Lance unblocking method and apparatus

An apparatus for removing a blockage in a solids injection lance extending into a direct smelting vessel, the solids injection lance having a single inlet coupled to a section of supply line that conveys gas and solids to the solids injection lance and that is upstream and co-axial with the solids injection lance, the apparatus comprising a drilling assembly that extends through the supply line section and the solids injection lance to remove a blockage of solid material and an assembly for advancing the drilling assembly through the solids injection lance and the supply line section to the blockage from an upstream side of the blockage, wherein the drilling assembly comprises a housing, wherein the housing includes a sleeve section and a drill bar contained in the sleeve section, wherein the apparatus further comprises a gas-pressure seal in the drilling assembly, wherein the gas-pressure seal surrounds an internal wall of the sleeve section and around an external wall of the drill bar, the gas-pressure seal enables gas pressure within the solids injection lance and the supply line section to be maintained above the gas pressure in the direct smelting vessel during normal operation, while the drilling assembly is advanced to the blockage.