Theory and Technology of Gas Drainage and Disaster Prevention in Complex Coal Seams

The occurrence condition of coal seam was found to be more and more complex with buried depth deeper and deeper, it was prone to induce coal and gas disaster due to low gas permeability, large gas quantity and high gas pressure. To solve the problem, a new theory and technology of using multi-phase oscillating water jet to promote gas drainage and regionally eliminate outburst was brought up, i.e. drilling, slotting, Cavitations sonic shock, promoting gas desorption, surfactant substitution and solid abrasive support. What's more, the related devices were also invented simultaneously. It was applied successfully in some mines in Chongqing, Sichuan, Guizhou, Henan and Shanxi of China. The results showed that the technology could improve the permeability of coal seam, and the gas drainage quantity was increased by 48.5%similar to 65.9% per ton of coal. And also, the time of outburst elimination regionally was decreased by 37.4%similar to 46.7%.