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Gas treatment of high gas outburst coal seam group with protection layer mining, based on the engineering geological conditions of the mine, combined with the field engineering test, study on the effect of B10 coal seam mining on the upper cover B11b and down to B8 under the protective layer in the protection layer 22108. The results showed that the protective layer mining combined with drilling pre pumping protected layer gas, the coal and gas outburst danger of the middle and lower coal seams were reduced, the coal seam gas occurrence law was changed, the permeability of coal seam was increased, and the effect of extraction was improved, which provided the technical basis and support for the regional gas control in the protective layer of the mine.

Coal and gas power risk was increased under the condition of high stress, high gas and low permeability of coal seam in deep mine, low permeability coal seam gas pre pumping was very difficult. Drilling enlarging by high-pressure water jet used high pressure water as the driving force to wash and peel the coal body in the drilling, it aimed to discharge the coal and release the gas in the coal seam quickly, the gas pumping efficiency was improved, the stress of coal seam was declined, and the goal of rapid pressure relief and permeability was achieved. It applied in some serious outburst rock cross-cut coal uncovering area, with drilling enlarging by high-pressure water jet technology, drilling equivalent get to 500~800mm after drilling enlarging, about 3~9 times of the original diameter, gas extraction concentration was 1~2 times higher than before, coal uncovering time was shortened by 1/3~1/2, the effect of field application was obvious.