How will they power the heavy epuipment needed for mining?
In space, with no atmosphere or clouds or nighttime to obstruct solar power, you can get about 1000 watts/square meter IIRC from my aerospace days.
A parabolic mirror provides heat for smelting, forging, etc.
Solar power is best for fixed installations and mining.
Nuclear rockets will take you anywhere in the Solar System. We built and tested a nuke rocket engine in 1971. It was the size of a 55 gal drum and produced five gigawatts, IIRC.