Toughening of requirements to enhance fuel efficiency and protect the environment from harmful emissions was a powerful stimulus for developing promising new technologies of using solid fuel, that allow solving environmental and economic problems. In this regard, the need of improving the quality of coal fuel, studying and improving the reaction properties of coals with different metamorphic grade is of significant practical applicability. The main aims of the study are to develop the methods and to study the influence of mechanical activation grinding on reactivity of coals with different degree of metamorphism. The method used in the study investigation of thermooxidative degradation by thermogravimetric analysis; determination of auto-ignition temperature of coal dust in a vertical tube furnace; calculation of constants of the combustion reaction and activation energy. The results. The authors have obtained the first estimates of mechanical activation grinding effect on coal dust reactivity using differential thermal analysis. The experimental stand was designed; the technique for determining dust temperature was developed and tested. The authors obtained the first results in using the methods of measuring ignition temperature of coals dust with various metamorphic stage to study their kinetic characteristics in inflammation. The activation energy and the reaction rate constant for lignite and hard coal, grinded at different mills were obtained. For lignite, comminuted on vibrocentrifugal mill, the activation energy and reaction rate constant was 115385 kJ/mol and 1,97*107 m/s, and for coal obtained in the disintegrator they are 103126 kJ/mol and 2,24*106m/s. The same values were obtained for hard coal - 125000 kJ/mol and 1,26*107m/s, 124185 kJ/mol and 1,23*107 m/s respectively. The results obtained are new. The novelty is determined by the use of special experimental approaches and in data processing to estimate the kinetic constants of volatiles release and combustion of coke residue, with respect to coals after pre-high-energy treatment.