Pantanillo Gold Project Shows 85.5% Recovery, 1.05Moz Gold Inventory Confirmed

Metallurgical Review Validates Pantanillo’s Gold Recovery Potential

Flagship Minerals Limited has completed a comprehensive review of historical metallurgical testwork on its 100%-owned Pantanillo Gold Project, located in Chile’s prolific Maricunga Gold Belt. The project hosts a qualifying foreign estimate (QFE) of 47.4 million tonnes at 0.69 grams per tonne gold, equating to approximately 1.05 million ounces of gold. While this estimate is not yet JORC-compliant, the review confirms encouraging gold recoveries from oxide mineralisation, a critical factor in advancing the project towards production.

Column leach testwork on oxide samples demonstrated gold recoveries reaching 85.5%, with composite oxide samples achieving 80% recovery after just 25 days of leaching. These results are particularly promising given the relatively coarse particle sizes tested (up to 38mm), which align with heap leach operational parameters. The rapid and high recovery rates suggest that Pantanillo’s oxide gold is highly amenable to cyanide leaching, a low-cost and widely used extraction method.

Dump Leaching: A Pathway to Lower Costs

Flagship’s Managing Director, Paul Lock, highlighted the potential for Pantanillo to adopt a dump leach approach similar to that of the nearby RIO2 Fenix Gold Project, situated about 40 kilometers to the north. Fenix is currently under construction and plans to produce approximately 82,000 ounces of gold annually over a 17-year mine life using dump leaching of run-of-mine ore without crushing. This method significantly reduces capital expenditure (Capex) and operating expenditure (Opex) by eliminating crushing, screening, and agglomeration processes.

Testwork comparisons indicate that while dump leaching may yield slightly lower gold recoveries (around 75% at Fenix) compared to crushed ore leaching (approximately 82%), the economic trade-off favors the simpler, lower-cost dump leach method. Flagship’s review suggests Pantanillo’s oxide mineralisation exhibits similar leach kinetics to Fenix, opening the possibility for a low Capex, low Opex start-up that could deliver high margins.

Strategic Development and Exploration Outlook

Flagship’s strategy focuses on converting the existing QFE into a JORC-compliant Mineral Resource through validation of drill data, infill and extensional drilling, and additional metallurgical testwork. The company aims to define a resource base capable of supporting open pit mining and heap leach processing targeting annual production of 100,000 ounces of gold over a decade or more.

Beyond the oxide zone, Pantanillo offers exploration upside for higher-grade sulphide mineralisation and extensions along strike and at depth. The project’s location adjacent to the Nevado Tres Cruces National Park and Ramsar wetlands introduces environmental considerations that will require careful management during development.

Context Within the Maricunga Gold Belt

The Maricunga Gold Belt is a well-established metallogenic province hosting numerous gold and gold-copper deposits. Pantanillo’s geological setting, featuring andesitic porphyry with sheeted quartz veins and oxide alteration zones, is typical of the region’s gold deposits. The project benefits from extensive historical exploration by major players such as Anglo American, Kinross, and Orosur Mining, providing a robust data foundation for Flagship’s advancement plans.

Flagship’s metallurgical review and strategic positioning leverage this legacy data and regional analogues to de-risk the project’s development pathway. The company’s next steps include confirmatory heap leach testwork to refine recovery parameters and optimize processing flowsheets, which will feed into future financial modelling and feasibility studies.