Flagship Minerals has wrapped up its metallurgical drilling and trenching at the 2.1Moz Isidora Gold Project in Chile, progressing to pilot scale heap leach test work and ongoing infill drilling targeting a resource update later this year.
- Metallurgical drilling and trenching completed with visible mineralisation
- Pilot scale heap leach test work to assess gold recovery and reagent use
- Infill and extension drilling underway within 2026 pit shell
- Mineral Resource Estimate update targeted for late 2026 or early 2027
- Project tenure secure despite proximity to protected environmental areas
Metallurgical Sampling Program Concludes at Isidora
Flagship Minerals Limited (ASX:FLG) has completed a key phase of metallurgical drilling and trenching at its 2.1 million ounce Isidora Gold Project in northern Chile. The program, consisting of four large-diameter metallurgical drill holes totalling 600.5 metres and five trenches spanning 600 metres, successfully intersected multiple zones of visually apparent mineralisation within oxidised and altered dioritic porphyry rock types.
These samples will underpin a pilot scale heap leach test work program focused on leach kinetics, gold recoveries, and reagent consumption; critical inputs for advancing development studies. Core processing is nearing completion with dispatch to a Chilean laboratory imminent.
Bulk Sampling and Trenching for Heap Leach Test Work
Alongside drilling, trenches were excavated to collect bulk samples intended for dump leach testing. Flagship plans to process a 300-400 tonne bulk sample to validate heap leach amenability, a process vital for confirming the economic viability of oxide zone mineralisation. Early trench results show consistent mineralisation with weathered and oxidised diorite porphyry hosting abundant secondary iron oxides, suggesting favourable leaching characteristics.
Infill and Extension Drilling Targets Resource Upgrade
With metallurgical drilling wrapped, Flagship has shifted focus to infill and extension drilling within and around the 2026 pit shell. This work targets unclassified and Inferred mineralisation to strengthen the Mineral Resource Estimate (MRE) and potentially increase the oxide/mixed component, which is crucial for heap leach processing. The company aims to deliver an updated MRE by late 2026 or early 2027, an important milestone for project advancement.
Managing Director Paul Lock emphasised the importance of the metallurgical test work in confirming leach consistency and feeding into the upcoming Pre-Feasibility Study (PFS). He highlighted that drilling will also refine mineralisation zoning, providing a better geological understanding ahead of the resource update.
Project Location and Environmental Considerations
The Isidora project covers approximately 120 square kilometres in Chile’s Atacama region, situated between established gold operations including Kinross’s Maricunga projects. The tenure is secure under a five-year option agreement, though development will require environmental impact assessments given proximity to Nevado Tres Cruces National Park and Ramsar wetlands. Flagship acknowledges these considerations as part of its ongoing project planning.
Technical Rigor and Quality Assurance
The announcement provides detailed geological context and robust QA/QC protocols supporting the drilling and sampling programs. Competent Persons statements confirm that data underpinning the current resource estimates and exploration results meet JORC Code (2012) standards. Historical drilling data from Anglo American, Kinross, and Orosur have been validated to ensure reliability for resource modelling.
Bottom Line?
Flagship’s completion of metallurgical drilling and commencement of infill drilling mark critical steps toward a resource upgrade and feasibility work, but outcomes of pilot test work and environmental permitting remain pivotal.
Questions in the middle?
- How will pilot scale heap leach test results influence the project’s economic modelling and feasibility?
- To what extent can infill drilling increase the oxide/mixed resource component amenable to heap leach processing?
- What environmental challenges might arise given the project’s proximity to protected areas, and how could these impact timelines?