Miners have "gold fever" and desperately seek to squelch the feeling. They spend their time (mostly underground) looking for valuable resources like gold, silver, gems, etc. The rest of the time they spend smelting and filtering their findings in order to obtain the pure valuables. Hauling all of that material out of the ground takes skill, and Miners know how to maximize their carrying capacity because of this. They are very handy with pick-axes, their tool of choice. In fact, they can hold their own in a battle if they have it with them!