Arzinian Avatar (level 50-56); combat level depends on amount of gold mined
The dwarven scholar
If you haven't yet completed The Giant Dwarf quest, you will need to talk to the dwarven boatman to visit Keldagrim for the first time, after which you can take the mine carts from Grand Exchange to the city; the boatman is at the entrance upon first crossing the water.
Players may keep their gold helmet and access the Arzinian Mine, where 146 gold rocks and veins can be found with minimal competition. After the quest's completion, a dwarven boatman due east of the mine will bank the player's gold ore for a small fee. He keeps 20% of the ores, rounded up, or 10% if the player has the Ring of Charos (a).