Application of gas drainage technology with separated sources in steep thick seam

In order to solve problems of gas overrunning in No.735 Coal Mining Face of Dahuangshan Mine, a gas drainage technology with separated sources was put forward based on analysis of main sources of gas emission of the coal mining face, that is, gas in goaf is drainaged directly through crossing borehole by optimizing drainage pipelines, so as to realize gas drainage in goaf and mining seam separately. The application results show that gas volume fraction in air return flow is 0.36%-0.46%, gas volume fraction in upper corner is 0.4%-0.6%, and gas drainage average rate is 59.17% after the gas drainage conducted with separated sources.