Strong Leach Recoveries and Low Impurities Drive Halleck Creek Closer to Unlocking Its Rare Earth Potential
MWN-AI** Summary
American Rare Earths (ASX: ARR | OTCQX: ARRNF | ADR: AMRRY) is making significant strides in unlocking the rare earth potential of its Halleck Creek Rare Earths Project in Wyoming. Recent leach testing results from the Cowboy State Mine ore indicate strong recoveries for key rare earth elements, with Praseodymium (Pr) achieving an 85% recovery and Neodymium (Nd) at 84%. Heavy rare earths also showed encouraging results, with Terbium (Tb) at 52% and Dysprosium (Dy) at 46% recoveries.
Importantly, the latest tests reflect a marked reduction in impurity levels of iron and aluminum—approximately 5.0x and 2.9x lower, respectively—compared to earlier studies. This reduction is anticipated to enhance the processing efficiency, as impurities can hinder the production of high-purity rare earth magnet oxides.
The preferred leach method selected is atmospheric tank leaching, recognized for its energy efficiency and cost-effectiveness compared to traditional acid-bake methods. The extensive testing—consisting of 25 trials at SGS’s Lakefield laboratory—provides essential data for the ongoing Pre-Feasibility Study (PFS) on mineral processing flow-sheet development. The implementation of optimal leach conditions aims to lower energy consumption while facilitating the removal of impurities, thereby promoting a more sustainable production process.
Looking forward, SGS will perform scoping tests focused on impurity removal, building on the successful current testing campaign. American Rare Earths is positioned strategically to enhance U.S. rare earth independence, as the project aligns with national interests in critical minerals while emphasizing environmentally responsible practices. As exploration and testing progress, Halleck Creek stands out as a pivotal asset in America's quest for self-sufficiency in rare earth elements essential for various technologies and defense applications.
MWN-AI** Analysis
American Rare Earths (ASX: ARR | OTCQX: ARRNF) has taken a significant stride toward solidifying its position in the rare earths market with the recent leach testing results from the Halleck Creek Rare Earths Project. The exceptionally high leach recoveries of Praseodymium (85%) and Neodymium (84%) at optimal conditions underscore the project's potential to produce critical materials efficiently. Moreover, the notable recoveries of heavy rare earths such as Terbium (52%) and Dysprosium (46%) further enhance the project's attractiveness, especially given the rising global demand for rare earth elements in advanced technologies, including magnets for green energy and defense applications.
A critical insight from the tests is the significant reduction in impurity concentrations. Levels of iron and aluminum impurities post-leach were reported to be approximately 5.0x and 2.9x lower, respectively, compared to earlier trials. This decline not only implies a cleaner end-product but also translates to cost savings in subsequent processing stages, benefiting the project's overall economics.
The adoption of the atmospheric tank leach method, a more energy-efficient and cost-effective approach compared to traditional methods, positions American Rare Earths favorably in an increasingly competitive landscape. With lower energy consumption and simplified impurity removal, this method can enhance profit margins as the company develops its Pre-Feasibility Study (PFS) and scales up production.
For investors, this milestone indicates a de-risked operational framework conducive to potential future growth. As demand for rare earths continues to spiral due to geopolitical shifts and technological advancements, American Rare Earths appears well-poised to capitalize on market opportunities. Monitoring developments at Halleck Creek will be crucial for stakeholders looking to leverage the strategic advancements in the U.S. rare earth sector.
