Talon Metals steps up exploratory drilling for a nickel mine in Minnesota, cites 'exceptional' find

Nearly a half-mile under the earth in northern Minnesota, an exploratory drill found something surprising: Minerals with the highest concentration of nickel yet identified by mining company Talon Metals, as well as copper, gold and platinum group metals.

The company, which seeks to supply nickel to Tesla for electric vehicle batteries, announced May 1 that it found minerals with 12.65% nickel — compared to an average of 1.73% that the company previously reported. The find was made in an existing hole the company extended last year near Tamarack, Minn., with the minerals starting at 2,320 feet deep.

The dig was part of Talon's accelerating exploration program, which has drilled or extended at least 292 holes from 2020 to 2024, according to the Department of Natural Resources website and agency records. That's four times as many samples taken by Talon's mine partner, a subsidiary of the international mining giant Rio Tinto, as in the preceding five years.

The sample "would be exciting if it was only the gold values, or the [platinum group] values, or the copper values, or the nickel values, but to have all of them together makes this intercept exceptional," Brian Goldner, chief exploration and operating officer at Talon, said in a statement.

Talon's proposed mine has not encountered the same pushback as the two other proposed hardrock mines in Minnesota, NorthMet and Twin Metals. The project would be in a part of Minnesota with little history of mining, and also faces the challenge of finding higher-grade minerals in a much more concentrated area.

Talon is in the process of completing a feasibility study this year that will inform how and where it mines for metals across the Tamarack Intrusion, an underground collection of sulfide rock formed over a billion years ago. The company is in the beginning stages of environmental permitting with the state, proposing an underground mine that would ship ore to North Dakota for processing.

But mapping out the underground resource, which is concentrated in smaller areas than other copper-nickel prospects in Minnesota, takes significant work. Talon has an in-house drilling team, and spent $65 million on the effort from 2020 to 2024, according to a company spokeswoman.

All that drilling has attracted the attention of the environmental group WaterLegacy, which wants the state to complete an environmental review of this exploratory drilling.

Ancient formations

The Tamarack Intrusion is a tadpole-shaped formation that stretches about 11 miles under Aitkin and Carlton counties. So far, Talon is proposing to mine a portion of the tadpole's tail, just north of the small city of Tamarack.

Like other valuable metal deposits in Minnesota, the intrusion is part of the midcontinent rift, a corridor of volcanoes and lava flows that crossed Minnesota and other parts of the Upper Midwest 1.1 billion years ago.

Along Tamarack, narrow channels allowed magma to flow upward through volcanoes or possibly fissures in the ground, concentrating valuable minerals in a relatively small area, said Joyashish Thakurta, an economic geologist with the University of Minnesota's Natural Resources Research Institute.

It took many tries for Kennecott, the Rio Tinto subsidiary, to originally find the minerals. Drilling began in 2002, and it took six years and 42 holes to hit high-grade nickel.

The Tamarack formation is significantly different from the area where two other proposed copper-nickel projects would mine in the Duluth Complex, which was formed later in the midcontinent rift. This formation in the Arrowhead region includes "enormous quantities of magma" that spread across a much broader area but has lower concentrations of metals, Thakurta said.

Still, Talon says its latest find indicates there's more metal in the Tamarack Intrusion than previously shown.

In news releases, Goldner has said the company expects its newest sample of high-grade nickel indicates a little-explored zone of valuable metals. He compared the phenomenon to Norilsk, the Siberian town that has been extensively mined for nickel since the 1920s.

Thakurta said geologists still have much to learn about Tamarack. The intrusion "is relatively new, and things are just beginning to appear. So it would be a mistake to compare [it to Norilsk]."

Still, analysts who track Talon on the Canadian stock exchange said the find was good news for the company.

Matthew O'Keefe, an analyst for Cantor Fitzgerald, wrote recently that drilling should find higher-grade minerals and a broader area worth mining as the company continues its study in 2025.

Environmental questions

To drill for samples of metals other than iron on state-leased lands, mining companies must get their plan approved by the DNR.

Paula Maccabee, an attorney with WaterLegacy, said Talon's plans should also require an environmental assessment worksheet (EAW), a low level of environmental review.

The region where Talon is drilling is home to wetlands and wild rice beds. The DNR requires any exploration directly in wetlands be done in winter to minimize disturbance.

"They are drilling in vulnerable areas," said Maccabee, who has formally petitioned the DNR to complete an EAW. "It's not been managed in a way that conforms with the most minimal laws we have on the books."

DNR officials said drilling plans are reviewed by nearby tribes and other agencies with environmental responsibilities. The agency, which is now considering WaterLegacy's petition, declined to comment on the request.

Talon spokeswoman Jessica Johnson wrote in an email, "Minnesota has a long-established system for reviewing and permitting exploration plans, with input from tribal governments, regulatory agencies, and the public. Using the highest standards of environmental protection, we strive to limit impacts."

One of the main issues WaterLegacy has raised is how Talon handles its sumps, or places that contain the debris from drilling. That could include potable water used to drill, some additives in that fluid and shavings from around the central core that Talon collects and analyzes.

If sulfide minerals from the drills interact with air and water, they have the potential to create toxic drainage, one of the reasons WaterLegacy has questioned what might be lingering inside the sumps.

Chris Baldwin, a retired mine supervisor who worked at the Haile Gold Mine in South Carolina and before that at Cleveland Cliffs' Minorca Mine, said Talon could avoid contamination by lining its excavated sumps with plastic.

Using liners at Talon "would be a really serious thing to show the public that you really are concerned about the future," said Baldwin, who has volunteered for WaterLegacy in the past.

Cheyanne Dusek , who inspects boring sites and sumps for the DNR, said she had never seen a liner at a Talon sump site. State agencies did not have information about the materials inside the sumps. Talon did not provide that information to the Minnesota Star Tribune.

The DNR checks to make sure material from the drill stays contained inside the sumps, Dusek said. "We're not monitoring the water quality of the sump itself."

The Minnesota Pollution Control Agency is generally responsible for water quality. "Because of the exploratory phase of Talon's work, they have not met the threshold, as defined in state statute, that requires a water permit from the MPCA," an agency spokeswoman said.

Maccabee said she has no data showing that water quality has been degraded by the drilling, but said of state agencies, "no one can tell us whether our water's being protected."

The DNR is considering WaterLegacy's request for an EAW; it's unclear when the agency will make its decision.

This story has been updated.