Minerals can be held forever when dealing with a goverment entity. The landowners that sold land for Toledo Bend will own the minerals forever. In 1921 the state constitution was ammended giving the State of Louisiana the ownership of all rights to the beds and bottoms of all navigable bodies of water in the state. It also gave the state the power to reserve minerals forever on any land the state accquired through tax sales not redeemed in the 3 year perscripted period.