You are posting a theoretical case and making a big fuss over it. Just pay the tools like anybody else and upgrade a gold mine to level 5.
IMO there is a good chance that no one has all their deposits (8 on the main land + some more on the expansion islands) occupied by industrial mines (neither do you).
Because putting all industrial mines makes no sense - you don't discover ore with geologists but just refill with buffs which cost much more.
To have 1-2-3(but not 8!) top level mines makes sense - to put all deposits found in lootspots there and still if they run 24/7 - with their production rate you wouldn't cope to fill them.