Genesis of the Koolyanobbing iron ore deposits, Yilgarn Province, WA, Australia

Lascelles, Desmond F.

doi:10.1179/174327507x167055

Cited by 7 publications

(5 citation statements)

References 7 publications

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“…The supergene dissolution of hypogene carbonate replacing chert bands that characterises the s-mh ore model (Barley et al 1999;Taylor et al 2001;Dalstra et al 2002;Dalstra & Guedes 2004;Thorne et al 2004Thorne et al , 2007Dalstra 2005;Lascelles 2006bLascelles , 2007b) is a process of hydrolysis (+oxidation) as in Equation 2.…”

Section: Saprolite Formationmentioning

confidence: 96%

“…Close examination of typical saprolite high-grade hematitic ore deposits reveals no evidence of the presence of chert bands prior to weathering, in sharp contrast to the surface ferrugenisation of BIF outcrops (Figure 1a) or the comparatively shallow supergene enriched ore deposits ( Figure 1b) where evidence of the former presence of chert bands is very clear. An exception occurs in the case of the supergene-modified hypogene (s-mh) high-grade ore deposits (Taylor et al 2001;Thorne et al 2004Thorne et al , 2007Lascelles 2006bLascelles , 2007b where voids or residual hematite/goethite typically indicate the leached carbonate bands that replaced the chert.…”

Section: Introductionmentioning

confidence: 96%

“…Only with the advent of deep diamond holes for stratigraphic studies and the evaluation of magnetite BIF resources (Lascelles 2006b) was the deeply weathered nature of the BIF realised. * The discovery of the supergene-modified hypogene (s-mh) ore at Mt Tom Price and elsewhere (Taylor et al 2001;Lascelles 2006bLascelles , 2007b has given grounds for reinterpretation of the major direct-shipping ore deposits around the world but has not affected the automatic assumption of supergene enrichment for martite goethite (M-G) ore deposits that show no trace of hypogene or metamorphic alteration.…”

Section: Introductionmentioning

confidence: 98%

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

Lascelles

2012

Australian Journal of Earth Sciences

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All the major worldwide direct-shipping iron ore deposits associated with banded iron formations (BIF) are characteristically deeply weathered. They extend to considerable depths below the water table and show well-preserved primary structures and textures, but characteristically most deposits contain no evidence of chert bands being present prior to weathering. Recent studies have found evidence of hydrothermal and/ or metamorphic influences in the development of certain ore deposits and new genesis models such as the supergene-modified hypogene model have been postulated for major high-grade iron ore deposits. Nevertheless, there are many high-grade deposits that show no evidence of hypogene alteration and for which a hypogene or metamorphic genesis is unreasonable that are automatically ascribed to supergene enrichment, commonly erroneously attributed to lateritic weathering in tropical environments. Laterite (sensu lato) is a soil formation in which primary textures are destroyed and is underlain by a pallid zone showing the preservation of chert and the depletion, not enrichment, of iron oxides and thus is totally incompatible with the formation of the high-grade ore deposits. Various theories and models that purported to explain the conditions under which such a uniquely BIF-related dissolution of quartz and residual accumulation of hematite could occur by supergene processes typically conflict with current understanding of groundwater hydrology, chemistry, weathering processes and soil formation.Supergene enrichment of ore is universal in the leaching of gangue minerals such as iron silicates, carbonates and apatite and supergene enrichment of BIF to low-grade ore is common in near surface environments above the water table such as ferrugenised BIF outcrops, detrital ore deposits, and some shallow ore deposits that have been subjected to prolonged exposure to fresh meteoric water. In all cases of supergene enrichment traces of the chert bands are visible and the dissolution or replacement processes for the removal of quartz are clear, in direct contrast to the most important deep saprolite ore deposits that show no trace of chert bands.The widespread acceptance of an inappropriate and untenable supergene enrichment model inhibits search for the true origin of the ore and our ability to predict and find concealed high-grade ore deposits.

