Shaft drill - GIF

[Jon]

Shaft drill.

[Frank S]

Back in 78 & 79 I worked at a company that built foundation drilling equipment. That rig on the crane looks a lot like the Watson 5000 unit.
We built a special unit for the Stan Anderson drilling company of California that could bore a 12 ft diameter hole 150 feet in the ground then bell the hole at the bottom ot 3x the diameter

[Ralphxyz]

I don't see where the spoil goes

Ralph

[hemmjo]

the rig seems to drill some, then pull the "bit", rotates Counter CLockwise, to dump the spoils, then returns to drill more. Happens really quickly in the fast motion video.

[Frank S]

the rig seems to drill some, then pull the "bit", rotates Counter CLockwise, to dump the spoils, then returns to drill more. Happens really quickly in the fast motion video.

That is how it works just like a post hole digger on the back of a tractor drill and spill then drill again. The video appears to have been taken right near the final depth of the bore possibly much of the spoils had already been cleared away since a bore of that size would create a significant amount.
Looking at it again I can see several times when a loader clears them away and the video had run from the beginning to make several up sizing's of the bore

[Wildwilly]

You should be watching the "whole" video & you will see the loader moving the spoil & building a berm.

[Wildwilly]

I don't see where the spoil goes

Ralph

If you were watching the "whole" video you would see the loader building a berm of the spoils.