The Eliwana iron ore deposits are a series of hematite and goethite deposits that form part of the future mine development of Fortescue Metals Groups Western Hub.
Located within the western Hamersley Range, Pilbara region, Western Australia, the deposits form several mineralised areas, occurring in both Brockman and Marra Mamba Iron Formation stratigraphies.Mineralisation is predominantly supergene in nature, in which the parent host lithology (primary BIF), has undergone oxidation and chemical alteration to depths often beyond 100 metres.
In geologically favourable conditions, this process has converted the dominantly magnetite + chert BIF to an iron oxide (martite-goethite) dominant unit.
Areas of higher supergene alteration generally coincide with areas of higher iron grade, and therefore areas of greater economic importance.Within the project area there are also occurrences of channel iron deposit and detrital iron deposit known to exist.
In certain areas these are of a size and grade large enough to add to the total mining inventory.
Evidence supporting the occurrence of microplaty hematite within specific zones of the deposit has also been found, inferring a more complex paragenesis than only a simple supergene mineralisation phase.Since the initial exploration of the Eliwana deposits, there have been several phases of development which have allowed the project to progress to the point of decision to mine.
This has included extensive reverse circulation drilling focussed on the best opportunity areas, together with a large amount of diamond core drilling.
Both have supplied the basic data required to complete a feasibility study upon the project.
CITATION:Simpson, C and Walker, R, 2019. Eliwana iron ore deposits, in Proceedings Iron Ore 2019, pp 492504 (The Australasian Institute of Mining and Metallurgy: Melbourne).