American Rare Earths Ltd (ASX:ARR, OTCQB:ARRNF) has wrapped up test mining at the Cowboy State Mine in Wyoming, producing more than 3,000 tonnes of ore for comminution and beneficiation optimisation. The work marks another step forward for the Halleck Creek rare earths project, which the company is advancing through subsidiary Wyoming Rare (USA) Inc.
The program provides both the physical ore needed for upcoming processing trials and vital operational data for the Halleck Creek pre-feasibility study, reinforcing its potential as a cornerstone US rare earths project.
Ore mined and samples dispatched
ARR excavated and crushed about 3,080 tonnes of rare earth ore under a License to Explore by Dozing, with weathered and fresh ore stockpiled at site.
Preparing the CSM Test Pit for the Second Blast
From this, four bulk samples totalling roughly 13.7 tonnes have been dispatched to international vendors for comminution testing:
- FLSmidth in Utah (7.0 tonnes) — high-pressure grinding roll (HPGR)
- Loesche GmbH in Germany (4.7 tonnes) — vertical roller mill
- Corem in Canada (1.0 tonne) — alternate HPGR
- DISA Technologies in Wyoming (1.0 tonne) — high-pressure slurry ablation
Ore samples to be sent to vendors for comminution tests
The remaining ore has been stored at Cowboy State Mine and at the Western Research Institute in Laramie to serve as feedstock for a planned demonstration plant.
Aerial view of excavating and crushing at the CSM test pit
Optimising processing economics
The tests, running through the rest of 2025, are designed to determine the most efficient milling methods while minimising fine particles that can hinder downstream beneficiation. ARR said this could enhance overall rare earth magnet element recoveries and strengthen project economics in its upcoming pre-feasibility study (PFS).
Alongside validating drill penetration, blast fragmentation and excavation rates, the program is expected to provide key technical inputs to the PFS and underpin design parameters for the demonstration plant.
The demonstration facility will play a central role in validating processing flowsheets, generating product samples and supporting future technical studies. ARR expects it will also help de-risk the Halleck Creek Project and boost confidence among potential partners and investors.
Test Pit As-Built Features
Environmental management
Local contractors are backfilling the excavation area with altered surface material and replacing topsoil, followed by preliminary seeding to reclaim the land. The company said this approach reflects its commitment to environmentally responsible mining practices.
Strengthening domestic supply chain
Halleck Creek is regarded as one of the largest rare earth deposits in the US, with the potential to supply a significant portion of the country’s growing demand for rare earth magnet elements critical to defence, clean energy and advanced technologies.
By establishing domestic mining and processing capacity, ARR is aiming to reduce US reliance on imports, particularly from China, and position itself as a cornerstone of an end-to-end US rare earth supply chain.