Study On Spontaneous Combustion Characteristics Of Goaf With High Gas High Sulfur And High Ignition In South Sichuan Mining Area

Due to the increase of mining depth in some mines in the south of sichuan,the amount of gas emission increases and the difficulty of gas control is increasing.The increase of mining depth also leads to the rise of ground temperature and ground stress,which directly leads to the increase of the degree of crushing of overlying coal and rock in the goaf,and the natural harm of residual coal in the goaf is prominent.At the same time,during coal seam mining,there are many faults,resulting in a lot of coal left in goaf,which is easy to cause natural oxidation of coal left in goaf.Gas extraction measures have common application in sichuan region,used for prevention and treatment problem of top corner gas concentration is too high,at the same time in sichuan area part mining area coal seam permeability(0.001 ~ 0.1)x 10-3 mu m ^ 2 interval,cause it is difficult for the measures to achieve due to the gas extraction effect,only with a single gas drainage technology is difficult to effective governance gas concentration in upper corner transfinite problem.In this paper,the coupling problem between gas extraction and spontaneous combustion of floating coal in actual production in south sichuan mining area is studied as follows.The closed oxidation test bed of residual coal was established,and the circulating air current was introduced into the coal sample in the test device.The critical oxygen concentration values of spontaneous combustion zone and asphyxiation zone were obtained.Through the program heating experiment,the law of coal oxidation gas product generation in the process of program heating was studied,and the concentration index of the signature gas of spontaneous combustion was obtained.Based on the oxygen concentration consumption rate,the goaf oxidation zone was divided into scattered zone.Based on the results of the closed oxygen consumption experiment,the critical oxygen concentration of oxidation zone and asphyxiation zone was analyzed,and the oxidation zone and asphyxiation zone were defined by the value,so as to obtain the personalized three-zone division suitable for the actual mining conditions of N3062 working face of China fir mine.It is the main content of the numerical simulation in this paper to obtain a reasonable range of high suction negative pressure through Fluent numerical simulation.N3062 working face is different from the traditional way of u-shaped ventilation,the ventilation system affected by the high pumping pressure,thus high smoke which collection of gas for predicting goaf spontaneous combustion process,has the high reference value,meanwhile CO judgement index,coefficient of Graham(Graham coefficient)to adjust,also find reasonable determine accurately the legacy of coal spontaneous combustion is the main research content of this part of the chapter.