 | | Journal (article/letter/editorial) | | specimens featured here were collected by Herman du Plessis HE MOUNTAIN KINGDOM OF LESOTHO is located in...Gauteng, South Africa brucec@uj.ac.za HERMAN du PLESSIS 10 Howick Gardens Webb Street, Farramere Benoni...round, thatched huts is on the left. Herman du Plessis photo, January 2017. 306 ROCKS & MINERALS Figure...geology at the University of Johannesburg. Herman du Plessis is an avid field collector. Most of his mineral...4 cm, Butha-Buthe district, Lesotho. Herman du Plessis specimen, Bruce Cairncross photo. Figure 8 (above |  | | Journal (article/letter/editorial) | | ores (Ozkaya et al., 2007; Nurmi et al., 2009; du Plessis et al., 2011). The subsequent oxidation of Fe2+...two-stage reactor configuration recently proposed by du Plessis et al. (2011) was used for biological Fe2+ oxidation...consists of a limonite zone with the major minerals goethite and kaolinite, a clay (smectite) zone with mainly...in the Case One study were nontronite (44%) and goethite (24%), with various minor phases typically present...Pyrite Pyrrhotite Quartz Talc Vermiculite Violarite Goethite Smectite (nontronite) Hematite Jarosite/alunite |  | | Journal (article/letter/editorial) | | (mostly associated with iron oxide phases, such as goethite) and cobalt (mostly associated with manganese...and the major iron phases consisted mainly of goethite (~60%) together with magnetite and hematite. The...process liquors produced would require less in goethite but contained no detectable magnesium oxide, therefore...enhanced the solubilization of iron from ferric iron goethite but contained no detectable magnesium oxide, therefore...the associated with ferric iron minerals such as goethite present in the ore, and, therefore, that reductive |  | | Journal (article/letter/editorial) | | 362±370 Ó Springer-Verlag 1997 ARTICLE G. du Plessis á G.J. Jonck á R. Kruger Potential low-grade iron...in the Editorial handling: P.G. Eriksson G. du Plessis (&) á R. Kruger Geology, Iron Ore Business, Iscor...lens-shaped bodies of serpentinite and chromitite (Du Plessis 1996). Intrusive pegmatite veins and diabase dykes...caused by secondary hematite, limonite and lesser goethite weathering products. The BIF is interbedded with...magnetite is often totally oxidised to hematite, goethite and limonite. Alteration and oxidation of the |  | | Journal (article/letter/editorial) | | nickel laterite ores (Hallberg et al., 2011; du Plessis et al., 2011). Further studies are required to...surface chemistry of different iron oxides such as goethite and whether the purified protein fractions described...ferric iron bearing minerals, including haematite, goethite and ferrihydrite (Lower et al., 2001). The cell...preferential adhesion of the bacterium to haematite and goethite surfaces under aerobic ‘non-reducing’ conditions...minerals such as apatite and phosphorus containing goethite are commonly found in many Australian iron ore |  | | Journal (article/letter/editorial) | | Jansen (19821 gives a maxtmum of 6000 m. and du PlessIs ( 1987) a figure of 7000 m or (quoted in a paper...T%zkelI(1975); De Bruiyn (1971a. 1971b. 1972a. 1972b); Du Plessis (1972a. 1972b): Jansen (1969,1970a, 1970b. 1975a...in the MainBasin. and correlates sequences. Du Plessis ( 19871 studied rocks lying to it with the Wilge...Sterk River Formation grades laterally into the du Plessis supported Jansen’s original theories of Alma Formation...berg Formation In the southwest. These in turn Plessis and Walraven (19901 suggest a pull-apart grade |  | | Journal (article/letter/editorial) | | associated mainly with ferric iron minerals, such as goethite (FeO(OH)). Consortia of acidophilic bacteria have...oxidation of sulfur to the reductive dissolution of goethite, leading to the release of nickel from limonite...two processes: (i) abiotic acidic dissolution of goethite (Reaction (3)): FeO(OH) + 2 H+ → Fe3+ + OH− +...