FMR, Southern Hemisphere Mining JV narrows hunt for Chilean copper porphyry core

FMR Resources and Southern Hemisphere Mining conducting diamond drilling at the company’s Llahuin project in Chile Credit: File

While the latest drill results from FMR Resources (ASX: FMR) and Southern Hemisphere Mining’s (ASX: SUH) Southern Porphyry joint venture in Chile may not have delivered headline-grabbing grades, they have provided something potentially just as valuable for porphyry explorers – a clearer path towards the heart of a large copper system.

Final assays from the latest diamond drill hole at the Southern Porphyry target have confirmed broad copper-gold-molybdenum mineralisation and strengthened the JV partners’ belief that drilling to date has only tested the outer portions of a much larger mineralised system.

Southern Hemisphere’s joint venture partner, FMR Resources, has now received the final results from the hole, which returned notable intercepts including 24 metres grading 0.14 per cent copper equivalent from 156m and 4m at 0.78 per cent copper equivalent from 582m.

The partners formalised their alliance in mid-2025 when FMR agreed to spend up to $13 million on exploration across five years to earn a 60 per cent stake in Southern Hemisphere Mining’s Southern Porphyry ground.

Importantly, the Southern Porphyry target sits immediately south of Southern Hemisphere’s existing Central, Ferro and Cerro deposits, a corridor which collectively hosts a substantial 218.2-million-tonne resource grading 0.38 per cent copper equivalent.

Although the grades fall below those reported from the existing Llahuin resource, which currently stands at 218.2 million tonnes grading 0.38 per cent copper equivalent across the Central Porphyry, Cerro and Ferro deposits, the results are broadly consistent with the geological model being tested.

Nevertheless, the scale of the existing resource underscores the fertility of the broader Llahuin district. The company says it strengthens the theory that a much larger, deeper porphyry source could be feeding mineralisation throughout the project area - precisely the prize the joint venture is chasing.

The key takeaway from the latest drilling is not necessarily the grades encountered, but rather what the geology reveals about the hole’s position relative to the broader porphyry system.

Company geologists believe the drill hole intersected the peripheral and intermediate zones of a large porphyry intrusive corridor rather than the higher-grade mineralised core. Structural measurements collected from the target show increasing vein density and complexity compared with earlier holes, a feature commonly associated with increasing proximity to the fluid source that drives porphyry mineralisation.

The hole also intersected multiple intrusive phases, extensive quartz-sulphide stockwork breccias and pervasive hydrothermal alteration. Visible chalcopyrite and molybdenite were identified within quartz-sulphide, magnetite-sulphide and anhydrite veinlets, all hallmarks of a potentially extensive porphyry system.

In large copper porphyry deposits, the strongest copper and molybdenum grades are often concentrated within a central mineralised core, surrounded by broader zones of lower-grade mineralisation. As a result, the geological and geochemical signatures encountered in the latest hole are being used to guide future drilling into what is believed to be the more prospective centre of the system.

FMR is now integrating assay results with structural data, thin-section petrography, whole-rock geochemistry and downhole geophysical information from all four holes drilled to date. The work aims to construct a detailed three-dimensional model of the porphyry system and refine drill targets for a planned phase two program.

Additional petrophysical studies, including density, magnetic susceptibility, resistivity and chargeability measurements, are also underway to improve geophysical inversion models and further constrain the geometry of the mineralised system.

The assays from Target L validate the geological observations from drilling, confirming a broad mineralised porphyry system containing copper, molybdenum and gold anomalism. Importantly, the geochemistry supports our interpretation that drilling to date has intersected the margins of an extensive porphyry system rather than the higher-grade core.

FMR Resources Managing Director Oliver Kiddie

Llahuin sits near the city of Illapel in Chile’s Coquimbo region, 250 kilometres north of Santiago. Perched 1300 metres above sea level, the project lies just eight kilometres from Pucobre’s operating El Espino copper-gold mine, a significant regional producer delivering about 26,000 tonnes of copper and 13,000 ounces of gold annually.

The Southern Porphyry target exhibits a broad surface footprint characterised by argillic alteration, silicification, epithermal quartz veining and widespread copper-gold-molybdenum anomalism. Collectively, these features are consistent with a sizeable porphyry system and support the interpretation that a deeper mineralised core remains to be tested.

With geological vectors now pointing toward a potentially stronger mineralised centre, attention is turning to the next phase of drilling, currently scheduled for the fourth quarter of 2026, when the joint venture plans to test the interpreted core of the system more directly.

Is your ASX-listed company doing something interesting? Contact: office@bullsnbears.com.au