Material of economic interest,
Material of economic interest, when used in the context of mineral resource determination, includes mineralization, including dumps and tailings, mineral brines, and other resources extracted on or within the earth's crust. It does not include oil and gas resources resulting from oil and gas producing activities, as defined in 210.4-10(16)(i) of this chapter, gases (e.g., helium and carbon dioxide), geothermal fields, and water.
17 CFR § 229.1300
As used in this subpart, these terms have the following meanings: