#7 - Jan. 21, 2009, 10:45 p.m.
Originally the Mining Skill at certain ranks would give you a toughness buff, the intention was to simply add health at each rank. Unfortunately at 225 the Toughness buff provided 70 stamina instead of 70 health, thus giving characters a much larger bonus of health than what was intended.
With 3.0.8 this issue has been resolved. 225 in Mining will give you 7 stamina which translates into 70 Health, as intended.
I'm sorry for any confusion this unintended health benefit caused you.