A burner assembly combines oxygen and fuel to produce a flame. The burner assembly includes an oxygen supply tube adapted to receive a stream of oxygen and a fuel supply tube arranged to extend through the oxygen tube to convey a stream of fluidized, pulverized, solid fuel into a flame chamber. Oxygen flowing through the oxygen supply tube passes through oxygen-injection holes formed in the fuel supply tube and then mixes with fluidized, pulverized, solid fuel passing through the fuel supply tube to create an oxygen-fuel mixture in a downstream portion of the fuel supply tube. This mixture is discharged into the flame chamber and ignited in a flame chamber to produce a flame.