en.Wedoany.com Reported - Nova Minerals has achieved positive results from flotation tests on low-grade ore at the Korbel deposit in Alaska, USA, recovering over 95% of precious metals and potentially reducing capital and operating costs.
Laboratory-scale tests were conducted on ore with grades between 0.39 g/t and 0.42 g/t, using flotation at a grind size of 250 µm or finer, producing concentrates with grades of 14.7–26.7 g/t. Nova Minerals (ASX: NVA) stated that this testing, part of the metallurgical program for the pre-feasibility study, reduced the volume entering downstream processing by 97–98%.
This result is expected to enhance the overall economics of the Estelle project by upgrading low-grade ore, reducing processing intensity, lowering energy consumption, and improving gold recovery. It may also potentially eliminate the need for ore sorting and heap leaching, and allow the use of a smaller carbon-in-leach plant to process the concentrate, thereby simplifying the flowsheet.
NVA CEO Christopher Gerteisen said these results represent a significant breakthrough in the company's metallurgical testing program. He stated that proving Korbel ore is highly amenable to coarse particle flotation, capable of producing high-grade concentrates comprising only 2–3% of the total mass while achieving over 90% gold recovery, could be a game-changer for the project.
The flotation tests were conducted on a composite sample generated from diamond drill core from the Korbel Main deposit, primarily representing fresh sulfide intrusive-hosted ore from an intrusion-related gold system. The ability to concentrate this material using coarse particle flotation could significantly simplify the processing flowsheet required to treat the Korbel resource, which totals 1.04 billion tonnes at 0.3 g/t (containing 8.65 million ounces of gold), thereby improving pre-feasibility study outcomes.
Further carbon-in-leach testing and additional coarse particle flotation studies are underway to refine the proposed flowsheet, confirm gold recovery and gangue rejection rates, and optimize plant design, scale, configuration, and project economics. Korbel constitutes the bulk of the overall Estelle resource (9.9 million ounces of gold), with the remainder located at the higher-grade RPM deposit, which has a resource of 62 million tonnes at 0.6 g/t, representing 1.24 million ounces of gold. Estelle also hosts seven antimony-gold prospects, with surface outcrop sampling returning grades of up to 60.5% antimony. This is sufficient for NVA to indicate the potential to commence production from a starter deposit before the end of this year.