**MWN-AI Summary and Analysis is based on asking OpenAI to summarize and analyze this news release.
Highlights
- High Light Rare Earths Leach Recoveries
- Praseodymium (“Pr”) leach recoveries of 85% at optimal conditions
- Neodymium (“Nd”) leach recoveries of 84% at optimal conditions
- Encouraging Heavy Rare Earths Leach Recoveries
- Terbium (“Tb”) leach recoveries of 52% at optimal conditions
- Dysprosium (“Dy”) leach recoveries of 46% at optimal conditions
- Significantly lower impurity elements of iron and aluminum
- Concentrations of iron and aluminum impurities post leach are approximately 5.0x and 2.9x, respectively, lower than the tests previously performed for the Scoping Study 1
- Atmospheric Tank Leach chosen as the preferred leach method
- Atmospheric tank leaching is typically more energy and reagent efficient and less costly than other rare earth leaching methods, such as an acid-bake (i.e. cracking)
DENVER, July 09, 2025 (GLOBE NEWSWIRE) -- American Rare Earths ( ASX: ARR | OTCQX: ARRNF | ADR: AMRRY) (“ARR” or the “Company” ) is pleased to announce the results of an extensive leach testing program undertaken on Cowboy State Mine ore, part of the Halleck Creek Rare Earths Project in Wyoming USA.
Twenty-five leach tests exploring various parameters and leach methods were completed at SGS’s laboratory in Lakefield, Ontario, Canada.
Why it matters? The leach tests provide key data for the on-going metallurgical testing and mineral processing flow-sheet development for the Cowboy State Mine Pre-Feasibility Study. The tests represent a significant milestone in the technical de-risking of the project as the results have established the optimal leach conditions and preferred arrangement for the PFS flow-sheet. Test results demonstrate leach parameters which may achieve favorable processing outcomes such as lower energy consumption and front end impurity removal. This is a key step forward in producing rare earth magnet oxides from Halleck Creek ore.
Metallurgical Testing Next Step
- SGS is performing scoping impurity removal tests, the next step in the mineral processing flow-sheet design for the Pre-Feasibility Study.
Additional Technical Details
The completion of the extensive leach testing campaign of Cowboy State Mine ore marks a major milestone for the project. The testing was completed at the Lakefield Ontario Canada location of SGS. All testing in this current campaign was conducted using sulfuric acid as the lixiviant (leaching agent). Previous leach testing completed at Nagrom (under the direction of Wood), and Virginia Tech demonstrated that sulfuric acid was the ideal lixiviant when optimizing for recovery, reagent cost, and shipping/logistics.
Building on the previous leach testwork, SGS tested the following leaching types and arrangements during the recent trials:
- Atmospheric Tank Leach
- Acid-bake and Water Leach
- Counter-Current Leach
SGS conducted 18 atmospheric tank leach tests, 5 acid-bake/water leach tests and 2 counter-current leach tests. The atmospheric tank leach was chosen as the preferred arrangement with operating conditions providing the optimal revenue minus raw material cost.
The selected atmospheric leach (“AL”) conditions for AL16 are shown in Table 1. The AL16 parameters represents the recommended feed for ongoing plant engineering and piloting trials. AL16 is composed of 80% Unaltered Concentrate that was created by gravity spiral separation followed by Induced Rolled Magnetic Separator (“IRMS”), and 20% of fines created during comminution and then concentrated using Wet High Intensity Separator (“WHIMS”). The combined feed was then processed through a regrind step for 100% passing 270 mesh (53 ?m). It should also be noted that altered material (i.e. weather) is a minority portion of the total ore body, as a result the main focus of the test work is on unaltered material. Two Atmospheric Leach Tests were performed on Altered Ore and leaching results were very similar to Unaltered Ore. Table 1 - Atmospheric Tank Leach Conditions and Results:
| Leach Condition | AL16 |
| Feed | 80% Unaltered Conc 20% WHIMS of Fines |
| Regrind Particle Size | -53 ?m |
| Acid Dosage | 400 kg/t |
| Retention Time | 8 hrs |
| Temperature | 90°C |
| % Solids | 10% |
| Leach Result | |
| La Extraction | 88% |
| Pr Extraction | 85% |
| Nd Extraction | 84% |
| Tb Extraction | 52% |
| Dy Extraction | 46% |
| Fe Extraction | 18% |
| Al Extraction | 23% |
| Mg Extraction | 28% |
| Ca Extraction | 20% |
| Final Acidity | 20 g/L |
Leachate Concentration
The Scoping Study concentrate was generated using WHIMS. The current concentrate was produced using gravity spiral followed by IRMS. The Scoping Study sulfuric acid tank leach test was performed at 250 kg/t and a 6 hr reaction time while the current spiral/IRMS concentrate was tested at 400 kg/t and a 8 hr reaction time.
