What is the oldest hole in the ground known to have been created by humans? I think I read somewhere once that a site was known where flint had been mined, but I couldn’t find the reference.
By humans, do you mean only Homo sapiens, or do you mean any member of the genus Homo?
I would suspect that the earliest known excavation would be a grave site.
Copper mines in the Timna Valley of southern Israel were first excavated in the 6th millenium BCE.
I don’t know anything about this, so it must have been after my time. 