In all likely hood you would build your colony as a mine.
I disagree. The most important resource on Mars will be water, and you don't have to be a
Starcraft fanatic to know you build your base near the resources. Nobody will be living in
a mine where there is no or little water to be found. Just because our ancestors lived in caves,
doesn't mean we have to. It's the 21th century. We don't have to live like rats anymore.
While it is a very important resource, other materials are equally important if you plan to build colonies. And nothing says the whole thing has to be within a small area. There will be a primary colony, where the bulk of people make their permanent home, and then feeder sites where resources are collected and shipped back to the main site.
Oil is often considered the most important resource of our current age, yet all my friends who work on oil fields live hear in Atlantic Canada, and fly out to their job site for extended shift work on set rotations.