| Gas Drainage is the main technical measures to prevent coal mine gas disaster. However, over 70% of Chinese coal seams permeability is less than 1mD, with increasing depth of mining, coal permeability will be lower, so the gas pumping effect is not ideal. Eight Mine Pingdingshan paper for the study, implementation of deep mine prominent, new technology research and comprehensive management of low permeability coal seam gas, in order to improve low permeability coal seam gas extraction was the starting point proposed pumping pressure alternate gas treatment technology. The main results are as follows:The research of deep mine prominent and management of low permeability coal seam gas was implemented in Eight Mine Pingdingshan. Improving low permeability coal seam gas extraction was the starting point and the pumping pressure alternate gas treatment technology was proposed. The main results are as follows:The samples of coal were tested by gas pressure experiment and then detecting coal pore structure characteristics by mercury. the internal pore pressure change laws of coal after gas injection as fellow:(1) micropore and small hole were the main types on the surface of coal, which accounts for more than 60% of the total pore volume.;(2) after various pressures and cycle numbers were applied on the coal, the pore volume of per unit mass was larger than the coal sample without pressure. So the pressure test was benefit to improve the porosity and breathability of coal.According to the principle of test, the alternately pump pressure test equipment was designed. two groups and one group experiments were tested in Eight Mine Drainage Roadway in 14140 and E 9,10-21050 machine Lane High Lane, respectively. according to the analyse of field data, it was found that the scope of injecting infection was 0-6m, which means that the scope of 6m around injecting hole Z was infected. The injecting can infected the area can keep more than 40 days. |
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