To burn open the tap hole a 10' long steel tube called a lance pipe (you can see them leaning next to the tapper) is attached to a coupler that feeds pure oxygen into the tube. When the end of the tube is exposed to the intense spark generated by the igniter box (seen on the right side of the image) the oxygen ignites and the tip of the steel lance begins burning at extremely high white hot temperatures consuming the lance as it burns thru the slag.