Your interest in space mining is very timely! It's both an interesting subject and ultimately a very important economic breakthrough for humanity as we move out into the solar system and beyond.
Not of great value, however, is bringing things back to Earth. The greatest value, at least at first, will be "mining" water, which can likely be done from (or at) virtually all asteroids. Ceres is certainly interesting, and may well be interesting as a destination, per se. But early on the most interesting asteroids will be the NEAs (near-Earth asteroids), and in particular those in the most Earth-like orbits.
Why? Simply because they are the least expensive to get to.
What's really needed to stimulate this development is the development of an infrastructure that will enable a genuine market for consumables in space. Think of it as a (or a set of) consumables depot(s). A set of water (hydrogen and oxygen) refueling stations which developers can deliver valuable consumables to and users can pull into and pay to fill their tanks.
And, while I'm at it, I loved your VASIMR reference... www.adastrarocket.com. Hopefully Franklin Chang-Diaz's great invention will be demonstrated in space. He's had a hard time getting it accepted by NASA, but he may be on the threshold of actually flying it.
AsteroidMan