New technological partition for “three zones” spontaneous coal combustion in goaf

On detailed analysis basis of spontaneous coal combustion for the three zones in mine goaf, we use O2 and CO concentrations to divide the three zones of the coal combustion. Through our experiment, we selected a typical working face and focused on the changes in gas concentrations. In order to overcome establishment limitations of actual layout location and underground conditions in a mine goaf, we based our observations on the three zones, combined them with numerical simulation, described the distribution and the changes in O2 and CO concentrations during the coal spontaneous combustion in the goaf, which provided us with an understanding of the distribution of coal spontaneous combustion in the three zones in the form of maps. Essentially, our study summarizes the changes of O2 and CO concentrations in the entire goaf and shows them to be in agreement with our observations at the scene. The study shows that it is feasible to divide the three zones, given our comprehensive targets of O2, CO and our numerical simulation. This method avoids the limitation of dividing the three zones with a single target and the likely errors of observations at the scene. In addition, the method offers a basis for optimizing measures of fire-fighting with important and practical effects.