Butte

Overview

Historic "Richest Hill on Earth." Vein and porphyry Cu-Mo system. Transitioned from underground to open pit.

Geological Context

Host Rock: Quartz monzonite (Laramide)

Tectonic Setting: Continental arc

Geological Province: Rocky Mountains

Metallogenic Belt: Western US Porphyry Belt

Resources & Operations

Mining Method: Underground

Production Start: 1880

Data Provenance

Source: USGS; Meyer et al. (1968)

Last Verified: 2025-12-01