While I am no authority on the subject of holes, I'd argue that a borehole is not dug as such, hence any borehole is disqualified from the 'deepest hole dug' contest.
A mine of the crazy deep variety, then, in my book, is more of a tunnel than a hole in the strict sense - hence it, too, is disqualified.
A mine of the crazy deep variety, then, in my book, is more of a tunnel than a hole in the strict sense - hence it, too, is disqualified.
YMMV. :)