Southern Hemisphere, FMR Resources close in on Chilean copper porphyry

Southern Hemisphere Mining and its joint venture (JV) partner FMR Resources are zeroing in on the core of a large copper-gold-molybdenum system at Llahuin in Chile, with fresh assays piling more weight onto the emerging “Southern Porphyry” target.

Assays are in for three diamond holes drilled by joint venture partner FMR Resources across Targets A, C and K within the Southern Porphyry area.

The best hit came from Target C, which returned 124m at 0.31 per cent copper equivalent from 258m, including 20m at 0.48 per cent copper equivalent.

The hole was aimed at what FMR believes is the system’s central corridor, boring through a long run of intense veining and broken, fluid-churned rock – classic signs of a busy geological plumbing system.

Mineralisation in the zone is gold-dominant, with copper and molybdenum tagging along in sulphide veins and fine-grained disseminations.

At Target K, 375m east of Target C, a second hole returned 104m at 0.16 per cent copper equivalent from 522m.

The third hole, put into Target A, 560m east of Target C, produced shorter but encouraging intervals, including 1m at 0.4 per cent copper equivalent and 10m at 0.45 per cent copper equivalent, and confirmed the area is shot through with porphyry intrusions and strong veining.

“These results confirm our visual observations that we have intersected the outer zones of a large and fertile mineralised system. Importantly, detailed petrographic and lithogeochemical analysis shows that while we are intersecting fertile intrusions, we have not yet drilled the causative porphyry.” FMR Resources managing director Mr Oliver Kiddie

Rock studies in the lab have backed up the field picture, confirming multiple pulses of intrusive porphyry threaded through the host volcanics. The chemistry of those intrusions looks like the right “recipe” to generate a copper system - even if the company says it still hasn’t been able to pierce the primary main source body.

Put simply, all three holes have picked up a broad halo of copper, gold and molybdenum and plenty of veining – but they haven’t hit the richer core yet.

FMR’s takeaway is that the drilling is clipping the margins of a big mineralising system and it now needs to narrow the search towards the centre, where grades would typically be expected to pick up.

That message aligns with February’s update, when FMR reported visible copper and molybdenum sulphides tied to a magnetotelluric geophysical anomaly at Target C, then stepped out to nearby Targets K and L to try to track down the main fluid source.

Drilling in late March at Target L also logged broad mineralised breccias and porphyry with visible copper and molybdenum, suggesting the search is heating up.

FMR says the higher gold-to-copper ratios point to the drilling still being relatively high in the system, while the stronger molybdenum signal in the second hole is another clue that the bit is edging closer to the porphyry “engine room”.

For now, the alteration minerals suggest the JV is sitting on the system’s outer shoulders rather than its hotter, higher-grade core, so the next job is to tighten up the targeting.

The next move for the joint venture will be to marry the assays with geology, structure and geophysics, including magnetotellurics, induced polarisation and downhole surveys, to lock in targets for the proposed phase two drilling.

If the next round can turn today’s broad halo into one or more tighter bullseyes, Southern Hemisphere and FMR could be lining up a genuine porphyry-scale discovery shot.

Either way, the upcoming phase two drilling at Llahuin now has a few clearer signposts, and the market will be watching for that first whiff of a higher-grade core.

Is your ASX-listed company doing something interesting? Contact:

matt.birney@wanews.com.au