Study on Three Stage Gas Drainage Mode of High Cutting and Long Coal Mining Face

According to the high difficulty problem of the gas control in the high cutting long coal mining face in high gassy Sihe Mine, a 3D type three stage gas dr ainage mode of a surface borehole gas drainage, the progressive shield gas drainage with 1 000 meters boreholes and the gas drainage with boreholes along seam wa S applied and the surface pressurized fracturing and underground gas drainage combination was realized.The results showed that, after the three stage gas drainage m ode conducted, the gas drainage value was improved from 18.28 m3/min to 184.00 m3/min, the total gas drainage value was 37 .830 81 million m3 and the gas drainage rate was 49%.The gas over limits at the coal mining face and the upper corner were effectively eliminated and the safety and high efficient coal mining of the coal minin g face was ensured.