Study On Reasonable Parameters Of Gas Extraction In Goaf Of Fully Mechanized Caving Face Of Spontaneous Combustion Coal Seam

Gas extraction technology of goaf is an effective method for gas control in the working faceof gas mine. Gas extraction in goaf of spontaneous combustion coal seam leads the amount of airleakage to goaf increasing, enlarging the range of oxidized dangerous spontaneous combustionbelt, which is not conducive to the prevention of spontaneous combustion in goaf. How to drawreasonable gas extraction methods and extraction parameters, which is effective to governanceface gas, but not lead to spontaneous combustion, is the impotrant issues that should addressedimmediately.In this paper, the comprehensive management of gas and spontaneous combustion in goafof5-2S fully mechanized caving face in five district of Hongmiao coal mine, is taken for anexample to the research of reasonable gas drainage. The large amount of gas emission during theperiod of5-2S fully mechanized caving face in fifth district cutting coal, seriously threatens themine production, approximately, two-thirds is coming from goaf. Meanwhile, the shortestspontaneous combustion period of the mining coal seam is only20d, existing dual disasters:spontaneous combustion and gas. Upper corner buried pipe drainage is used to control the goafgas, and nitrogen injection is used to prevent spontaneous combustion. All these make the airflow field of the goaf very complex. The impacts on the air flow field and concentrationdistribution of the goaf are analyzed, that the changes of gas drainage value, and the location ofdrainage outlet as well as injection capacity of nitrogen. The results show that, the larger of thevolume of gas drainagen, the greater risk of gas explosion and spontaneous combustion.Appropriate increasing gas drainage volume is used to ensure the safety of the working face,with injecting nitrogen or accelerating the speed of face promote. The drainage outlet locationshould also be in an appropriate range (5~25m) after the break line of the face. The result hasimportant guiding significance in goaf of inflammable thick seam of gas mine, on the selectionof gas extraction parameters, which is reasonable to prevent both gas explosion accident andspontaneous combustion caused by drainage excessive.