Its not inches Claw. Its minutes.. I believe I can do it if I break stones..
I was joking, but ' isn't the unit for time. I made a mistake, it is actually feet, but still.
Anyway, a diamond pick lasts for atleast 1/2+ hour (At the
very least, 99% of time more). I think ZX was mining for me for hours, and he needed only 1 pick (Diamond).
EDIT: Sorry, this post was typed in a hurry.