Lemhi Pass Overview

The addition of our sizeable Lemhi Pass land package is both significant from a land holdings perspective as well as a mineral endowment perspective. It is well-known that Lemhi Pass is regarded as the “largest concentration of Thorium resources in the United States” by the United States Geological Survey (USGS), however Lemhi Pass’ Rare Earth Elements mineral endowment has seen much less attention until IDR acquired the project in May of 2022.

The Company’s Lemhi Pass holdings covers approximately 11,425 acres and is comprised of a mixture of 568 unpatented lode mining claims and 1 State of Idaho mineral lease. The recently acquired Lemhi Pass land package is strategically located approximately 35 miles from the company’s Diamond Creek and Roberts Rare Earth Element holdings and 124 miles from Idaho National Laboratory. IDR has completed a number of sampling programs across its property package and has received Rare Earth Element numbers far exceeding the historically reported findings. The Lemhi Pass project has significant Rare Earth Elements mineralization and potential for expansion.

Rare Earth Elements Mineralization

The Company initially staked the Lemhi Pass Project to target an area with the greatest concentration of known veins where the Lemhi Pass, Dan Patch, and Bull Moose faults intersect or approach one another. REE and thorium mineralization at Lemhi Pass is found in the REE mineral monazite, which is a phosphate mineral associated with most of the Company’s strongest REE values. To date, Idaho Strategic has conducted surface sampling programs and geologic mapping throughout its ownership of the mineral claims. Select Idaho Strategic sample results have revealed rare earth grades up to 4.26% TREO in which 2.56% of the TREO is solely made-up of Neodymium. Six other samples were collected at Lemhi Pass that show a similar Neodymium to TREO ratio.

“The Lemhi Pass ores are unusual in that they consistently show a strong enrichment in the middle rare earths, especially neodymium.  Electron microprobe analyses of monazite reveal as much as 35 weight percent Nd oxide (Gillerman, 2008; Gillerman and others, 2009), which is possibly the highest content known in the world.” –Gillerman, V.S., 2011, Idaho GeoNote 44: Rare Earth Elements and Other Critical Metals in Idaho

Lemhi Pass Claim Staking

Lemhi Pass Rare Earth Project

  • Technology Readiness Level represents a standard method of measuring a project’s current development status. See the link below for an explanation of the 9 TRL levels.

Idaho GeoNote

Lemhi Pass Photos

IGEM Partnership