Table 2 below compares the difference in leachate concentrate for the major impurity elements for the Scoping Study concentrate with the current concentrate. Concentrations of iron and aluminum impurities post leach are approximately 5.0x and 2.9x, respectively, lower than the tests previously performed for the Scoping Study.
It is theorized that the gravity spiral step removed some of the Fe and Al containing heavy minerals and the IRMS was able to separate out the highly magnetic minerals such as hematite and magnetite. These minerals were readily leached in the sulfuric acid tank leach tests for the WHIMS concentrate resulting in much higher impurity concentrations in the leachate. With greater proportions of Fe and Al removed from IRMS concentrate, downstream Impurity removal steps should use less reagent (i.e. potential for lower operating costs) and achieve lower concentrations of these elements in the leachate.
| Unit | SGS Spiral/IRMS Conc (AL16) | Scoping Study WHIMS Conc | % Change | |
| Si | mg/L | 1,250 | 3,627 | -66% |
| Al | mg/L | 1,300 | 3,748 | -65% |
| Fe | mg/L | 4,450 | 22,230 | -80% |
| Mg | mg/L | 74 | 210 | -65% |
| Ca | mg/L | 1,670 | 1,495 | 12% |
| Na | mg/L | 92 | 292 | -68% |
| K | mg/L | 158 | 510 | -69% |
| Ti | mg/L | 231 | 562 | -59% |
| P | mg/L | 45 | 190 | -76% |
| Mn | mg/L | 111 | 541 | -79% |
| Zn | mg/L | 19 | 101 | -81% |
This release was authorized by the board of American Rare Earths.
Investors can follow the Company’s progress at www.americanree.com
For the full press release with additional technical information and the updated JORC Table please see the full release here .
About American Rare Earths Limited:
American Rare Earths (ASX: ARR | OTCQX: ARRNF | ADR: AMRRY) is a critical minerals company at the forefront of reshaping the U.S. rare earths industry. Through its wholly owned subsidiary, Wyoming Rare (USA) Inc. (“WRI”), the company is advancing the Halleck Creek Project in Wyoming—a world-class rare earth deposit with the potential to secure America’s critical mineral independence for generations. Located on Wyoming State land, the Cowboy State Mine within Halleck Creek offers cost-efficient open-pit mining methods and benefits from streamlined permitting processes in this mining-friendly state.
With plans for onsite mineral processing and separation facilities, Halleck Creek is strategically positioned to reduce U.S. reliance on imports—predominantly from China—while meeting the growing demand for rare earth elements essential to defense, advanced technologies, and economic security. As exploration progresses, the project’s untapped potential on both State and Federal lands further reinforces its significance as a cornerstone of U.S. supply chain security. In addition to its resource potential, American Rare Earths is committed to environmentally responsible mining practices and continues to collaborate with U.S. Government-supported R&D programs to develop innovative extraction and processing technologies for rare earth elements.
For additional information:
Susan Assadi
Media Relations US
sassadi@americanree.com
347 977 7125
Beverly Jedynak
Investor Relations US
Beverly.jedynak@viriathus.com
312 943 1123
1 Refer ASX Announcement titled ‘Full Updated Scoping Study’ released 7 March 2025
FAQ**
How do the leach recoveries for praseodymium and neodymium compare to industry standards, and what implications does this have for American Rare Earths Limited ARRNF's competitiveness in the rare earth market?
Considering the significantly lower impurity levels of iron and aluminum, how will American Rare Earths Limited ARRNF leverage these results to enhance processing efficiency and reduce operational costs in future projects?
What specific factors contributed to the decision to choose atmospheric tank leaching as the preferred method for American Rare Earths Limited ARRNF, and how might this influence the overall economic viability of the Halleck Creek project?
With ongoing impurity removal tests being conducted by SGS, what potential impacts could the findings have on the expected timeline and cost of the Pre-Feasibility Study for American Rare Earths Limited ARRNF?
**MWN-AI FAQ is based on asking OpenAI questions about American Rare Earths Limited (OTC: ARRNF).
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