- Talk to Oggbi in Port Bastok inside the Steaming Sheep Restaurant located at (E-6) as a MNK level 40+.
- Once flagged, you can complete the quest on any high-level job, not just monk.
- Obtain a Pickaxe (you can buy one from Numa (E-7) in Port Bastok for about 190 gil).
- Head to Gusgen Mines and look for a ??? in the lowest level around G-7.
- Go straight north across the first map and down the stairs. Use the left hand door to enter the second map.
- Go to the room in the northwest corner and follow the corridor that runs on the west side from this room to the next room.
- Take the passage in the NW corner, which is in the SW corner of (F-5). Follow it down.
- Go to the second room. The ??? is located on the left side of the room in the NW corner.
- Use a pickaxe there and it will trigger the Wandering Ghost to spawn.
- Defeat it and it will drop the Miner's Pendant (make sure to Cast Lots on it if doing it with others).
- Return to Port Bastok and trade it to Oggbi for your reward.