The Berkeley Pit is seen in August 2022. After long being a source of copper and strife, the contaminated Berkeley Pit has also shown to be chock-full of something potentially a little more positive: rare earth elements. (Photo by Trent Sprague)
Story by Kasey Faur, Montana Standard
After long being a source of copper and strife, the contaminated Berkeley Pit has also shown to be chock-full of something potentially a little more positive: rare-earth elements.
Rare-earth elements, or rare-earths, like neodymium, dysprosium, cerium, lanthanum, yttrium, praseodymium and europium are just a handful of those used in electric and hybrid cars and Special Forces gear, as well as everyday applications such as lightbulbs.
This isn’t the first time Butte has been a source of metals useful in national defense.
“The Berkeley Pit literally got us through two world wars,” said Mark Thompson, vice president of environmental affairs for Montana Resources.
During World Wars I and II, the demand for copper ramped up for use in bullets and other weaponry and Butte's mines were able to supply it.
Historically sourced from countries like China — which has had a hold on the rare-earth market for years but has recently seen a decrease due to extensive mining — rare-earths have been a popular topic in the U.S. government over the last couple of years.
Specifically, there’s been chatter about sourcing rare-earths domestically.
Enter Paul Ziemkiewicz, director of the West Virginia Water Research Institute, which operates out of West Virginia University. Ziemkiewicz has also been involved with advising on acid mine drainage from the Berkeley Pit for approximately 25 years, so he has relationships with hydrogeologists from the Montana Bureau of Mines and Geology and Montana Resources.
Ziemkiewicz’s journey with extracting rare-earths from local sources started in 2015, when the U.S. Department of Energy sent out a solicitation for proposals regarding extraction of rare-earths from coal-related wastes.
He said it occurred to him that rare-earths could possibly be found in acid mine drainage, so he asked the DOE if the proposal would be within the scope.
“Sure enough, enriched in rare-earths,” Ziemkiewicz said.
In 2020, he asked Ted Duaime, hydrogeologist at the Montana Bureau of Mines and Geology, to send him a sample of the Berkeley Pit water for analysis at the lab at West Virginia University. The lab found the Pit had 10-times the amount of rare-earths found in coal drainage.
Duaime said although it was as recent as 2020 that he sent the Berkeley Pit water sample to Ziemkiewicz, the lab at the Bureau of Mines has known for as long as two decades that the Berkeley Pit water has elevated concentrations of neodymium.
“So we've known they've always been there,” Duaime said. “It's just trying to get people that have the money to come forward and say, ‘OK, you know, let's look at this in more detail.’ And West Virginia was able to give us just a much more complete list of all the rare-earths that are there.”
Samples of Berkeley Pit water taken at a depth of 166 feet showed elevated levels of rare-earths, the top four being cerium, neodymium, yttrium and lanthanum. There were lesser concentrations of gadolinium and dysprosium, according to a graph provided by Montana Bureau of Mines and Geology Hydrogeologist John Metesh.
Metesh helped complete an application that ultimately secured a grant from the United States Army Research Laboratory that has funded seven projects in the Bureau of Mines, and eight in Montana Technological University’s metallurgical and materials engineering department, according to Metesh.
The projects through the Bureau of Mines include looking for rare-earths in abandoned mine sites, coal wastes, large waste sites and a few others.
In 2021, Ziemkiewicz and his team at West Virginia University put in a grant application to the U.S. Department of Energy with a proposal to extract rare-earths from the Berkeley Pit to demonstrate and test the process of extracting rare-earths from the Pit, sending the resulting concentrate to WVU, and refining the concentrate to a point where it produces metals that can be sold and used in defense and everyday capacities.
The proposal wasn’t funded, but Ziemkiewicz’s team will submit a similar application
for $3 million to the U.S. Department of Defense that is due Jan. 17. Ziemkiewicz
said that although he doesn’t know when he’ll hear back on the application, it
will probably be at least a couple of months.
The Horseshoe Bend Water Treatment Plant treats Berkeley Pit water with lime and a polymer. Local groups hoping to extract rare earth elements from the Pit think the plant could be used to extract the elements from the water and get it down to concentrate while still maintaining day-to-day operations. (Photo by Meagan Thompson, The Montana Standard)
If the project were funded, Montana Resources’ Horseshoe Bend Water Treatment Plant would be used to extract the elements from the water and get it down to concentrate, while still maintaining day-to-day operations. This process would probably take a few months, Ziemkiewicz said.
The process is not unlike what Montana Resources does at its Horseshoe Bend Water Treatment Plant to get the water to drinking standards. It’s a multi-phase process that involves changing the pH-levels of the water multiple times to extract contaminants.
To extract the rare-earth metals, the treatment plant would use slightly different pH-levels and possibly experiment with add levels to get the most out of the water, Ziemkiewicz said.
“The process being proposed by West Virginia University is not dissimilar from the process that we use anyways to treat the Berkeley water, so it's happening anyway,” Thompson said. “And I’m comfortable that we can do this and that we can sustain this.”
He added that he’s excited about the prospect of the Berkeley Pit becoming an asset when it’s been known for so long as a liability.
Ziemkiewicz said that ultimate goal is to get a rare-earths refinery in the U.S. so the country won’t have to send the byproduct to China.
He said his team recently put in an application to the DOE that proposes building a refinery in the U.S.
For the rest of the story, go to the Montana Standard.