Man. There are so many factors that can affect productivity. That would be a tough subject to detail, particularly when considering if it's development or production - contractor or mining company.

Shaft sinking and Raise Boring is highly specialized work and tends to be done by contractors who have expertise in those fields. Shaft sinking, particularly, is a speciallized subset unto itself. There are people who work in contracting all their lives who have never been down to the Galloway, never mind to shaft bottom.

And each Project Manager on a sinking project will have his own way of doing a setup - something that's worked well for them before.

Raise Boring? The setup for a machine isn't anything mysterious, but again contractors will always be unwilling to share hard earned information that could give them a competitive advantage.

With Raise Boring, the ability to evaluate ground conditions and be able to estimate a reasonable advance rate for a certain sized reamer can only be done with decades of experience, and that's not something people are willing to share.

I would agree that the Miner's Handbook could use an update. I don't know that anyone sinks shaft with anything but circular and concrete lined anymore. Timber shafts, whether three or five compartment just don't give the airflow volume or hoisting capacity for the mines of today.