Determination and predication on three zones of coal spontaneous combustion at fully-mechanised working face with nitrogen injection

Coal mine fire is one of the major disasters for coal enterprises. Among which spontaneous combustion of float coal in the goaf is particularly serious, what is worse, the float coal in goaf of fully mechanised working face in a large number of coal mines are more vulnerable to spontaneous combustion. Therefore, it is of great significance to determine and predict the dangerous zone of coal spontaneous combustion of in goaf of fully mechanised working face. This paper we took the 21,305 working face of the CuiMu coal mine as an example, experimental research, field observation and numerical simulation were adopted to determine the dangerous zone of goaf. Results showed that the field measured data before and after nitrogen injection were in good agreement with the numerical simulation results. Nitrogen injection can effectively prolong the period of spontaneous combustion and reduce the probability of spontaneous combustion of coal. The research results and method of this paper provide theoretical guidance and reference significance for the prevention and control of coal fires. [Received: May 9, 2017; Accepted: December 1, 2017]