Source : THE AGE NEWS
Flagship Minerals has ticked off a major technical milestone at its flagship Isidora gold project in Chile, completing the metallurgical drilling and trenching needed for pilot-scale processing studies.
The rig has now swung into resource growth mode ahead of the next mineral resource estimate (MRE), expected later in the year.
The company’s twin-stream drilling strategy has been designed to combine a pilot-scale metallurgical program – de-risking the proposed processing route – with exploration to convert inferred mineralisation into higher-confidence categories and expand the resource.
The metallurgical field program comprised four large-diameter PQ diamond holes totalling 600.5m and five 600m trenches to collect representative samples for pilot-scale test work. The holes targeted key zones in the existing MRE and intersected visually apparent mineralisation hosted in predominantly oxidised, altered and fractured dioritic porphyry.
‘We are targeting an MRE update later in 2026 / early 2027.’
Flagship Minerals managing director Paul Lock
Together, the drilling and trenching collected bulk samples from the oxidised zone to determine whether Isadora’s ore is suitable for heap leach processing.
The trenching program will also supply the material for a 300-400 tonne bulk sample for a pilot-scale heap leach trial, an important step towards assessing the proposed processing route under mining conditions.
Core processing is nearing completion ahead of the dispatch of samples to a specialist Chilean metallurgical laboratory. Trench assay results are expected within two weeks and will determine how the excavated material is blended into the 300-400 tonne bulk sample for pilot-scale heap leach testing.
Those samples will be used to assess leach kinetics, gold recoveries and reagent consumption, generating important engineering data for the project’s prefeasibility study (PFS).
Flagship Minerals managing director Paul Lock said: “Our metallurgical drilling and trenching program is now complete, providing the sample material needed to conduct pilot scale met test work, targeting completion in the fourth quarter 2026 or early 2027. This test work will confirm the leaching consistency of the oxide zones, which will feed into the Isidora PFS. The drilling will also provide additional information on mineralisation zoning, which will be used in future MRE updates.”
With the metallurgical program complete, Flagship has now moved on to infill exploration holes within the existing resource footprint. The campaign will then broaden to include extension drilling around the current pit shell and confirmatory drilling of historical reverse-circulation holes. The aim is to increase the oxide and transitional component of the resource ahead of the next MRE.
Flagship’s rapid progress since acquiring the project little more than 12 months ago was given a big leg up after the company struck a deal with Anglo American, the former project operator, to buy almost 20,000m of historical diamond drill core and the project’s entire geological database for $3million.
The savvy move allowed it to fast-track decades of work and accelerate the journey from resource definition into pilot-scale metallurgical studies, avoiding what management estimates would have cost about $30 million and taken five years to replicate from scratch.
The latest milestone comes only weeks after Flagship muscled its way into the multi-million-ounce club by defining a JORC-compliant 115.2-million-tonne resource grading 0.56 grams per tonne (g/t) gold for 2.1 million ounces at Isidora. More than 90 per cent of the ounces already sit in the higher-confidence measured and indicated categories, reducing geological uncertainty as the project advances through future feasibility studies.
The project sits within Chile’s Atacama region in the prolific Maricunga gold belt, one of South America’s premier gold districts, home to more than 65 million ounces in world-class deposits such as Norte Abierto, Maricunga, Lobo-Marte, Salares Norte, La Coipa and Fenix.
Success in the metallurgical program would validate Flagship’s preferred heap-leach strategy and reinforce a development pathway already proven elsewhere in the district. Nearby, Rio2’s Fenix gold project is demonstrating in real time that a five-million-ounce, near-surface oxide gold deposit can successfully make the leap from development to production using heap leach.
Flagship is targeting an updated MRE for later this year or early 2027 once the metallurgical program delivers the engineering inputs required for its prefeasibility study.
If pilot-scale testing confirms anticipated heap leach performance and the drilling campaign delivers additional higher-confidence ounces, the company could quickly emerge with an even bigger resource and a stronger development story, potentially enabling Flagship to become one of Maricunga’s next producers
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