Actually mining does play a bit of a part. Copper, gold, and lommite are two mineable minerals that play a role in stockpiling. At the moment varmigio is also mineable as well, but is less important in that the trade routes to get them aren't nearly as bad. For example:
Copper: Mined in Imp space (

), OR sold at Endor. The NR can either risk getting caught mining our copper or take the pirate infested route.
Lommite: Mined in Imp Space (

), OR sold at Bespin. Risky, risky, lommite is particularly annoying because it is sold at the notorious Hurrim Stations. Have fun making that choice...
Gold: Mined in Imp Space (

), OR sold at Muunilinst. This is kind of a freebie for the Imps, but it means we can harass NR who are in need of it.
Varmigio: Mined in NR Space (

), OR sold at Garqi. This one is plentiful for both factions, but is easier to obtain for the NR.
You may have noticed most of those are in Imperial Space, before crying foul I would like to remind everyone that I have only touched one field in NR Space, and haven't tested Hutt or CorSec Space. And as an Imperial it is kind of easier to figure out where our mining fields are because I don't get shot at (as much).