Relationship between the fracture zone and cave of coal or gas outburst caving in coal and rock seams

The fracture zone of gateway driving face of 2124 machine roadway of a coal mine in Chongqing was simulated by Ansys, and had been compared with the true cave of coal and gas outburst. The results show that the ground stress was the predominant factor which influences coal and gas outburst cave, and the fracture zone could be divided using numerical simulation. Furthermore, the outburst cave of coal and gas evolved from fracture zone in coal body. The data of coal and gas incidents during more than 30 years in this mine was analyzed. The characters of coal and gas outburst cave was far from geological structures: Outburst cave located at the roadway top, present 'pocket shape'; The length of long axis of outburst cave was 5~15 m, extension along trend was less than 5 m; The most outburst cave in this mine was developed from fracture zone which resulted from the ground stress filed mainly was horizontal tectonic stress.