Abstract:
Based on the characteristics of small angle uncovering coal in the main return way of Duanshi Coal Mine, using the traditional uncovering coal technology will have many difficulties, like the larger outburst prevention quantities, the long cycle of uncovering coal, the high outburst hazard. The study uses the vertical crossing drainage technology which is combined by the layer-through boreholes and consequent layer boreholes, through about 72 days of gas pre-drainage, the gas content in coal seam from 20.5 m
3/t decreased to 6.25 m
3/t, the gas drainage rate of the mine reaches 70%, and the gas pressure is dropped from 1.56 MPa to 0.48 MPa, the coal seam outburst hazard is eliminated completely, the time of elimination outburst than the time by traditional outburst prevention measures is shorted by 64 days. The uncovering coal section is larger by small angle, it is difficult to uncover the section by using the traditional uncovering coal technique, we use remote vibration blasting technology to successfully and safely uncover the coal seam, compared with traditional methods, the time shortens 39 days. After the uncovering coal, the maximum gas concentration of the return-air is 0.3%, the maximum of gas desorption index of drill cuttings (△
h2) is 80 Pa. Using small angle rapid uncovering coal technology, the total time is less than the expected of 103 days, the mine has ensured a safe production and excavation replacement.