Technical Research On Shaft Uncovering The Coal Seam Group Which Is Soft And With High Outburst Risk

Both at home and abroad, during the process of vertical sinking, people mainly use the methods of natural gas emission through drilling and pre-draining coal seam gas by using gas-discharging holes and some other auxiliary methods in prevention coal and gas emissions. These methods have a very good effect on prevention coal and gas emissions but the times of discharging coal seam gas will last1to3months.The middle group coal seam which the new vice-shaft of Hai Zhi coal mine uncovered buried depth nearly a kilometer. Coal outstanding happened many times in these coal seams during drifting and recovery process, these coal seams have a high risk of outburst. If we use the traditional program to uncover these coal seam, each layer of coal will last2-3months, which will be seriously influence the production schedule.Through the analysis of the cournt conditions of the coal mine. We decided to take the advanced construction of regional coal gas extraction drilling in the well parking space of the third level to extract the coal gas of the middle group coal seam, Ensure the gas extraction time and the extraction effect. Improve the construction technique, using drill for extraction, using pipe to protect drill wall, cover the progressive construction, and intercept floor fracture water from periphery, dredge the old drill, and dredge water in drill. Success in solving the low concentration of gas extraction, the gas and coal inject from the drill, the drill collapse and borehole water, etc. Optimize the process of uncovering the coal seam, research the key technology on forecasting the outburst risk and detecting and eliminating the risk during uncovering the coal seam with high risk of outburst. For the group of coal with high risk of out-burst, we use "intensive drilling to discharge gas+hydraulic punching+metal skeleton+coal solidifying" measures to ensure the process of uncovering the coal seam safely and quickly. Through a series of measures, the total time accelerate3months than the original time we planed.