Dear Mr. RJ,
Your question has many people confused. If you bought the property without the mineral rights, then you missed your chance. (You really needed to have a good Realtor representing you in the first place.)
If the Seller kept the mineral rights, and has now died, then his heirs (or estate) now owns them. You would have to negotiate a purchase of the mineral rights from the person or persons who now is the owner. You don't get to "reacquire them" just because the seller died and you didn't buy them in the first place.
Realtors don't deal in mineral right sales. Maybe you need to talk to an attorney who does, but attorneys are not cheap to work with. Is it realy worth it?? Maybe you could contact the heirs of the seller and see if they will sell the mineral rights to you. That transaction is not covered by a real estate license.
Many people, and some of them are real estate agents, don't know that the mineral rights do not automatically stay with the seller of a house. If they are not mentioned in a TREC contract, then the buyer gets the mneral rights when title is transferred. This has been traditional in our Texas contracts for all these many years because the "mineral rights" were not such a big deal to people in the past. The practice may change in the future.
It is my personal opinion that the mineral rights should be sold with all residential lots when a buyer buys the house. The amount you might get from them is usually not a big deal anyway on a small lot. I have never received ANY royalties on my lot, and I signed a lease with Chesapeake who said they were drilling nearby!
So, ~if you think it's a big deal, go see if the owner of the mineral rights will sell them to you. And the next time you buy a house, get a Realtor to represent you and get the mineral rights included in your negotiations.
ULTRA Real Estate Services