Iron formation-hosted iron ores in the Hamersley Province of Western Australia

Abstract

Iron formation-hosted iron ore deposits account for the majority of current world iron ore production and consist of three classes: unenriched primary iron formation with typically 25 to 45 wt-%Fe; martite-goethite ore formed by supergene processes, with abundant hydrous iron oxides containing 60 to 63 wt-%Fe; high-grade hematite ores thought to be of hypogene or metamorphic origin overprinted by subsequent supergene enrichment with 60 to 68 wt-%Fe. Individual iron ore deposits range from a few millions of tonnes to over two billion tonnes at .64 wt-%Fe, although most are within the range of 200 to 500 Mt. In the Hamersley province of Western Australia, martitegoethite ores are largely developed in the Marra Mamba iron formation, although high (.0 . 08 %P) phosphorous mineralisation is also well developed in the stratigraphically higher Brockman iron formation. While the vast majority of high-grade microplaty hematite ore is best developed in the Brockman iron formation, the present paper provides the first textural evidence of locally significant microplaty hematite mineralisation in the Nammuldi member of the Marra Mamba iron formation, in the Chichester Ranges at the Christmas Creek, Cloud Break and Mount Nicholas prospects. Petrographic studies have identified a high-grade Fe texture composed of nanometre scale plates of hematite in mineralised sections of primary microplaty hematite deposits in the Pilbara and elsewhere, well below the normal depth of weathering or dehydration. The population of nanometre to micrometre scale hematite plates is interpreted to represent various stages of nucleation, crystallisation and progressive growth of hematite from the primary ore-forming fluid in areas that were once iron-rich carbonates or silicates in the banded iron formation.

Types and geological characteristics of iron deposits in China

“…These high-grade ores are formed by weathering and leaching of silica from the BIFs (Clout, 2006;Beukes et al, 2008), though there are many other theories about what upgrades BIFs to high-grade hematite ores (e.g. Rosière and Rios, 2004;Beukes et al, 2008;Rasmussen et al, 2014).…”

Mineralogical, chemical, and physical characteristics of iron ore

“…There are many other major to minor gangue minerals associated with iron ore deposits including many different 1 Ternary mineralogy plot for various seaborne-traded iron ore products from Western Australia (Pilbara) and Brazil. Furthermore, Clout (2005) provided evidence that it is these complex textures and not mineralogy alone that control metallurgical process performance from crushing to screening, beneficiation and agglomeration (sintering or pelletizing) of fine ores or concentrates, and lump burden behavior in the blast furnace. From Clout and Fitzgerald (2011). silicates (including amphiboles and chlorites), carbonates (siderite and ankerite), sulfides (e.g., pyrite), and oxides (e.g., pyrolusite).…”

“…Vertical scale = horizontal scale, and depth of supergene alteration is 5-150 m. Modified from Clout (2005 a term to describe loose detrital material and cemented martite-hematite conglomerate at the surface. Vertical scale = horizontal scale, and depth of supergene alteration is 5-150 m. Modified from Clout (2005 a term to describe loose detrital material and cemented martite-hematite conglomerate at the surface.…”

“…Analogous ore textural groups have been documented from iron ore deposits in Australia, Brazil, and Africa (Clout, 2002(Clout, , 2005. The principles of the ore group classification scheme formed the basis for the material-type classification used by Rio Tinto Iron Ore for logging of drill holes and geologic mapping (Box et al, 2002;Clout, 2002).…”

Banded iron formation to high-grade iron ore: a critical review of supergene enrichment models

“…This has been construed as a prerequisite for their existence instead of merely the discovery of the ore. In describing deposits, many authors simply state that the ore is supergene implying a genetic relationship without presenting any supporting evidence or explanation of how this occurred (Leith 1903;Dorr 1964;MacLeod 1966;Neale 1975a;Berge et al 1977;Bourn & Jackson 1979;Morris 1983;Kneeshaw 1984;Podmore 1990;Taylor et al 2001;Clout 2005;Clout & Rowley 2009;Hannon et al 2005). Other authors have listed factors such as special structures, igneous intrusions, aquacludes and extreme long-term weathering to account for the supergene enrichment of the particular ore body that are not only present in the adjacent unenriched BIF but are absent from many other high-grade iron ore deposits (Neale 1975b;Harmsworth et al 1990;Paquay & Ness 1998;Hodgekiewicz et al 2005;Bodycoat 2007).…”