Code of Federal Regulations Title 43. Public Lands:  Interior § 43.3594.5 Minerals soluble in water;  brines;  minerals taken in solution

(a) In mining or prospecting deposits of sodium, potassium or other minerals soluble in water, all wells, shafts, prospecting holes and other openings shall be adequately protected with cement or other suitable materials against the coursing or entrance of water. The operator/lessee shall, when ordered by the authorized officer, backfill with rock or other suitable material to protect the roof from breakage when there is a danger of the entrance of water.

(b) On leased, license or permit lands containing brines, due precaution shall be exercised to prevent the deposit from becoming diluted or contaminated by the mixture of water or valueless solution.

(c) Where minerals are taken from the earth in solution, such extraction shall not be within 500 feet of the boundary line of lands contained in the approved mine plan without the written permission of the authorized officer.

(d) Any agreement necessary for allocation of brine production shall be made a part of the mine plan.