This batch of Fable III screenshots from the Game Developers Conference are indeed all mine, at least in the 'underground area where ore is extracted from the earth' definition of the word.
It's pretty much a given these days that any fantasy role-playing game worth its salt much have a mining area in it. Hell, it's been a rule for decades now. There's just something about mine carts that scream fantasy. When all the kids in my neighborhood growing up would play Dungeons & Dragons outdoor imagination adventures, I was always the mine cart.