Magna • The tailing ponds for Rio Tinto Kennecott stretch across nearly 9,000 acres on the western edge of Salt Lake County.
Those residue basins, along with the mine’s sometimes rocky relationship with nearby communities, have turned the operation into a predominant presence in Magna.
While longtime residents agree that their impact has lessened through the years, on intensely windy days, views can be faded by the dust. The industrial sprinklers are just not enough to dissipate the particles in the air.
Now, as Kennecott explores digging deeper and extending the Bingham Canyon mine’s life until 2040, it is considering expanding the eastern portion of the historic south impoundment to provide 100 million tons of tailings storage.
Some environmental activists worry that this eastern extension is closer to homes in Magna and raised concerns about their air and water quality. But for metro township officials, the picture is more complex and keeping the mine running also ranks high in their priorities.
“A lot of people in our town work for Kennecott,” said Magna Mayor Dan Peay. “They have to have a place to put their tailings if they’re going to continue to run.”
The project would impact 539 acres, including 327 acres of the existing south impoundment, 39 acres of an existing canal and a closed sediment pond along with 173 acres without previous tailing deposits.
This would be enough to store two years of tailings, which, along with the remaining space at the north impoundment, would keep the copper flowing until 2040.
Peay trusts that Kennecott is taking the necessary precautions to make the site safe and acknowledges all of the work and influence that the company has had in Magna.
Still, he understands his constituents’ concerns.
“Like everybody else, I probably wish they wouldn’t do it,” he said. “However, it’s their property, and they have the right to do what they want on their property.”
Earthquake protection
(David Howells | Rio Tinto) Kennecott's north tailings impoundment on Oct. 26, 2021. The company is seeking an extension on the east side of the site to accommodate the expansion of the Bingham Canyon mine.
Kennecott has an operational north tailings impoundment, near Interstate 80. From State Road 201, drivers can see the south impoundment, which hasn’t received active tailings since 2001. It is dry and being reclaimed.
In the 1980s, before draining the south site, Kennecott concealed for decades that the southeastern corner of its tailings pond could fail in a major earthquake, sending a “soupy sludge” into Magna.
Now, the attention is back to that area. After undertaking remedial measures and building the north impoundment, Kennecott hopes to work on that southeastern corner to improve its stability by fortifying its walls, extending them for proposed eastern expansion.
If the project wins federal approval, the homes near SR-201 (also known as the 2100 South Freeway) and 8000 West would become neighbors again to active tailings.
What’s in the dust?
When Molly Blakowski drove past the tailing piles on her way back from Saltair’s boat harbor in mid-April, she found a dusty scene amid the strong winds.
“Because we were right next to the Kennecott tailings, there was pretty reduced visibility on the road,” she said. “It was really unpleasant and tough to breathe and really something unpleasant to experience.”
The visit prompted Blakowski, a doctoral candidate at Utah State University’s Department of Watershed Sciences, to consider the PM2.5 and PM10 that people near the tailings were breathing.
Dust generated from tailings in many mining operations is elevated in heavy metals, she said, so those may also be enriched from metals like copper, lead and zinc.
Kennecott’s tailings are of better quality than some of its counterparts, according to Paula Doughty, the company’s manager of tailings and water services. They do contain metals but the latest environmental study pointed to levels replicable in many backyards.
“It’s very comparable to Western soils from a metal standpoint” Doughty said. “The only thing that’s a little bit higher is copper.”
Even so, Blakowski worries about what’s in that dust with a metallic taste.
“Regardless of chemical composition, exposure to elevated concentrations of fine particulates is an acute health hazard,” she said. “But then, when that dust is enriched in heavy metals, there may be additional health concerns associated with exposure.”
Advocates such as Friends of Great Salt Lake also worry about a possible extension of an industrial operation that discharges some waste, including selenium, into water that reaches the Great Salt Lake.
Doughty is not concerned about the quality of the water that Kennecott sends to the Great Salt Lake, though.
“We’re highly regulated,” she said. “It meets all our permit requirements. And we meet those pretty easily. The only challenge that we have is when we get high winds. It will stir that up and so we’ll have suspended solids.”
In those cases, she said, her team stops the discharges until the solids settle. In addition, Kennecott mitigates dust by keeping sprinklers on at all times in the tailing sites — except when there’s heavy rain.
“Our air quality permit requires that we spigot at every location on the impoundment at least once every four days,” Doughty said. “So we will rotate where we need to and where we can to meet that requirement.”
Location, location, location
(Alixel Cabrera | The Salt Lake Tribune) Site of the east tailings expansion project on May 8, 2023. Kennecott is seeking an extension of its tailings storage to accommodate the expansion of the Bingham Canyon mine.
Lynn de Freitas, executive director of Friends of Great Salt Lake, said it was “unfortunate” that Kennecott couldn’t find a better spot to store its waste products, one that wouldn’t impact wetlands and air quality adjacent to the lake.
“Kennecott has pretty much extensive ownership of the Oquirrh Mountains, and there are some abandoned mines there,” de Freitas said. “That would be a logical place.”
De Freitas also worries that the dust suppression methods may be ineffective, especially when the ponds are located next to a growing metropolitan area that is already grappling with air pollution.
Kennecott studied various options to expand its tailings storage across its properties, said Laura Ingersoll, Rio Tinto’s senior adviser for the company’s community and social performance team. The company determined that the eastern expansion would be the one that best minimized any environmental impacts.
“The area where the expansion will go was an area that was previously used for industrial purposes, [like] processed water channels, sediment, ponds, roadways, pipelines, equipment storage,” she said. “The closest residence to the east tailings expansion area, is about 1,100 feet away, and it’s separated by SR-201″
(Christopher Cherrington | The Salt Lake Tribune)
Environmental impacts under review
Whenever a project could affect U.S. waterways and wetlands, the Army Corps of Engineers steps in to review it.
Since Kennecott’s plans would entail 44.86 acres of water, including wetlands, the corps is drafting an environmental impact statement, weighing factors like aquatic resources, air and water quality, alongside socioeconomic aspects like jobs.
Though there have been public notices, the tailings expansion has remained a somewhat-obscure process for the community. Though some residents and nonprofits submitted comments, only one person attended the scoping meetings.
“That was a little disappointing,” said Nicole Fresard, the corps’ senior regulatory project manager, “because you do want to hear from the public whenever you’re processing these types of projects.”
Like most environmental impact statements, the “no action” alternative is being considered. The corps also will examine on-site and off-site alternatives. Whichever option creates the least community impact will likely prevail.
“What Kennecott would prefer to do is not necessarily what they will end up doing,” Fresard said, “because the project can change throughout the EIS process.”
The public comment period ended in April. But the corps will continue to evaluate additional input as it drafts the analysis. A final study may wrap up in two years.
Alixel Cabrera is a Report for America corps member and writes about the status of communities on the west side of the Salt Lake Valley for The Salt Lake Tribune. Your donation to match our RFA grant helps keep her writing stories like this one; please consider making a tax-deductible gift of any amount today by clicking here.
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