World Art Utopia

The Berkeley Pit

The Berkeley Pit in Butte, Montana: a green lake of acidic water filling an old copper pit, below banded red and brown terraced walls and a forested mountain
Artwork FileUnited States

The Berkeley Pit

SeenSep 2025

No artist: dug by the Anaconda Copper Mining Company, later run by ARCO · Butte, Montana, USA

Photo: Carol M. Highsmith / Library of Congress (Public domain), as also published in Street Art Utopia.

The Berkeley Pit in Butte, Montana, is a former open-pit copper mine. Mining began in 1955 and stopped in 1982, when the pumps were shut off and groundwater began to fill the pit. Today it holds a lake of acidic, metal-laden water inside a federal Superfund site, and water is pumped and treated to keep it below a set level. Source Source Source Checked

Seen Sep 2025: a news report describes the 1,780-foot-deep pit holding billions of gallons of toxic water; in March 2024 the mining company told state lawmakers it can extract rare earth minerals from that water. Source Source Checked

More photos

Pale terraced walls of the dry Berkeley Pit with haul roads and machinery at the bottom, mountains behind under a blue sky
1980 The pit still dry and being minedPhoto: Jet Lowe (Historic American Engineering Record) / Wikimedia Commons (Public domain)
Deep terraced Berkeley Pit with a small dark pool of water at its bottom, seen through a chain-link fence under cloudy sky
1984 A small pool forms at the bottomPhoto: Hadu (Wikimedia Commons user) / Wikimedia Commons (CC BY-SA 3.0)
Red-brown water of the Berkeley Pit lake beside a sandy point with sheds, pipes and a floating pump barge
2005 Red pit water and pump stationPhoto: Matt Dente / Wikimedia Commons (CC BY-SA 2.0)

💡 4 things to know

  1. Dug from 1955 to 1982The Anaconda Copper Mining Company began open-pit mining here in July 1955. ARCO bought Anaconda in 1977. Mining stopped in 1982 and the Kelley Mine pumps were shut off. Source Source Source Checked
  2. A lake that must not riseAbout 49 billion gallons of water have filled the pit since 1982. It must stay below 5,410 feet above sea level, so water is pumped out and treated before release to Silver Bow Creek. Source Source Source Checked
  3. The 2016 snow geese deathsIn late November 2016 a huge flock of migrating snow geese landed on the pit during a snowstorm. Despite hazing with noise and gunfire, thousands died. Source Source Checked
  4. Rare earths in the waterIn 2024 Montana Resources said a pilot test showed very high levels of rare earth minerals in the pit water. It said a processing plant could cost up to $200 million. Source Checked

📍 Where it is

A viewing stand on the southwest rim, run by the Butte Chamber of Commerce, looks over the pit lake and nearby mine workings. It is open daily 10 a.m. to 5 p.m., May to October (weather permitting), for an admission fee. Group tours can be booked through PitWatch from March to November. Source Checked

Open in Maps

Opens a Google Maps search for the coordinates (46.01733, -112.51017); no Street View panorama was checked for this file.

🗓️ Sightings

  1. 1955Jul

    Anaconda Copper Mining Company begins open-pit mining · EPA Record of Decision

  2. 1980

    Dry, terraced pit while still being mined (HAER, Jet Lowe) · archive date

  3. 198222 Apr

    Mine closes; Kelley Mine pumps shut off and the pit starts to fill · Wikipedia

  4. 1984

    Small pool at the bottom of the pit two years after pumping stopped · uploader date

  5. 200520 Sep

    Red-brown pit water and pump barge · camera date

  6. 20167 Dec

    Thousands of migrating snow geese die on the pit lake · news

  7. 202421 Mar

    Montana Resources pitches rare earth extraction from pit water · news

  8. 202530 Sep

    News report: pit water holds rare earth elements; Montana Resources is exploring extraction · news

Green stamps mark dated photographs; amber stamps mark dated records and reports. Publication dates are not camera dates.

🗞️ In the sources

Montana Public RadioInterview, 7 Dec 2016

Thousands Of Migrating Snow Geese Die In The Berkeley Pit

“Last week, migrating snow geese made an ill-fated decision to take a break at the toxic Berkeley Pit in Butte, Montana.”

Read the source →

Montana Public RadioNews, 21 Mar 2024

Montana Resources wants to extract rare earth minerals from the Berkeley Pit

“Officials with Butte’s lone active copper mine said it has a commercially-viable process to extract rare earth minerals from the contaminated waters of the Berkeley Pit.”

Read the source →

Western Montana NewsNews, 30 Sep 2025

Federal Coal Initiative Could Unlock Valuable Minerals from Berkeley Pit

“The 1,780-foot-deep pit holds more than 40 billion gallons of toxic water containing copper, arsenic, cadmium, zinc and rare earth elements.”

Read the source →

✅ The facts

Mined
July 1955 – 1982 (the EPA record says 1983 in one place; 1982 elsewhere) Source Source Source Checked
Operators
Anaconda Copper Mining Company; ARCO from 1977 Source Source Checked
Depth
1,780 feet (540 m) Source Source Checked
Size
About 1 mile by 0.5 mile; about 675 acres Source Source Checked
Water
About 49 billion gallons since 1982; kept below 5,410 ft Source Source Checked
Cleanup
Part of the Silver Bow Creek/Butte Area Superfund site Source Source Checked
Status today
Flooded pit; water pumped and treated; viewing stand May–Oct Source Source Source Checked

🔗 Related

All sources & image credits

Last checked: 5 November 2026. How we verify art