I finally got a perfect run: A full-clear with 13 hearts leftover at the end!
That can only happen if you do not use any health refills until you've looted all treasure chests, picked up the gnome, and killed the Mine King and cleared out all mines.
It took many attempts, and more than a few... educated guesses? You'll need to take some risks to do this, but usually just inferring which squares are most likely to be chests without actually seeing the minotaurs.