Failure Mechanism of Gas-Bearing Coal during Outburst and a New Method for Outburst Prediction

[Image: see text] Coal and gas outbursts are among the most serious disasters affecting the safety of coal mines. Gas is an important factor in these types of disasters. To analyze the characteristics of the damage caused by gas to the coal body during the sudden release of the gas process, a self-developed high-pressure gas release cause coal particle ejection experiment device was used to conduct gas release experiments under different conditions. The results show that at the moment of gas release, coal particles and gas are ejected at high speed, crushing coal particles into smaller particles. With the increase in gas pressure and gas adsorption performance, the crushing effect will increase. Also, the coal ejection strength (CES) will increase nonlinearly. By analyzing the mass ratio of ejected coal particles, based on the theory of crushing work and energy, we developed a new coal particle fragmentation index, which can be fitted linearly to CES. The index is based on the f value, which makes up for the limitations of the forecasting method, and can be used more flexibly to predict the coal sample crushing situation. Moreover, the fitting parameter values can more accurately describe the coal particle crushing grade.