Research And Application Of Comprehensive Gas Drainage Technology In Fully Mechanized Top Coal Caving Face Of Extra Thick Coal Seam In Xia Gou Mine

Mine gas disaster is one of the most important factors affecting mine safety production,which restricts and threatens the safe production of coal mines and the safety of workers,while gas extraction is the most effective control measure to solve the hidden trouble of mine gas disaster and realize the safety production in coal mine.The main content of this study is the background of the gas extraction project of the Trench mine,which has the characteristics of thick seam,high seam gas content and large gas emission,especially in three mining area.As the mining position continues to deepen,the coal seam occurrence depth also increases,the coal seam gas pressure and the content increase,is not easy to release,to the mine safety production brings the very big challenge,therefore this paper studies the gas emission law in the deep thick coal seam high gas gush face,studies the corresponding coal face gas control technology.In this paper,the distribution law of overlying strata fissure in goaf of fully mechanized caving face is studied,the physical model of the "three belt" height of overlying rock fissure,the analysis of porous medium and pore gas property,the coupling effect of mining fissure field and gas flow field,and the calculation of gas emission in working face and heading face by using the method of source prediction,The aim is to predict the methane emission in GOAF and mine gas discharge.By using the fluent numerical simulation software,the advantages of the gas in the high rock drilling and pumping mining area are analyzed and studied in the return air of the mining face.Combined with the actual situation of coal mine and the characteristics of gas emission in 302 fully mechanized caving face,this paper determines the extraction technology of gas in the coal mining area using the gas pre-pumping(side-pumping)and the High rock drilling.,and establish a complete gas extraction system.The gas content of the coal seam is reduced obviously before the working face is extracted,and the average gas extraction rate reaches 85.3% during the mining period,which guarantees the safe production of the mine and also plays a good guiding role for the gas control work of the surrounding mine.