# American Rare Earths: Cowboy State Mine Study Strengthens Foundation for Domestic U.S. Rare Earth Supply Canonical Atlas analysis: https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133 Original source: https://www.juniorminingnetwork.com/junior-miner-news/press-releases/3206-otcmkts/arrnf/212075-cowboy-state-mine-study-strengthens-foundation-for-domestic-u-s-rare-earth-supply.html Publisher: jmn Original announcement: 2026-09-30T04:13:26.000Z Analysis by Minestarters Atlas Atlas analysis published: 2026-09-30T14:20:43.822Z Atlas analysis updated: 2026-09-30T14:20:43.822Z - Company: American Rare Earths - Ticker: ARRNF - Exchange: OTCMKTS - Region: Wyoming - Primary commodity: Rare earth elements - Secondary commodities: Neodymium, Praseodymium, Terbium, Dysprosium, Samarium, Europium, Gadolinium - Document categories: Resource update, Metallurgy - Extracted: 2026-09-30 14:20:44 UTC Narrative sentiment: 0.80 · Bullish ## Minestarters Atlas summary American Rare Earths has announced an updated Scoping Study for its Cowboy State Mine, projecting an after-tax NPV of approximately US$1.07 billion and a 26-year mine life, representing a significant increase in scale and value compared to the previous study. The updated plan includes a 50% increase in throughput to 4.5 Mtpa and a 36% increase in annual NdPr oxide production to 2,500 tonnes, based entirely on Indicated Mineral Resources. However, initial capital costs have risen to US$900 million, and reported metallurgical recoveries for rare earth oxides have decreased, particularly for heavy rare earths, which the company is addressing through ongoing optimization test work. Reasoning: American Rare Earths has released an updated Scoping Study for its Cowboy State Mine, showing a substantial increase in NPV and mine life, and higher planned production, which is positive for project scale and economics. However, this comes with significantly increased capital costs and a notable decrease in reported metallurgical recoveries for rare earth oxides, particularly heavy rare earths, which presents a challenge that the company is actively addressing through ongoing test work. The study's preliminary nature and reliance on Indicated Resources, while positive for confidence, still highlight the need for further de-risking. - Positive factor: Significant increase in NPV and mine life for the Cowboy State Mine project, indicating improved project economics and scale. - Positive factor: Increased planned throughput and average annual NdPr oxide production, strengthening the project's potential contribution to domestic supply. - Positive factor: The production target is based entirely on Indicated Mineral Resources, demonstrating a higher level of geological confidence. - Positive factor: Ongoing recovery optimization and pilot/demonstration work, including a pathway to NdPr metal production, shows commitment to de-risking and value addition. - Positive factor: Compliance with both JORC Code \(2012\) and SEC Regulation S-K, Subpart 1300, enhances reporting credibility and market access. - Negative factor: Initial capital costs have significantly increased, reflecting the expanded development case and revised engineering, which will require substantial funding. - Negative factor: NdPr oxide recovery has decreased from 63.9% to 58.2% in the updated study, and heavy rare earth recoveries have seen material reductions, indicating metallurgical challenges. - Negative factor: The study is a preliminary technical and economic assessment \(Scoping Study\) and is insufficient to support Ore Reserves or assure economic development, carrying inherent risks. - Negative factor: The higher NPV is partly due to a lower discount rate \(8% vs 10%\) and a higher NdPr oxide price assumption \(US$151/kg vs US$91/kg\), which may not be solely attributed to technical improvements. - Negative factor: The project is highly sensitive to NdPr recovery and pricing, which are subject to market volatility and ongoing test work. Facts used in scoring: 20 ## Classification and evidence **Tonnage Growth** Polarity: positive Definition: Significant tonnage increase \(≥15%\) vs prior estimate with grade maintained or improved. Why it applies: The updated Scoping Study shows a significant increase in material mined in the mine plan from 62.3 Mt to 135.0 Mt, which is a substantial tonnage growth. Evidence · table > 135.0 Mt Context: 2026 Scoping Study base case **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: The work was reviewed and approved for release by Mr. Kelton Smith, Mr. Patrick A Sobecke, Mr. Alfred J Gillman, and Mr. Mark W. Travis, all of whom qualify as Competent Persons as defined in the 2012 JORC Code. Evidence · text > This work was reviewed and approved for release by Mr. Kelton Smith \(Society of Mining, Metallurgy & Exploration \#4227309RM\) who is employed by Tetra Tech Inc. and has sufficient experience which is relevant to the processing, separation, metallurgical testing