Eliwana - Flying Fish |
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Western Australia, WA, Australia |
Main commodities:
Fe
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Eliwana and Flying Fish Iron Ore deposits are located in the SW Hamersley Basin, 60 to 110 km WNW of Tom Price in the Pilbara Region of Western Australia.
See the Hamersley Basin Iron Province record for the regional setting and stratigraphy.
These deposits are developed over a strike length of 50 km along a pair of parallel ridges that are 1 to 5 km apart, composed of Marra Mamba and Brockman Iron Formation respectively. Mineralisation is distributed variably over a width of 3.5 km across strike. The deposits comprise a number of discrete zones of predominantly supergene martite-goethite and martite-ochreous goethite mineralisation, with minor occurrences of economic Channel Iron Deposit and Detrital Iron Deposit. There is also evidence of micro-platy hematite within specific zones of the deposit inferring a more complex paragenesis than only supergene mineralisation (Kepert et al., 2017).
This part of the Hamersley Province is characterised by a dome and keel structural regime crosscut by Ophthalmian folding. Both Eliwana and Flying Fish are located on the south dipping limb between the Rocklean Jeerinah Anticline and the Brockman Syncline. The subdued northern Marra Mamba Iron Formation ridge hosts the Flying Fish and Broadway deposits to the east and west respectively. The southern, more rugged Brockman Iron Formation hosts the Eliwana deposit to the west and the west and the Brockman 1 deposit in the east (Kepert et al., 2017).
This 50 km strike length is divided into three structural domains; i). western or Eliwana domain with a regional trend of ~100° cross-cut by 1 to 2 km wavelength. 110° trending Ophthalmian folds; ii). eastern or flying fish Domain striking at ~80° with no notable Ophthalmian folds; iii). far eastern domain on the east-dipping flexure of the Jeerinah Anticline cut at a high angle by Ophthalmian fold. Late Ophthalmian NW and west striking extensional faulting is best developed in the west and defines subdomains that control mineralisation (Kepert et al., 2017).
Supergene oxide mineralisation within the Marra Mamba Iron Formation is mainly found within the upper Mount Newman Member near surface, but extends Down stratigraphy through the MacLeod and Nummuldi members. The overlying West Angela Member also hosts some mineralisation at Flying Fish. Mineralisation extends from the surface to depths of 150 m, ranging in true thickness from 5 to 50 m, averaging 15 to 20 m, developed as a stratigraphic top down enrichment process (Kepert et al., 2017).
Within the Brockman Iron Formation the enriched mineralisation mainly occurs within the Dales Gorge and lower Joffre members as a number of discrete lenses. The most significant of these is West End where martite-goethite mineralisation extends over a stratigraphic thickness of >200 m. The Palaeosurface controls the mineralisation which at depth splits into a number of stratigraphic controlled fingers. Ophthalmian folding influences discrete shallow east plunging lenses of mineralisation through localised structural thickening that focused supergene fluid flow (Kepert et al., 2017).
Late Ophthalmian faulting produced a set of NW trending grabens and half grabens abd discrete east-west trending faults that locally controlled supergene mineralisation. Locally significant martite-microplaty hematite related alteration is preserved adjacent to faults. There is evidence that Proterozoic fluid flow along faults has been preferentially overprinted by Cretaceous to Paleogene supergene fluids producing well developed mineralising systems (Kepert et al., 2017).
Within the Eliwana-Flying Fish deposits, pre-mining Ore Reserves and Mineral Resources at 30th June 2019 (Fortescue Metals Group Reserve and Resource Statement, 2019) were:
Proved + Probable Reserves - 213 Mt @ 60.1% Fe, 4.88% SiO2, 2.42% Al2O3, 0.126% P;
Measured + Indicated + Inferred Resources - 1010 Mt @ 58.8% Fe, 5.48% SiO2, 3.03% Al2O3, 0.083% P;
NOTE: Mineral Resources are inclusive of Ore Reserves.
The most recent source geological information used to prepare this decription was dated: 2017.
This description is a summary from published sources, the chief of which are listed below. © Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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Kepert, D., Robinson, S., Clarke, N. and Nitschke, N., 2017 - Nyidinghu and Eliwana-Flying Fish bedded iron deposits: in Phillips, G.N., (Ed.), 2017 Australian Ore Deposits, The AusIMM, Melbourne, Mono 32, pp. 359-362.
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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