Unfortunately, there may not be too much you can do, because the general rule is that the escrow instructions are superseded by the subsequent deed. Also, if there was a contract for the sale that was separate from the escrow instructions, and the escrow instructions were the only place where the reservation of mineral rights was ever mentioned, then it raises the issue of whether the escrow instructions were incorporated into the contract, and if so, whether the mention of mineral rights was a modification of the contract, and if so, whether the modification of the contract was even valid.
In other words, it is a very complicated and fact intensive inquiry. To compound matters, nearly 30 years have passed since the transaction.
Find a local lawyer who is experienced in mineral rights claims, because this is a specialized area within the specialized area of real estate law, and have the lawyer review the documents.
Please note that, while I am a lawyer, I am not your lawyer. This information is for general educational and informational purposes only, and is not legal advice. You should review your particular situation with a qualified lawyer of your choosing.
I agree with Mr. Buckingham's analysis. After all this time it is doubtful you can locate the original sale agreement, unless you have a copy. A review of it, the escrow instructions, and the deed would be necessary to form any opinion on the merits of your claim.
A further complication is if the property has been sold since your sale. If the current owner is not the owner you sold to the property to the probability is the current owner is a BFP. Your rights against a BFP would be severely limited.
Did you, by chance, take back any paper? If so, your loan title insurance documents should also be consulted and may be your best hope.
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