30 U.S. Code § 521 - Mineral leasing claims
Labor performed or improvements made after the original location of and upon or for the benefit of any mining claim which shall be entitled to the benefits of this chapter under the provisions of subsection (a) of this section, shall be recognized as applicable to such mining claim for all purposes to the same extent as if the validity of such mining claim were in no respect dependent upon the provisions of this chapter.
As to any land covered by any mining claim which is entitled to the benefits of this chapter under the provisions of subsection (a) of this section, any withdrawal or reservation of lands made after the original location of such mining claim is hereby modified and amended so that the effect thereof upon such mining claim shall be the same as if such mining claim had been located upon lands of the United States which, subsequent to July 31, 1939, and prior to the date of such withdrawal or reservation, were subject to location under the mining laws of the United States.
Act Aug. 13, 1954, which enacted this chapter, amended section 1805 of Title 42, The Public Health and Welfare, and enacted provisions formerly set out as a note under section 1805 of Title 42, is popularly known as the Multiple Mineral Development Act.
Act Aug. 13, 1954, ch. 730, § 13, 68 Stat. 717, provided that: