Porous structure parameters of different rank Kuzbass coal and gas- and mass-exchange processes under coal heating are analyzed. The main part of volatile matter is dissolved in the volume of coal beds. For all coal specimens, it is typical that mass fraction of methane and ethane decreases with temperature while mass fraction of hydrogen, carbonic oxide and ethane increases. The latter gases can be the sources of violent burning of coal beds. UHF pyrolysis of bituminous coal reveals physical balance and composition of gaseous products. The results permit coal rating based on carbonization, enable recommending the use of inert gases in underground fire fighting and allow estimating temperature level in fire source zones in coal beds based on chemical composition of emitted gases.