I think it's the next logical step after adding a cheese dungeon!!! Sometimes when walking past the ore smelters there should be a % chance for the door to open on it's own, and if it does you can click it to enter the ore smelter!!!!
the enemies should be easy to fight and you should find chests full of metal bars depending on the type of dungeon that spawned, I think steel is probably just as easy to obtain as any other metal so there should be a chance to find a steel dungeon too with chests full of steel bars!!!!!