[ZeroAdunn]

The way I handle asteroid systems is to build one ships and one base. The base lightly armed with a constructionyard and a bunch of cargo space around the star. Then I build a small transport with satelite launchers.

Then I just build satelites with various mining components and send my ship to drop them in asteroid fields. Unless you have remote mining does not decrease asteroid value on this is the best way to do it in my opinion.