1960—Pub. L. 86–391 substituted “lease or permit” for “lease” in two places.

1948—Act June 3, 1948, increased lands to be used from 40 to 80 acres, excepted national forest lands from its provisions, and substituted “The holder of any lease issued under the provisions of sections 211 to 214 of this title”, “public lands not a part of his lease”, and “or convenient for the extraction” for “Any qualified applicant to whom the Secretary of the Interior may grant a lease to develop and extract phosphates, or phosphate rock, under the provisions of this chapter”, “lands”, and “for the proper prospecting for or development, extraction”, respectively.