(57) A method of operating a coal burner in which particulate coal is fed to the burner main nozzle (21) in which pulverized coal is fed to the main burner (21) and a mixture of ultrafine pulverized coal and a gaseous medium are additionally fed to the burner at a sufficient temperature significantly to increase the reactivity of the ultrafine pulverized coal at least during the light up of the burner. The coal may be pulverized in a pulverizer vessel (12) by interparticle collision in at least one stream of gaseous medium to produce the ultrafine pulverized coal and a flow of the mixture of the ultrafine pulverized coal and the gaseous medium is fed directly from the pulverizer vessel to the burner.