; (C) was supported by a discovery of a valuable mineral deposit within the meaning of the general mining laws as in effect immediately prior to the date of enactment of this subsection; and (D) continues to be valid under this Act. (2) Disposal Subject to valid existing rights, effective beginning on the date of enactment of this subsection, notwithstanding the references to the term common varieties in this section and to the exception to the term relating to a deposit of materials with some property giving it distinct and special value, all deposits of mineral materials referred to in this section (including the block pumice referred to in subsection (c)(1)) shall be subject to disposal only under the terms and conditions of the Act of July 31, 1947 (commonly known as the Materials Act of 1947 ) ( 30 U.S.C. 601 et seq.). . (b) Conforming amendment The first section of the Act of July 31, 1947 (commonly known as the Materials Act of 1947 ) ( 30 U.S.C. 601 ), is amended in the first sentence by striking common varieties of . 505. Review of uranium development on Federal land (a) Definition of Federal land In this section, the term Federal land means land administered by the Secretary or the Secretary of Agriculture. (b) Review (1) In general Not later than 90 days after the date of enactment of this Act, the Secretary, in consultation with the Secretary of Agriculture, shall enter into an arrangement under which the National Academy of Sciences shall conduct a study of uranium development on Federal land. (2) Matters to be addressed The study shall describe and analyze— (A) the laws applicable to the development of uranium on Federal land and the agencies responsible for administering and enforcing those laws; (B) the requirements relating to the development of uranium under sections 2318 through 2352 of the Revised Statutes (commonly known and referred to in this section as the Mining Law of 1872 ) ( 30 U.S.C. 21 et seq.)