Research On Gas Prevention And Control Technology In ?₃ Mining Area Of Western Well In Shuoshi Coal Mine

At present,coal mine gas accidents still occur from time to time,which is one of the important threats to coal mine safety production.Combining with the actual production of coal mine,further research on gas prevention and control technology is of great practical significance for guaranteeing the personal safety of coal mine employees and national property safety.Combining with the concrete conditions of Shuoshi Mine,this paper makes a deep research on the gas control technology in West Well II₃ Mining Area,and the research results have been initially successfully applied in the field.Based on the combination of theoretical analysis and field practice,this paper analyzed the gas geological characteristics and local accumulation reasons in the west well II₃ mining area of Shuoshi Mine,predicted the risk of coal and gas outburst in the II₃ mining area and the II332 working face,and analyzed and adopted relevant technologies suitable for gas prevention and control in the II₃ mining area to reduce the gas safety threat.The main research results are as follows:?1?The causes and occurrence of coal seam gas and the main factors affecting the content of coal seam gas are analyzed.It is concluded that the local accumulation of gas in II₃ mining area is mainly caused by the large degree of destruction of magmatic rocks,the decrease of permeability coefficient of mining coal seam and the absence of outcrop coal seam on the surface.?2?The early warning index of coal and gas outburst in working face and the method of gas judgment in mining area are analyzed,and the outburst risk of coal roadway driving face is predicted by the method of drilling cuttings index.The early warning of coal and gas outburst in working face II332 can adopt such index parameters as gas pressure,initial velocity of gas release,change of geological structure,stress concentration,permeability of surrounding rock,change of thickness of coal seam,change of inclination angle of coal seam and strength of coal body,etc.For the basis of identification,the actual measurement confirms that there is no outburst danger in II332 mining area,and the maximum value of K₁ is 0.32ml/g min^1/2 and?h₂ is 180Pa by drilling cuttings index method,confirming that there is no outburst danger in II332 working face.?3?Appropriate gas control technology was adopted during excavation and mining of working face II332,and good gas control effect was achieved.Local ventilation,gas monitoring,dynamic pressure water injection,loosening blasting and advance drilling were adopted during the excavation of roadway in working face II332.The gas content in front of the roadway was less than 0.05%during the excavation process,and there was no gas accident in the whole process.Gas drainage in mining seam was carried out with the method of stepping buried pipe drainage in old pond,which effectively alleviated the return of working face II332.During the period of mining,the gas concentration has never exceeded 0.5%,which ensures the safety of production.