- Unlocked in: The Final Mystery
The River Raft is a variation on the Old Mine. When a Quest directs you to search the River Raft, you will use 1 to 3 Pickaxes, whether you find a chest or not. 3 Pickaxes is most likely. Once you have found the item, tap the Raft to collect it.
Avoid searching unnecessarily, as the chests you find will not be enough to pay for the pickaxes you spend.