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Mike McGivern, Montana Resources’ vice president of human resources, talks about mining the Continental Pit and the history of mining in the Berkeley Pit. The Berkeley Pit, which is filled with water, can be seen in the background.

The Continental Pit on the left has been mined by Montana Resources since 1986, with a break from 2000 to 2003. On the other side of the Continental Fault, the Berkeley Pit on the right was mined by the Anaconda Company and then ARCO from the 1950s to 1983.

The Continental Pit mined by Montana Resources. Some water collects in the bottom of the pit from seepages, drainages and rainfall. There are some carbonates in the water, but it is much cleaner than the acidic water that flows into to Berkeley Pit.

The Berkeley Pit, which contains about 55 billion gallons of water, sits at the edge of Butte. The Environmental Protection said it is “a Superfund Site with the largest body of contaminated water in the United States.”

Butte’s Berkeley Pit is filled with about 55 billion gallons of acidic water. The water treatment plant on the far side of the water was built in the early 2000s. About 2.8 million gallons of water flows into the pit every day, so at least that much water is sent through the treatment plant and then goes to a polishing plant and is then discharged into Silver Bow Creek. The water treatment, which began in 2019, is a joint project of Atlantic Richfield and Montana Resources. The horns on the right are one of the tools for hazing birds away from the water.

The Berkeley Pit next to Butte has been filling with acidic mine drainage ever since the mining stopped and the groundwater pumps were shut off in 1983.

Montana Resources usually mills around 47,000 tons of ore per day. The mill was commissioned in 1964 and looks about the same as it did back then, although there are new electronics.

In the flotation circuit at the Montana Resources mine, the copper, molybdenum and silver bubble to the surface and are captured for concentrates. The process produces concentrates that are about 26 to 32% copper and 54 to 57% molybdenum.

Haul trucks and a water truck at Montana Resources’ Continental Mine in Butte. Dust abatement is a major focus because the mine is right next to the city.

Montana Resources’ mine in Butte runs 18 Caterpillar 793 haul trucks and uses three 495HD shovels which have 40 cubic yard buckets.

Many Butte images and logos feature headframes, where miners were lowered into and raised out of a mine. There are still 14 historic headframes throughout Butte.

Everywhere in Butte there are reminders that this is a mining town. The walls of the Berkeley Pit can be seen in the distance at the base of the green mountainside.

When travelers are sailing along the interstate in mountainous western Montana and they look over and see Butte, the city is sure to make an impression. As you drive along Interstate 90 or 15 and descend from or ascend toward the Continental Divide, you see the city laid out along the valley and hillside, with the enormous Berkeley Pit with its stripes of multi-colored earth stretched above the town.

This is definitely a mining town.

Many people with a little familiarity with Butte as they drive by probably know it is a historic mining town, with a history of mining going back into the 1800s, but they may not know that mining is still going on in Butte today. In Montana Resources’ Continental Pit just to the east of the Berkeley Pit, miners in haul trucks and loaders and shovels are still at work 24 hours a day, seven days a week, nearly 160 years after mining first started in Butte.

The Butte area used to be a vast network of underground mines. There are about 10,000 miles of mine tunnels under the city—some as deep as a mile under the ground. Many of the tunnels are now filled with water. The Anaconda Company increasingly put more focus on open pit mining at the Berkeley Pit in the mid-1950s, and underground mining stopped in the mid-1970s.

Mining had been very profitable for some companies in the early days, but in the 1970s a variety of factors, including low copper prices, led to economic difficulties for Butte mining.

In 1977 the Atlantic Richfield Company, ARCO, bought the Anaconda Company. Growing financial challenges led ARCO to shut down mining in Butte on June 30, 1983, for what was said to be a one-year hiatus. In 1985 the mine was still closed and ARCO was working on selling it.

Dennis Washington, the industrialist who created Washington Construction, which became the largest highway contractor in Montana in the 1960s, had an interest in buying the Butte mining company to get some of the equipment and scrap out the facilities. Frank Gardner, the general manager for Anaconda’s mining operations, talked to Washington about the possibility of restarting mining in Butte. He believed that there could be profitable mining in the Continental Pit.

