Critical minerals deposits present at Bald Mountain

Erin Mullins

Critical minerals, rare and essential to electronics, are deposited at Bald Mountain east of Lovell in the form of radioactive conglomerates that were sampled there.
The Wyoming State Geological Survey (WSGS) recently released two scientific reports on paleoplacers, or ancient placer deposits made up of heavy minerals, which are denser than quartz, said WSGS geologist Derek Lichtner, lead author on the reports. These deposits are potential sources of titanium, zirconium and rare earth elements, which are important for applications like aerospace, nuclear energy, electronics and batteries.
Since paleoplacers tend to have critical minerals, Lichtner said they are an important area of study.
“The U.S. Geological Survey defines critical minerals as materials that are essential to the economic and national security of the United States. So what that means is they play an important role in the manufacture of essential products, and they also have supply chains that are vulnerable to disruption,” he said. “(Critical minerals have) inspired and guided a lot of geologic research in the last few years, both in Wyoming and throughout the U.S.”
Critical minerals are not necessarily as rare as minerals like gold and platinum, but they are rare enough that the supply chain is vulnerable, Lichtner said. Historically, Wyoming has focused on their gold resources, but there are other minerals in the state.
The demand for rare earth minerals has grown rapidly due to their use in electronic components, Lichtner said.
The radioactive conglomerates found at Bald Mountain and the Big Horn Mountains in general are similar to the known rare earth deposits, Lichtner said. The radioactive conglomerates are ancient riverbeds ranging in age from 50 million to 2 billion years old. While 50 million years sounds like a long time, it is young in a geological time frame.
The varying conglomerates were created by the erosion of a rock upstream, with the lighter minerals being settling out and heavier minerals flowing downstream, he said. The minerals transported downstream include some gold, but what is currently of greater interest is minerals like monazite, zircon and titanium.
The Bald Mountain deposit was discovered more than 100 years ago due to the rise of gold mining, Lichtner said. In the early 1900s, a mining town of around 1,500 people popped up, which was soon abandoned due to limited gold deposits. In the 1950s, the deposit was of interest again due to its thorium.
“Now, what we’re interested in always keeps changing. New technologies require different minerals. So, what we did is we revisited this deposit and some similar deposits trying to get a more complete geochemical analysis,” he said. “Rare earth elements being focused, but really we just want a full suite of chemical data. Just who knows what important decades in the future will be?”
Bald Mountain is moderately enriched in light rare earth elements, which are rare earth elements that have a smaller atomic number and weigh less, Lichtner said. The lighter earth elements are used to make magnets, steelmaking, metal making, battery and electronic components.
Lichtner said that he is not an expert on how feasible a critical mineral mining operation would be at Bald Mountain, and that it would depend on the specifics of the operation and global market conditions.
Many mineral deposits in the state are from a seaway that was in the middle of the U.S. 80 million years ago called the Western Interior Seaway, Lichtner said. The flooding of the seaway created shores with deposits due to wave action, which sorted and concentrated the critical minerals.
Wyoming is a mineral rich state. There are rocks ranging in age from billions of years old to a few million years old, he said. Minerals found in the state include gold, rare earth elements and metals like titanium, iron and uranium, which Lichtner says just skims the surface of the many minerals in the state.
There will likely be further research reevaluating potential geologic deposits around Wyoming and seeing what is available, he said. Although there is historical geologic data for much of Wyoming, there are still a lot of unknowns.
 “I think there’s a lot of work to be done on getting updated, modern geotechnical data for some deposits that were looked at in the past,” Lichtner said. “But looking at them with fresh eyes and new tools might reveal something interesting, especially as we have new goals in recent years, as well.”
It is important to fund geologic science because research by the WSGS is the foundation of exploration into future mining operations in Wyoming, he said. Mining is critical to the economy of Wyoming and the job force, he said.