Underground dark mining drilling well gas extraction method

Abstract

The invention discloses an underground dark mining drilling well gas extraction method, comprising the following steps: firstly constructing a gas extraction lane in a hard rock layer below an upper-group coal seam worked out area or above an unmined coal seam of the vertical distance of a firstly mined coal seam; carrying out middle construction on the gas extraction lane along the pushing direction of the firstly mined working face; starting the construction from a dark mining well of an open-off cut side and the part of the open-off cut in the gas extraction lane after construction; constructing the dark mining well the bottom of which is vertical to the top plate of the firstly mined working face at intervals; arranging an extraction pipe connected with the gas extraction pipeline; and connecting the extraction pipelines in the dark mining well into a mine gas extraction system through the gas extraction pipeline for gas predraining before mining, gas extraction in mining and gas extraction after mining. The method has the advantages of a ground drilling well extraction coal seam group, namely large extraction amount, high extraction concentration and good extraction effect, is good in stability and small in work amount, has low possibility to break and is easy to drain.

Description

technical field [0001] The invention relates to the technical field of coal seam gas drainage, in particular to a method suitable for mining the upper coal formation first and then recovering the lower coal seam group or the surface terrain is complex and the ground drilling cannot be carried out, and the ground drilling is prone to errors due to the thick Quaternary alluvial layer. The underground mining gas drainage method of Duan mine. Background technique [0002] With the mining of mines to the deep, the gas content of coal seams is getting higher and higher, and many coal seams have changed from non-outstanding coal seams to outburst coal seams. In order to control the gas emission in the mining face or eliminate the risk of coal and gas outburst in the outburst coal seam, and reduce the gas content and pressure of the coal seam, coal seam gas drainage is required. Most coal seams in my country have low air permeability, generally at 0.01m 2 / (MPa 2 .d) below, belon...

AI Technical Summary

Problems solved by technology

However, under complex conditions such as rough terrain and numerous gullies on the surface of the well field, ground drilling cannot be carried out, which limits the popularization and application of surface drilling gas drainage methods

[0004] Although the surface drilling gas drainage method has good application effect, it is greatly affected by the coal seam recovery sequence, rock formation stability and surface topography, which seriously restricts the effect of pressure relief gas control under the condition of coal seam groups

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