09 degrees 33 minutes North
02 degrees 15 minutes East
(NOTE: You will need a rope for this one) Head to Almera's house, west of the Coal Cart Mine (this is where you start the Waterfall Quest). Go west through the house and get on the raft, it will crash on an island. Go to the southern end of the island. Turn your camera angle until you can see the island to the south with a rock on it. Use your rope with the rock. Do not try to swim to the rock, you will go right over the edge of the waterfall. Dig just south of the rock. To leave the island, use your rope the dead tree to lower yourself to the ledge below. Next click on the barrel to try to get in, it will fall over the edge. You will end up west of the Fishing Guild.
11 degrees 41 minutes North
14 degrees 58 minutes East
Go to the bar in Burthorpe. Go through the bar and into the fenced in area with the picnic benches. Dig 1 space west of the south side of the eastern picnic bench.
19 degrees 00 minutes North
27 degrees 13 minutes East
This spot is at about level 32 of the Wilderness, it is almost straight north of the Lumber Yard east of Varrock (south of the Demonic Ruins). You will see a small half circle (can be seen on the World Map), go inside. There are 2 barrels, dig 2 'spaces' east of the southern barrel.
20 degrees 05 minutes North
21 degrees 52 minutes East
This is near the pool of water between the Lava Maze and Red Dragon Isle at about level 36 of the Wilderness (Note: the coords in the pics are a little off, but this is where I dug and got the chest...)