Metallurgical Test Work Improves Gold Recovery to 85% (+22%) for the Whistler Gold-Copper Project, Alaska
U.S. GoldMining (NASDAQ: USGO) announced improved metallurgical test results for its Whistler Gold-Copper Project in Alaska. The updated test work achieved 85.3% gold recovery, marking a significant 22% improvement over previous results. The process combines sulphide flotation and leaching techniques, with the flotation producing a copper concentrate grading 23.7% Cu with 79.1% copper and 54.1% gold recovery, while subsequent leaching recovered an additional 31.2% gold.
The test program, conducted by Base Metallurgical Laboratories, included 28 flotation tests and four leach tests using master composites and variability samples. The results will provide crucial inputs for the company's ongoing Preliminary Economic Assessment (PEA). The process flowsheet employs proven technology to produce both marketable copper concentrate and gold doré through a simple but effective approach.
U.S. GoldMining (NASDAQ: USGO) ha annunciato miglioramenti nei risultati metallurgici del progetto Whistler Gold-Copper in Alaska. Il lavoro di test aggiornato ha raggiunto un recupero dell’oro dell’85,3%, segnando un significativo incremento del 22% rispetto ai risultati precedenti. Il processo combina flottazione di solfuri e lisciviazione, con la flottazione che produce un concentrato di rame con una gradazione del 23,7% Cu con un recupero di rame del 79,1% e dell’oro del 54,1%; la successiva lisciviazione ha recuperato ulteriori 31,2% di oro. Il programma di test, condotto da Base Metallurgical Laboratories, ha incluso 28 test di flottazione e quattro test di lisciviazione utilizzando master composites e campioni di variabilità. I risultati forniranno input cruciali per l’attuale Valutazione Economica Preliminare (PEA) della società. Il flusso di processo impiega tecnologie comprovate per produrre sia un concentrato di rame commercializzabile sia oro dorato tramite un approccio semplice ma efficace.
U.S. GoldMining (NASDAQ: USGO) anunció resultados metallúrgicos mejorados para su Proyecto Whistler Gold-Copper en Alaska. El trabajo de pruebas actualizado logró un recupero de oro del 85,3%, un incremento significativo del 22% respecto a los resultados anteriores. El proceso combina flotación de sulfuros y lixiviación, con la flotación produciendo un concentrado de cobre que promedia un 23,7% Cu con un 79,1% de cobre y un 54,1% de recuperación de oro, mientras que la lixiviación subsiguiente recuperó un 31,2% adicional de oro. El programa de pruebas, realizado por Base Metallurgical Laboratories, incluyó 28 pruebas de flotación y cuatro pruebas de lixiviación utilizando composites maestros y muestras de variabilidad. Los resultados proporcionarán insumos cruciales para la Evaluación Económica Preliminar (PEA) en curso de la compañía. El diagrama de proceso emplea tecnología probada para producir tanto un concentrado de cobre comercializable como oro doré a través de un enfoque simple pero eficaz.
U.S. GoldMining (NASDAQ: USGO)은 알래스카의 Whistler Gold-Copper 프로젝트에 대한 금속학적 시험 결과가 개선되었다고 발표했습니다. 업데이트된 시험 작업은 금 회수율 85.3%를 달성하여 이전 결과에 비해 22%의 중요한 개선을 보였습니다. 이 공정은 황화물 플로테이션과 추출(리씰링) 공정을 결합하며, 플로테이션은 구리 회수율이 79.1%인 23.7% Cu 등급의 구리 농 concentratest를 산출하고, 이후의 리씰링으로 추가로 31.2%의 금이 회수됩니다. 시험 프로그램은 Base Metallurgical Laboratories가 수행했으며, 28건의 플로테이션 테스트와 4건의 리얼를 포함합니다(master composites 및 가변성 샘플 사용). 결과는 회사의 진행 중인 예비 경제성 평가(PEA)에 중요한 입력값이 될 것입니다. 공정 흐름도는 검증된 기술을 사용하여 시장에서 판매 가능한 구리 농 concentrated와 금 도리(Gold doré) 모두를 간단하지만 효과적인 방식으로 생산합니다.
