What Happens If You Throw A Stone At An Abandoned Oil Shaft

These guys found an abandoned and open oil shaft from old oil rig and throw a few stones in it and the result is what you can hear and see.

The sound waves where extremely loud especially at the end of each video – when a big and loud boom came out (like big gun firing).

After the boom, the rock seemed to have gone even deeper as high pitch noise was still coming out from the tube (like the rock was still hitting metal walls).