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Section: Saprolite Formationmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 98%

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

Lascelles

2012

Australian Journal of Earth Sciences

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“…2,5,6 High grade iron ore deposits formed owing to enrichment of these formations by gradual removal of silica. 4,18 It is possible that the massive ores are the result of direct precipitation while powdery blue dust is formed owing to circulating waters developed in palaeo-hydrological channels, which leached away the silica from massive ores. The principal iron minerals are oxides (haematite and magnetite) and hydroxides (goethite and limonite) in Jilling-Langalota while the Chitradurga deposit has a predominantly oxide-sulphide-carbonate association indicating differences in the environment of deposition.…”

Section: Geological Aspects and Controls Of Mineralisation Of The Thr...mentioning

confidence: 99%

“…Most of the iron ore slimes are very fine in nature (,150 mm) and proper characterisation is very difficult. 9,12,13,18,22,24 Most of the reported characterisation studies in these cases have been concerned more with the chemical composition rather than with the mineralogy, grain morphology, liberation studies, particle size distribution, etc. Hence, mineralogical and geochemical characterisation is important before beneficiation.…”

Section: Introductionmentioning

confidence: 99%

A comparative mineralogical and geochemical characterisation of iron ores from two Indian Precambrian deposits and Krivoy rog deposit, Ukraine: implications for the upgrading of lean grade ore

Das¹,

Venkatesh²

2008

Applied Earth Science

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Iron ores from two important Precambrian belts in India are studied in detail. The first of these is the Jilling-Langalota deposit, hosted by banded iron formations along with generations of shales, tuffs belonging to Iron Ore Group of Eastern India and is hosted in the Singhbhum-North Orissa Craton. The second group of ores is from the Chitradurga basin in Eastern Dharwar Craton, Southern India. These form part of the Archaean greenstone belts and show a typical oxidecarbonate-sulphide association. The Jilling-Langalota deposit contains considerable amounts of blue dust that is absent in the Chitradurga deposit. Comparisons are made between the Indian iron ores and those of the Krivoy Rog province of the Central Ukrainian Shield. The Indian iron ores are relatively richer in Fe and contain higher amounts of alumina and phosphorous compared with those of the Krivoy Rog deposit. The Indian iron ore samples contain porous and friable oxides and hydroxides of iron with kaolinite, gibbsite and quartz. In contrast, the ores from Krivoy Rog are massive with negligible clay and a higher quartz content leading to very low alumina and very high silica contents in the ores and slime. The Indian ores and slimes are manganiferous in nature with high alumina, which is deleterious to processing and is due to the presence of intercalated tuffaceous shales and clay. The Eastern Indian iron ore deposits could have been formed due to enrichment of the primary ore by gradual removal of silica. It is believed that the massive ores result from direct precipitation while powdery blue dust is formed owing to circulating fluids, which leach away the silica from the protore. The host rock is exhalatic banded iron formation and the ubiquitous presence of intercalated tuffaceous shales point towards a genesis that could have involved Fe leaching from sea floor volcanogenic rocks. The nature of these ores along with the parting shale is responsible for production of large amounts of alumina rich slime during mining and handling. The detailed mineralogical characterisation studies aided by X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, physical parameters and chemical characteristics have indicated the presence of various mineral phases and established the nature of iron-bearing and gangue assemblages of the bulk ores and slime samples from the three iron ore deposits. These in turn are useful in understanding the amenability of the ores and slimes for beneficiation and waste utilisation.

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3D implicit modeling of the Sishen Mine: new resolution of the geometry and origin of Fe mineralization

Stoch¹,

Anthonissen²,

McCall³

et al. 2017

Miner Deposita

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Genesis of the Koolyanobbing iron ore deposits, Yilgarn Province, WA, Australia

Cited by 7 publications

References 7 publications

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

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

A comparative mineralogical and geochemical characterisation of iron ores from two Indian Precambrian deposits and Krivoy rog deposit, Ukraine: implications for the upgrading of lean grade ore

3D implicit modeling of the Sishen Mine: new resolution of the geometry and origin of Fe mineralization

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