U.S. GoldMining Inc. (NASDAQ: USGO) saw its shares jump 26.22 per cent on Monday after releasing updated results from its 2025 metallurgical test program at the Whistler Gold-Copper Project.
The project is located 105 miles northwest of Anchorage, Alaska, and these new results show promising improvements in gold recovery that could significantly enhance the project’s economic potential.
The company’s test work combined traditional sulphide flotation with a sequential leach process, achieving a total gold recovery of 85.3 per cent. Copper recovery reached 79.1 per cent, while silver achieved 55.3 per cent.
This represents a major step up from previous metallurgical tests, which recovered roughly 70 per cent of gold using only flotation. According to U.S. GoldMining CEO Tim Smith, the combination of flotation and leaching has been key to boosting recovery, using proven technology to produce both a saleable copper concentrate and gold doré.
The 2025 metallurgical program focused on samples from the Whistler Deposit, collected from fresh 2023 and 2024 drill cores. The team created seven quarter-core composites from four drill holes, which were further combined into a single master composite. This composite represents the average metal grade across the project’s resource, ensuring the results reflect what could be expected in real-world production.
Crushing and grinding tests classified the rock as ‘Hard’ to ‘Very Hard.’ Optimal recovery occurred at a primary grind size of 120 micrometres, followed by a finer regrind of 16 micrometres. Flotation tests then separated copper, gold, and silver from the rock.
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Further testing will continue to optimize the process: U.S. GoldMining
The final locked cycle test, LCT28, produced a copper concentrate containing 23.7 per cent copper with a 0.6 per cent mass pull. This concentrate captured 79.1 per cent of the copper, 54.1 per cent of the gold, and 55.3 per cent of the silver.
Subsequently, the rougher flotation tails were subjected to gold leaching using cyanide, which recovered an additional 31.2 per cent of gold. This step alone extracted 88.7 per cent of the gold still contained in the pyrite rougher tails.
Combining flotation and leaching delivered the overall 85.3 per cent gold recovery. Future improvements may be possible by bypassing the pyrite rougher step. Also, by sending all copper rougher tails directly to leaching, potentially increasing gold recovery slightly.
In total, the program completed 28 flotation tests and four leach tests. Variability testing across different rock types showed consistent results, indicating that the recovery process is likely robust across the deposit.
U.S. GoldMining emphasized that further testing will continue to optimize the process. It will also account for differences in ore grade and mineralogy over the project’s life.
These metallurgical results will directly feed into the company’s preliminary economic assessment (PEA), which is ongoing. High gold recoveries are essential for demonstrating the Whistler Project’s potential profitability.
Additionally, the ability to produce a copper concentrate and gold doré in parallel strengthens the project’s revenue profile.
Smith noted that the test work used simple but effective technology, which relies on well-understood flotation and leaching methods.
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