Intercepting and Drainage Technology of Fissure Gas Based on Floor Sandstone with High Permeability

In view of the problem of gas overlimit in 31847 working face and roadway, which was caused by the fissure gas in the floor sandstone in 384 mining area of Tangjiahe Coal Mine overflows after the floor fissure water drainage. The controlling technology of intercepting and drainage fissure gas of floor sandstone in the mining area was put forward. Through drilling at downward layer at 63° angle of depression in 31847 machine lane, the fissure gas that gushing into the floor sandstone in 384 mining area was intercepted and drained, the rational space between intercepting boreholes was determined to be 8 m through numerical simulation. The application results showed that the volume fraction of the return gas in the working face was always within 0.8% after the intercepting drilling, at the same time, about 691.2 thousand m³ of fissure gas was cut off and pumped in the process of gas control, completely eliminating the hidden danger of gas over limit in 31847 working face.