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Entering an immature exploration search space (Sandstone Greenstone Belt, W. Australia)

- By: John P Sykes
Posted in: Blog, Exploration, Management, Mineral Economics, PhD, Publications, Recommended, Research, Technical Paper Reviews


Last week, a publication by colleagues Sam Davies (University of Western Australia & Alto Metals), David Groves (Orebusters), Allan Trench (UWA), and Jon Standing (Model Earth), to which I also contributed was published in the peer reviewed journal ‘Ore Geology Reviews’. The paper is entitled “Entering an immature exploration search space: Assessment of the potential orogenic gold endowment of the Sandstone Greenstone Belt, Yilgarn Craton, by application of Zipf’s law and comparison with the adjacent Agnew Goldfield.”

In this paper, which is the first from Sam’s PhD research looking at applying mineral systems theory to practical exploration, we estimate the undiscovered gold endowment of the Sandstone greenstone belt in Western Australia, by anology to the more fully explored, but nonetheless similar in terms of mineral systems, Agnew goldfield, using Zipf’s Law. We estimate there is in excess of 20 million ounces of gold to be discovered at Sandstone, most of it in the poorly explored fresh rock below the oxide zone. Such an application of Zipf’s Law to not only estimate the undiscovered endowment of a mineral province but also identify where this endowment may be hidden is an important step-forward in applying academically generated mineral exploration theories in the practice by industry.

An abstract of the paper is included below, whilst a copy is available on ResearchGate.

“The Sandstone Greenstone Belt is an exploration-immature, regolith-covered, approximately 1000 sq. km belt, in the Southern Cross Domain of the Yilgarn Craton. In order to estimate potential endowment, historical gold production and deposit resource estimates are required to be quantitatively analysed for calculation of natural and residual gold endowment. The total residual gold endowment within the oxide zone of the Sandstone Greenstone Belt is estimated, by application of a Zipf’s law statistical assessment, to be 2.3 Moz. This mineralisation is most likely contained in extensions of known deposits and several undiscovered deposits. The fresh rock of the Sandstone Greenstone Belt remains poorly explored. However, a conceptual endowment estimate can be made, based on a minerals system comparison between the exploration-immature Sandstone Greenstone Belt and the well-explored, geologically-similar Agnew Greenstone Belt, 100 km to the east. It is possible that natural endowment at Sandstone could total 21.3 Moz, with nine undiscovered deposits of>0.5 Moz. Application of such a minerals-system integrated endowment assessment represents an effective motivator to embark on a well-resourced gold exploration campaign in the Sandstone Greenstone Belt, a currently immature exploration search space.”