Technology and application of coal and CBM co-mining in east fifth panel of sihe mine

The gas content of coal seam in high gas mine is large. and the simple underground gas extraction is restricted by time and space, which leads to the limited effect of underground gas extraction. At the same time, because the underground usually only rely on drilling for negative pressure extraction, the lack of coal seam anti-reflection means and transformation methods leads to insufficient gas extraction. The overall gas reduction is small, which couldn’t meet the requirements of working face gas outburst elimination and ensure mine safety production. The use of oil and gas development technology for coal seam gas extraction on the ground, coal seam permeability improvement measures are not limited by space. Various means could be used to stimulate coal seams and improve reservoir permeability. At the same time, according to the mining plan, the gas extraction project is arranged in advance on the ground. The coal seam gas is pre-extracted for a long time. Which could reduce the underground gas extraction project, shorten the underground gas extraction and standard time, and ensure the safe production of the mine. In order to greatly reduce the gas content and improve the efficiency of coal mining and the level of safe production, according to the gas geological characteristics of the east fifth plate of Sihe mine, combined with the mining and excavation connection planning of the plate, the corresponding surface and underground gas extraction technology and process research are carried out to explore the efficient and coordinated development of coal and CBM in high gas mines. By combining theoretical analysis and field test, a variety of ground and underground gas extraction attempts are carried out in the east fifth plate to comprehensively reduce the gas content of the coal seam. And through the ground extraction effect test well, the gas extraction effect of the east fifth plate is evaluated. After nearly 20 years of continuous extraction, the remaining gas content of No.3 coal seam in the planning area is reduced to less than 8 m3/t, with an average decrease above 50%. The extraction time of the preparation area is shortened by more than 15%, which ensure the high yield and high efficiency of the mine. The methane concentration of underground precise extraction in the production area is increased by more than 5%, and the extraction rate of working face is increased by more than 5%, which ensure the efficient extraction of underground. The large-scale advance pre-extraction on the ground in the east fifth plate have basically realized low-gas mining in high-gas coal seam. The co-mining of coal and CBM not only greatly reduces the gas content and increases the production of CBM through ground advanced pre-extraction, but also fills the blind area of ground extraction through underground precise extraction. Which realize the full coverage of gas extraction and save the cost of underground gas extraction. The successful implementation of the co-mining of coal and CBM in the east fifth plate of Sihe coal mine not only effectively guarantees the low-gas mining in high-gas coal seam, but also greatly reduces the atmospheric environment polluted by CBM emptying. At the same time, it also promotes the construction of the Qinnan CBM industrial base, and provides reference for the co-mining of coal and CBM in other high-gas mines. It has important value for the promotion of coal and CBM co-mining.