Special Report: Great Southern Mining (ASX:GSN) has identified three “high-priority” porphyry copper-gold targets at the Edinburgh Park project in north Queensland.
Great Southern’s ~1000sqkm Edinburgh Park project is next door to Evolution Mining’s (ASX:EVN) highly profitable Mt Carlton gold mine, which produced ~107,000oz in FY19 at a low all-in sustaining cost of ~$740 per ounce.
And yet less than 15 per cent of the Edinburgh Park area has been explored using modern techniques.
In October last year, Evolution offered to pay half the cost of flying a ‘hyperspectral survey’ over Great Southern’s project area.
Hyperspectral surveys — an invaluable (but expensive) tool which maps the ’exposed surface mineralisation’ of potential deposits deeper down — bring up a lot of targets, very fast, over a big area.
The result for Great Southern is a word-class dataset that is the envy of many a major mining company, not just junior explorers.
In April, the explorer identified a number of large, +2km-long Mt Carlton-like gold targets using the hyperspectral data – many of them are bigger than the original ‘signature’ at Mt Carlton.
Now it has uncovered other styles of gold mineralisation zones known to exist in this district, like intrusive related gold systems (IRGS) and porphyry systems.
When it comes to porphyry deposits, size counts.
These are multigenerational mines responsible for ~60 per cent of the world’s copper, most of its molybdenum, and significant amounts of gold and silver.
Three porphyry targets at Edinburgh Park are considered “high priority” due to the scale of the alteration zones evident in the hyperspectral data — which can extend up to ~2km — and the evidence of alteration zonation.
Great Southern will now begin geochemical (soil sampling) work over these prospective porphyry and IRGS areas, as well as the previously defined epithermal targets.
This program will be the first systematic gold-focused exploration program undertaken over the highly prospective targets identified from the hyperspectral data.
Great Southern’s chief operating officer Mark Major says the explorer’s attention is now focused on getting on the ground to follow up these targets.
“The company’s philosophy has been to employ modern ‘smarter’ exploration techniques to screen the whole project and allow a focus on the key targets, reducing time and expenditure,” Major says.
“We have close to 15 priority targets, several of which are at the Leichhardt Creek area, where our initial soil geochemical program is being undertaken.
“We look forward to seeing the assay results over this extensive porphyry stockwork system which has never been sampled for gold or silver.
“Additional geochemical and mapping programs are being planned over the other high priority areas following the Leichhardt Creek geochemical program.”