U.S. GoldMining (NASDAQ: USGO) a annoncé des résultats métallurgiques améliorés pour son projet Whistler Gold-Copper en Alaska. Les nouveaux essais ont permis d’atteindre un taux de récupération d’or de 85,3%, soit une amélioration significative de 22% par rapport aux résultats précédents. Le procédé combine flottation des sulfures et lixiviation, la flottation produisant un concentré de cuivre à 23,7% Cu avec 79,1% de cuivre et 54,1% de récupération d’or, tandis que la lixiviation subséquente a permis de récupérer 31,2% d’or supplémentaires. Le programme d’essais, réalisé par Base Metallurgical Laboratories, comprenait 28 essais de flottation et quatre essais de lixiviation utilisant des composites maîtres et des échantillons de variabilité. Les résultats fourniront des entrées cruciales pour l’évaluation économique préliminaire (PEA) en cours de la société. Le schéma de procédé emploie une technologie éprouvée pour produire à la fois un concentré de cuivre commercialisable et de l’or doré par une approche simple mais efficace.
U.S. GoldMining (NASDAQ: USGO) gab bekannt, dass die metallurgischen Testergebnisse für das Whistler Gold-Copper-Projekt in Alaska verbessert wurden. Die aktualisierte Testarbeit erreichte eine Gold-Rückgewinnung von 85,3%, eine signifikante Steigerung von 22% gegenüber dem vorherigen Ergebnis. Der Prozess kombiniert Sulfide-Flotation und Laugung, wobei die Flotation einen Kupferkonzentrat mit 23,7% Cu erzeugt, bei 79,1% Kupfer- und 54,1% Gold-Rückgewinnung, während die anschließende Laugung weitere 31,2% Gold zurückgewinnt. Das Testprogramm, durchgeführt von Base Metallurgical Laboratories, umfasste 28 Flotations-Tests und vier Laugungstests mit Master-Kompositen und Variabilitätsproben. Die Ergebnisse liefern entscheidende Eingaben für die laufende Preliminary Economic Assessment (PEA) des Unternehmens. Das Prozess-Flowsheet verwendet bewährte Technologie, um sowohl marktfähiges Kupferkonzentrat als auch Gold-Doré durch einen einfachen, aber effektiven Ansatz zu produzieren.
U.S. GoldMining (NASDAQ: USGO) أعلنت عن نتائج مختبرية معدلة لإثراء المعادن في مشروع Whistler Gold-Copper في ألاسكا. أحرزت أعمال الاختبار المحدثة استعادة ذهب بنسبة 85.3%، وهو تحسن كبير بمقدار 22% عن النتائج السابقة. تجمع العملية بين التعويم الكبريتي وعمليات الاستخلاص بالترشيح، حيث يؤدي التعويم إلى منتج تركيز نحاس بتركيز 23.7% Cu مع استرداد نحاس 79.1% وذهب 54.1%، في حين أن الترشيح اللاحق استعاد 31.2% إضافية من الذهب. شمل برنامج الاختبار، الذي أجرته Base Metallurgical Laboratories، 28 اختباراً للتعويم و4 اختبارات للاستخلاص باستخدام مركبات رئيسية وعينات تفاوت. ستوفر النتائج مدخلات حاسمة لتقييم الاقتصاد الأولي (PEA) الجاري للشركة. يستخدم مخطط التدفق عملية تقنية مثبّتة لإنتاج كل من تركيز النحاس القابل للتسويق وذهباً دَوريّاً عبر نهج بسيط وفعّال.
U.S. GoldMining (NASDAQ: USGO)宣布,其在阿拉斯加的Whistler金铜项目的冶金测试结果有所改善。更新的测试工作实现了黄金回收率85.3%,较之前的结果提升了显著的22%。该工艺结合了脉冲浮选和浸出法,浮选产生的铜精矿品位为23.7%Cu,铜回收率79.1%,黄金回收率54.1%,随后浸出进一步回收了31.2%的金。测试计划由Base Metallurgical Laboratories执行,包含28次浮选测试和4次浸出测试,使用母体组合物与变异性样本。结果将为公司正在进行的初步经济评估(PEA)提供关键输入。该流程流程图采用成熟技术,通过一种简单而高效的方法同时生产具有市场潜力的铜精矿和金铢(金锭)。
- Significant improvement in gold recovery to 85.3% (22% increase from previous tests)
- High-grade copper concentrate achieved at 23.7% Cu with strong recoveries (79.1% Cu, 54.1% Au)
- Process uses proven technology combining flotation and leaching
- Modest reagent consumption in leaching process (0.48 kg/t NaCN and 1.28 kg/t lime)
- Additional optimization opportunities identified through future variability testing
- Ore classified as 'Hard' to 'Very Hard', indicating potentially higher processing costs
- Additional variability test work still required for comprehensive deposit representation
- Silver recovery remains relatively low at 55.3%
Insights
U.S. GoldMining's new metallurgical tests increased gold recovery from 70% to 85.3% at Whistler, significantly enhancing project economics.
