Comparison analysis on spontaneous combustion danger ofgoaf with upward and downward ventilations in Xiaonan Mine

In order to compare the upward and downward ventilations of the coal mining face affected to the spontaneous combustion danger of the goaf, in combination with the certain engineering background of No. W2722 coal mining face in Xiaonan Mine, a closed oxygen consumption experiment of the coal samples was applied to have a linear relationship between the coal sample oxygen consumption speed and the environment oxygen concentration in Xiaonan Mine. With the application of the CFD simulation technology to simulate the flow field in the goaf, an air leakage condition of the coal mining face was obtained and also the oxygen concentration field and the temperature field in the goaf were obtained. When only the gas emission condition was considered, the goaf of the downward ventilation coal mining face would be affected by the upward floating effect of the gas, could restrain the air leakage from the coal mining face to the goaf and the air leakage rate was 3.68%. Conversely the gas upward flotation of the coal mining face with the upward ventilation would accelerate the air leakage of the coal mining face and the air leakage rate would be 7.35%. The simulation on the flow field of the goaf with energy source item could make the air leakage rate of the downward ventilation coal mining face further reduced to 2.94%. In comparison with the simulation calculation of the upward ventilation, the air leakage rate of the coal mining face would be increased to 8.09%. The results showed that with the upward ventilation, the high gassy and easy spontaneous combustion goaf would promote the spontaneous combustion danger occurred. Therefore,in the actual production, the application of the downward ventilation method could restrain the danger of the spontaneous combustion.