Washington agreed to buy the Continental Pit and other Anaconda properties from ARCO.

“They agreed on a deal where Dennis would buy the operation for the value of the equipment,” said Mike McGivern, Montana Resources’ vice president of human resources. “The price was somewhere around $7 million.”

Mining started again in Butte in June 1986, three years after ARCO had shut down the mine.

“The mine from ‘86 to 2000 had some really good years, and some up and down years with the copper cycles,” McGivern said.

In 2000 the mine was hit with very low copper prices and very high power prices, and the mine shut down.

In 1999 power was deregulated in Montana, which many people later agreed was the wrong move. Power prices skyrocketed, and Gardner wrote in his memoir that power costs for Montana Resources went from about $12 million a year to about $120 million a year.

“Power has typically been our number one consumable product,” McGivern said. “We have been the second largest consumer of electricity in the state of Montana, although we may be third now because of some Bitcoin activity going on.”

“When power settled back down, we were able to lock in some decent power contracts. Copper started to squeak up a little bit, and the mine reopened in October of 2003. And it’s been running ever since.”

The Continental Fault runs between the Continental Pit and the Berkeley Pit, McGivern said, and the geology of the two pits is completely different.

The Berkeley Pit “had a much higher copper content which we wish we had,” McGivern said. “They had a fair bit gold, and we have almost non-existent gold. But we have molybdenum, and they didn’t.”

Montana Resources’ Continental Mine produces copper, molybdenum, and some silver. They generally mill around 47,000 tons of ore per day, McGivern said.

“Typically, in the last 10 years we make around 65 million pounds of copper a year and between 8 and 9 million pounds of molybdenum, and about 600,000 ounces of silver.”

It is a low-grade copper deposit, generally around 0.225%, McGivern said. However, this year they are mining in an area with around 0.5% copper but no molybdenum in some of the ore, which will change their production numbers.

“Hopefully we’ll make north of 80 million pounds of copper, and probably around five million pounds of molybdenum,” McGivern said. “Just because we’re mining in a different zone at this point.”

Montana Resources has about 390 employees.

The mine runs 18 Caterpillar 793 haul trucks, which are 240- to 250-ton haul trucks, depending on the model. The mine uses two Atlas Copco drills.

“One of the things that’s a little bit newer for us is we’ve added a couple of large front-end loaders, 994 Caterpillars, as loading devices,” McGivern said. “Typically, we’ve always used electric rope shovels. But this year we went pretty heavy into Caterpillar 994s as loading equipment. Very versatile. Certainly not as efficient as rope shovels, but they move around quite good compared to electric shovels.”

Montana Resources is installing a MineStar system for the trucks to communicate with each other.

The mine does concurrent reclamation in any areas where they are sure they are not going to mine again.

In the tailings area, they are working toward completing their last permitted lift, which is 50 feet.

“Each 50-foot lift gives us about eight to 10 years of capacity for tailings,” McGivern said.

“We’ll start submitting permits next year for another lift. We’ll probably ask for 110-foot lift, and that should take us out to end of mine life, which is currently about 33 years.”

The mine’s mill was commissioned in 1964.

“Prior to that, the Anaconda Company was mining the Berkeley pit and they would ship the rocks to Anaconda, to their concentrator and smelter,” McGivern said. “And they decided, we’re probably spending a lot of money railroading rocks, so they built a concentrator and a mill and a flotation circuit, and then they shipped the concentrate over to Anaconda instead of just rocks.”

“So we’ve got an old facility, 60 years old. … It looks very much the same, I’m sure, as it did in 1964.”

The electronics running the facility have been changed out and modernized, however.

In the flotation circuit, the copper, molybdenum and silver bubble to the surface and are captured for the concentrates. The process increases the concentration of the copper by about 100 times, McGivern said. The ore is about 0.25% copper, and the concentrate which the facility produces is about 26 to 32% copper.

The molybdenum concentrate is about 54 to 57% molybdenum, and is “one of the highest quality concentrates in the world,” according to the Montana Resources website.

The Anaconda Company used to have a smelter in Anaconda, about 24 miles west of Butte, but ARCO shut down the smelter in 1980. The smelter stack, at 585 feet, is the tallest masonry structure in the world.

