Chris Byrne: Bauloora, Black Range, and Drake – rediscovering NSW’s large epithermal systems

Exploration in NSW has been largely dominated by a focus on porphyry systems and is known for hosting Australia’s largest porphyry deposit at Cadia (50Moz Au, 9Mt Cu). While host to some large epithermal deposits, including Cowal (15Moz) and Bowden’s (400Moz), there has been comparatively little exploration for low sulphidation epithermal systems in the Lachlan Orogen. Actively reviving exploration for these systems, Legacy Minerals (ASX: LGM) Minerals controls three major projects, Black Range, Bauloora (under a 2023 JV with Newmont Corporation) and Drake located in the New England Orogen.

Black Range and Bauloora are Devonian/Silurian (Palaeozoic) aged systems and have been largely overlooked because they are the ‘wrong aged rocks’ further complicated by overprinting mineralisation. Normally found in later geological settings, like PNG, Japan, and South America, there was a perception that preservation of an economic deposit was unlikely. However, the petrographic study of sinter lithology by Legacy Minerals for the first time on both projects was a technical breakthrough, confirming preservation and recognition of some of the world’s oldest preserved sinter related lithologies.

While Bauloora and Black Range are relatively early in their exploration lifecycle, Drake is a more advanced, Permian aged system with similarities to other Pacific Rim carbonate base metal deposits. Legacy Minerals is aiming to reset the exploration narrative, rethinking the targeting and deploying a large scale and systematic approach that moves away from viewing it through a mining focused project development lens.

This weeks talk with Christopher Byrne presents the system models used for mineralisation at the Bauloora Project, Black Range, and Drake. It will also provide an overview on how the Legacy Minerals exploration approach to a broad, systematic model drivel exploration program, has resulted in some significant technical breakthroughs across the projects.