Ha. 48 hours into the game and I've only now realised I can sprint :D
To those who don't know if you Load instead of Continue it says the amount of time for each save game.
I bet they also levelled up their health* at every opportunity rather than their stamina, meaning they couldn't carry much more than a couple of loads of coal at any one time.
* - Has to be health as I don't remember many magic-using miners