“ARCO could not swing the $400 million investment to bring the smelter emissions to standard,” Gardner wrote in his memoir.

So Montana Resources’ final copper product is the concentrate, and they look for the best customers based on smelting and refining charges.

“Currently we’re sending some product to Quebec,” McGivern said. “And then we have some shipments going to the port of Washington the next few months, and that will I believe go to China.”

“The molybdenum primarily goes down to Idaho to the Thompson Creek mine. They’re no longer mining, but they’re still processing molybdenum. A lot of it ends up in steel mills out in Pennsylvania.”

Molybdenum is used for hardening steel and is used in lubricants and greases.

“It’s in a lot of different products,” McGivern said. “If you drink one of those Ensure breakfast drinks one day, look on the back and you’ll see it’s got molybdenum in it.”

In the early days of mining in Butte, the huge amount of copper that was produced was used to wire the world for electricity. Today, there continues to be lots of uses for copper.

“It’s in everything,” McGivern said. “It’s in your electronics, it’s in your piping.”

The rising demand for electric vehicles will increase the demand for copper.

“Electric vehicles have five times more copper than gas combustion vehicles or diesel vehicles,” McGivern said. “If we’re going to have green energy, we’re going to need more copper.”

One big difference between today’s mining and Butte’s early mining days is that mining is now much, much safer. Back when miners worked with their tools in the hot tunnels far underneath Butte, mining deaths were a common occurrence. At the World Museum of Mining across town from the Montana Resources mine, at the Memorial Garden marble walls are engraved with the names of 2,500 people who died in mining accidents since 1865.

“My grandfather is on that wall,” McGivern said.

“My great grandfather came from Ireland and mined. My grandfather mined. He was involved in a fatality in 1942. My dad did not go into the mining industry. I ended up going to school here at Montana Tech and I got into the mining industry.”

Today, accidents are very rare at Montana Resources.

“We were approaching 13 years without a lost-time accident,” McGivern said in late June. “Unfortunately, we had an incident a couple weeks ago so we had to reset the clock.”

“It was an incredible record that we had over 10 million hours without a lost-time accident.”

One of the big issues the Continental Mine deals with is dust, since the mine is right at the edge of the city of Butte.

McGivern commented that a lot of mines, like the big mines run by Nevada Gold Mines, are “out in the middle of nowhere.”

“We are right on the edge of people’s homes and habitats.”

A story written by Katheryn Houghton and published by Kaiser Health News in June said that in the Greeley neighborhood across the street from the mine, “many people have a hard time believing the air they breathe is safe.”

“For years, the company and the state Department of Environmental Quality have collected air samples in the neighborhood,” Houghton wrote. “The results have been consistent: Pollution levels don’t warrant alarm.”

“However,” the story went on to say, “additional studies, which government and mine officials have often bucked, have indicated potential problems …”

A review commissioned this year by the Montana Environmental Information Center said “not enough research has been done to determine conclusively whether the mine is harming Butte residents.”

“You’d like to say mining will not produce any dust, but it will,” McGivern said. “Despite anybody’s best efforts, it’s something that we have to deal with every day.”

“Water trucks constantly wet down haul roads in never-ending circuits to minimize dust,” the Montana Resources website says. “At all crushing facilities, suction dust collection systems and water sprays are used to capture the fugitive dust.”

“There’s been air sampling going on in this town for decades,” McGivern said. “We fund a lot of third-party air sampling.”

McGivern said, “I think we spend more time talking about dust management and water management than we do mining.”

The water used in the mining process is in a closed circuit, going from the concentrator and thickener tanks to the Yankee Doodle Tailings Pond above the mine and then back to the mine operation.

“From this closed circuit not a drop of water leaves the site,” the Montana Resources website says.

Montana Resources is involved in the ongoing, long-term project of cleaning up the water that’s in the Berkeley Pit.

In the early 1980s ARCO was losing money with its Butte mining operations, and part of this loss was the approximately $10 million a year it was spending to pump groundwater to keep it from flowing into the underground tunnels and the Berkeley Pit. In March 1982 the decision was made to turn off the pumps and stop mining the Berkeley Pit while decisions were made on what next steps to take. The water started to fill the tunnels and the pit.

