Montana’s bird-killing, metal-eating lake has a gift shop and $3 entry

Toxic water may hold cancer cures

For a few bucks, you can stand on a platform in Butte, Montana and stare into one of the most toxic bodies of water in North America.

The Berkeley Pit stretches a mile long and half a mile wide, filled with enough acidic, metal-laden water to kill thousands of birds over a single week.

It sounds like something to avoid.

But scientists have found life thriving in the poison, organisms that may help fight cancer and supply minerals the Pentagon desperately needs.

The story of how Americas ugliest hole in the ground became one of its most valuable starts with copper, greed, and a decision made on Earth Day 1982.

Butte Was Americas Copper Capital

Buttes story begins with the discovery of gold in the 1860s, a silver boom in the 1870s, but it was the mining of copper that put Butte on the national stage.

Western Union had established the first transcontinental telegraph line in 1861, but the telephone and electric light were the real drivers behind copper consumption.

Copper ore mined from the Butte mining district in 1910 alone totaled 284 million pounds, making Butte the largest copper producer in North America.

By 1917, Butte was the largest city from Minneapolis to Denver to Salt Lake City to Spokane, and not just the largest but the richest as well.

The Mine Ate Entire Neighborhoods

The Anaconda Company faced the task of dismantling communities it had helped create.

East Butte, Meaderville, McQueen, Dublin Gulch, and Finn Town were working-class immigrant neighborhoods close enough to the Berkeley Pit that the company deemed their destruction necessary.

Anaconda already owned most of the land and needed only to buy or trade the houses on top of it. People said they’d fight, but then they jumped.

A sign at the pit today claims many relocated residents welcomed the change because it meant jobs would stay in the community.

The Pumps Stopped on Earth Day

The mine opened in 1955 and operated by the Anaconda Copper Mining Company, later by Atlantic Richfield Company, until its closure on April 22, 1982.

Although the pumps were supposed to operate in perpetuity to prevent groundwater from infiltrating the mine, they were turned off on Earth Day 1982.

Groundwater began slowly filling the pit, rising at about one foot per month and creating the toxic lake visitors see today.

Over the active lifespan of the mine, approximately 320 million tons of ore and over 700 million tons of waste rock were removed.

The Water Eats Through Metal

The pit is one mile long by half a mile wide and over 1,780 feet deep, with roughly 1,000 feet filled with acidic water.

The water has a pH level between 2.5 and 4.5, about the acidity of beer or tomatoes.

It contains high concentrations of copper, iron, arsenic, cadmium, zinc, and sulfuric acid, water so corrosive it can dissolve the propeller of a boat.

The iron-rich water near the surface appears reddish, yielding to a vibrant lime-green hue below where copper concentrations are higher.

A Blizzard Killed 4,000 Geese

On November 28, 2016, residents of Butte heard the unmistakable honking of some 60,000 snow geese circling the Berkeley Pit.

A snowstorm had pushed the birds into the area, and their typical stopping point at Freezout Lake was frozen. About 10,000 birds landed on the water, one of the only open bodies of water in the area.

Staff tried hazing methods through the night, but between 3,000 and 4,000 geese perished from drinking the water.

The toxicology report indicated the birds died from a combination of both the sulfuric acid and the heavy metals.

Drones and Cannons Guard the Water

After the 2016 disaster, mine operators began pouring money into an arsenal of new tools to prevent a repeat.

Montana Resources and Atlantic Richfield spent over half a million dollars on state-of-the-art deterrent and hazing devices.

The equipment includes drones shaped like eagles, handheld lasers, air cannons that blast 200 mph gusts, and strobe lights.

They also built an extensive early warning network with wildlife refuges and meteorologists from Alberta to Utah to track bird movements and weather patterns.

When white geese massed at the Canadian border in fall 2017, staff worked around the clock for four days and not a single bird died.

Scientists Found Life in the Poison

The Berkeley Pit seems like an inhospitable place for organisms big and small, but scientists have found life there.

Researchers have discovered over 100 species of bacteria, fungi, and other microorganisms thriving in this toxic environment.

These extremophiles have adapted to survive in conditions that mirror those found on other planets, and some actually feed on the heavy metals that make the water so deadly.

One yeast species had previously only been found in the digestive tracts of geese and absorbs metals like copper and iron from its surroundings.

Pit Microbes May Fight Cancer

The microbes thriving in the heavy-metal-laden, acidic lake synthesize molecules that help keep them alive in this extreme environment.

Novel compounds isolated from Penicillium species in the pit show activity relevant to cancer and Huntingtons disease.

Two Montana Tech chemists, Don and Andrea Stierle, have isolated 12 antibiotic compounds from fungi cultured from the Berkeley Pit.

Only 8% of the culturable microbes isolated from the pit have been fully studied, and even these organisms still have untapped potential.

The research continues with funding from the National Institutes of Health.

The Pentagon Wants Whats Inside

In December 2025, Montanas Environmental Quality Council approved a letter requesting federal funding to extract rare earth and critical minerals from the Berkeley Pit.

The Department of Defense is reportedly considering a $75 million grant to build a concentrator facility near the pit.

Samples taken at 166 feet showed elevated levels of rare earths including cerium, neodymium, yttrium, and lanthanum.

If tapped successfully, researchers estimate the pit could yield up to 40 tons of rare earths annually, elements essential for smartphones, electric vehicles, and precision-guided missiles.

Treatment Plants Keep It Contained

The site has two primary treatment systems: the Horseshoe Bend Water Treatment Plant and the Horseshoe Bend Capture System.

Water levels in the pit are monitored monthly, and to ensure levels stay below the critical threshold of 5,410 feet, water is pumped out and treated.

The treatment plant uses lime to raise the pH and precipitate metals from the water, which then settle out in large vessels called clarifiers.

Since 2019, water has been pumped from the Berkeley Pit for treatment, and as a result, water levels have remained stable.

Visit the Berkeley Pit in Butte, Montana

The Berkeley Pit is the most expensive site on the EPAs Superfund list. The viewing stand sits at 300 Continental Drive, accessible from I-90 Exit 126.

The Berkeley Pit Viewing Stand is open from mid-May through mid-September, with admission at $3 per person. Hours run Monday through Saturday from 8 a.m. to 8 p.m. and Sunday from 9 a.m. to 6 p.m.

You walk through a gift shop, buy your ticket, then pass through a tunnel to emerge on a platform overlooking the massive pit.

Informational signs explain the history and ongoing environmental work. Give yourself about 30 minutes, and dont expect to see any birds on the water.

This article was created with AI assistance and human editing.

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