From MTG Salvation Wiki
Kuldotha, the Great Furnace. Art by Rob Alexander.
Kuldotha, the
Great Furnace, is a massive furnace-city once used by the
goblins of
Mirrodin for the creation of utilities and the practice of their religion. Molten metal is produced in the fires of Kuldotha. It was believed by the goblins that by sacrificing all metals and the bodies of the dead into the furnace, the objects and souls would be returned to the
Steel Mother, also keeping the Furnace running for her.