30 U.S.C. § 124 — Agricultural entry or purchase of lands withdrawn or classified as containing sodium or sulphur

This section deals with public land that has been withdrawn, classified, or reported as valuable for sodium and/or sulphur. Normally, that kind of land can only be explored ("prospected"), leased, or developed under the General Leasing Act of February 25, 1920 (and any laws that amended or added to it, found at 30 U.S.C. 181 and following). This section says such land can still be appropriated, located, selected, entered, or purchased by settlers or claimants — but only if it is otherwise available, and only under the reservations, provisions, limitations, and conditions of an earlier law: the Act of Congress approved July 17, 1914 (38 Stat. L. 509, listed as 30 U.S.C. section 123). There is an important exception, marked "Provided, however" in the text. Land does not qualify for this kind of appropriation, location, selection, entry, or purchase if any of the following is true: the land lies within the geologic structure of a field (an underground mineral formation); the land has been withdrawn, classified, or reported as valuable for sodium, sulphur, or any other mineral named in this section or the related sections; or someone has already applied for, or been granted, a lease or prospecting permit to produce any of those minerals on the land. Even then, the Secretary of the Interior can still allow the appropriation, location, selection, entry, or purchase to happen — but only if the Secretary determines that doing so will not unreasonably interfere with mining or leasing operations already happening under those sections.