Optimization and application of gas control parameters in the upper corner of large diameter borehole

In order to solve the problem of gas overrun in the upper corner of the working face, the technology of gas drainage in the upper corner of the working face is put forward.The parameters of the large diameter borehole are optimized by using the numerical simulation method, and the optimal hole diameter, hole distance and final hole position are determined.The application effect of large diameter borehole in the 18401 working face of Xiqu mine shows that when the spacing between large diameter borehole is 5 m and the aperture is 350 mm and the distance from the end of the borehole to the roof is 0.3 m, the gas drainage effect of the upper corner is the best; compared with the high extraction, the cost of gas drainage in the upper corner of the large diameter borehole hole is reduced by 85.79%; in the process of mining, the gas concentration of the upper corner is reduced by 85.79%, all of them are kept below 0.2%, which effectively controls the gas concentration in the upper corner and ensures the safety production of the working face.