Study On Spontaneous Combustion Law Of Goaf In No.9 Coal Seam Of Donghuantuo Coal Mine

The Ninth Coal Seam of Donghuantuo Coal Mine is a class II spontaneous combustion coal seam.In recent years,high temperature oxidation of coal has occurred in the mining process.Coal spontaneous combustion has always been one of the main reasons affecting the safety of mine production.In order to ensure the smooth progress of safety production,according to the actual situation of 2394 working face,the spontaneous combustion mechanism of No.9 coal seam was studied.The main conclusions are as follows:?1?Fourier transform infrared spectroscopy?FTIR?was used to compare the oxidation characteristics of coal samples in 2394 working face.The experimental results show that the two methods have consistency in the low temperature oxidation stage of coal,that is,CO index gas is selected as the indicator gas in the low temperature oxidation process of coal,and C₂H₄ is selected as the auxiliary prediction index gas.?2?Laying a thermocouple monitoring system in the air inlet and return lanes on both sides of the working face to monitor the temperature changes in the goaf behind the working face in real time and dividing the three spontaneous combustion zones behind 2394 working face according to the field measured data.The cooling zone behind 2394 working face is 8-10 meters,beyond which the temperature of the goaf rises.The temperature of the measuring point at 80 meters behind the working face tends to be stable,so it is considered that the oxidation bandwidth is about 70 meters.The asphyxiation zone is 80 meters behind the goaf of the working face.?3?Based on the actual conditions of 2394 working face,the mathematical model is established,and the measured parameters are taken as the benchmark.The goaf oxygen concentration is simulated by software.The goaf"three zones"are divided by oxygen concentration.The simulation results are similar to the measured results.?4?Fluent software was used to simulate the influence of different air supply and the change of air flow on the three zones distribution of goaf in 2394 working face.The simulation results show that with the increase of air supply,the oxidation zone moves to the depth of goaf,and the width of oxidation zone increases.Therefore,with the development of mining,air supply should be controlled in time to reduce the oxidation bandwidth.