30 U.S.C. § 90

Unreserved public lands of the United States, exclusive of Alaska, which have been withdrawn or classified as coal lands or are valuable for coal shall, in addition to the classes of entries or filings described in sections 83 to 85 of this title be subject to selection by the several States within whose limits the lands are situate, under grants made by Congress, and to disposition, in the discretion of the Secretary of the Interior, under the laws providing for the sale of isolated or disconnected tracts of public lands, but there shall be a reservation to the United States of the coal in all such lands so selected or sold and of the right to prospect for, mine, and remove the same in accordance with the provisions of said sections, and such lands shall be subject to all the conditions and limitations of said sections.