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Benefits and limitations of applying directional shear strengths in 2D and 3D limit equilibrium models to predict slope stability in highly anisotropic rock masses
Published in Vladimir Litvinenko, Geomechanics and Geodynamics of Rock Masses: Selected Papers from the 2018 European Rock Mechanics Symposium, 2018
Neil Bar, Geoffrey Weekes, Senaka Welideniya
The stratigraphic units of economic interest to the iron ore mining industry consist of banded iron formation (BIF) with interbedded shales and carbonates. BIF thickness can vary due to differing amounts of carbonate dissolution and silica replacement during iron ore enrichment phases. The BIF sequences usually contain thick interbedded shale bands, some of which are useful stratigraphic marker horizons in the mining areas as they are very persistent across hundreds of kilometers (Harmsworth et al. 1990).
Benefits and limitations of applying directional shear strengths in 2D and 3D limit equilibrium models to predict slope stability in highly anisotropic rock masses
Published in Vladimir Litvinenko, EUROCK2018: Geomechanics and Geodynamics of Rock Masses, 2018
Neil Bar, Geoffrey Weekes, Senaka Welideniya
The stratigraphic units of economic interest to the iron ore mining industry consist of banded iron formation (BIF) with interbedded shales and carbonates. BIF thickness can vary due to differing amounts of carbonate dissolution and silica replacement during iron ore enrichment phases. The BIF sequences usually contain thick interbedded shale bands, some of which are useful stratigraphic marker horizons in the mining areas as they are very persistent across hundreds of kilometers (Harmsworth et al. 1990).
Iron ore beneficiation in the USA: Past and future
Published in Gülhan Özbayoğlu, Çetin Hoşten, M. Ümit Atalay, Cahit Hiçyılmaz, A. İhsan Arol, Mineral Processing on the Verge of the 21st Century, 2017
The iron ores in the Lake Superior Region is a typical example of banded iron formation (BIF). BIF is a sedimentary rock deposited about 2 billion years ago with layers of iron oxides, either hematite or magnetite, alternately banded with layers of silica and silicates, analyzing normally 20–30%Fe. By the action of meteoric water, the leaching of siliceous components led to the oxidation of magnetite and enrichment of iron, thereby forming hematite and goethite deposits. Ore grades in the enrichment zone tend to decrease with depth and eventually reach the protore as mining proceeds.
The isotope geochemistry of host rocks of the late Archean Guandi and Banshigou banded iron formations, southern Jilin Province: temporal and tectonic significance
Published in Australian Journal of Earth Sciences, 2023
Banded iron formations (BIFs) are ferritic metasedimentary rocks that were widely deposited in the Precambrian, first appeared at 3.8 Ga and were continuously distributed from 3.6 to 1.6 Ga (Wang et al., 2011). The quantity and reserves peaked at 2.8–2.7 Ga, 2.5–2.4 Ga and 1.9–1.8 Ga, and then disappeared at 1.4 Ga. BIFs are classified as either Algoma-type or Superior-type based on depositional settings and, to some extent, on their depositional ages (Gross, 1980). BIFs serve as a record of the evolution of the lithosphere, hydrosphere, atmosphere and biosphere of the Earth (Cloud, 1973). BIFs are made up of iron oxides, silicates and carbonate minerals (Li et al., 2007). BIFs are widely distributed in the Yilgarn and Pilbara cratons in Western Australia with large or giant iron ore deposits in the Hamersley Basin and Youanmi Terrane. Considerable research has been conducted on these deposits. In addition, BIFs in the North China Craton (NCC), such as the Dengfeng BIFs (Huang et al., 2019), are different from those in Australia. Although they have similar metallogenic ages, the Chinese BIFs do not appear to have suffered the deep weathering seen in the Australian systems.
Geometallurgical characterisation of a Channel Iron Deposit (CID) Ore
Published in Mineral Processing and Extractive Metallurgy, 2022
Huibin Li, D. J. Pinson, P. Zulli, L. Lu, R. J. Longbottom, S. J. Chew, B. J. Monaghan, G. Zhang
The typical structure of the hematite lumps selected from Ore A is presented in Figure 4. It consists of banded iron-formation (BIF) which is finely layered sedimentary rock composed of alternating bands of dense and porous iron oxide. The bands of the ore marked as H1 and H2 represent the dense skeleton of the ore body. The porous layers between these bands contain small amounts of distributed clay, observable in the EDS results of points C1 and C2 in Table 2. The carbon mapping in Figure 4 shows that resin has penetrated the porous layers, while the Si and Al distributions show that fine clay particles were dispersed in the porous layers. Traditional hematite Ore A was selected as reference due to its simple structure and stable characteristics under high temperatures. After heating at 1200°C individually, the changes of the Ore A structure were negligible, because hematite and clay mentioned above were stable at high temperature without existence of fluxing materials, and the XRD patterns of Ore A after heating at high temperatures were the same as the original patterns.
Petrography of martite–goethite ore and implications for ore genesis, South Flank, Hamersley Province, Western Australia
Published in Australian Journal of Earth Sciences, 2021
The M–G style of mineralisation was first described petrographically by Morris (1980) and further descriptions appear in Morris (1983, 1985, 1991) and Ramanaidou and Morris (2010). One of the key diagnostic features of this ore type is the way in which the primary texture of the banded iron formation (BIF) is preserved during the iron enrichment process. Original magnetite euhedra are pseudomorphed by hematite (this pseudomorphic hematite is termed ‘martite’) and the gangue phases are pseudomorphed by goethite (carbonate rhombs are replaced first, followed by Fe-silicate phases and finally quartz: Morris, 1985; Ramanaidou et al., 2008). The goethite that forms after carbonate is significantly more aluminous and siliceous than the goethite that forms after quartz, and goethite after silicate is intermediate in composition between the two (Ramanaidou et al., 2008). Ramanaidou and Morris (2010) point out that although this ore-forming process is supergene, there is a clear distinction between the ‘mimetic’ textural preservation typical of M–G ores and the texturally destructive iron enrichment associated with lateritic weathering.