so on. When the gas drainage concentration is lower than 16 percent, a shock tube which is connected with a compressed air pipe is inserted into the coal seam drill hole on the basis of primary drilling and hole sealing and then close to a primary polyurethane hole sealing place; fine expanding powder materials are blown into the coal seam drill hole by compressed air with certain pressure until the coal seam drill hole is full of the fine expanding powder materials, and then the shock tube is extracted and accelerated cement is quickly used for sealing an orifice of the coal seam drill hole. The secondary hole sealing method for improving the gas drainage concentration of the coal seam drill hole can greatly improve the gas drainage concentration and prolong the effective drainage period of the drainage drill hole after secondary hole sealing, and not only improve the utilization rate of the drill hole but also obviously improve the gas drainage effect and guarantee the safety of a gas drainage system.

Description

technical field [0001] The invention relates to a hole sealing method for gas drainage concentration, in particular to a secondary hole sealing method for increasing the gas drainage concentration of coal seam boreholes. Background technique [0002] In the coal mine gas drainage work, the sealing quality of the borehole is the key factor of the drainage effect. At present, the most commonly used method for gas drainage and sealing is mainly to use polyurethane to seal the hole, that is, to put the hole sealer wrapped with polyurethane material into the coal seam drilling at a depth of about 10m, and rely on the chemical reaction of polyurethane to expand , to achieve the purpose of sealing the borehole, and then carry out gas drainage. After a certain period of gas drainage, the coal seam will be deformed and displaced, causing the pores (cracks) in the coal seam around the borehole to expand and develop. The concentration of gas drainage decreased significantly, which sh...

AI Technical Summary

Problems solved by technology

After a certain period of gas drainage, the coal seam will be deformed and displaced, causing the pores (cracks) in the coal seam around the borehole to expand and develop. At this time, the outside air will enter the air extraction borehole from the crack channel, resulting The concentration of gas drainage drops significantly, which shortens the effective drainage period of the drainage borehole and reduces the utilization rate of the borehole

In addition, when the gas concentration to be drained is reduced to within 16% of the gas explosion limit, it will seriously affect the safety of the gas drainage system

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