The Upper Missouri Waterkeeper secured a temporary restraining order Friday in Beaverhead County District Court to temporarily suspend operations at the Calvert Tungsten Mine in the Big Hole River watershed.

The nonprofit alleged the Montana Department of Environmental Quality failed to provide public notice before granting the mine, a project of Mithril Mining Corp., a Small Miner Exclusion Statement, or SMES.

According to DEQ, a SMES is a written agreement a miner signs attesting that they will follow certain rules and conditions to be exempted from obtaining a full mining permit.

The issue is set to be back in court in Beaverhead County on Tuesday, June 30, at 9 a.m., when Missouri River Waterkeeper will ask District Court Judge Luke Berger to make the injunction permanent.   

District Court Judge Luke Berger in a file photo from 2022.  Duncan Adams

Mining at the Calvert Tungsten Mine had been set to begin June 22. Tungsten is a key critical mineral. The U.S. Geological Survey reports that tungsten is “primarily used to make wear-resistant metals for jet engines, ammunition and mining and cutting equipment.” It is said to offer an exceptionally high melting point and excellent corrosion resistance.

Mithril Mining reported in a May 26 press release that it had received permit approvals from the U.S. Forest Service and DEQ to commence mining in June.

On Tuesday, Taylor Sulik, CEO of Mithril Mining, responded to a request for comment.

“Due to active litigation, we are advised not to comment on specifics at this time,” he said. “We look forward to discussing our plans for the Calvert, as we already have done with the surrounding neighbors of Wise River and the Big Hole Watershed Committee, when this legal complaint has been resolved.”

Sulik added, “As an American and veteran-owned company, we remain committed to working through the appropriate legal and regulatory processes while continuing to advocate for responsible domestic mineral development. Projects like the Calvert are an important part of rebuilding secure American supply chains and reducing reliance on foreign sources of critical minerals.” 

The Upper Missouri Waterkeeper’s complaint seeking a restraining order alleged that DEQ approved a SMES for Mithril Mining and the Calvert project “absent any public notice, public participation opportunities or any review under the Montana Environmental Policy Act.”

Waterkeeper then cited a host of environmental issues affecting the Big Hole River, which has recorded declining trout populations in some reaches. And the nonprofit’s quest for a temporary restraining order listed all the ways DEQ could have offered more public notice or gathered comment before approving the SMES.

Anglers float down the Big Hole River in Beaverhead County on June 19. MEGAN NIELSEN, Montana Standard

A news release Tuesday from Waterkeeper said its efforts to secure information from DEQ about the SMES have been unsuccessful.  

That same release quoted Waterkeeper Dane Strother, who owns property in the vicinity of Calvert Hill, as saying he learned about the mine from a restaurant server.

"Hopefully, this isn’t a backroom deal at the expense of our private property values, water and community,” Strother said. “It’s unacceptable, and we demand to know the full story of who all are behind this potential environmental disaster and did state agencies rubber-stamp any plan without due process and study. Bottom line, is the law being followed?”

DEQ’s response: “Per department policy, DEQ does not comment on ongoing litigation.”

Mithril Mining provided a history of the Calvert mine site and other information. Mining began in the mid-1950s, ceased in 1958 and then resumed in 1960, by enlarging the mine’s open pit, and continued until 1962.

Exploration projects followed during the 1960s and early 1970s.

The Trump administration and the U.S. Department of Interior have made a big push for the mining of critical minerals deemed vital to national security. Montana Tech hosted a critical minerals roundtable in February. Doug Burgum, secretary of interior, was a participant.

Meanwhile, Guy Alsentzer, executive director of Upper Missouri Waterkeeper, described the temporary restraining order as a victory for the public and the Big Hole River.

Executive director of Upper Missouri Waterkeeper Guy Alsentzer walks to his seat during an Environmental Quality Council meeting at the Capitol on March 25, 2026. SONNY TAPIA, Independent Record

“We’re not only seeing this pattern and practice of keeping the public out of the loop on decisions that impact our public lands, waters and resources at the federal level, but under the Gianforte administration, too,” Alsentzer said. “If it weren’t for the diligence of citizens and groups staying alert and stepping up, huge decisions with the ability to significantly impact our environment would be rubber-stamped without any public participation.” 

Yet Matt Vincent, executive director of the Montana Mining Association, said the mining project reached out through meetings at the H Bar J Saloon and Cafe and with the Big Hole Watershed Committee.

Vincent also said the SMES is perfectly appropriate for the Calvert Tungsten Mine's early phase, which will focus on removal and metallurgical evaluation of waste rock. 

Matt Vincent, executive director of the Montana Mining Association, speaks during a roundtable with Secretary of the Interior Doug Burgum during a visit at Montana Tech in Butte on Feb. 27. MEGAN NIELSEN, Montana Standard

Duncan Adams covers the environment, natural resources, Montana Tech and other beats for The Montana Standard. Reach him at (406) 496-5572 or duncan.adams@mtstandard.com