and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 JORC Code. **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: The 2026 Scoping Study has been prepared under the JORC Code \(2012\). Evidence · text > The 2026 Scoping Study has been prepared under the JORC Code \(2012\) **NI 43-101 Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with NI 43-101 \(Canada\) — high reporting standard. Why it applies: The 2026 Scoping Study reflects the same technical basis as the parallel U.S. SEC Regulation S-K, Subpart 1300 Assessment, which is a comparable reporting standard to NI 43-101. Evidence · text > The 2026 Scoping Study has been prepared under the JORC Code \(2012\) and reflects the same technical basis, mine plan and cost estimates that underpin the parallel U.S. SEC Regulation S-K, Subpart 1300 Assessment. **Inferred Resource** Polarity: negative Definition: Speculative category — limited drilling, geological continuity assumed but not confirmed. Cannot support economic studies alone. Why it applies: The document states that while the broader Halleck Creek Mineral Resource includes Inferred Mineral Resources, the production target described in this announcement is based entirely on Indicated Mineral Resources, implying Inferred resources are present but not used for the production target. Evidence · text > While the broader Halleck Creek Mineral Resource includes Inferred Mineral Resources, the production target described in this announcement is based entirely on Indicated Mineral Resources. **Low Recovery** Polarity: negative Definition: Recovery below the weak band for the commodity and processing route. Why it applies: NdPr oxide recovery has decreased from 63.9% to 58.2%, and heavy rare earth recoveries \(Terbium, Dysprosium, SEG\) have seen material reductions to 28.7%, 12.4%, and 25.8% respectively, which are below the weak band for rare earth elements. Evidence · table > 58.2% Context: 2026 recovery **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: The company is advancing a pilot and demonstration program to confirm and optimize rare earth recovery. Evidence · table > Confirm and optimize NdPr and heavy rare earth recovery; separated rare earth oxide targeted for late Q2 2027. Context: Pilot and demonstration program **Recovery Stagnant** Polarity: negative Definition: No improvement across multiple test programs on comparable material. Why it applies: The recoveries for NdPr oxide, Terbium oxide, Dysprosium oxide, and SEG product have all decreased from the 2025 study to the 2026 study, indicating a negative trend in recovery. Evidence · table > 58.2% Context: 2026 recovery **Maiden Resource** Polarity: neutral Definition: First formal MRE for the project — establishes baseline but typically exploration-stage with high Inferred component. Why it applies: The document refers to the 'Cowboy State Mine' as the 'first phase of Halleck Creek', implying this is the initial assessment for this specific mine plan within the broader Halleck Creek resource. Evidence · text > Cowboy State Mine, the first phase of Halleck Creek in Wyoming **Resource Update** Polarity: neutral Definition: Revised estimate for an existing resource — compare to prior to assess progress. Why it applies: The announcement is for an 'updated Scoping Study' for the Cowboy State Mine, replacing a previous 2025 Scoping Study. Evidence · text > updated Scoping Study for Cowboy State Mine **PEA-Supporting** Polarity: neutral Definition: Resource estimate prepared to support a Preliminary Economic Assessment — early-stage study. Why it applies: The document explicitly states that the 'Scoping Study is a preliminary technical and economic assessment', which is equivalent to a Preliminary Economic Assessment \(PEA\). Evidence · text > The Scoping Study is a preliminary technical and economic assessment. **Mill Route** Polarity: neutral Definition: Processing via mill or concentrator \(CIL, CIP, tank leach, flotation\). Why it applies: the document describes a flotation route \("concentrate"\) ## Extracted facts Stored fact records: 20. Some facts used in scoring do not have a stored record. ## Resource Estimates (12) ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-0) Cowboy State Mine · rare earth elements Historical result Needs review: historical\_restatement #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:9b347731c339201f077c #### Resource Data - Category: indicated - Tonnes: 62300000 - Contained Metal: 1833 - Contained Unit: t #### Prior Estimate - Resource Date: 2025-02-24 #### Review - Needs Review: Yes - Review Reason: historical\_restatement - Historical: Yes - Historical Source Date: 2025-02-24T00:00:00.000Z #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: This represents the prior Scoping Study base case, now superseded by the updated study. It provides a baseline for comparison but is not new information. - Negative factor: This is a historical estimate, superseded by the current study. Evidence · table > 62.3 Mt Context: 2025 Scoping