Re: Private asteroid mining?
Orbiting power satellites might be a good bet.
I did a lot of work on this concept years ago, too. It's actually workable if you can get transportation costs low enough.
It's safe, too. The beam designs were very low power, spread across wide areas, and controlled by fail-safe aiming systems (active focus). The receiving antenna was basically a metallic net covering many acres, supported high in the air on tall poles.
Light would pass through the net, and you could even grow crops underneath. The space beneath it would be as safe as the space outside the door of your microwave.
Birds flying through the low-power beam might get warm, but would have no permanent effects.
Some designs built the nets offshore on pylons.