Researching Of The Law And Control Technology Of Loose Coal Spontaneous Combustion In The Re-mining Workface Of Xipang Coal Mine

Coal is among the most important energy resources around the world, and sustainable conservation of the coal resources becomes increasingly important. Re-mining the residual coal in the mined out area can effectively improve the utilization rate of coal resources, especially more significant for aging mines with resource depletion. As physical structure of coal was destroyed during former mining, the abandoned coal in the gob becomes loose and porous where spontaneous combustion is more readily to take place. Therefore, it is very necessary to research the law and control technique of spontaneous combustion in the loose coal during re-mining.In this article, the No.108 re-mining working face in Xipang coal mine of Hebei province was taken as example; methods of experiment, field observation and numerical simulation were combined to study the law of loose coal spontaneous combustion; then colloidal fire-fighting technology was proposed to fill and block high-temperature regions. First, coal samples of different sizes and same sizes pre-oxidized at different temperature were carried out temperature-programmed experiments separately, and its spontaneous combustion characteristics were obtained by analyzing the results comparatively; then characteristic parameters, particle size influence function and limited parameters of coal spontaneous combustion can be got by associating to previous coal self-heating oxidized experiment using numerical simulation method. Secondly, the distribution of rock pressure, porosity, leakage channels and permeability of the re-mining gob were studied through theoretical analysis and flied observation. Then a mathematical model of Seepage and air species concentration was built and simplified using the theory of heat and mass transfer in porous media. After that, distribution of oxygen concentration and the velocity of air flow in the gob were calculated by simulating the flow field using fluent software numerically. Then, with the result of simulation, coal spontaneous combustion dangerous zones were partitioned by combining its division criterion and the critical parameters from the experiments of coal sample of the re-mining workface. Accordingly the law of loose coal spontaneous combustion can be summarized with the analysis results. Finally, the fly ash composite gel fire prevention and control technique was adopted to cool the high-temperature zone and to block leakage in the predicted coal spontaneous combustion danger zones. The results showed that after implementing with the fire extinguishing technique, temperature of the spontaneous fire zones around the airway decreased to 26~28 degree concentration, carbon monoxide near the high-temperature zone dropped sharply and eventually disappeared, and the re-mining work face was mined out safely to the designed stop mining line. The researching of the law and the control technology of loose coal spontaneous combustion in the re-mining workface can has some reference value.