An evaluation of particle size of loose coal around roadway using fuzzy synthesis method

The coal particle size, which is influenced by the hardness of coal, geological structure, the pressure indices, the method of coal mining and so on, is the main influencing factor for spontaneous combustion of coal around roadway. It is very difficult to accurately measure the particle size of loose coal and there is a grave error by plotting a rough range using expert's experience. By analyzing the each factor which influences the particle size of loose coal around roadway, an evaluation of the particle size grade is performed using analytic process and fuzzy synthesis methods and according to maximum subjection degree. This method proved the credibility and precision of the result. The criterion method and the result are proved correct by the engineering test. Foundation for judging the spontaneous combustible zone and predicting the spontaneous combustion term also has been provided.