Analysis of the Desorption and Outburst Characteristics of Soft and Hard Coal during Gas Pressure Relief

This work discussed the results from tests conducted to study the desorption and outburst characteristics of soft and hard coal under different gas conditions. The research found that gas type has a greater influence on the outburst and desorption characteristics of soft coal. Triaxial compression failure can improve the desorption rate of coal specimens, and the gas desorption rate of hard coal is more affected by triaxial compression failure. In the outburst experiments, the greater the test gas pressure, the greater the crush degree of the coal specimen, and the proportion of small-sized coal powder (<0.1 mm) increases but gradually stabilizes. Moreover, the acoustic emission (AE) signals during the outburst process were recorded, and the evolution law of gas pressure in the outburst carven was also analyzed. Finally, the changes in AE signals and gas pressure could be used to predict the damage and destruction characteristics of coal specimens well.