The gold and copper-rich Macquarie Arc in central west NSW, is living up to its title as Australia’s foremost porphyry province and demonstrating just how fertile, underexplored, and large the systems within it are.

Unlike many other Tier 1 copper provinces in Australia, Macquarie Arc is favourably located close to existing infrastructure and under relatively shallow cover, and hosts a number of highly profitable world-class mines, including Newcrest Mining’s (ASX:NCM) Cadia operation, which is Australia’s largest gold mine and boasts negative operating costs after copper credits.

This week’s news of the maiden 10.1-million-oz gold equivalent resource released by Alkane Resources (ASX:ALK) for its Boda deposit, one of multiple prospects within its Boda project, demonstrates just how prospective the region is for clusters of new large-scale porphyry and epithermal gold-copper deposits.

The initial resource was confined to a 1,000-metre strike length with drilling by Alkane since demonstrating a mineralised system over more than 3-kilometres across the wider Boda project.

Step out drilling is ongoing with extensions to the deposit being tested to the south (at the Boda Two prospect) and northwest (towards the Kaiser prospect) of the initial Boda resource.

As Alkane puts it “this resource at Boda is just the beginning”, a maiden resource at the neighbouring Kaiser prospect is expected in 4Q 2022, and the Boda project is expected to further significantly add to the existing estimated endowment of the Macquarie Arc that hosts over 105Moz of gold and over 25Mt of contained copper.

To announce a 10.1Moz gold equivalent resource as an initial resource for any deposit is a rarity, particularly in a greenfield setting (ie in a new part of the Macquarie Arc, not near an existing mine) and the size of the prize at Boda beat consensus expectations.

Another good example of the treasure that lies in the Macquarie Arc is Kincora Copper’s (ASX:KCC) Trundle project, which prior to Kincora starting drilling in April 2020 had witnessed limited prior drilling at depth.

With assay results pending for 8 prospects across two projects, including Trundle and having made a new discovery in the last quarter at Trundle, Kincora has positioned itself as the leading pure play porphyry explorer in the Macquarie Arc, and looking to follow in Alkane’s shadow with a new globally significant porphyry deposit.

Kincora’s Trundle project is favourably situated in a brownfield environment that hosts up to a third of the Northparkes Igneous Complex, a proven world-class mineral system which already hosts a plus 26-million-oz gold equivalent mineral endowment at the Northparkes mine (Australia’s second largest porphyry mine behind Cadia).

As outlined in a recent exploration strategy and progress video, “Kincora’s approach has been to follow up positive vectors to greater depths, develop a detailed 3D model to advance and refine interpretations, identify mineralised trends, rank and then systematically test targets,” CEO Sam Spring explained.

Like at Boda, historic drilling is interpreted to have been too shallow at Trundle, despite a large and near-surface gold and copper footprint being identified across an 8.5km strike.

“This significantly improved geological understanding has both guided and justified deeper drilling.”

Kincora’s first hole, which returned 51m at 1.17 grams a tonne (g/t) gold and greater than 0.5% copper from just 39m downhole with further notable deeper intervals, was the most significant in the Trundle project’s history, despite 2,208 prior explorer drill holes.

Step out drilling, meanwhile, significantly expanded the mineralised skarn and intrusive footprint in the Central and Eastern Zone discoveries, with notable high-grade intervals at relatively shallow and some potentially open pittable depths.

Only in the last quarter has Kincora made a new, third discovery at the Southern Extension Zone, where drilling has intersected cumulative gold and copper mineralisation of up to 200m across a greater than 325m strike (and open in all directions) in a tabular, three-horizon skarn system.

Skarn deposits are generally formed on the peripheral to, and mineralising fluids sourced from, porphyry systems. The Northparkes and Cadia mines both host skarn and porphyry resources.

“This new discovery supports one of, if not the, largest skarn systems in Australia and a system that is very different to the Eastern and Central Discovery zones,” Spring noted.

“Drilling by Kincora has expanded the previously known near-surface mineralisation at the Trundle Park prospect from a 700m strike to now over 1.3km and open with a vertical depth of approximately 800m.”

Step out drilling is ongoing at the Southern Extension Zone discovery, with assay results and reviews (internal and external) pending. After completion of the next hole at the Southern Extension Zone, the diamond rig is expected to be moved approximately 9km to the north to the Mordialloc North-East prospect.




This article was developed in collaboration with Kincora Copper, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.