43 C.F.R. § 3501.5
You need to know the following terms, which are used frequently in this part:
Acquired lands means lands or interests in lands, including mineral estates, which the United States obtained through purchase, gift, or condemnation. It includes all lands BLM administers for hardrock mineral leasing other than public domain lands.
Chiefly valuable, for the purposes of this part, means the land is more valuable for the development of sodium, sulphur or potassium than for any non-mineral use of the land.
Hardrock minerals include base metals, precious metals, industrial minerals, and precious or semi-precious gemstones. Hardrock minerals do not include coal, oil shale, phosphate, sodium, potassium, or gilsonite deposits. Also, hardrock minerals do not include commodities the government sells such as common varieties of sand, gravel, stone, pumice or cinder. The term hardrock minerals as used here includes mineral deposits that are found in sedimentary and other rocks.
Leasable minerals, for purposes of this part, means the chlorides, sulfates, carbonates, borates, silicates or nitrates of potassium or sodium and related products; sulphur on public lands in the States of Louisiana and New Mexico and on all acquired lands; phosphate, including associated and related minerals; asphalt in certain lands in Oklahoma; and gilsonite (including all vein-type solid hydrocarbons).
MMS means the Minerals Management Service.
Permit means prospecting permit, unless otherwise specified.
Valuable deposit, for the purposes of this part, means an occurrence of minerals of such character that a person of ordinary prudence would be justified in the further expenditure of his or her labor and means, with a reasonable prospect of success in developing a profitable mine.
43 C.F.R. §3501.5