Ever since then, people have been concerned about the ever-rising level of acidic water in the pit.

“As the groundwater level rose, the Berkeley Pit rapidly filled with acid mine drainage from the pit walls, the network of underground mines, waste rock dumps and leach pads in the area,” the Environmental Protection Agency wrote in a 2002 press release.

“What was once a regulated mining and de-watering operation has now become a Superfund Site with the largest body of contaminated water in the United States,” said John Cruden, who at that time was the deputy assistant attorney general for the Justice Department’s Environment and Natural Resources Division.

In a 2020 Washington Post story Kathleen McLaughlin wrote that the “cavernous” Berkeley Pit is “now a mile-long, 900-foot-deep poison lake.”

“There is both weariness and wariness in the city of 34,000, a fading political and financial powerhouse,” McLaughlin wrote.

There are now about 55 billion gallons of water in the Berkeley Pit.

The 2002 EPA press release said that an $87 million settlement had been reached with ARCO, Montana Resources and related companies on plans for dealing with the water in the pit.

McGivern pointed out that although the Berkeley Pit is a Superfund site, “Never has there been a tax dollar paid for any cleanup in Butte, Montana.”

The costs are all covered by Atlantic Richfield and Montana Resources, he said.

“We’re responsible for some of the water treatment costs with our partner Atlantic Richfield,” McGivern said.

An average of about 2.8 million gallons of water a day flows into the Berkeley Pit, McGivern said. The water was allowed to accumulate for years because it was well below what is called the “protective water level” of 5,410 feet above sea level. If the water gets above that level, there is the potential for the water to migrate through the alluvium and leave the boundaries of the Berkeley Pit, McGivern said.

At the rate the Berkeley pit was filling with water, it would reach the “protective water level” in 2024. So water began to be pumped out of the Berkeley Pit in September 2019.

“At a minimum we need to pump out 2.8 million gallons of Berkeley Pit water, treat it and discharge it every day,” McGivern said.

“Atlantic Richfield and Montana Resources, working together, installed the pumping systems, the piping systems,” McGivern said. “Atlantic Richfield put in what we call a polishing plant, which has some reverse osmosis and sand filter technology.

The water treatment plant is a two-stage lime precipitation plant.

“We raise the pH by lime and then the metals drop out,” McGivern said. “It’s really that simple of a science.”

“The water gets treated here and then it enters the Atlantic Richfield polishing plant and then from there it gets discharged into Silver Bow Creek.

“And every day that water is sampled by a third party. We’ve had over 9,000 analytes sampled for, and every one of them have been in compliance with DEQ water quality standards for the state of Montana.

“So it’s worked, it’s worked as it’s supposed to.”

They have discharged a little over six billion gallons of water into the creek so far, McGivern said.

McGivern pointed out that Wikipedia says the pH of the water in the Berkeley pit is 2.5, and that is not correct. The water used to have that pH, but now that there is less oxygen in the water-filled underground tunnels, and with the lime addition from the water treatment plant, the pH of the water in the Berkeley Pit is 4.2.

There are ongoing efforts to keep birds from landing on the water in the Berkeley Pit.

A December 2016 BBC story said that in an unusual bird migration event, “as many as 25,000 birds landed in the Berkeley Pit last week, and since then have been seen dropping dead in the area.”

The story said that “in 1995, 342 snow geese corpses were found floating in the pit’s metal-laden waters, leading federal authorities to force the abandoned mine’s caretakers to take measures to scare off the birds.”

A bird shack has been set up next to the pit lake, and every hour or every four hours, depending on the season, someone from Montana Resources goes to the shack to see if there are birds on the lake that need to be hazed away.

A fireworks stand has also been set up next to the bird shack.

“If we get notified we have a large flock moving in, then we can set off the Fourth of July to try to deter them from coming.”

They haven’t had to set off the fireworks yet.

“But we’ve put it in place just to be prepared.”

According to a 2019 story by Matt Vincent on PitWatch.org, “since the last tragic bird die-off in 2016, scientists and managers at the pit have successfully scared off and saved 99.8% of all birds that have landed.”

