Mining
Mining means the science, technique, and business of mineral development including, but not limited to: opencast work, underground work, and in-situ leaching directed to severance and treatment of minerals; Provided, when sand, gravel, pumice, cinders, granite, building stone, limestone, clay or silt is the subject mineral, an enterprise is considered mining only if the extraction of such a mineral exceeds 5,000 cubic yards in any given year.
Source
25 CFR § 211.3
Scoping language
As used in this part, the following words and phrases have the specified meaning except where otherwise indicated: