Mark & Juanita wrote:
....
At one time, my grandfather, who had a farm in TX indicated that there was
a limit to the amount of time that mineral rights could be separated from
the land ownership (20 years?). Do you know if that is the case, or just a
bit of verbal lore he picked up somewhere. His father was in the oil
business in South Texas before they moved to the Wichita Falls area in the
early 1900's.

Not except under lease. If the land is sold but the mineral rights
retained, they're gone from the buyer of the surface rights in perpetuity.

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