deep mine| dynamic phenomenon of gas| extrusion| mechanism| forecast|

According to the gas geological features of the sudden extrusion region of deep mine in Dingji coal mine of Huainan mining area,the frictional sliding instability mechanism of sudden extrusion in fully mechanized driving face (FMDF) is analyzed. The critical values including sensitive index drilling bits S,hole depth coefficient S',drilling gas inrush initial velocity q and attenuation coefficients Cq are obtained. They are S0=6.0 kg/m,S0' =0.9kg/m/m,q0=2.5 L/min,2.5≤q0﹤5 and Cq=0.65,respectively. The hole depth coefficient S' is put forward to forecast the low-index outbursting induced by the ground stress at the first time,and the forecasting accuracy rate is improved. The results show that the forecasting non-outbursting risk rate is 87%,and the forecasting non-outbursting accuracy rate is 100% during a 3000 m-tunnel driving in the test area. The research achievements can provide beneficial references for other similar mines to control abnormal dynamic disasters due to coal methane.