Study base case #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-1) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:ee2f1aee2f7943b5a804 #### Resource Data - Category: indicated - Tonnes: 135000000 - Contained Metal: 2500 - Contained Unit: t #### Prior Estimate - Resource Date: 2026-09-30 - Prior Tonnes: 62300000 - Prior Contained Metal: 1833 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The updated Scoping Study shows a substantial increase in the scale of the project, with a significantly larger mine plan and higher annual NdPr oxide production, all based on Indicated Resources, which is a strong positive for the project's potential. - Positive factor: Significant increase in material mined and NdPr oxide production, indicating a larger and more robust project. - Positive factor: Production target based entirely on Indicated Mineral Resources, enhancing confidence in the estimate. - Positive factor: Compliance with JORC Code \(2012\) and SEC Regulation S-K, Subpart 1300, provides strong reporting standards. - Negative factor: The estimate is from a Scoping Study, which is preliminary and does not support Ore Reserves or assure economic development. Evidence · table > 135.0 Mt Context: 2026 Scoping Study base case #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **Tonnage Growth** Polarity: positive Definition: Significant tonnage increase \(≥15%\) vs prior estimate with grade maintained or improved. Why it applies: 135000000 against 62300000 previously **Contained Metal Growth** Polarity: positive Definition: True scale improvement — contained metal ounces/tonnes increased vs prior, accounting for both tonnage and grade changes. Why it applies: 2500 against 1833 previously ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-2) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The extended mine life to 26 years significantly improves the project's long-term viability and attractiveness. - Positive factor: Increased mine life provides a longer operating platform and enhances project longevity. Evidence · table > 26 years Context: 2026 Scoping Study base case #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-3) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The updated Scoping Study shows a robust after-tax NPV at 10% real, indicating a financially attractive project, though it is still at a preliminary study stage. - Positive factor: High after-tax NPV indicates strong project economics. - Negative factor: NPV is from a Scoping Study, which is preliminary and has a stated accuracy of ±30% to ±50%. Evidence · table > US$764 million Context: After tax NPV at 10% real #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-4) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The headline NPV of US$1.07 billion at an 8% discount rate is a very strong indicator of project value, despite being from a preliminary study and benefiting from a lower discount rate assumption. - Positive factor: Very high after-tax NPV at 8% real indicates strong project economics and potential for significant returns. - Negative factor: NPV is from a Scoping Study, which is preliminary and has a stated accuracy of ±30% to ±50%. - Negative factor: The 8% discount rate is lower than the 10% used in the prior headline case, which inflates the NPV. Evidence · table > Approximately US$1.07 billion Context: After tax NPV at 8% real #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-5) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: A 21% after-tax IRR is a strong indicator of project viability, though it represents a decrease from the prior study and is still at a preliminary stage. - Positive factor: A 21% after-tax IRR indicates a financially attractive project. - Negative factor: IRR is from a Scoping Study, which is preliminary and has a stated accuracy of ±30% to ±50%. - Negative factor: The IRR has decreased from 24% in the previous study, suggesting a slight reduction in relative profitability. Evidence · table > 21% Context: After tax IRR #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-6) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: A payback period of 6.9 years is moderate, but the significant increase from the previous study suggests a longer capital recovery time, which is a negative factor. - Negative factor: The payback period has significantly increased from 2.7 years to 6.9 years, indicating a longer time to recoup initial investment. - Negative factor: Payback figures require confirmation on a consistent timing basis before comparison. Evidence · table > 6.9 years Context: Reported after tax payback from first capital #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-7) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The substantial increase in initial capital to US$900 million is a significant negative factor, as it materially exceeds the company's current cash resources and introduces considerable funding risk, despite the larger project scale. - Negative factor: Initial