The new metallurgical test work results for the Whistler Gold-Copper Project in Alaska represent a significant technical breakthrough with substantial economic implications. By combining conventional sulphide flotation with sequential leaching, U.S. GoldMining has achieved an 85.3% gold recovery rate - a 22% improvement over previous test work that only utilized flotation.
The technical approach is particularly elegant in its simplicity. The dual-stream process first produces a high-grade copper concentrate (23.7% Cu) with acceptable precious metals recovery (54.1% Au, 55.3% Ag), then captures an additional 31.2% gold through cyanidation of the rougher tails. This approach maximizes revenue streams while using proven, commercially established technologies.
The metallurgical characteristics of the ore (classified as 'Hard' to 'Very Hard') indicate standard crushing and grinding requirements, with optimal recoveries achieved at a primary grind size of 120μm and regrind size of 16μm. These parameters are well within conventional processing capabilities.
Perhaps most significant is what these results mean for project economics. Improved recoveries, especially of gold, translate directly to increased project value. For context, in mining economics, a 10% increase in recovery often provides more value than a 10% increase in resource size, as it requires no additional mining costs. The 22% improvement in gold recovery could substantially enhance the Preliminary Economic Assessment (PEA) currently underway.
While the company indicates further variability testing is needed across different zones of the deposit, the consistency of results from the seven variability tests already performed suggests these recovery rates should be achievable across most of the deposit. The modest reagent consumption in the leaching process (0.48 kg/t NaCN and 1.28 kg/t lime) also indicates reasonable operating costs for this component of the flowsheet.
Highlights:
- Recovery of up to
85.3% gold (Au),79.1% copper (Cu) and55.3% silver (Ag) from the combined sulphide flotation and leaching test work using a master composite derived from Whistler Deposit drill core that is representative of the average metal grade within the Project's mineral resource estimate ("MRE").- Sulphide flotation locked cycle tests ("LCT") produced a copper concentrate grading
23.7% Cu with a0.6% mass pull at a P80 grind size of 120µm (rougher circuit) and a regrind of 16µm (cleaner circuit). The initial concentrate metal recoveries include54.1% Au,79.1% Cu and55.3% Ag. - Leach testing of the rougher sulphide flotation circuit tails recovered an additional
31.2% Au, for the combined overall recovery of85.3% Au.
- Sulphide flotation locked cycle tests ("LCT") produced a copper concentrate grading
- A total of 28 flotation tests were completed together with four leach tests on a combination of master composites and variability samples that were conducted by Base Metallurgical Laboratories Ltd., of
Kamloops, B.C. ,Canada . - The Program results provide key metallurgical recovery and process flowsheet inputs to the initial economic assessment (the "PEA").
Tim Smith, Chief Executive Officer of U.S. GoldMining, commented: "The Company is delighted with the 2025 metallurgical test work results which have confirmed that high gold recoveries in excess of
2025 Metallurgical Program Details
Sample Selection and Preparation
The 2025 metallurgical test program had the objective of achieving optimized metal recovery results from a set of Whistler Deposit drill core samples. To this end, sampling was completed on fresh 2023 and 2024 drill core comprising seven quarter core composites assembled from four drill holes (WH23-01, WH23-02, WH23-03 and WH24-02). These composites were further homogenized down to a single Master Composite that was selected to represent the global average resource grade from the 2024 MRE (see news release dated October 7, 2024).
Crushing and Grinding Testwork
Comminution tests were completed on the master composite material resulting in being classified as 'Hard' to 'Very Hard'. From preliminary test work, a primary grind size of 120 µm was selected with a secondary grind (regrind) size of 16 µm to yield the optimal recoveries.
