[Taera]

I;ve no experience in PBW but i'd have to say that remote mining is rather useful, especially when coupled with Crystalline Restructuring Plant (-10%, -20% and -30% to ALL maintenance in system, accordingly to levels) and -5% to maintenance.
I have developed a neat system for remote mining. Here it is:

It requies a single (probably dedicated) planet in the system on which you will build Ressuply Depot and, if available, the Crystalline Restructurer. It can be a way to use those systems where you only have 2 tiny unbreathable planets and no chance of colonizin anything else.
Now the way it works: i build a ship (preferably LC as they have the best output for cost) with ion3 engines and self-destruct device (useful).
Now i order them to go to the (mining field), sentry and go to ressuply planet. Repeat orders. Now untill an enemy invades the system i would absolutely forget about their existance as with -30% maintenance it would take a while for their cost to overcome the income.
Example:
Spade class LC mining a 144%-121%-61% asteroid field with 2 robo-miners and 1 farmer.
Income: 2016,672,0
Upkeep: 915,28,121

And thats with crystalline restructurer 2 only.
Useful. And i never have to worry about the ships again. They also occassionaly appear up in the Next Ship list so i can monitor their income vs upkeep.

Same system (go,sentry,go back) works with asteroid fields too, given you can place the ressuply planet about three turns from the mining field.