For example oil could be refined into natural gas and diesel or something, but pipes/liquids might be out of scope, idk if you wanna stay focused on minerals or not... there could also be a selling thing for gas/diesel with fluctuating prices so you have to decide when to hoard and when to sell
this would also tie nicely into power generation, there could be a gas or diesel generator so iit would have a use outside of just selling. since auto miners have an engine on top, maybe they could also use diesel