ASX listed PolarX’s suspicions that it may be sitting on a significant porphyry-style copper-gold-molybdenum mineralised system at its Alaska Range project in the USA appear to have been confirmed by the first diamond drill hole assays returned from the Mars prospect.
According to management, whilst a 102 metre intersection at Mars containing 0.22% copper, 0.1 grams/tonne gold and 20 parts per million molybdenum did not intersect the core of the system, where the highest grades are often found, it may have come close.
The Mars prospect features a linear geomagnetic high that is associated with a copper-gold-molybdenum-arsenic anomaly that extends over an area that is around 1,500m by 800m and occurs at the western end of a 12 km long mineralised corridor.
This corridor also hosts the high grade Zackly copper-gold skarn and, at its eastern end, the Saturn porphyry target – both of which are also part of the 261 square kilometre Alaska Range project.
Zackly currently has a JORC-compliant resource of 3.4 million tonnes grading 1.2% copper and 2g/t gold, whilst Saturn has been identified as a possible porphyry intrusive centre following a recently completed gravity survey.
The first 417m deep drill hole at Mars also returned 2m at 0.24% copper, 0.05g/t gold and 11ppm molybdenum from 175.96m and another 2m at 0.24% copper and 0.15g/t gold and 57ppm molybdenum from 308.2m.
The mineralisation at Mars is associated with a type of clay that Geologists say is usually coincident with higher copper grades.
Management also said that the lack of pervasive potassic alteration usually found in high grade intersections, indicates that the hole is not in the hottest core of the system where the highest grades are often located, suggesting there is still plenty of discovery upside.
Importantly, the porphyry-style mineralised veins occur from within 6m of the surface and extend to the bottom of the hole, providing PolarX with a strong incentive to drill deeper to find the potentially higher-grade core of the system. It is also important to note that the mineralised intensity broadly increases with down hole depth, particularly from 321m onwards.
PolarX Managing Director Dr Frazer Tabeart said: “When coupled with the size and nature of the surface geochemical and geophysical anomalies, the assays confirm our view that a very large mineralised system may be present.”
“A significant drilling program is being planned to follow-up this target.”
“These results also confirm that the entire 12km length of the Mars-Zackly-Saturn corridor is prospective for porphyry-style mineralisation.”
Lower grade porphyry copper deposits are the main source of copper globally. Porphyries are the dominant form of mineralisation underpinning some of the largest copper mines in the world and are often found in well known copper-rich countries like Chile, Peru and the USA.
Whilst the primary ore of a typical porphyry is generally lower grade, with an average copper grade of 0.5%, and a gold grade ranging from 0.05 grams/tonne to about 1g/t, this is more than compensated by size, with many such deposits containing hundreds of millions to billions of tonnes of mineralisation.
It is perhaps no surprise then that the Perth based PolarX has caught the eye of Canada’s Lundin Mining Corporation, which earlier this year invested $4.3 million into it to secure the right to enter a staged earn-in joint venture in the Stellar project, which makes up part of the larger Alaska Range holdings and covers the Mars, Saturn, Gemini, Moonwalk and Jupiter prospects.
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By Matt Birney
