Study on the effect of different extraction conditions on "three zones" of coal spontaneous combustion in goaf

In order to study the influence of different extraction conditions of coal seam with high gas content on "three zones" and dangerous zone of coal spontaneous combustion in goaf of 4204 working face in Jianbei Coal Mine, based on theoretical analysis, numerical simulation, in situ observation and other research methods, by using CFD simulation software, the seepage model of goaf under drilling drainage and upper corner buried pipe drainage was established to simulate the distribution law of oxygen concentration field in goaf under different drainage conditions. The distribution law of oxygen concentration field in goaf was observed by using pre-buried beam tube monitoring system, and the distribution of "three zones" of coal spontaneous combustion in goaf was determined and compared with the simulation results, the results were consistent. According to the actual situation of the working face, the minimum safe propulsion speed was determined, and the corresponding fire prevention and extinguishing technical measures were put forward, such as reducing residual coal, blocking two corners, injecting nitrogen on the inlet side and grouting on the return air side, which provided guidance for the integration of the coupling control scheme of gas extraction and spontaneous combustion of goaf.