The entryman or owner of any land or the assignee of rights therein, including lands granted to States, with respect to which the coal deposits have been reserved to the United States pursuant to the provisions of section 81 of this title or sections 83 to 85 of this title, excepting lands embraced within a coal prospecting permit or lease, upon the discovery of valuable source material in lignite situated within such entered, granted, or patented lands, who, except for the reservation of coal to the United States would have the right to mine and remove such source material, shall have the exclusive right to mine, remove, and dispose of lignite containing such source material and lignite necessary to be stripped or mined in the recovery of such material, subject to the reporting and payment requirements of section 541 of this title, and subject to the provisions of the Atomic Energy Act of 1954 [42 U.S.C. 2011 et seq.], upon filing in the land office designated in section 541 of this title, an adequate description sufficient to identify the land containing such lignite.