Safety technologies for the excavation of coal and gas outburst-prone coal seams in deep shafts

An analysis of the stress distribution characteristics of shaft working faces in deep underground coal mines was performed using theoretical analyses and field tests. The analysis of the outburst risk within the studied shaft demonstrated that a funnel-shaped pressure relief zone existed below the working face, and a zone of concentrated stress surrounding the shaft was a critical area for a potential outburst disaster. We then divided the process of coal excavation within the shaft into four stages to manage and propose improved technical, drainage and protective measures as well as other requirements. When using the processes and requirements provided, the Haizi and Taoyuan coal mines, which are located in the Huaibei mining region and have depths of up to 1000m, realized safe and rapid excavation through outburst-prone coal seams. It was determined that the technical systems developed in this paper could provide for safe coal excavation in deep shafts, which could be established as new regulations for rapid and safe coal extraction in outburst-prone coal seams.