Relationship between mining seismicity and gas outburst in coal mine——Some scientific questions of mining safety

The phenomena in which mining shocks and gas outburst occur simultaneously are enumerated. These examples reveal the close relationship between mining seismicity and gas outburst or gas overflow in coal mines that are rich in gas. It is suggested that the strong mining shocks plus the low delay time response?? are early warning signals. Thus, the joint observation of mining seismicity and gas for early warning of disasters is necessary for maintaining safety and mitigating disasters. The mechanism of the relationship between mining seismicity and gas outburst is analyzed based on the shock location, source?? focus mechanism, cause of the shocks, and gas outburst conditions. The trigger effect of gas fluid, especially the important effects of special characteristics of ultra-critical fluid on the eruption of mining shocks are discussed.