I've often thought about asteroid mining and the challenges of doing so in a vacuum in microgravity. There are a number of challenges that I haven't worked out how to get around, and I thought someone in the community might have some ideas.

• How do you separate the minerals? There are a number of things that could be done, although they're much easier with gravity. They all require large amounts of energy, however, and so the real challenge becomes doing them economically.
• How do you extract the minerals without them flying off into space? For most asteroids, escape velocity is going to be quite low, and if you extract by blasting or chipping or some other method of fragmenting the rock, how do you ensure that you don't lose the castoff?
• In terms of getting the mined materials back to Earth, would it be more efficient to move the entire asteroid into orbit, or to continually send transport craft back and forth to the asteroid? If you could move the asteroid into orbit, would you be allowed to or would that be viewed as the ultimate WMD?

Just some thoughts.

While that's certainly a possibility, I think it's more likely that the early asteroid mining systems are going to be robotic rather than human. You'd probably start with the smaller asteroids (10-200 meters in diameter) which would be far too small to colonize, but could be picked apart by a swarm of autonomous robots. You'd use those materials from the early asteroid mining projects as raw materials for an orbital construction facility that would create your long-term habitats and colonies for mining other asteroids.

At least, that's my impression.