Gotta Catch Them All: Hit all cragmite soldiers with the Mag-Net Launcher.
From the ship, head back the way you came and hop across to the second fallen stalactite. There, pan the camera around and search the south (your left) wall near the bottom to find a platform with a Heli-Pod suspended just slightly above the questionable water that fills this cavern. Float down to the low platform and raise it with a Heli-Pod. Follow the path to the gold bolt.
Backtrack some more until you reach the Weapons Vendor. Look behind this Vendor to see a series of large flat stones stacked on top of one another. They essentially form steps to a much higher platform, on which sits the gold bolt.