Buxton Resources has discovered an extension to the porphyry copper-molybdenum system at its Copper Wolf project in Arizona that is not a part of the nearby joint venture (JV) it shares with mining giant IGO.
The newly-identified and shallow “Wolverine” prospect, which sits just 2.5km from the project’s main mineralised body, gave up rock chip samples going as high as 14.1 per cent copper and 1160 parts per million molybdenum. It was found in zones of surface alteration and veining that are typically highly-leached and the company believes it implies the potential for a fertile porphyry system below.
Management says geochemical data from the 96 rock chips taken at Wolverine suggests the highest copper and molybdenum grades are likely to be preserved below the surface. The field data will provide a focus for an upcoming scout drilling program to test the continuation of mineralisation at depth, with drill permitting already underway.
An earn-in and JV agreement for the main mineralised part of Copper Wolf was set in August 2022, with IGO getting an exclusive option to earn a 51 per cent interest in the tenements by incurring and sole-funding $350,000 of exploration expenditure in a 24-month period that started on October 4 that year.
Buxton Resources chief executive officer Martin Moloney said: “The discovery of an outcropping porphyry Cu-Mo system at Wolverine is a game-changer for Buxton with mineralisation present at surface and tenure which is not subject to any JV Agreement. This discovery also highlights the incredible exploration potential at Copper Wolf where previous work from the 1960s to 1990s has barely scratched the surface of what is shaping up to be a very large porphyry Cu-Mo system."
Wolverine sits in the north-east of the Copper Wolf project area, a 16.7-square-kilometre chunk of land in north central Arizona and about 80km north-west of the city of Phoenix. The huge porphyry intrusive complex is about 70.3 million years old and is concealed by a younger sequence of volcanic and sedimentary rocks.
Similarly-aged intrusive complexes in adjacent western parts of the United States and northern Mexico host giant copper deposits such as Resolution, which is about 130km south-west of Copper Wolf and is considered to be one of the word’s biggest undeveloped copper resources. It is estimated to have a mineral resource of 1.7 billion tonnes at 1.52 per cent copper.
About 100km to the north-west of Copper Wolf, in another similarly-aged porphyry complex, the Bagdad deposit has an estimated reserve of 873 million tonnes grading at 0.36 per cent copper. The area has not seen any exploration drilling since the 1990s and Buxton’s 2022 airborne magnetic survey was the first geophysical work undertaken since the early 1990s.
The company says mineralisation at its Copper Wolf project extends through an area of at least 4km by 1.5km and has a 1993 “mineral inventory” estimate made by Orcana Resources totalling 388.3 million tonnes at 0.83 per cent copper and 0.07 per cent molybdenum disulfide. It says 74 per cent of that estimate, which is 286.2 million tonnes at the same grades, lies within its tenure.
Liontown Resources also had a crack at a mineral resource estimate for the project, quoting a 2007 inferred total of 108 million tonnes at 0.8 per cent copper and 0.03 per cent molybdenum for 864,000 tonnes of contained copper metal, in addition to 32,400 tonnes of molybdenum metal at a 0.4 per cent copper equivalent cutoff.
The surface mineralisation at Wolverine is encouraging and investors will be watching closely for the results of drilling at the prospect to see just how loud Copper Wolf can howl.
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By Andrew Duffy
