Initial Publication Date: June 17, 2005
Geology of the Butte Mining District
Route
Start point
Alice pit on Daly StreetEnd point
Montana Tech Mineral MuseumRoads
Various streets in ButteAccess
The pits are inaccessible, but geologic features can be viewed from a distance.Total distance
Not givenGeology
Summary
The Butte mining district is one of the major mining districts of the world with continuous production from both underground and open pit mines for 119 years, from 1864 to 1983. During this time, mining activites at Butte have introduced many firsts in mining methods, techniques of mine mapping, and the detailed recording of geologic data. This field guide describes the geology of the mineral deposits, provides a geologic map of the district, and concludes with a tour of eight locations of interest, including Alice pit, Syndicate pit, Berkeley pit, the Emma and Orphan Boy veins of the Anaconda system, the World Museum of Mining, and the Montana Tech Mineral Museum.Key Lithologic Features
- Butte Quartz Monzonite, in places with pervasive sericitic alteration
- 17-20 foot-wide siliceous vein with Cu-Fe-Zn ore minerals (in two outcrops)
- excellent museum collection of Butte minerals
Structures
- Rarus Fault exposed in Berkeley pit
Landforms
Other Features
- exhibit of historical mining equipment, methods, and life around the turn of the century in Butte