A method of operating a shaft furnace includes inserting a mixture including anthracite coal and coke into a cavity defined by the furnace, and disposing a metal feedstock within the cavity. The method includes injecting natural gas at a natural gas flow rate and a first quantity of oxygen gas at a first oxygen gas flow rate into the cavity simultaneously through at least one burner. The method also includes driving a second quantity of oxygen gas at a supersonic oxygen gas flow rate into the cavity through at least one lance, wherein the supersonic oxygen gas flow rate is greater than the first oxygen gas flow rate. The method also includes combusting the mixture within the cavity to produce a stack gas, melting the metal feedstock to produce a melted metal material, and monitoring the stack gas to thereby operate the shaft furnace. A shaft furnace is also disclosed.