Just a quick thought, as factories exhaust resources nearby, we have to venture further afield.
How about a 'rare' event of an asteroid smashing down somewhere that provides rich mineral resources in it's impact crater?
Would be unfortunate if it landed in the middle of you factory but thems the breaks!
Resource Depletion
Resource Depletion
...Lyall
Re: Resource Depletion
You should try this mod https://mods.factorio.com/mods/Gangsir/SupplyDrop