Iron Ore – Hamersley Province, WA

The Hamersley Province is being mined at a rate of >850Mt of iron ore per year so understanding the mineralisation and its relationships with the weathered landscape of the Province to target new deposits and to better characterise orebodies is critical for the long-term sustainability of this iron ore province.

The MRIWA 557 Project (2020-2022) involves petrological, chemical, spectral, textural and age characterisation of selected and available drill cores of Martite-Goethite (M-G) ores and their weathering mantle to establish the parameters for distinguishing between the unweathered ore and the hydrated zone as well as the domaining within this hydrated zone including the boundary with the carapace. This fundamental understanding will be transformed into indicators or geomarkers (combinations of petrology, mineralogy, chemistry including trace elements, reflectance spectroscopy, 3D CT scanning, δ18O/ δ16O for goethite, hematite and kaolinite and datation with U-Th/He) that will be used to generate a guide to profile development and recognition of key weathering phenomena affecting M-G ores will developed including:
• To develop loggable weathering profile indicators.
• To predict the 3D distribution of ochreous and vitreous goethite, gibbsite, kaolinite and P-bearing minerals and the relationship to the structural architecture and geomorphology of the Hamersley Basin.
• Understand the minor and trace element distribution with martite-goethite ores and weathered mantle.
• Date the timing of martite-goethite mineralisation within the Brockman and Marra Mamba iron Formations.
• Date the timing of weathering processes overprinting the martite-goethite ores.
• Understand the paleoclimate of primary mineralisation and weathering.
• To predict the 3D distribution of martite-goethite ore and its relationship to the structural architecture and geomorphology of the Hamersley Basin.
• Develop a genetic model for martite-goethite ores and its weathering mantle.

This large, multidisciplinary research project by all West Australian iron ore producers and Bureau Veritas and, supported by Curtin University, UWA and the Geological Survey of WA will provide an integrated 4D understanding of the landscape evolution and weathering history of the Hamersley Province and its relationship to genesis and mineralisation of Martite-Goethite iron ore deposits. The understanding of the mineralisation events will improve orebody knowledge and support enhanced decision making from exploration to mining.

Iron ore is a vital commodity for WA with $5b of royalties and 50,000 employees in 2018. The enhanced understanding of the Hamersley Province orebody knowledge will assist find new deposits as well as optimise mining resulting in greater profitability, sustained royalty and employment for WA.