what can you do if we sold the farm many years ago and now the farm owners want the mineral rights back by court order
Here is a piece of the ORC that covers this: Any mineral interest held by any person, other than the owner of the surface of the lands subject to the interest, shall be deemed abandoned and vested in the owner of the surface of the lands subject to the interest if the requirements established in division (E) of this section are satisfied and none of the following applies: (a) The mineral interest has been the subject of a title transaction that has been filed or recorded in the office of the county recorder of the county in which the lands are located.
So this now depends, as you said, on the definition of a title transaction. I'm inclined to believe that a lease is an interest in land (as evidence by the fact that only the grantor must sign, much like a deed) and it constitutes a transaction. But I could end up being wrong.
I spoke to an attorney friend of mine and he assures me that an O&G lease constitutes a title transaction as defined by ORC.
If it were me, personally, I would still file the affidavit of preservation, to make sure there is absolutely no question on ownership. I have heard other attorneys state that a lease is not a title transaction, as it can have nothing to do with actual ownership.
"If it were me, personally, I would still file the affidavit of preservation, to make sure there is absolutely no question on ownership."
Agreed. It can't hurt to be cautious.