Sultan Resources (ASX: SLZ) has defined three large-scale porphyry-style gold-copper targets at its Big Hill project within central New South Wales’ Lachlan Fold Belt after returning “spectacular” high-grade results from a first batch of soil and rock chip samples.
The junior explorer today announced rock chip assays from the historical Gowan Green working returned grades as high as 24.6 grams per tonne of gold and 26.1% copper.
Rock chip assays grading up to 2.50% copper were also recovered from altered porphyry rocks over a 1.5km strike length further south at the Big Hill prospect.
In addition, Sultan said soil sampling over the western flank of a 6km long magnetic feature has defined a series of gold and copper anomalies with classic porphyry geochemical pathfinder signatures that are coincident with the mineralised rock chip samples and discrete magnetic highs, thereby confirming large-scale targets.
These priority targets have been confirmed as Gowan Green, Big Hill and Wattle Ridge. These prospects so far remain untested by drilling, and more importantly, are open to the east.
The news comes just two months after the company announced it would be acquiring three exploration licences (including Big Hill) in the highly prospective Lachlan Fold Belt through the takeover of Colossus Metals.
The acquisition of Colossus was approved by Sultan shareholders earlier this month.
“Receipt of such outstanding soil and rock chip results within weeks of shareholders approving the acquisition is a timely reward,” Sultan chairman Jeremy King said.
“To have such high-grade gold and copper results returned from within new large-scale soil anomalies, coincident with the right rock types, porphyry-style alteration and mineralisation, all sitting above a large magnetic complex confirms the Big Hill area as one with significant potential,” he added.
To the north of the Big Hill prospect is the Gowan Green historic gold and copper working, where Sultan said rock chip samples returned “spectacular” results.
Sample highlights include: 24.6g/t gold, 26.1% copper and 65.5g/t silver; 2.69g/t gold, 7.55% copper and 20g/t silver; 1.16g/t gold, 12.55% copper and 24.8g/t silver.
According to Sultan, the high-grade gold-copper samples validate a newly defined large low-level gold-copper pathfinder soil geochemical anomaly, while litho-geochemical studies of the assays confirmed Gowan Green rocks are calc alkaline basalts with a volcanic arc tectonic signature, consistent with being part of the Molong Volcanic Belt.
“The target is therefore considered highly prospective for the discovery of porphyry related copper-gold deposits,” Sultan said.
Big Hill prospect
At the Big Hill prospect, which has been defined by mapping and soil geochemistry as a 2.2km by 400m target area, significant rock chip samples included multiple grades ranging between 1.3-2.5% copper.
Here, geochemical features align with upper or outer parts of an alkalic porphyry gold-copper system such as Newcrest Mining’s (ASX: NCM) high-grade Cadia Ridgeway porphyry gold-copper mine located 50km to the south and Alkane Resources’ (ASX: ALK) Boda discovery about 50km to the north.
Ongoing exploration program
This first batch of soil and rock chip assays from Big Hill is part of an ongoing exploration program aimed at identifying drill targets with high potential to host porphyry-style gold-copper or epithermal gold mineralisation.
Along with Big Hill, the program is running across Sultan’s Ringaroo and Tucklan project areas.
At Big Hill, Sultan will continue to undertake geochemical sampling and mapping to the east of the current soil anomaly to test the remainder of the magnetic complex.
Ground induced polarisation geophysical surveying is also planned in the next quarter to refine the drill targets.
Soil and rock sampling results are currently pending for the Tucklan project, and a soil and rock chip sampling program has also started at Ringaroo.