| Guizhou province is the richest province of coal resources in Southwest China,and more than 40% of the province's land contains coal resources.However,the geological conditions of Guizhou are complex,and the original gas content of coal seam is large.At the same time,most of the coal seam is soft rock,mostly muddy siltstone,sandy mudstone and mudstone.The gas permeability is poor,gas extraction is difficult,the effect is general,the number of outburst mine and high gas mine is more.According to the latest statistical data of Guizhou Coal Mine Safety Supervision Bureau,by the end of May 2018,there are 1113 coal mines in the province,of which there are 776 high gas mines and outburst mines,accounting for 69.7% of the total,and the mine gas disaster is serious,which seriously restricts the efficient mining and safety production of the mine.Wulunshan Coal Mine is a outburst mine.the main coal seam gas content is generally high.1803 working face mining 8 coal seam is the first.The average interval between 8 coal and other main coal seams in Wulunshan Coal Mine is about 20 m,and the interval between layers is small.After mining of 8 coal in the close distance coal seam group,the pressure release will result in the influence of the upper and lower near-ground strata,which will cause the gas emission in the vicinity and the upper and lower strata.In addition,the problem of overflowing gas in the upper corner and return air roadway frequently occurs in 1801 coal face,which affects its safe and efficient production.Therefore,more attention should be paid to the research on mine safety related to gas control.Production and sustainable development have important practical significance.In this paper,by combining theoretical analysis and field test,the basic parameters of gas pressure,content and gas permeability of 6-3 coal seam and 8 coal seam in Wulunshan Coal Mine are measured and evaluated,and the method of source separation prediction is used.The quantity of gas emission from 1803 coal face and 1805 coal face is predicted,and the relative and absolute gas emission is obtained,and then the actual gas emission of 1803 coal face and 1805 coal face is statistically analyzed.The main reasons affecting gas emission in coal face are found out,and the comprehensive gas treatment scheme is put forward.In order to solve the problem of long perplex coal mine with low concentration of gas extraction drilling,"two plugging and one injection" with pressure seal hole,"gas lift drainage method","set pipe protecting hole" and "fixed-point hole sealing" are studied.The results show that the application of high efficient gas extraction sealing technology can effectively solve the problem of drilling water accumulation,improve the sealing quality and improve the gas extraction effect obviously. |
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