Where are mineral rights stated?

In the deeds, have you done a search of deeds on the property

You start with the original patent ("deed from the government") and look at the legislation under which such patents were conveyed. For example, the Stock-Raising Homestead Act of 1916, unlike other such legislation, reserved the mineral rights in the Federal government. Then, if the patent conveyed the mineral rights as well as the surface rights, trace from deed-to-deed to the present.