How Did Flagship Achieve 80%+ Gold Recovery at Pantanillo So Quickly?
Flagship Minerals has confirmed exceptional gold recoveries exceeding 80% from oxide material at its Pantanillo Gold Project in Chile, significantly derisking its path toward resource conversion and heap leach development.
- Over 80% gold recovery achieved from oxide mineralisation after 30 days of column leach testing
- Review of historic metallurgical data supports fast-tracking JORC-compliant Mineral Resource conversion
- Next phase to focus on heap and dump leach testwork optimizing capital and operating costs
- Pantanillo hosts a qualifying foreign estimate of 1.05 million ounces of gold
- Nearby Rio2 Fenix project provides operational and cost benchmarks
Exceptional Metallurgical Results
Flagship Minerals Limited (ASX – FLG) has delivered a promising update on its Pantanillo Gold Project in Chile’s prolific Maricunga Gold Belt. A comprehensive review of previous metallurgical testwork has revealed that oxide mineralisation at Pantanillo can achieve gold recoveries exceeding 80% after just 30 days of column leach testing. This performance notably outpaces typical peer group oxide recoveries, which generally range between 50% and 75%.
The testwork, originally conducted by prior explorers and recently reviewed by Flagship, involved cyanidation of crushed material and demonstrated rapid and high gold extraction rates. These findings materially derisk the project’s next phase of metallurgical evaluation, which will focus on heap leach and dump leach testwork to refine processing parameters and optimize capital and operating expenditures.
Advancing Resource Conversion and Development
The Pantanillo deposit 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. Flagship is actively working to convert this QFE into a Mineral Resource Estimate compliant with the JORC Code (2012), a critical step toward project development and financing.
Managing Director Paul Lock emphasised the significance of the metallurgical results, stating that the data supports the company’s strategy to develop an open pit mine with heap leach processing capable of producing 100,000 ounces of gold annually for over a decade. The upcoming testwork will explore coarser crush sizes and dump leach scenarios, which could substantially reduce pre-production capital and ongoing operating costs.
Benchmarking Against Regional Peers
Flagship’s approach is informed by the nearby Fenix Gold Project, operated by Rio2 Limited, located about 40 kilometers northwest of Pantanillo. Fenix is currently under construction and plans to produce approximately 82,000 ounces of gold per year over a 17-year mine life, using a dump leach process without crushing. Rio2 anticipates a 75% gold recovery from this method at a head grade of 0.48 g/t, with all-in sustaining costs around US$1,237 per ounce.
Comparative testwork shows Pantanillo’s crushed oxide material achieves higher recoveries (~82%) than Fenix’s dump leach material (~75%), suggesting potential for both high recovery and cost-effective processing. Flagship aims to leverage these insights to optimize its processing flowsheet and economics.
Future Work and Exploration Potential
Flagship plans to undertake confirmatory heap leach testwork, focusing on the interplay between particle size, gold recovery, and leach time. This will inform trade-off studies balancing recovery gains against capital and operating cost savings. Additionally, the project area offers significant exploration upside, including strike extensions of oxide mineralisation and potential higher-grade sulphide zones beneath post-mineral cover.
Environmental considerations are also in focus, given Pantanillo’s proximity to the Nevado Tres Cruces National Park and Ramsar wetlands. Flagship acknowledges the need for thorough permitting and environmental impact assessments as part of its development pathway.
Bottom Line?
Flagship’s strong metallurgical foundation at Pantanillo sets the stage for resource upgrade and cost-competitive gold production, but upcoming testwork and permitting will be pivotal.
Questions in the middle?
- How will dump leach recovery rates at Pantanillo compare to those at Rio2’s Fenix project in practice?
- What timeline and capital requirements will Flagship face to convert the qualifying foreign estimate into a JORC-compliant Mineral Resource?
- How might environmental permitting challenges near protected areas impact project development schedules?
