So it's a case of pot luck?????
What am I supposed to do with an exhausted mine.
you can demolish it, or just leave it. deposits are in fixed places on your map. if you send your geologist out again, he will find a new deposit in the same place (or possibly a different place, if you haven't found all possible deposits of that type). he doesn't need the exhausted mine to be demolished to find a new deposit there.
Tear it down and re-discover it. It's an ongoing thing. That's why leveling them up is a mixed blessing, they just deplete faster and you have to find them more often.
Note - this does not apply to special mines like the arctic iron mine, you handle those differently. I'm talking about your generic normal copper/iron/coal mine.
Sorry, but I've slept since then...
The game will not let me buy anything