Analysis and governance of air leakage law in goaf of shallow coal seam mining

Taking 22104 goaf of Shangwan Coal Mine as the research object, SF₆ tracer gas was released on the surface to verify the existence of air leakage channel and calculate the air leakage velocity. The Fluent fluid simulation software was used to analyze the gas migration law of goaf. The physical models of numerical simulation analysis of goaf were established with the actual production parameters of working face and measured data of air leakage in goaf as modeling boundary conditions. Simulation of leakage airflow field and gas migration rule in goaf with or without surface air leakage shows that under the condition of surface air leakage, hypoxic gas in goaf abnormally flows out, resulting in more serious hypoxic problem in corner of the working face. In view of the problem of hypoxia, local equalized pressure ventilation measures are put forward to treat it. The practice shows that the air leakage volume and pressure difference in goaf are reduced, the oxygen volume fraction in the return air corner is increased, and the hypoxia phenomenon is improved.