La. Stat. tit. 38 § 2611
Whenever it shall become necessary for the district or the department of public works, state of Louisiana to acquire the fee simple title to any land for the purpose of constructing any work or facility within the district, the owner thereof in his own behalf or in behalf of his assigns in the event of a prior assignment may retain the mineral rights to such property together with the right to grant mineral leases and servitudes thereon. No form of prescription shall divest such owner or his assigns of these rights so long as the district, the department of public works or some other department or agency of the state retains the ownership of the property, but should ownership pass into private hands, the prescription of non-user provided by R.C.C. Arts. 789 and 3546 shall apply as in the usual case.
La. R.S. § 38:2611