Lvl 3 Sexrex with ergo grip, coffee/food buff, yes, pretty much non-stop (even lvl 2 does real well)
Steel tools want lvl 4 and the consumables. Which is just fine.
Oh, this is with no points in faster melee. Start upping that and your results may vary.
(gee, swing faster, thus more often, use more stamina. hrmmm... Who let Capt Obvious in here!!)
I rarely used coffee before. Now I do for the night time mining sessions. I'll go through a whole stack.
(3 min for the cheap coffee. can't make the good stuff yet, and need points in iron tummy for it to last longer)
Stamina while running has always been a pain, but hey, padded armor, jacket and HP running shoes and you can go a long long time.
Crush for the Benny Hill effect. (which is hilarious on a horde night)
So, if yer doing it right, you won't run out of stamina while mining. It be that smiple.