Broken Hill Gold has launched a 3000-metre drilling campaign at its White Dam project in South Australia to test a major geophysical target lurking beneath recent high-grade copper-gold hits, raising the tantalising prospect of linking several deposits into one large system.
The company’s latest induced polarisation (IP) and ground magnetic surveys have outlined a robust 1.5-square-kilometre chargeability anomaly coinciding with a one-square-kilometre magnetic anomaly beneath its Icebreaker discovery, suggesting the once gold-focused project could be emerging as a massive copper-gold system at depth.
With drilling set to kick off this weekend, Broken Hill is poised to put its compelling new target to the test in a rapidly emerging iron ore copper gold (IOCG) province, where the potential for major discoveries has major players circling.
The discovery of a high-grade sulphide system at Icebreaker came about almost entirely by accident, after the company punched through its shallow, 20,400-ounce oxide gold resource into a richer gold-copper sulphide zone below.
Now, the geophysics suggests Icebreaker could be just the tip of the iceberg. The IP survey defined two key features, including a shallower northwestern anomaly sitting directly beneath high-grade sulphide mineralisation already struck at Icebreaker, pointing to potential extensions of the known copper-gold system both at depth and along strike. However, a deeper and much stronger eastern anomaly is shaping up as the main prize. It shows a chargeability reading six times the background level and trends north from the edge of another historic Hannaford deposit.
A ground magnetic survey has also defined a hefty one-square-kilometre high-intensity feature coinciding with the IP chargeability anomalies, which the company says points to iron oxide alteration, consistent with the magnetite-pyrite alteration observed at Icebreaker and a hallmark of large IOCG deposits.
This is an excellent result, delivered in a very short turnaround time, and the geophysics crews have performed exceptionally. We now have coincident IP and magnetic anomalies over a large area, in a zone we already know is well mineralised – that is an extremely compelling set of drill targets. The strength and consistency of the IP anomaly makes it an outstanding target in its own right.
The project sits within South Australia’s Curnamona Province, a region renowned for its major IOCG deposits. Havilah Resources’ Kalkaroo project, just 40km north of White Dam, hosts a massive 1.1 million tonnes of copper and 3.1 million ounces of gold, alongside 23,200 tonnes of cobalt. That project has now attracted heavyweight interest, with Sandfire Resources securing the right to acquire an 80 per cent stake for consideration of up to A$222.6 million, while committing a further A$30 million to regional exploration.
Importantly, the existing Hannaford deposit, which hosts a resource of 43,300 ounces of gold, along with the Icebreaker and Rolling prospects, all sit around the margins of the combined geophysical anomalies. Their positioning suggests they could form part of a single, much bigger alteration system that remains largely untested at depth, with most historical drilling averaging just 50m.
The company is now preparing to put the theory to the test with an initial reverse circulation (RC) and diamond drilling campaign designed to probe the system at depth for the first time. Deeper diamond holes will reach depths of up to 400m, providing the first serious test of both the northwestern and main eastern induced polarisation (IP) anomalies.
With White Dam continuing to produce gold doré and offering a potential pathway to self-funded exploration, Broken Hill has an enviable platform from which to chase a much bigger prize.
If the drill bit backs up the geophysics, the company could be on the cusp of transforming White Dam from a modest gold producer into a much bigger copper-gold story, with Icebreaker potentially opening the door to a district-scale discovery.
Is your ASX-listed company doing something interesting? Contact: matt.birney@wanews.com.au
