The law of gas initial desorption from coals is greatly important for understanding the occurrence mechanism and predicting coal and gas outburst (hereinafter referred to as ‘outburst’). However, dynamic characterization of gas initial desorption remains to be investigated. In this study, by monitoring the gas pressure and temperature of tectonically deformed (TD) coal and primary-undeformed (PU) coal, we established the evolution laws of gas key parameters during the initial desorption. The results indicate that the gas pressure drop rate, mass flow rate, initial desorption rate, and gas velocity increase with increasing gas pressure, with stronger gas dynamic effect, generating a high pressure gradient on the coal surface. Under the same gas pressure, the pressure gradient formed on the TD coal surface is greater than that formed on the surface of the PU coal, resulting in easily initiating an outburst in the TD coal. Moreover, the increased gas pressure increases temperature change rates (falling rate and rising rate) of coal mass. The minimum and final stable temperatures in the TD coal are generally lower compared to the PU coal. The releasing process of gas expansion energy can be divided into two stages exhibiting two peaks which increase as gas pressure increases. The two peak values for the TD coal both are about 2–3 times of those of the PU coal. In addition, the total gas expansion energy released by TD coal is far greater than that released by PU coal. The two peaks and the total values of gas expansion energy also prove that the damage of gas pressure to coal mass increases with the increased pressure, more likely producing pulverized coals and more prone to initiate an outburst.

In this study, we propose a set of rapid prediction technologies for the outburst risk of coal uncovering in crosscuts and shafts (CUCS). These technologies are needed because of the ideal model to uncover coal in crosscuts and the law that coal seam outburst intensity increases as the initial expansion energy of released gas (IEERG) increases. Our technologies include rapid coal seam gas pressure determination under complex geological conditions, complete coal-core coring and the IEERG measurement. We successfully applied these technologies in the Panyi Coal Mine in Huainan. The field application results demonstrated that these technologies could accurately and rapidly measure coal seam gas pressure, greatly minimize human damages to coal samples in the coal coring process, and accurately predict outburst risks in CUCS.