by high reaction temperatures this further reduces nox formation such as from infiltrating air or fuel nitrogen over that which would be generated by combustion with pure oxygen as the oxidant in a preferred mode of operation the minimum oxidant mixture velocity necessary for carrying out the invention may be calculated using the following equation the figure is a stylized representation of a furnace intended to illustrate different modes of operation of the invention referring now to the figure there is shown furnace 1 wherein a fuel stream 2 and an oxidant mixture stream 3 are provided into the furnace by means of burner 4 and lance 5 respectively the oxidant mixture and fuel mix within the furnace and combust the figure also illustrates a premixed embodiment wherein oxidant mixture and fuel are combined in premixed burner or cavity and passed as a mixture 7 into furnace or combustion zone 1 wherein they further mix and combust in actual practice only one mode of operation would generally be used the resulting combustion reaction generates heat and combustion reaction products such as carbon dioxide and water vapor the heat may be used to heat and or melt the charge in the figure the charge 8 is molten glass and glass forming materials which pass through the furnace underneath the combustion reactions the combustion reaction products are passed out.