[Cyclop]

I know for a fact that a little investment can turn into a huge gain. If you build a ship with a Construction Yard, move it to an astroid with %200+% in minerals, build a Space Yard Construction base, then a Battle Station with 14 mineral miners, that a 25k a turn mineral surplus. Do that in an asteroid field you can easily produce more than your planets. Granted this will take a 20+ turns to deploy but if you start small the gains will outweigh the investment. Not to mention other tricks that could enhance the mining field.