re: Just bought 40 acres

They aren't just going to waltz on to your property and build a rig in your back yard (contrary to popular belief), but you definitely lose a lot of bargaining power if you don't hold the mineral rights. Work with the mineral owner to get a no drill within XXX feet ( start with something like 750- they probably won't go for it, but I'm sure they can work something out. 500 feet is not all that uncommon.

I don't necessarily recommend a lawyer unles you're a) going to work out a surface agreement now or b) going to try and get the sale rescinded because you think the previous owner didn't disclose the possibility of a lease (which may or may not be a valid excuse.

At this point, I'd wait and see what happens- it may end up being all for nothing if they don't drill or don't find anything. And even if they drill, it's not a certainty that your 40 acres will be disturbed.