10,000 Year Clock: raise bore excavation (02011)

This onsite footage from 02011 shows the completion of the 500 foot deep vertical shaft for the 10,000 Year Clock in West Texas.
We used an excavation technique called raise boring to create the 12.5 foot diameter shaft. Instead of drilling down from the top, a large diameter reamer was pulled up from the bottom to the surface, starting from a smaller diameter pilot hole. It's more efficient than a top-down drill because the rubble isn't fighting gravity. It rains down beneath the advancing bore and gets hauled out a horizontal shaft at the bottom.
Following this work, we began to cut the spiral stairway into the walls of the shaft using a robotic stone-cutting saw as well as the manufacture and testing of the full size Clock components.

[@sq3nto]

What is the current status of the project?

[@andyw3152]

Impressive. Never knew the bit would rotate so slowly.

[@KevinP32270]

epic.

[@kellerr13]

But you had to have a tunnel at the bottom first which means all the material falls into that cave and is at risk of a giant cave in.