Predicting grade-tonnage characteristics of undiscovered mineralisation: application of the USGS Three-part Undiscovered Mineral Resource Assessment to the Sandstone Greenstone Belt of the Yilgarn Block, Western Australia

ABSTRACT

The United States Geological Survey (USGS) Three-part Undiscovered Mineral Resource Assessment provides a framework for estimating undiscovered mineral endowment. Previous studies that applied the Three-part Assessment to estimate the undiscovered orogenic gold endowment of the Sandstone Greenstone Belt, Western Australia, have relied upon dated or expert-derived grade-tonnage models. Here, several assessments are conducted using local grade-tonnage models, comprising known orogenic gold deposits within the entire Yilgarn Block and several individual terranes with contrasting lithosphere- to terrane-scale characteristics. These models are generated through comprehensive review of historical exploration, resource and production data. Based on these models, the Sandstone Greenstone Belt is estimated to contain significant undiscovered gold mineralisation, with a median total endowment of between 166 and 298 t gold, and mean of 167–319 t gold. Although these updated grade-tonnage models provide an approximately 80 per cent variation in predicted gold endowment, it is still evident that the belt remains an under-explored region within the Yilgarn Block, Western Australia.

KEYWORDS:

• Sandstone Greenstone Belt
• Yilgarn Block
• orogenic gold
• USGS Three-part Undiscovered Mineral Resource Assessment

Acknowledgements

This research was funded by an Australian Government Research Training Program (RTP) Scholarship and Society of Economic Geologists (SEG) Graduate Student Fellowship Grant. Thanks are due to Rebecca Seal for her continuing feedback and support. The support of this project by Alto Metals Ltd., and particularly Dermot Ryan, Mike Kammerman, and Changshun Jia, is also gratefully acknowledged.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Department of Education Employment and Workplace Relations Australian Government [22056287]; Society of Economic Geologists Foundation [GSF_18-05].