AIG Gold24 International Symposium 2024

Abstract

Gosowong re-born - Discovery and geology of the Shallut deposit, Halmahera, Indonesia

Authors: Roderick Carlson (AMC Consultants), Daud Silitonga, Sejati Awang Wibowo, Reza Ardiansyah (PT Nusa Halmahera Minerals).

The Shallut (a.k.a Salut) deposit within the Gosowong epithermal field contains Indicated and Inferred Mineral Resources of 2.7 Mt @ 11.7 g/t Au for 1 Moz Au. Discovery of this classic low to intermediate sulphidation quartz vein-hosted gold deposit adjacent to the Toguraci deposit in Gosowong is testament to corporate belief, the right address, and classic epithermal system architecture.

Gosowong gold mine on the island of Halmahera in North Maluku Province, Indonesia (Figure 1) was first discovered by geologists from Newcrest Mining Limited (Newcrest) in 1994 (in a Joint Venture with PT Aneka Tambang), a Contract of Work was granted in 1997, and first gold doré poured in July 1999. It has produced over 6.7 Moz Au up to 2022 averaging 290 koz Au per year (S&P Global, 2024).

The Gosowong discovery and geology have been described by many authors including Carlile et al, (1998), Olberg et al. (1999), Richards and Priyono (2004), Gemmell (2007), Corbett (2012), Fitzpatrick et al. (2015), Clark and Gemmell (2018) and Saputro et al. (2023b).

The original Gosowong vein found via mapping and stream float (Carlile, 1998) started a long history of discovery and expansion commonly with limited Ore Reserve mine life. The discovery of the Shallut Vein continues the story on from Gosowong, Kencana and Toguraci where drilling was used to test and expand initial low-grade intercepts resulting in the discovery of high-grade gold-silver epithermal veins.

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