Flotation Testwork
A series of rougher flotation tests were completed, followed by cleaner flotation tests, which set the design criteria for a final series of locked cycle tests. The final test circuit (LCT28) consisted of the rougher concentrate reporting to a copper cleaner circuit to produce a copper concentrate of
Table 1 Results of sulphide flotation test work to produce a saleable copper concentrate. Test ID LCT28 produced final optimized recoveries of
Type | Sample | Head | Head | Head | TestID | Product | Mass % | Con Grade | Cu Rec | Au Rec | Ag Rec |
OCT | WC-Var 1 | 0.16 | 1.35 | 1.50 | C21 | 1st Cln Con | 0.5 | 21.6 | 68.2 | 49.7 | 32.9 |
OCT | WC-Var 2 | 0.11 | 0.45 | 0.80 | C22 | 1st Cln Con | 0.4 | 21.3 | 64.5 | 49.2 | 40.6 |
OCT | WC-Var 3 | 0.18 | 0.06 | 0.80 | C23 | 1st Cln Con | 0.7 | 25.3 | 82.2 | 60.0 | 57.0 |
OCT | WC-Var 4 | 0.29 | 0.88 | 2.10 | C24 | 1st Cln Con | 0.9 | 25.4 | 74.7 | 61.3 | 43.1 |
OCT | WC-Var 5 | 0.28 | 0.41 | 1.20 | C25 | 1st Cln Con | 0.8 | 29.7 | 83.7 | 62.3 | 44.3 |
OCT | WC-Var 9 | 0.14 | 0.22 | 4.20 | C26 | 2nd Cln Con | 0.5 | 20.5 | 65.8 | 54.6 | 46.9 |
OCT | WC-Var 10 | 0.20 | 0.78 | 0.90 | C27 | 2nd Cln Con | 0.6 | 29.2 | 82.5 | 74.5 | 49.6 |
OCT | Master | 0.17 | 0.43 | 0.80 | C09 | 3rd Cln Con | 0.5 | 24.9 | 77.5 | 50.6 | 41.9 |
LCT | Master | 0.17 | 0.43 | 0.80 | LCT28 | Final | 0.6 | 23.7 | 79.1 | 54.1 | 55.3 |
Seven variability tests were performed to determine variability across rock types in both the rougher and cleaner circuits. All tests were completed in an open circuit configuration with sequential rougher flotation, regrind of the rougher concentrate and three sequential cleaning circuits to produce a final concentrate product. Results from all tests were favorably comparable with no significant outliers. Observed metal recoveries from sulphide flotation were as high as
Gold Leaching Testwork
Pyrite rougher tails from the locked cycle tests were subsequently subjected to cyanidation (NaCN) leach testing, with a final extraction of
Table 2 Summary metallurgical test results for sulphide flotation (LCT 28, see Table 1) to produce a copper concentrate, plus subsequent Py rougher concentrate and cyanidation leaching of the Py concentrate tails.
Product | Sample | Assay - percent or g/t | Distribution - percent | |||||||
% | grams | Cu % | Au g/t | Ag g/t | S % | Cu % | Au % | Ag % | S % | |
Feed | 100 | 3,971.4 | 0.18 | 0.39 | 1.0 | 0.93 | 100 | 100 | 100 | 100 |
Cu Cleaner Concentrate | 0.6 | 24.1 | 23.7 | 35.0 | 92 | 27.6 | 79.1 | 54.1 | 55.3 | 18.0 |
Py Rougher Concentrate | 4.0 | 157.7 | 0.17 | 1.06 | 4.1 | 9.10 | 3.8 | 10.7 | 16.2 | 38.9 |
Py Rougher Tail Leach | 95.4 | 3,789.6 | 0.033 | 0.15 | 0.3 | 0.42 | 17.1 | 35.2 | 28.5 | 43.1 |
Combining gold recovery from both the copper concentrate and from leaching thus provides a final gold recovery of
About U.S. GoldMining Inc.
U.S. GoldMining Inc. is an exploration and development company focused on advancing the
For further information regarding the Project, refer to the technical report summary titled "S-K 1300 Technical Report Summary Initial Assessment for the Whistler Project,
Tim Smith, P.Geo., Chief Executive Officer of the Company, has supervised the preparation of this news release and has reviewed and approved the additional scientific and technical information contained herein. Mr. Smith is a "qualified person" as defined under NI 43-101.
Visit www.usgoldmining.us for more information.
Forward-Looking Statements
Except for the statements of historical fact contained herein, the information presented in this news release constitutes "forward-looking statements" within the meaning of
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SOURCE U.S. GoldMining Inc.