capital has significantly increased from US$456 million to US$900 million, representing a substantial funding requirement. - Negative factor: The estimate remains at Scoping Study level, with stated accuracy of approximately ±30% to ±50%, indicating significant uncertainty. Evidence · table > US$900 million Context: Initial capital, including contingency #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-8) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The increased contingency allowance, while prudent for a preliminary study, contributes to the higher overall capital cost, which is a material negative. - Positive factor: A higher contingency allowance \(30% vs 20%\) provides a more conservative estimate for project costs. - Negative factor: The increased contingency contributes to the overall higher initial capital, which is a negative factor for funding. Evidence · table > Approx. US$210 million; 30% of direct capital Context: Contingency #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-9) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The inclusion of US$56 million for closure capital provides a more complete financial assessment for the project. - Positive factor: Explicit disclosure of closure capital provides a more comprehensive financial picture. Evidence · table > US$56 million Context: Closure capital #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-10) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The higher NdPr oxide price assumption contributes to the improved project economics but also highlights the project's sensitivity to commodity price volatility. - Negative factor: The NdPr oxide price assumption has significantly increased from US$91/kg to US$151/kg, which positively impacts project economics but introduces sensitivity to market price fluctuations. - Negative factor: The assumed price is a study input, not a contracted sales price. Evidence · table > US$151/kg Context: NdPr oxide price assumption #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ### indicated [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-resource-facts-11) Cowboy State Mine · rare earth elements #### Identity - Project: Cowboy State Mine - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Resource scope - Estimate type: resource - Reporting standards: jorc, sec\_sk1300 - QP Signed: Yes - Qualified person names: Kelton Smith, Patrick A Sobecke, Alfred J Gillman, Mark W. Travis - Resource group id: resource:37cd8e5dc8cc346032a0 #### Resource Data - Category: indicated #### Prior Estimate - Resource Date: 2026-09-30 #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The average operating cost provides a key input for project economics, but its reliance on 2023 cost inputs introduces some uncertainty. - Negative factor: Operating costs are based on 2023 cost inputs, which may not fully reflect current or future cost environments. Evidence · table > US$39.68/t ROM processed Context: Average operating cost #### Tags used in scoring **Indicated Resource** Polarity: positive Definition: Reasonable geological confidence based on adequate drilling; continuity can be assumed. Basis for Probable Reserves. Why it applies: category is "indicated" **Cut-off Undisclosed** Polarity: negative Definition: High-grade interval reported without stating the cut-off grade used for compositing. Why it applies: no cutoff\_grade was stated **QP/CP Signed** Polarity: positive Definition: Qualified Person \(QP\) or Competent Person \(CP\) named and signed off — a member of a recognized professional association \(e.g., AusIMM, SME, AIG, P.Geo\) with relevant experience. Why it applies: qp\_signed is true **JORC Compliant** Polarity: positive Definition: Resource estimate prepared in compliance with JORC Code \(Australia\) — high reporting standard. Why it applies: reporting\_standards includes jorc **No Contained Metal** Polarity: negative Definition: Tonnage and grade reported but contained metal not calculated or disclosed — incomplete reporting. Why it applies: contained\_metal was not reported ## Metallurgical Results (8) ### pilot plant [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-metallurgical-facts-12) Halleck Creek · rare earth elements Historical result Needs review: historical\_restatement #### Identity - Project: Halleck Creek - Commodity: rare earth elements - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Test Work - Program Status: preliminary - Test Type: pilot plant - Processing Route: mine site comminution and concentration, with a separate hydrometallurgical refinery #### Recovery - Recovery: 63.9 % - Recovery Basis: actual\_test #### Review - Needs Review: Yes - Review Reason: historical\_restatement - Historical: Yes - Historical Source Date: 2025-02-24T00:00:00.000Z #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: This represents the NdPr oxide recovery from the prior 2025 study, now superseded. It serves as a baseline for comparison but is not new information. - Negative factor: