Kaiser Reef Limited has established its first defined mineral resource for historical tailings material at the A1 Gold Mine in Victoria, delivering an Inferred Mineral Resource estimate of 77,427 tonnes at 1.25 grams per tonne gold for 3,124 ounces of contained gold.

The new estimate follows the company placing the A1 underground mine on care and maintenance last year. Kaiser completed 28 vertical air-core drill holes totaling 284 metres earlier in the year using an 85-millimetre blade bit, with samples collected at one-metre intervals via a cone splitter. Assays were completed at the NATA-accredited Gekko Laboratory in Ballarat using 30-gram fire assay methods.

Because the deposit comprises unconsolidated material derived from historical processing dating back to the 1800s, geological and grade continuity is subject to a high degree of uncertainty. Kaiser applied inverse distance and nearest neighbour block estimation techniques using Datamine RM software, adopting a bulk density of 1.6 tonnes per cubic metre based on industry benchmarking for Victorian and Australian tailings.

Open-pit mining methods will be used to reclaim the material for trucking to the company's Porcupine Flat Processing Plant at Maldon. Material from the Union Hill stockpile currently feeds the Maldon plant at 10,000 tonnes per month under operations scheduled to run until 2030. The A1 material will complement these existing sources with higher-grade feed while simultaneously cleaning up the A1 site.

"This is a good result, and with gold again recently touching A$200 per gram, it makes sense to reclaim this historical material, adding to the processing options at our Maldon Gold Project and cleaning up the A1 site. We are currently working on our plans for execution. Testing to date indicates above 80% gold recovery."

— Brad Valiukas, Managing Director

Kaiser is currently advancing execution plans to reclaim the surface stockpile, which represents the first reported resource for the tailings material.

Read the full announcement: A1 Stockpile Estimate Completed