Abstract: A method of determination and monitoring of a fuel mass stream supplied for partial oxidation of fine-grain up to pulverized fuels to a gasifier includes determining a total density .rho..sub.tot of a fuel stream conveyed by a fluidizing gas in an outlet conduit of a fuel bin with the aid of a radiometric density measurement, subsequently determining a total volume stream q.sub.v.sbsb.tot of said stream by a differential pressure measurement, determining a difference between volume streams of a fluidizing gas supplied to the fuel bin q.sub.v.sbsb.gas supplied and discharged from the latter q.sub.v.sbsb.gas discharged by differential pressure measurements, determining a volume stream of the fluidizing gas q.sub.v.sbsb.gas fuel in accordance with the following equation:q.sub.v.sbsb.gas =(q.sub.v.sbsb.gas supplied -q.sub.v.sbsb.gas discharged)-q'.sub.v.sbsb.gas',determining the volume stream of the gas part q'.sub.v.sbsb.gas in accordance with the following equation: ##EQU1## wherein .rho..sub.