Why Should Investors be Interested in the Gawler Craton?

Updated: Apr 21

It's the next commodity rush, again.

Where is the Gawler Craton?

Most ASX investors think of Yilgarn Craton as the Mecca of Australian Goldfields, especially when you mention Kalgoorlie. The more knowledgeable investors will be familiar with names like the Pilbara, Ballarat and Cloncurry.

Actually, world-class deposits are found in Cadia (New South Wales) and the Olympic Dam. I think they are lesser known because they are not in the realms of the average investors' playing space. Most people are not aware of the significance of Gawler Craton. Some parts of the brokering fraternity do not even pay attention to this area.

The Gawler Craton is the oldest and largest geological province in South Australia, preserving a complex tectonic history spanning from c. 3200 Ma to 1450 Ma. The craton comprises a Meso- to Neoarchaean core enclosed by Palaeoproterozoic to Mesoproterozoic rocks. The Mesoarchaean history of the Gawler Craton is dominated by felsic magmatism, the Neoarchaean to Palaeoproterozoic history by sedimentation and bimodal volcanism, and the Mesoproterozoic history by felsic volcanism. - Source: South Australian Department of Energy and Mining.

The Gawler Craton is best known for the discovery of Olympic Dam in 1975, which was the culmination of nearly a decade of exploration. Olympic Dam is a monster in the world class category so this discovery is not something you find often. Not long after, several smaller mines were discovered such as Prominent Hill, Cairn HiIl and Carrapateena proving that the Gawler Craton is a very fertile place.

The Olympic Dam mine is a large poly-metallic underground mine located in South Australia, 550 km NNW of Adelaide. It is the fourth largest copper deposit and the largest known single deposit of uranium in the world. Copper is the largest contributor to total revenue, accounting for approximately 70% of the mine's revenue, with the remaining 25% from uranium, and around 5% from silver and gold. BHP has owned and operated the mine since 2005. The mine was previously owned by Western Mining Corporation. - Wikipedia

Olympic Dam Mine

Figure 1: Olympic Dam Mine (source: BF Magazine)

The discovery of Olympic Dam by Western Mining Corporation Resources Limited (Now part of BHP) sparked a rush for land around the discovery. Olympic Dam was a major discovery in an area that had little work, at that time.

In the mid 1990s, a small exploration company, Dominion Mining Limited discovered the Challenger Gold Mine (Figure 2). It was a blind discovery that came from regional calcrete sampling. Have a read of the Samso Insight that I published in November 2019 - Challenger Gold Mine - Calcrete Anomaly Exploration Success.

The discovery of Challenger brought about a hive of activity that resulted in companies like Helix Resources Limited (ASX: HLX) who announced news of drill holes hitting a 150 metre wide zone of gold mineralisation along the Yarlbrinda Shera Zone at Tunkillia (Source: AFR - Nov 19, 1996).

The Challenger Gold Mine was discovered by Dominion Mining Limited in 1995.

Figure 2: The Challenger Gold Mine was discovered by Dominion Mining Limited in 1995. (Source: Microsoft News)

The excitement that amplified the activities was due to Helix returning assays including 35m at 4.4 grams per tonne and 112m at 1g/t beneath a sand cover of between 60 metres and 100 metres (Source: AFR - Nov 19, 1996).

The significance of Challenger is that it produced a resource of over 1.2 Moz of gold but there are no cousins, brothers or sisters in the immediate area. There are small deposits like those in the Jumbuck project that was formerly in Tyranna Resources Limited (ASX: TYX) and now sold to Marmota Limited (ASX: MEU). Marmota have themselves found the Aurora Tank deposit which has yet to have resources but is definitely showing the same kind of mineralising signals as those discovered in the Jumbuck Project.

There are no significant deposits within a couple hundred kilometres. The closest significant deposit is the Tunkillia and Tarcoola to the south east or Cairn Hill to the north east. When you compare this to Kalgoorlie, there are hundreds of mines of all sizes and major exploration projects within that space.

Currently, the market space has changed and I see there have been a lot more attention on the Gawler Craton.

The Gawler Craton.

Figure 3: The Gawler Craton. (Source: Gum, Justine 2019. Gold mineral systems and exploration, Gawler Craton, South Australia, MESA Journal 91, Issue 3)