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Highlights
- Marmota reports up to 93% gold recoveries from Aurora Tank testing
- Rapid gold extraction achieved within first 10 days of leaching
- Low levels of impurities to simplify recovery plant operations
Marmota (ASX:MEU) has delivered promising results from metallurgical testing at its Aurora Tank project, located in the resource-rich Gawler Craton. Recent metallurgical studies have revealed gold recoveries reaching an impressive 93%, reinforcing the project's potential as a low-cost, high-value heap leach operation.
The metallurgical program, carried out by Australian Minmet Metallurgical Laboratories in collaboration with heap leach specialists, involved extensive testing across 31 sub-composites representing 197 metres of drill core. Remarkably, all columns demonstrated rapid leaching performance, with more than 55% of gold extraction occurring within the initial 10 days.
Testing incorporated a wide range of composite samples from Aurora Tank, differentiated by weathering profiles, crush sizes, and leach durations. Notably, the moderately weathered MC-1 master composite achieved a gold extraction of 93% over 59 days at an 8-millimetre crush size. Meanwhile, the partially weathered MC-2 composite reached 83% extraction at 12.5 millimetres over 87 days and 86% extraction at 8 millimetres during a prolonged 159-day cycle.
The metallurgical team noted that coarser crush sizes greater than 12.5 millimetres are likely to deliver similar leach behavior for weathered materials, a finding that could streamline future processing methods.
Alongside the impressive gold results, silver values were recorded at low levels, averaging less than 0.5 grams per tonne. Copper, mercury, and sulphur contents were also minimal, suggesting a straightforward recovery process with minimal impact on plant design and operation.
Looking ahead, Marmota (MEU) plans to proceed with physical testing of whole core pieces, including bond crushing work index and abrasion index measurements, to further optimize processing parameters.
The chair of Marmota, Dr Colin Rose, emphasized that although metallurgical testing has been a lengthy journey, the outcomes are highly rewarding. Aurora Tank stands out with multiple bonanza-grade gold zones, predominantly near the surface and hosted in soft ground conditions—perfectly suited for low-capital, low-operating cost heap leach processing.
Dr Rose highlighted that these latest results open a highly attractive commercial avenue, allowing Marmota (MEU) to potentially develop the project without the significant expenses associated with building a carbon-in-leach plant and tailings dam.
The Aurora Tank success story positions Marmota at the forefront of new gold opportunities, especially at a time when gold prices are scaling historic highs, enhancing the commercial allure of this exciting development.
