Dark Ore Mine
The Dark Ore Mine is located within the Fire Realm. It is an area from which Gorons excavate the valuable Dark Ore, which is susceptible to lava and melts quickly.[1][2] Link must transport the material in several sidequests.
The area is unlocked by transporting Ferrus to Aboda Village. After this is complete, Link will receive a letter from Ferrus asking for his service once more. Link must pick up Ferrus at the Fire Realm and drive him to the Ocean Temple in order to receive a Force Gem.
Sidequests
Linebeck III asks Link to transport five pieces of Dark Ore back to his station. Link must brave a tunnel containing a Rocktite to accomplish this, however. Upon successful completion of the task, Link is awarded with a Force Gem, which unlocks the Lost At Sea Station located within the Ocean Realm.