Since enactment of the Act on August 13, 1954, and subject to its conditions and provisions, including the reservation of Leasing Act minerals to the United States as provided in section 4, mining claims and millsites may be located under the mining laws of the United States on lands of the United States which at the time of location are—

(a) Included in a permit or lease issued under the mineral leasing laws; or

(b) Covered by an application or offer for a permit or lease filed under the mineral leasing laws; or

(c) Known to be valuable for minerals subject to disposition under the mineral leasing laws: This is inclusive of lands in petroleum reserves, except Naval petroleum reserves;

to the same extent in all respects as if such lands were not so included or covered or known.