Application of Reduction Method for Desorption Gas Content in Investigation of Gas Drainage Radius by Boreholes along Seam

The accurate knowledge of the gas drainage radius in an outburst seam is not only an important basis for working out outburst prevention measures,but also the fundamental guarantee for the realization of outburst elimination in the pre-drainage period.In this paper,investigation was made on the gas drainage radius of Φ75 mm borehole along No.5 seam of 5102 working face in Gouchang Coal Mine by applying the reduction method for desorption gas content.The practice proved that the reduction method for desorption gas content can be used for the investigation on the drainage radius of the boreholes along the seam and it has higher success rate and accuracy.The investigation results showed that the relation between the drainage radius R of Φ75 mm borehole along No.5 seam in this mine and the gas pre-drainage time t was R=0.666ln t-1.422.