You can go to PitWatch.org to find out more about the pit and check on the current water level.

Mining built Butte, and the mining industry has continually played a huge role in the life of the city and its citizens over the past 150 years.

Today, Montana Resources has a lot of positive impacts in the Butte community.

“Montana Resources contributes significantly to the local and state economy, with wages and taxes paid and local and statewide purchases averaging more than $74 million annually,” the company’s website says. “We take seriously our corporate responsibility to give back to the communities in which we live and work.”

“Our tax payments account for approximately 25 percent of the county’s tax base. We also make it a priority to purchase as much as possible from local and Montana businesses.”

The Dennis and Phyllis Washington Foundation, in conjunction with Montana Resources, gives grants to support the community in the areas of arts and culture, community service, education, and health and human services.

“We’re just wrapping up a $10 million gift to the city to revitalize the city’s Stodden Park,” McGivern said. “It’s been about a four- or five-year project now. Just a few finishing touches and we should wrap that project up.”

The Washington Foundation and Montana Resources have been supporting Butte’s Montana Folk Festival with annual grants of $200,000. During this year’s grand opening of the Folk Festival on July 8, McGivern announced a $600,000 grant commitment to continue the grants to the festival over the next three years.

“This news is absolutely fantastic and clearly illustrates the Foundation’s strong support for the high-quality performers we bring to Butte and that they join with us in believing that the festival’s economic impact on the entire region and Montana is significant and growing each year,” Montana Folk Festival director George Everett said. 

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The Big Hole River recently hit some of the lowest flows and highest temperatures recorded in modern times. The drop in water quantity poses risks to ranches, fish populations and other stakeholders. 

BUTTE, Mont. — Steve McGrath stood in an empty lot a block from his home watching for dust.

In a town where mining has been going on as long as in Butte, Montana, there is sure to be a multitude of stories – and almost all of them are…

Mike McGivern, Montana Resources’ vice president of human resources, talks about mining the Continental Pit and the history of mining in the Berkeley Pit. The Berkeley Pit, which is filled with water, can be seen in the background.

The Continental Pit on the left has been mined by Montana Resources since 1986, with a break from 2000 to 2003. On the other side of the Continental Fault, the Berkeley Pit on the right was mined by the Anaconda Company and then ARCO from the 1950s to 1983.

The Continental Pit mined by Montana Resources. Some water collects in the bottom of the pit from seepages, drainages and rainfall. There are some carbonates in the water, but it is much cleaner than the acidic water that flows into to Berkeley Pit.

The Berkeley Pit, which contains about 55 billion gallons of water, sits at the edge of Butte. The Environmental Protection said it is “a Superfund Site with the largest body of contaminated water in the United States.”

Butte’s Berkeley Pit is filled with about 55 billion gallons of acidic water. The water treatment plant on the far side of the water was built in the early 2000s. About 2.8 million gallons of water flows into the pit every day, so at least that much water is sent through the treatment plant and then goes to a polishing plant and is then discharged into Silver Bow Creek. The water treatment, which began in 2019, is a joint project of Atlantic Richfield and Montana Resources. The horns on the right are one of the tools for hazing birds away from the water.

The Berkeley Pit next to Butte has been filling with acidic mine drainage ever since the mining stopped and the groundwater pumps were shut off in 1983.

Montana Resources usually mills around 47,000 tons of ore per day. The mill was commissioned in 1964 and looks about the same as it did back then, although there are new electronics.

In the flotation circuit at the Montana Resources mine, the copper, molybdenum and silver bubble to the surface and are captured for concentrates. The process produces concentrates that are about 26 to 32% copper and 54 to 57% molybdenum.

Haul trucks and a water truck at Montana Resources’ Continental Mine in Butte. Dust abatement is a major focus because the mine is right next to the city.

Montana Resources’ mine in Butte runs 18 Caterpillar 793 haul trucks and uses three 495HD shovels which have 40 cubic yard buckets.

Many Butte images and logos feature headframes, where miners were lowered into and raised out of a mine. There are still 14 historic headframes throughout Butte.

Everywhere in Butte there are reminders that this is a mining town. The walls of the Berkeley Pit can be seen in the distance at the base of the green mountainside.

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