Private company US Critical Materials announced on Wednesday that its Sheep Creek deposit in Montana contained the highest reported rare earth grades in the US, along with significant concentrations of gallium - an element deemed critical to national security.

Citing independent analysis conducted by Activation Laboratories, US Critical Materials said Sheep Creek had confirmed rare earth oxide grades nearing 9% (89 932 ppm), with neodymium and praseodymium concentrations of 2.4% (23 810 ppm). The site also boasted gallium concentrations ranging from 180 ppm to 385 ppm, surpassing the 50 ppm grade previously imported by the US, predominantly from China.

"Sheep Creek has higher rare earth grades than known deposits in Greenland and Ukraine," said Jim Hedrick, president of US Critical Materials and former rare earth commodity specialist at the US Geological Survey. "These findings reinforce the site’s strategic importance as the US seeks to secure critical mineral supplies."

The Sheep Creek project spans 25.9 km², with an initial focus on a 6.5-km² area containing more than 60 carbonatite formations. US Critical Materials is advancing its development under a cooperative research and development agreement (CRADA) with Idaho National Laboratory, which has been extended through 2027. This collaboration aims to refine environmentally sustainable separation and processing technologies.

The discovery comes amid increasing global competition for critical minerals, particularly following China’s recent restrictions on gallium exports. Gallium is a key component in semiconductor production, defence systems, and AI applications, making its domestic supply crucial for national security.

"Sheep Creek represents an opportunity for the United States to reduce its dependence on foreign sources for rare earth elements and gallium," Hedrick said. "Over my 30-year career evaluating geological formations, I have never encountered a deposit of this grade."

US Critical Materials, a privately held company, holds mineral assets in Montana and Idaho. The company is focused on securing a high-grade, domestically sourced supply of critical minerals to support US industry and defence needs.