Study and Application of Gas Drainage Technology to High Level Gateway with Two Utilizations

In order to eliminate the coal and gas outburst danger occurred in the mine seam gateway driving period and to solve the gas content over the limit of th e coal mining face, a high level gateway was made in the upward of No. 1031 coal mining face of Sanghe Mine .Boreholes dilling through strata of the floor in the high le vel were made for the gas pre-drainage of the driving strip before the driving operation.The high level gateway could be applied to drain the upper corner gas in the goa f during the mining operation of the coal mining face.With the high level gateway gas drainage method of the one gateway with two utilizations, there was no coal and g as outburst occurred during the gateway driving.During the mining of the coal mining face, the max gas volume fraction in the air retuning flow was not over 0.8% and th e max gas volume fraction in the upper corner was not over 0.96%.