Discussion on characteristics and outburst conditions of Jurassic coal seam gas disaster in Shaanxi Province

With the transfer of coal production to the west of China, the coal mine gas disaster in the west, especially in the northwest, has become an important problem that must be faced seriously. Taking 6 typical mines in Huangling, Xunyao and Yonglong mining area of Jurassic coal field of Huanglong, Shaanxi Province as the research objects, the characteristics of coal mine gas occurrence were analyzed and summarized, and the coal seam outburst risk was discussed from the aspects of single index, energy and dynamic effect of coal seam outburst risk. The main conclusions are as follows: the coal in Huanglong coalfield is mainly low-metamorphic bituminous coal, with small degree of coal destruction and relatively high hardness. The gas of the coal seam showing obvious characteristics of high pressure and low content (from 1.71 m³/t to 4.36 m³/t). Due to the low gas content, the gas potential energy and elastic internal energy in the coal seam lower than the energy value required for coal crushing and throwing to do work, and are not enough to complete the transportation of outburst coal in the roadway space to form a typical outburst disaster. However, a large amount of gas gushing out in a short time will become the main gas accident risk in these mines when dynamic phenomena such as sheet wall or rock burst occur. It is pointed out that the coal wall roof and rock burst should be controlled at the same time of gas extraction in the Jurassic coal field of Shaanxi Province, which can effectively reduce the occurrence of gas accidents.