Coal seam group with high gas content pressure relief and co-mining method based on gob-side entry retaining of working face of first mining total rock pressure relief

Abstract

The invention discloses a coal seam group with high gas content pressure relief and co-mining method based on gob-side entry retaining of a working face of first mining total rock pressure relief. When a first mining pressure relief coal seam can not be selected, the coal and rock seams are moved and broken through the working face of first mining total rock pressure relief, an upper covered coal seam with high gas and a lower covered coal seam which high gas are subjected to pressure relief and swollen, fractures of a surrounding rock mass are developed, the gas permeability is increased, the gas is subjected to desorption and transportation, and finally a top plate pressure relief annular fracture area and a bottom plate pressure relief annular fracture area are generated. To create a favorable stress environment of retained roadway surrounding rock, retained roadway mining empty side cantilever crest truncation is conducted to first advance mining drill site toward and backward the working face in a bi-directional mode, according to the top plate lithologic characters, the first advance is subjected to top plate deep hole pre-splitting and cover caving so that it is guaranteed that the top plate is sufficiently collapsed to fill a worked out section. By means of the method, the prominent problems of exhausting and mining of coal seam group pressure relief gas and safe mining when the first mining pressure relief coal seam of the coal seam group with high gas content is difficult to select are solved.

Description

technical field [0001] The invention relates to a method for mining high gassy coal seam groups in coal mines, in particular to a method for extracting pressure relief gas from high gas coal seam groups by retaining roadways along the gob-side of the first-mining whole-rock pressure relief working face, so as to realize the safety of high gas coal seam groups. efficient mining method. Background technique [0002] The main coalfields in my country have complicated geological conditions, high coal seam gas content and low permeability. Practice has shown that once the coal seam is disturbed by mining, even the coal seam with low permeability will increase its permeability by tens to hundreds of times, creating conditions for gas migration and extraction. This determines that the focus of my country's gas drainage should be based on the active pressure relief of underground mining. [0003] In the invention patent application with the application number of 200810023383.9, th...

AI Technical Summary

Problems solved by technology

Although this invention can well solve the mining problem of high gassy coal seam group when there is a suitable first mining pressure relief coal seam, but when there is no suitable first mining pressure relief coal seam group in high gas coal seam, this scheme is applied difficulty

Especially when the gas is extracted from high-gas coal seams for the first time, the efficiency is low, the gas extraction is not thorough, and cannot reach the safety value, and it is prone to gas explosions or coal and gas outbursts and other vicious accidents, posing huge safety hazards

Therefore, under the above engineering conditions, the mining problem of high gassy coal seam groups has not been well resolved

Images