Partial assays from a drilling program at the Thursday’s Gossan copper-gold prospect in western Victoria have returned the thickest and highest-grade intervals to date for junior explorer Stavely Minerals (ASX: SVY).
The company said results received for the top 980 metres of a recently-completed diamond hole encountered a “very broad zone” of copper sulphide mineralisation including an “absolute whopper intercept” of 952m at 0.23% copper.
The assays also contained “outstanding intervals” of bornite mineralisation and have provided the “best visual intercepts” from the wholly-owned Stavely copper-gold project to date.
Drilling aimed to progress into the hotter part of the mineralised porphyry system at Thursday’s Gossan, targeting higher-grade copper and significantly higher-grade gold deposits.
Best results included 10m at 2.43% copper and 0.30 grams per tonne gold on the Copper Lode Splay structure within the prospect, and 38.3m at 1.59% copper, 0.27g/t gold and 8g/t silver on the North-South structure.
Both structures have been recognised as having copper lode-style mineralisation similar to that at the historic Magma mine in the US and closely associated with the giant Resolution porphyry copper deposit in the same region, believed to host an inferred resource of 1.8 billion tonnes at 1.53% copper.
Stavely executive chairman Chris Cairns said the results were a pivotal development in the company’s ongoing search for a world-class porphyry deposit.
“Following a series of technical breakthroughs in recent months, we now feel we are making really big, important and rapid steps towards unlocking a major discovery,” he said.
“We believe the broad zone of copper mineralisation, in predominantly propylitic alteration, reflects the very large scale of the mineralised hydrothermal system at Thursday’s Gossan and reinforces the size of the prize.”
He said Stavely had long chased the copper-gold grades it is now encountering at its flagship project.
“We have always felt Thursday’s Gossan had the attributes of a well-mineralised porphyry copper-gold system and it is very pleasing to finally see the grades we have been seeking,” Mr Cairns said.
“It is important to note we are not yet into the target porphyry, but these results do represent a very significant step forward in that these structurally-controlled copper lodes are recognised as potentially proximal to a porphyry source similar to Magma and Resolution.”
He said the convergence of the North-South structure and the Copper Lode Splay to the south of the recently-completed hole has been considered an ideal focus for a porphyry intrusion and will be targeted with the next drill hole.
At midday, shares in Stavely Minerals were down 4.48% to $0.320.