The paper presents thermal analysis of combustion of Borodinsky brown coal with combustion heat of 16.34 MJ kg-1 and Balakhtinsky brown coal with combustion heat of 20.49 MJ kg-1 and their mixture in the mass proportion of 50/50%. Using the method of extrapolation of curves, the ignition and ignition temperatures of the coke residue were determined. The ignition temperature of Borodinsky coal was 332°C, the combustion temperature was 656°C. The ignition temperature of Balakhta coal was 358°C, the burnout temperature was 672°C. When adding 50% of Balakhta coal to 50% of Borodinsky coal the ignition temperature of the mixture decreased, the burnout temperature did not change, the fuel combustion index calculated in the work decreased and the heat of coal mixture combustion increased.