S.C. Code § 10-9-180
The department is hereby vested with full and complete power and control over all mining in the phosphate territory belonging to this State and over all persons digging or mining phosphate rock or phosphatic deposit in the navigable streams and waters or in the marshes thereof, with full power and authority, subject to the provisions of Sections 10-9-130 and 10-9-190 to fix, regulate, raise, or reduce such royalty per ton as shall from time to time be paid to the State by such persons for all or any such phosphate rock dug, mined, removed, and shipped or otherwise sent to the market therefrom. Six months' notice shall be given all persons at such time digging or mining phosphate rock in such navigable streams, waters, or marshes before any increase shall be made in the rate of royalty theretofore existing.
S.C. Code § 10-9-180