Analysis of the statistical laws and dynamic effect characteristics of coal and gas outburst accidents in China in recent 10 years

The excavation of historical accident cases characteristics can improve the understanding of the outburst mechanism and contribute the disaster prevention and control practice. This paper analyzed the patterns and dynamic characteristics of coal and gas outburst accidents by collecting statistical data which occurred in the past ten years. The results show that, in recent years, major outburst accident had been basically eliminated. However, the proportion of casualties by outburst accidents out of the total number of coal mine accidents remains high. The average number of deaths in outburst accidents being 2.9 times that of the average coal mine accidents. The locations of accidents are mainly on coal seam roadways, which account for 43.2%. The outburst accidents induced by coal cutting with fully mechanized excavators has increased significantly by around 57.0% in the past five years. Compared with other geological structures, the faults and changes in coal thickness are more likely to triger outburst accidents. The average outburst intensity near a fold structure is the highest. The average outburst intensity and gas emission of 38 accidents are 521.34 t and 35 500 m³ respectively. As the data suggests, the outburst intensity and gas emission per ton of coal in the major outburst accidents both showed a fluctuating downward trend. Borehole spraying is the most common indicator of outbursts, and rational utilization of borehole information for disaster detection and early warning is an important development direction. The three stages of the development and evolution of outburst dynamic effects in roadway space have been confirmed. Gas counterflow can not only occur through the outburst prevention airlocks into the intake roadway, but may also enter other mining and excavation working faces along the return air route.