Freezing-thawing cycle anti-reflection promoting extraction safe and efficient rock cross-cut coal uncovering method

Abstract

The invention provides a freezing-thawing cycle anti-reflection promoting extraction safe and efficient rock cross-cut coal uncovering method. The freezing-thawing cycle anti-reflection promoting extraction safe and efficient rock cross-cut coal uncovering method comprises the following steps that (1) the influence radius Phi of a coal seam high-pressure water injection is measured; (2) drilling holes are constructed in a drilling field to a coal seam top plate or a bottom plate; (3) the drilling holes are divided into water injection hole bodies and freezing hole bodies, and the water injection hole bodies and the freezing hole bodies are arranged alternately; (4) hole sealing is carried out on the water injection hole bodies and the freezing hole bodies; (5) water injection is carried out on the water injection hole bodies, liquid nitrogen is injected into the freezing hole bodies to enable coal bodies on the periphery of the water injection hole bodies to be frozen, after a period of time, hot nitrogen is injected into the freezing hole bodies to enable the frozen coal bodies on the periphery of the water injection hole bodies to be unfrozen and thawed, and the liquid nitrogen is gasified; (6) gas discharged from the water injection hole bodies is extracted; (7) after gas extraction is carried out for 48 hours, the step (5) is repeated; and (8) rock cross-cut coal uncoveringoperation is carried out. According to the freezing-thawing cycle anti-reflection promoting extraction safe and efficient rock cross-cut coal uncovering method, through a coal body freezing-heat injection technology, the coal seam air permeability is effectively increased, the coal seam gas extraction effect can be greatly increased, the coal seam gas pressure is reduced, and the coal seam outburst risk is eliminated.

Description

technical field [0001] The invention belongs to the technical field of coal mine safety production, and in particular relates to a safe and high-efficiency method for uncovering coal at a stone gate through freeze-thaw cycles, anti-reflection and promotion of pumping. Background technique [0002] Coal and gas outburst is one of the main disasters that threaten the safety of coal mine production, especially when Shimen exposes the coal seam, the outburst is the strongest and most dangerous. The stress state of the coal and rock in front of the coal mining face in Shimen is prone to sudden changes, and the elastic potential of the rock and coal seam and the large amount of gas energy are released to cause high-strength outbursts. More than 80% of the super-large outbursts occurred in the process of unearthing coal in Shimen, and the average outburst intensity is more than six times that of other types of roadway outbursts. Due to the particularity of the Shimen coal uncoveri...

AI Technical Summary

Problems solved by technology

In terms of coal seam pressure relief and permeability enhancement, measures such as hydraulic punching, loose blasting and hydraulic slotting are mainly implemented to fully relieve coal seam pressure and reduce ground stress and gas pressure; but at the same time, the integrity of the coal seam is destroyed, reducing In addition to the outstanding resistance, it also has a disadvantageous side to the work of preventing outbursts

In terms of coal reinforcement, measures such as metal skeleton and coal grouting are mainly adopted to achieve the purpose of increasing the strength of coal and increasing the outburst resistance, thereby reducing the risk and strength of gas outburst; but in the process of coal reinforcement, Cement mortar can only infiltrate and diffuse in the cracks. Since the cracks in the coal seam are very small, the diffusion range of the cement slurry is limited. It can only improve the strength of the coal seam in the exposed coal area in a small range, and cannot achieve regional reinforcement and effectively reduce the gas pressure. Coal seams in coal regions still have high in-situ stress and gas pressure, and the risk of coal outburst is still high

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