Tuition seems to have gone up since I last looked.
$4K of that cost is based on staying in the dorms. You can rent a house for $800-1000/month in Socorro, split 2 to 4 ways, and there are studio apartments in the area for as low as $250. Still, these costs are essentially for your first year; after that it goes down considerably, and if you have a 3.25 or 3.5 you're eligible for a $4/5K/year transfer scholarship.
I have no idea where they got that $1600 "travel" cost estimate from.
http://www.nmt.edu/tuition-and-fees