Using robotic means for most of the processing would be necessary, but crews would have to be rotated in and out to keep things operating.
The useful materials processed out could be “piled” for eventual delivery.
The tailings could be processed with some available gas (or water vapor) into mineral foam — lightweight, strong, and plentiful — and extruded into very large structures.
Titanium, which is probably somewhat plentiful, could be extruded (perhaps as a foam)into reentry vehicles, which would be equipped with basic, necessary methods of control (sent up from Earth, no doubt), loaded with the useful metals and such from the “piles”, and dead-sticked down to Edwards etc.
The bonus to this approach is, reentry vehicles — basically, space shuttles — rain down with the useful materials aboard, and are available thereafter as launch vehicles.
I look at it as a means of building the large ships we need for real space travel but yes, the materials could also be returned to earth. The profitability would have to start on earth but the future is beyond.
A while back I was watching a show about colonizing mars and they were demonstrating a full sized concrete printer for standing structures. Obviously its cost prohibitive to carry concrete to mars but a lot of mars has sulfur rich soil. That soil can be heated to 239 degrees to melt the sulfur and then printed into structural walls like concrete. I think people really underestimate the possibilities 3D printing opens up.
http://www.videobash.com/video_show/this-3d-printer-can-build-a-house-in-20-hours-355491
Here’s a video with a better demonstration of the structural printing at work. Its hard to understand the Indian narrator but very interesting just the same.
http://www.youtube.com/watch?v=-YaEEHzU-RQ