Hazardous Areas Distribution Of Coal Spontaneous Combustion In Shallow-Buried Compound Gobs Of Coal Seam Group

Coal spontaneous combustion in gobs is one of the main disasters in coal mining process.The coal spontaneous combustion in shallow-buried compound gobs of coal seam group is particularly prominent.In the west coal area represented by Shendong coal area,the coal seam is characterized by shallow burial,thin bedrock,short distance and easy spontaneous combustion,etc.At the same time,it is significantly affected by the repeated mining of coal seams,and the surface is easy to form connected fractures,and the air leakage occurs when the surface connects the underground gobs.Coal seam group mining constitutes composite gobs,resulting in residual coal occurring coal-oxygen reaction.Therefore,it is of great significance to study the hazardous areas distribution law of coal spontaneous combustion in shallow-buried compound gobs of coal seam group.In this paper,taking the Bulianta coal mine as the research object,the distribution and evolution mechanisms of surface fractures have been analyzed theoretically,and it is found that the surface fractures are mainly distributed around the working face and two roadways;The combined method of "pressure difference + air volume difference + tracer gas" was used to measure the air leakage volume and air leakage area on the surface,and it is found that the surface air leakage is mainly concentrated on the surface return side.The simulation experiment platform of shallow-buried compound gobs of coal seam group is established.The influences of surface air leakage rate and working face ventilation rate on the oxygen concentration distribution have been researched.According to the condition of spontaneous combustion of coal in gobs,the reason of oxygen concentration change and the distribution characteristics of residual coal are analyzed.Based on the determination method coal spontaneous combustion hazardous area,the distribution law of coal spontaneous combustion hazardous area is determined,and the influence of different factors on coal spontaneous combustion hazardous area is analyzed.According to the maximum width of coal spontaneous combustion hazardous area,the rating indicator is established to determine the risk of coal spontaneous combustion in gobs.Combined with the general situation of coal spontaneous combustion of Bulianta mine in Shandong coal area,and based on the regional distribution law of coal spontaneous combustion hazard in shallow coal seam group compound gobs studied in this paper,some guiding suggestions are put forward for the prevention and control of coal spontaneous combustion hazard in gobs of Bulianta coal mine.