Diamond drilling by PolarX at its high-grade Caribou Dome copper prospect in Alaska has intercepted massive sulphides in the opening holes of its 1500m diamond drilling program. Several 2m - 11m thick zones of possible copper-bearing massive sulphides were logged in the first three drill holes of the drill program that is designed to test three new targets and provide fresh samples for metallurgical test work.
PolarX has tapped several thick zones of massive sulphides in the first three holes of its high-grade Alaskan Caribou Dome diamond drilling program that will see 1500 metres of drilling undertaken to test three new targets and provide fresh samples for metallurgical test work.
Remarkably, the first three holes of the program each intersected several 2m - 11m thick zones of possible copper-bearing massive sulphides, however the fourth hole was terminated after hitting heavily faulted rocks. The holes were drilled into zones predicted to be copper-rich by the block model used to calculate the maiden mineral resource estimate at Caribou Dome of 2.8 million tonne at a welcome 3.1 per cent copper.
The drill core is in the process of being cut and submitted for assay, however whilst visual estimates of copper grades have not been made due to the extremely fine-grained nature of the sulphides, company geologists have eyeballed copper-bearing chalcopyrite. PolarX says it is confident there is a very high probability that the holes will contain significant grades of copper based on historical drilling results.
The very first hole in the program intersected three distinct zones of massive to semi-massive sulphides each of which were between 8m and 9m thick within a 39m sedimentary zone. The sulphides are particularly fine-grained and form thin laminations within very fine-grained sediments. Chalcopyrite occurs as small blebs and filigree veinlets and as thin zones within zones dominated by pyritic iron sulphide. The next two holes, CD21-002 and CD21-003 also hit lenses of fine-grained sulphides in sediments and the sediment package appears to be fault-bounded on either side by andesitic volcanic rocks
Copper mineralisation within the existing mineral resource at Caribou Dome occurs in nine known lenses of massive sulphides over 800m of strike. Previous exploration in the area has revealed these lenses show strong copper anomalisms in surface soil sample assays and can be broadly predicted using induced polarisation geophysical surveys according to the company.
PolarX says the same features are present in the new targets which are being drilled. Managing Director, Dr Frazer Tabeart, who is on-site in Alaska for the duration of the drilling program said: “These samples look spectacular. They are close to holes from 2015 and 2016 which yielded up to 51.1m at 5.3% copper. These new samples will be assayed and used for metallurgical test work as part of our current scoping study on the Alaska Range Project. We’ve now moved onto the three exciting new exploration targets, with the first drill hole already underway.”
The Caribou Dome Project is located in the Alaska Range, approximately 250km northeast of Anchorage in Alaska, USA. The Alaska Range lies within a larger mineralised province on the famed “ring of fire” which hosts various giant ore deposits which include the 10.9 billion tonne Pebble porphyry copper-gold discovery, the 78.9-million-ounce Donlin gold project and Northern Star’s 5-million-ounce Pogo gold mine which lies a little closer to PolarX’s ground.
PolarX’s tenure in Alaska stretches along more than 35 kilometres of strike and contains a wealth of prospects including the Caribou Dome sulphide system in the south through to the Zackly skarn and Mars porphyry copper-gold discoveries in the north.
Copper mineralisation was discovered at the Caribou Dome way back in 1963 and from 1963-1967, several lenses of volcanic sediment-hosted copper mineralisation were delineated over approximately 700m. However, only limited exploration was undertaken after 1970, until PolarX secured the rights to explore and develop the project in 2015. The company then rapidly compiled all historic technical information, completed a ground geophysics survey, geochemical soil sampling and two programs of diamond core drilling.
The copper mineralisation occurs in deformed lenses of fine-grained massive sulphides comprising the sulphide minerals pyrite and chalcopyrite. The mineralisation currently extends from surface to depths of over 300m and the company says multiple high-priority targets delineated by surface geochemical soil sampling and IP surveys remain undrilled.
PolarX’s exploration program in Alaska is hitting high gear now with the drilling at Caribou and extensional drilling over the Zackly deposit scheduled in the weeks ahead. The buoyant red metal market together with PolarX’s comprehensive ground holdings in the mineral-rich American state present an opportunity for PolarX to muscle its way onto the radars of the copper bulls in the coming months.
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