This is a historical recovery figure, superseded by the current study. - Negative factor: The recovery is moderate for rare earth elements. Evidence · table > 63.9% Context: 2025 recovery #### Tags used in scoring **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: test\_type names pilot-scale work ### pilot plant [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-metallurgical-facts-13) Halleck Creek · neodymium #### Identity - Project: Halleck Creek - Commodity: neodymium - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Test Work - Program Status: optimization - Test Type: pilot plant - Processing Route: mine site comminution and concentration, with a separate hydrometallurgical refinery #### Recovery - Recovery: 58.2 % - Recovery Basis: actual\_test #### Lab - Laboratory: Nagrom and SRC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The reported NdPr oxide recovery of 58.2% is a material decrease from the previous study and falls into the weak recovery band, posing a challenge for project economics, although optimization work is underway. - Positive factor: Ongoing recovery optimization work is planned to address the reduction. - Negative factor: NdPr oxide recovery has decreased from 63.9% to 58.2%, which is a material reduction. - Negative factor: The recovery is below the moderate band for rare earth elements, indicating a challenge for project economics. Evidence · table > 58.2% Context: 2026 recovery #### Tags used in scoring **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: test\_type names pilot-scale work ### pilot plant [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-metallurgical-facts-14) Halleck Creek · terbium Historical result Needs review: historical\_restatement #### Identity - Project: Halleck Creek - Commodity: terbium - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Test Work - Program Status: preliminary - Test Type: pilot plant - Processing Route: mine site comminution and concentration, with a separate hydrometallurgical refinery #### Recovery - Recovery: 70.2 % - Recovery Basis: actual\_test #### Review - Needs Review: Yes - Review Reason: historical\_restatement - Historical: Yes - Historical Source Date: 2025-02-24T00:00:00.000Z #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: This represents the Terbium oxide recovery from the prior 2025 study, now superseded. It serves as a baseline for comparison but is not new information. - Negative factor: This is a historical recovery figure, superseded by the current study. - Negative factor: The recovery is moderate for rare earth elements. Evidence · table > 70.2% Context: 2025 recovery #### Tags used in scoring **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: test\_type names pilot-scale work ### pilot plant [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-metallurgical-facts-15) Halleck Creek · terbium #### Identity - Project: Halleck Creek - Commodity: terbium - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Test Work - Program Status: optimization - Test Type: pilot plant - Processing Route: mine site comminution and concentration, with a separate hydrometallurgical refinery #### Recovery - Recovery: 28.7 % - Recovery Basis: actual\_test #### Lab - Laboratory: Nagrom and SRC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The reported Terbium oxide recovery of 28.7% is a very significant decrease from the previous study and falls into the red flag recovery band, indicating a major metallurgical challenge for this commodity. - Positive factor: Ongoing recovery optimization work is planned to address the reduction. - Negative factor: Terbium oxide recovery has significantly decreased from 70.2% to 28.7%, which is a very material reduction. - Negative factor: The recovery is well below the weak band for rare earth elements, indicating a severe challenge for project economics regarding this commodity. Evidence · table > 28.7% Context: 2026 recovery #### Tags used in scoring **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: test\_type names pilot-scale work ### pilot plant [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-metallurgical-facts-16) Halleck Creek · dysprosium Historical result Needs review: historical\_restatement #### Identity - Project: Halleck Creek - Commodity: dysprosium - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Test Work - Program Status: preliminary - Test Type: pilot plant - Processing Route: mine site comminution and concentration, with a separate hydrometallurgical refinery #### Recovery - Recovery: 66.5 % - Recovery Basis: actual\_test #### Review - Needs Review: Yes - Review Reason: historical\_restatement - Historical: Yes - Historical Source Date: 2025-02-24T00:00:00.000Z #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: This represents the Dysprosium oxide recovery from the prior 2025 study, now superseded. It serves as a baseline for comparison but is not new information. - Negative factor: This is a historical recovery figure, superseded