All public lands belonging to the United States heretofore, now or hereafter withdrawn or reserved for power development or power sites shall be open to entry for location and patent of mining claims and for mining, development, beneficiation, removal, and utilization of the mineral resources of such lands under applicable Federal statutes: Provided, That all power rights to such lands shall be retained by the United States: Provided further, That locations made under this chapter within the revested Oregon and California Railroad and reconveyed Coos Bay Wagon grant lands shall also be subject to the provisions of the Act of April 8, 1948, Public Law 477 (Eightieth Congress, second session): And provided further, That nothing contained herein shall be construed to open for the purposes described in this section any lands (1) which are included in any project operating or being constructed under a license or permit issued under the Federal Power Act [16 U.S.C. 791a et seq.] or other Act of Congress, or (2) which are under examination and survey by a prospective licensee of the Federal Energy Regulatory Commission, if such prospective licensee holds an uncanceled preliminary permit issued under the Federal Power Act authorizing him to conduct such examination and survey with respect to such lands and such permit has not been renewed in the case of such prospective licensee more than once.