Speak with Initiate Goldmine at the Elementium Depths in the Twilight Highlands.
The Earthcaller has a goblin initiate? Goldmine is his name? He has need of you.
I think that they're ready for you to do their dirty work with whatever's down in that mine.
You will also receive:
- 6,940 experience
- 58 50 (if completed at level 90)
- 10 reputation with The Earthen Ring