By Evelyn Pyburn

A Utah-based company has discovered rare earth minerals in southwestern Montana so vast, as to “far exceed any other domestic rare earth resource.”

US Critical Materials Corp reports that the find in Ravalli County, near Darby, has “the highest reported total rare-earth oxide grades of any rare earth deposit in the United States.”  US Critical Materials Corp is a privately held company that focuses on rare-earth exploration and development.

Rare earth minerals have become essential to almost all future technology in almost every segment of modern business, industry and military.  The minerals are not only vital to the future, but the need to be able to source them in the US is just as critical. Despite the extensive need for them, the US depends upon China to provide almost 90 percent of the rare earth minerals it needs – a perilous situation for the military, which requires rare earths metals in the production of most of its weapons and equipment.

Ed Cowle and Harvey Kaye, both of whom are directors of US Critical Materials Corp, spoke to the Big Sky Business Journal about the status of the project and its importance. The USGS has confirmed that they will be mapping, sampling, and exploring the property this summer and will conduct fly overs as part of the earth MRI program.

According to Cowle and Kaye, there is in fact much collaboration going on with numerous entities, including the U.S. Geological Survey, the Montana Bureau of Mines and Geology, and the Idaho Geologic Survey. They are assisting US Critical Minerals in a comprehensive investigation of the Sheep Creek mineralogy, geochronology, and trace element geochemistry. The U.S. Government agencies are also undertaking detailed mapping of the Sheep Creek district and conducting stream sediment surveys.

The deposits seem to bear thirteen of the most essential critical minerals that are in demand for making such things as rechargeable batteries, electric vehicles, wind turbines, mobile phones, permanent magnets, electric motors, lasers, computer chips, semiconductors and microchips.

And, most remarkable, the underground data shows a low thorium level, which is quite rare. Thorium is usually a “waste” that must be removed during the mining process. Not having it present means the company will not have to go through the permitting process required by the Nuclear Regulatory Commission, and it will make “extraction and processing easier, faster, and less damaging to the environment.”

“We have confirmed that Sheep Creek is the highest-grade rare-earth deposit in the United States, with a multibillion-dollar resource

value. Over the course of my career

independently evaluating rare earth properties within the US, I have never encountered a property with the grades being generated by Sheep Creek “ stated Jim Hedrick, US Critical Materials President, and former rare-earth Commodity Specialist at the U.S. Geological Survey (USGS).

Kaye said Sheep Creek “is quite superior to any other discovered in the US,” And, further given the quality and the economics of the discovery and its ultimate profitability, “It will be more environmentally friendly because you don’t have to dig up huge quantities of rock to make the economics work.”

The site was that of a previous mining project 30 or 40 years ago, but had never been explored for rare earth minerals. The explorers were looking for niobium.  Previously, they drilled horizontal adits  (tunnels) into “the side of the mountain about 400 feet long.” Since US Critical Materials, Corp. held the mining rights at Sheep Creek on what is mostly land administered by the US Forest Service, in October 2022, they opened up the tunnels and took a geologist into them.

What they saw in terms of rare earth metals “was actually jaw dropping,” said Kaye. We found rare earth mineralization 125 feet below the surface in those tunnels. The underground rare earths came out with very high percentages. This gave us a “window” into the deposit.

The Sheep Creek site could very well be “the most valuable rare earth property ever discovered,” exclaimed Kaye. On the website, Mining.com, President Hedrick , is quoted as saying that as a pre-resource-stage deposit the inferred value of the discovery  is a “conservative” $43 billion.

The company has only explored 35% of its property. Within the 800 acres explored, there are 50 surface carbonatites, which is quite rare. Kaye explained that because of the number of carbonatites they strongly believe the dikes originate from a deeper, larger source – sort of like “the mother lode”.

Sheep Creek spans 223 lode claims representing approximately 4,500 acres of total land package. Historical grab and chip sampling of carbonatites indicate the potential for high-grade mineralization with up to 18.0% total rare earth elements, including 2.4% (23,810ppm) combined neodymium and praseodymium, plus credits in niobium and other strategic metals.

“Sheep Creek samples collected so far are higher grade than most global rare earth deposits, which tend to run from 0.1% to 4% TREO.”

Rare earth samples have been taken from 125 feet underground, according to a press release, and they confirm the presence of over 10% (100,000 ppm) of total rare earth oxides, (TREO) including high levels of neodymium and praseodymium. The results included previously mentioned channel samples from two underground tunnels that were unsealed in October 2022 and sampled in November 2022. These tunnels were dug up to 400 feet horizontally and are 125 feet below the surface.

There remains considerable uncertainty as to how soon US Critical Materials Corp can begin mining – it won’t be for a matter of years – maybe as many as ten years, even though the company has high hopes of accelerating that time line. This year the company will be doing more research and exploration, sampling and mapping, said Cowle. Only about 35 percent of the Sheep Creek area has been examined.

The company will hopefully do some drilling this summer in attempt to find out if the underground drilling samples match the surface samples. The drilling will only occur if US Critical Materials is approved to drill.

US Critical Materials does not do mining and will engage a company to do it. They expect to process the ore in Darby, which Kaye said has all the infrastructure that will be needed.  The cost of developing the project to the mining stage will require at least $100 million.

Finding the investors to continue exploration and mining is part of the challenge before them, but Cowle and Kaye say there is a great deal of interest among potential investors.

The development will be significant for Darby, which has a population of 783, as it will be for the state of Montana. “We believe it will be extremely positive for the economy of the entire area,” said Kaye, “It will provide  high paying, quality jobs.” In addition, Kaye said, “We want everyone to know we have the same concerns as they do — how to do it with the latest technology and best environmental protections.“

 While there are three or four other areas in the US where it’s been announced that rare earth minerals have been found in great enough quantity to be mined profitably, there is only one operational mine in the US, MP Materials in Mountain Pass, California, and its ore is processed in China.

(It is interesting to note that rare earth minerals are not all that rare—what is rare is to find them in deposits large enough to be economically mined.)