Mineral interests can escheat. Each state has an escheat period — usually triggered by years of unclaimed royalty or undeliverable suspense funds — after which the unclaimed interest is presumed abandoned and turned over to the state's unclaimed-property division.
For curative purposes, escheated minerals are recoverable through the appropriate state agency. The original heir or their successor has to prove the chain back to the decedent and file a claim. This is real money sitting at state treasuries — Texas alone holds tens of millions in escheated mineral royalties.
The other side of escheat: a county-clerk or operator suspense list of "owner not found" payments is a roadmap to potential heirs. If the operator is paying a 0.0026 fraction to "Estate of John Smith deceased," John Smith's great-grandchildren are the heirs the operator can't find. Probate research closes the loop.