The geological structures of the coal fields in China are complex. With a continuous increase in the mining depth, the coal seams show the characteristics of high gas and low permeability, and the disaster potential for a coal and gas outburst intensifies in the process of coal mining. Gas drainage is one of the primary measures used to prevent and control gas disasters. Effectively improving the permeability of a coal seam requires urgent attention. Currently, the method of loose blasting is used in engineering to enhance the permeability of coal seams. However, the technology of loose blasting easily leads to the poor development of coal fractures or the severe crushing of coal, which will affect the gas drainage. Thus, this paper studied the technology of liquid CO2 phase-transition fracturing in a coal seam. COMSOL was used to determine the influence radius of the liquid carbon-dioxide phase-transition cracking, which was 13.4 m, and to design the scheme of the borehole. The field test was carried out in the 81506th working face of the Baode Coal Mine. From the onsite-monitoring data, the results showed that the drainage effect increased by 293.9%, the gas-drainage concentration increased by 242.4%, the permeability coefficient of the coal seam increased by 3–7.75 times, and the permeability enhancement effect was good.

Outburst closed distance coal seam distances are extremely difficult to mine, and are commonly involved in safety accidents in the process of mining. Based on the engineering background of the Wulan Coal Mine at the western margin of the Ordos Basin, this paper presents a theoretical analysis, engineering analogies, and numerical simulations to determine the optimal mining sequence for the Wulan Coal Mine #7, #8, #2, and #3 coal seams. Floor penetration drilling was used to eliminate outbursts in the #7 and #8 coal seams, and gas control in the #2 and #3 coal seams was achieved using ground drilling to pump and release the pressured gas. We established a comprehensive management technology system for gas emissions from the short-distance joint protection layer in the outburst coal seams of Wulan Coal Mine, where pressure relief and drainage were carried out by drilling through the floor and surface drilling pressure relief extraction. Through field tests, the pre-drainage rate of the #2 coal seam in the Wulan Coal Mine was 66.8%, and the pre-drainage rate of the #3 coal seam was 68.1%. This shows that protective layer mining of the #7 and #8 coal seams combined with surface drilling to extract pressure-relief gas can protect the #2 and #3 coal seams.