I've never rented out a well but I am a geologist and mining engineer and if you have relied on that well then I personally wouldn't rent it out because The mining company will rent your water from you at a wholesale price, if you have to buy in water from else where in an emergency you will pay a premium price.
Even if they don't pump the aquifer dry they can pump it hard enough to cause a 'draw down come' meaning a new well would need to be sunk.
European mining companies these days are heavily regulated and mostly well behaved (There a couple of bigglobal companies known for shady practice).
Unfortunately in the states you guys seem to have less regulation on mining and water use and many more, smaller mining operations and smaller companies don't have the huge budgets for PR departments that care about public relations 24/7.
Basically find other people they rent Wells off and ask about their experiences and get a very good lawyer to make sure any contract you enter into covers you properly.