You'd may did not notice it, but resource delivery is not free!
Coal ore is pretty cheap, so you could think that it is a good idea to build store, import ore into it, process ore and feed your coal powerplant, isn't it? Hell no!
There is such thing as cost of delivery, and it will cover all possible profits. 1 ton costs 10,07 rubles, delivery is 24,51, total 34,58. 1 ton of coal, produced from such ore will costs you 60,5 rubles.
Importing coal without processing will cost 49,4 rubles, and keep in mind that you will not waste precious working shifts of your citizens for ore processing.
In comparison, coal ore costs 10,87 rubles per ton near soviet border. All you have to do - is just to deliver it into the industrial heart of your Republic. Currently it is much more profitable to mine ore from nearest republics rather than actually mine it from underground.
Keep counting and carry on, comrades.