Study on difference and control factors of coal and gas outburst disasters in Huaibei Coalfield

Huaibei coalfield is an important coal resource development base in China,and it is also one of the most serious coal mine gas disasters in China. In ord er to master the gas occurrence and disaster characteristics of Huaibei coalfield,the gas geological characteristics,outburst disaster differences and the main controlling factors of Huaibei Coalfield were systematically studied through the methods of outburst disaster case analysis,gas geological parameter statistics and theoretical rese arch. The results showed that Huaibei Coalfield is located in Xusu arc-shaped structure circle,the network fracture structure is Crisscross in the coalfield,the maximum s tructure density can reach up to 51 bars/km2 ,the maximum coal seam gas pressure is close to 6 MPa. Some mines have serious magmatic intrusion,and the occurrence of gas presents a"bipolar" distribution. Coal and gas outburst accidents occurred in Huaibei coalfield were mostly concentrated in the Suxian Mining Area in the high gas zone, ,accounting for 57% of the accidents.The coalfield as a whole shows a gas occurrence of"high in the south,low in the east,low in the west, and highest in the southe ast" distribution characteristics of gas disasters. The coalfield experienced multi-stage tectonic movement,the local regional structure distribution is very complex,and th e in-situ stress distribution is abnormal. The thermal evolution of magmatic intrusion makes the micropores development of coal and the ability to absorb gas is enhance d. The trap effect of magmatic rock is the underlying coal body. The gas preservation provides good conditions,making the coal seams in this area prone to coal and ga s outbursts. A total of 15 accidents in the Haizi and Wolonghu Coal Mines occurred in the thermal evolution area under the magmatic rock. Some coal seams in the coal field are thick,such as Luling extra thick soft coal seams with a thickness of more than 10 m. The roof and floor of coal seam are mostly mudstone or siltstone with poor permeability,which effectively inhibits the escape of gas in the coal; the wide distribution of I- -V tectonic coals is conducive to the generation of gas in coal seams; so me mines have been extended t0-900- -1 000 m,with the characteristics of large mining depth and large in-situ stress.Research results provides support for accurate pr evention and control of gas disaster and safe and efficient mining in Huaibei Coalfield.