by the current study. - Negative factor: The recovery is moderate for rare earth elements. Evidence · table > 66.5% Context: 2025 recovery #### Tags used in scoring **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: test\_type names pilot-scale work ### pilot plant [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-metallurgical-facts-17) Halleck Creek · dysprosium #### Identity - Project: Halleck Creek - Commodity: dysprosium - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Test Work - Program Status: optimization - Test Type: pilot plant - Processing Route: mine site comminution and concentration, with a separate hydrometallurgical refinery #### Recovery - Recovery: 12.4 % - Recovery Basis: actual\_test #### Lab - Laboratory: Nagrom and SRC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The reported Dysprosium oxide recovery of 12.4% is an extremely significant decrease from the previous study and falls into the red flag recovery band, indicating a major metallurgical challenge for this commodity. - Positive factor: Ongoing recovery optimization work is planned to address the reduction. - Negative factor: Dysprosium oxide recovery has significantly decreased from 66.5% to 12.4%, which is a very material reduction. - Negative factor: The recovery is well below the weak band for rare earth elements, indicating a severe challenge for project economics regarding this commodity. Evidence · table > 12.4% Context: 2026 recovery #### Tags used in scoring **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: test\_type names pilot-scale work ### pilot plant [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-metallurgical-facts-18) Halleck Creek · samarium Historical result Needs review: historical\_restatement #### Identity - Project: Halleck Creek - Commodity: samarium - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Test Work - Program Status: preliminary - Test Type: pilot plant - Processing Route: mine site comminution and concentration, with a separate hydrometallurgical refinery #### Recovery - Recovery: 70.1 % - Recovery Basis: actual\_test #### Review - Needs Review: Yes - Review Reason: historical\_restatement - Historical: Yes - Historical Source Date: 2025-02-24T00:00:00.000Z #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: This represents the Samarium, Europium and Gadolinium \(SEG\) product recovery from the prior 2025 study, now superseded. It serves as a baseline for comparison but is not new information. - Negative factor: This is a historical recovery figure, superseded by the current study. - Negative factor: The recovery is moderate for rare earth elements. Evidence · table > 70.1% Context: 2025 recovery #### Tags used in scoring **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: test\_type names pilot-scale work ### pilot plant [Link to this fact](https://atlas-staging.minestarters.com/news/american-rare-earths-cowboy-state-mine-study-strengthens-foundation-for-domestic--606ded2a-d5b5-410d-8f6f-7113c8eaa133#fact-metallurgical-facts-19) Halleck Creek · samarium #### Identity - Project: Halleck Creek - Commodity: samarium - Region: wyoming - Reported Region: Wyoming - Ticker: ARRNF #### Test Work - Program Status: optimization - Test Type: pilot plant - Processing Route: mine site comminution and concentration, with a separate hydrometallurgical refinery #### Recovery - Recovery: 25.8 % - Recovery Basis: actual\_test #### Lab - Laboratory: Nagrom and SRC #### Review - Needs Review: No - Historical: No #### Dates - Event date: 2026-09-30T00:00:00.000Z Reasoning: The reported Samarium, Europium and Gadolinium \(SEG\) product recovery of 25.8% is a very significant decrease from the previous study and falls into the red flag recovery band, indicating a major metallurgical challenge for these commodities. - Positive factor: Ongoing recovery optimization work is planned to address the reduction. - Negative factor: Samarium, Europium and Gadolinium \(SEG\) product recovery has significantly decreased from 70.1% to 25.8%, which is a very material reduction. - Negative factor: The recovery is well below the weak band for rare earth elements, indicating a severe challenge for project economics regarding these commodities. Evidence · table > 25.8% Context: 2026 recovery #### Tags used in scoring **Pilot Scale Complete** Polarity: positive Definition: Pilot or demonstration plant testing completed under continuous operation. Why it applies: test\_type names pilot-scale work ## How Atlas produces this analysis Minestarters Atlas uses automated extraction to summarize mining announcements, identify reported measurements, and classify supporting evidence. Sentiment reflects the extracted narrative and classification rules; it is an interpretation, not a reported measurement. Evidence quotes and context are provided where available. Missing data, low-confidence results, and review flags indicate limitations. Check the original publisher announcement before relying on an interpretation.