Characteristics of air leakage and gas migration in goaf of pillarless coal mining face
To understand the characteristics of goaf air leakage and gas migration in different mining periods of Y-type ventilation working face without coal pillar mining,97312 working face in Sihe No.2 coal mine of Jinneng Holding Equipment Manufacturing Group Co.,Ltd.was selected.The sulfur hexafluoride(SF6)tracer gas approach was used to determine the air leakage area distribution,air leakage type,and air leakage volume of 97312 working face and the roadways under different connectivity states with the adjacent 97311 working face goaf.The air leakage flow field distribution and gas migration characteristics in the goaf area were analyzed by numerical simulation.The results showed that 97312 working face had four air leakage areas of positive pressure-negative pressure-positive pressure-negative pressure along the wind direction.The main air intake roadway 97222 had positive pressure leakage.The air return roadway 97224 had mainly negative pressure air leakage along the gob-side entry retaining section,but positive pressure leakage was prone to occur near the extraction pipe and in the area where the roadway was severely deformed.After connectivity with the adjacent goaf area,an additional air leakage path was created.Moreover,the connection status with the adjacent goaf affected the internal air leakage flow field and gas migration of the goaf.Air leakage from the 97311 goaf area carried gas to the 97312 goaf,causing an increase in gas volume fraction in the 97312 goaf,working face,and the gob-side entry retaining section of the 97224 roadway.After the closure of the 97311 working face,the gas volume fraction near the connected goaf area decreased.
pillarlesscoal mining faceair leakage in goafgas migrationY-type ventilationgob-side entry retainingconnection state of goaf
万方数据
维普
