Study on gas migration law and extraction parameters of hard roof extra-thick coal seam
The unique characteristics of gas emission and migration in the extra-thick,hard-roofed coal seam present specific challenges.By studying these characteristics,it is possible to determine the gas control scheme and solve the problem of gas overflow at the coal face.Based on mining the Carbonifer-ous extra-thick hard-roof coal seam in the Datong mining area,this study investigates the gas migration law,mining and processing technology and parameters through theoretical analysis,numerical simulation and field measurement.The research shows that the complex roof's mining influence zone and the sus-pended roof zone are large,resulting in abnormal gas emission and accumulation areas lacking ventilation under the broken roof.When the working face is pressed,the gas enters the working face with the collapse of the suspended roof,which quickly causes the gas to overflow.Merely employing U-shaped ventilation at the working face does not effectively address gas overflow in the upper corner,and the high-drainage roadway is proposed as the prevention and control technology of the working face gas.The concept of extraction weight is defined for the first time,and,the vertical layout layer and extrac-tion parameters of the high drainage roadway are determined based on the dynamic adjustment of extrac-tion weight.The vertical distance of the high drainage roadway is 18 m from the working face,and the horizontal distance is 15 m from the air return roadway.The optimum negative pressure for extraction is 7 kPa,and the optimum extraction weight range is 0.25-0.5.The maximum gas concentration in the upper corner is only 0.63%,the gas extraction concentration is 3.92%,and the average gas extraction rate during the pressure period of the coal face can reach 80.8%.These research findings provide valua-ble insights for managing gas-related risks in fully mechanized coal faces with extra-thick hard roofs.
hard roofextra-thick coal seamgas migrationhigh pumping alleydrainage weigh
万方数据
维普
