Abstract:In order to solve the problem of concentration drop and low concentration of gas drainage in the bottom drainage roadway through crossing hole, Jiulishan coal mine was investigated for its variation rule of gas drainage by such practice and theoretical analysis was carried out on the reasons for the drop in gas concentration; And based on the floating accumulation theory of CH4 molecule under gravity field and negative pressure drainage theory, a method of secondary sealing to crossing hole was proposed to raise drainage gas concentration. Technological feasibility was analyzed on the concentration increase of secondary sealing to crossing hole that had low gas concentration. Field test was conducted in the 16101 bottom drainage roadway of Jiulishan mine. As was proved by test, the concentration increase technology for holes with low concentration could greatly improve hole drainage concentration. The gas drainage concentration of test drill hole was increased by more than 2 times, with much less mixed volume and higher drainage efficiency, which realized efficient utilization of the drainage capacity.
