Has Staveley Minerals found another Kalgoorlie in western Victoria?
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Staveley Minerals thinks its may have found another Kalgoorlie in western Victoria, writes Barry FitzGerald in his weekly Garimpeiro column.
Excitement is building that Stavely Minerals (ASX:SVY) is onto a big porphyry copper and gold discovery beneath flat wheat and canola fields in the shadows of the Grampians in western Victoria.
Porphyry — a crystal-like orebody formed from molten rock — is the world’s main source of copper.
Stavely managing director Chris Cairns leads the cheer squad, saying last week the size of the prize could be globally significant. Think of finding another Kalgoorlie in western Victoria is how he likes to put it.
Such a find deep beneath Stavely’s Thursday’s Gossan near Glenthompson would be a first for the region, a 3-hour drive west of Melbourne and better known for its cropping, its fine red and sparkling wines, and bushwalking tourism.
The Victorian government is also cheering on Stavely’s exploration by co-funding $400,000 in drilling, as is the drilling contractor Titeline through a share subscription agreement for drilling services.
Stavely last traded at 17c for a market value of $21 million. That in itself says that the company does not yet have a big porphyry copper-gold deposit on its hands.
But it is close to finding out whether it is on its way to the big time. More than three years of multi-faceted drilling, sampling, and research work has built the case for the existence of a deep porphyry orebody.
A seasoned geologist with experience of exposed porphyry systems in the Philippines, Cairns first noticed the porphyry potential of Thursday’s Gossan when running his eye over core shed material when the property was up for sale as small near-surface copper deposit by the previous owner.
Cairns was quick to snap up the project and it became the main asset in Stavely’s $6 million float in May 2014.
Apart from anything else, the rebound in copper prices has heightened interest in the potential of Thursday’s Gossan.
But it was drilling earlier this year that gave Stavely’s concept of big porphyry being present at depth fresh momentum with investors.
The drilling was designed to further evaluate the long known inferred near-surface supergene resource at Thursday’s Gossan (28mt at 0.4 per cent copper for a contained 110,000t of contained copper).
The drilling returned thick porphyry copper-gold intersections with best results including 24m at 0.64 per cent copper and 1.2g/tonne gold, and 124m at 0.31 per cent copper and 0.12g/tonne gold.
Porphyry systems supply the bulk of the world’s red metal needs. They are characterised by being low-grade – the global average grade of copper mines is currently running at about 0.62% copper — but big tonnage propositions positions.
Cairns said last week the results were the “clearest and strongest indications that we have had to date that we are now closing in on a game-changing discovery.
“All of the recent work is now pointing in the same direction, supporting our model for the mineralisation at Thursday’s Gossan, where structurally controlled mineralisation close to surface is interpreted to be ‘leaking’ from a copper-gold mineralised porphyry intrusion at depth,’’ Cairns said.
Intervals of strong copper-gold mineralisation have now been intersected at shallow depths over a strike extent of more than 400 metres with the zone remaining open in all directions.
Follow-up deeper diamond drilling is planned as a priority to follow the structures down towards the expected high-grade copper-gold core.
“The only thing left now is for us to put our hard work, theorising and systematic exploration to the test by drilling a series of ‘sighter’ holes before we drill one or two major diamond holes, in all likelihood up to 1000 metres deep, to hopefully make the company-changing discovery we have been pursuing,’’ Cairns said.
“This is a very exciting time for Stavely — and it’s all going to kick off within a matter weeks with our drillers ready to get going by early November.”