Marmota Limited (ASX: MEU) has announced highly promising gold recoveries from metallurgical testing at its Aurora Tank heap leach operation, located in the Gawler Craton. Conducted by Australian Minmet Metallurgical Laboratories (AMML) in collaboration with Kappes Cassiday & Associates, the test work on composite samples extracted from drill cores demonstrated gold recoveries as high as 93%. The company reported rapid leaching across all tested columns, achieving over 55% gold extraction within the first 10 days.
The testing program, which included head assays, sizing analyses, and diagnostic leach tests, utilized various composite samples from Aurora Tank, each representing distinct weathering profiles, crush sizes, and leach durations. Notably, a moderately weathered master composite sample yielded an exceptional 93% gold extraction over 59 days at an 8-millimeter crush size. Moreover, silver values remained low across all samples, averaging less than 0.5 grams per tonne, minimizing potential impact on recovery plant design.
Marmota’s chairman, Dr. Colin Rose, emphasized the significance of these results, highlighting the potential for low-cost heap leach recovery due to the ore’s soft ground, near-surface bonanza grades, and outstanding metallurgy. He also noted the commercial appeal of processing Aurora Tank ore using this method, potentially avoiding the complexities and expenses associated with carbon-in-leach plants and tailings dam construction, particularly as gold prices reach record highs.