[CrossRef] [PubMed] Hallberg, K.B.; Grail, B.M.; du Plessis, C.A.; Johnson, D.B. Reductive dissolution of ferric... Miner. Eng. 2011, 24, 620–624. [CrossRef] du Plessis, C.A.; Slabbert, W.; Hallberg, K.B.; Johnson, D |  | Möller, V., Klemd, R., Joachimski, M., Barton, J.M. (2014) Hydrothermal controls on iron and lead mineralization on the farms Leeuwbosch and Cornwall, Thabazimbi District, South Africa. Ore Geology Reviews, 63. 40-63 doi:10.1016/j.oregeorev.2014.04.009 | Journal (article/letter/editorial) | | Thabazimbi (Fig. 2) (Anhaeusser and Poujol, 2004; Du Plessis and Clendenin, 1988). The Black Reef Formation...rhythmically banded iron oxide (hematite, magnetite, goethite), iron-silicate (chert, stilpnomelane, minnesotaite)...pinches out towards the northeast (Fig. 2; Du Plessis and Clendenin, 1988). To the east and north of...pre-existing zones of weakness in the basement (Du Plessis and Clendenin, 1988). The Thabazimbi–Murchison...Transvaal stratigraphy south of Thabazimbi (Du Plessis and Clendenin, 1988; Gutzmer et al., 2005) including |  | | Journal (article/letter/editorial) | | dolomite, calcite; (c) fluorite, apatite; and (d) goethite, chromite, magnetite and hematite. The density...dolomite, (G) calcite, (H) apatite, (I) fluorite, (J) goethite, (K) (D) quartz, (E) kaolinite, (F) dolomite,... (G) calcite, (H) apatite, (I) fluorite, (J) goethite, (K) chromite, chromite, (L) magnetite and (M)...Chlorite Chromite Corundum Dolomite Fluorite Gibbsite Goethite Grossular Hematite Ilmenite Kaolinite K-feldspar...their presence. A similar situation exists between goethite and chromite (Figure 6J,K) where the linear attenuation |  | | Journal (article/letter/editorial) | | on Fig. 1. Altered magnetite and precipitated goethite in ferricrete at the Salobo mine. (a) Backscattered...ferricrete particle. Fractures are infilled with goethite. (b) Microprobe data plot of magnetite, altered...martite) and goethite in (a) and similar particles. (c) Magnetite altered to hematite with goethite precipitates...calcite, allanite, Ca-amphibole, biotite, chlorite, goethite, apatite; Fig. 2b, d). Minerals were identified...at the Salobo mine and, along with hematite and goethite, forms a major component of the hard ferricrete |  | | Journal (article/letter/editorial) | | of tailings impoundments Hematite—magnetite (goethite-ferrihydrite) e.g., As, Se, Th, Cr, Cu, Zn, Ni...(Supergene) and Pegmatites Coal and Lignite Coal Goethite, hematite, kaolinite, e.g., As, Se, Th, Cr, Cu...oxides like for example magnetite, hematite, or goethite, these oxide minerals will not be stable under...(between Fe8O8(OH)6SO4 and Fe16O16(OH)10(SO4)3), and goethite (FeO(OH)), and the more stable secondary minerals...precipitate to ferrihydrite (fh), schwertmannite (sh), goethite (gt), or jarosite (jt) depending on pH-Eh conditions |  | Du Plessis, Pieter I., Gazley, Michael F., Tay, Stephanie L., Trunfull, Eliza F., Knorsch, Manuel, Branch, Thomas, Fourie, Louis F. (2021) Quantification of Kaolinite and Halloysite Using Machine Learning from FTIR, XRF, and Brightness Data. Minerals, 11 (12) 1350 doi:10.3390/min11121350 | Journal (article/letter/editorial) | | from FTIR, XRF, and Brightness Data Pieter I. Du Plessis 1 , Michael F. Gazley 2,3, *, Stephanie L. Tay...2 3 4 5 * Citation: Du Plessis, P.I.; Gazley, M.F.; Tay, S.L.; Trunfull, E.F.;...quartz, muscovite, smectite, anatase, rutile, goethite, calcite, dolomite, zircon, and florencite. Kaolinite...Iron has a positive correlation (PCC ≥ 0.4) with goethite, smectite, and muscovite, sug3.2. Mineral and...by on sample location. Apart from the Fe-oxide goethite, smectite is the main source of Fe other processes |  | | Journal (article/letter/editorial) | | this region are dominated by boehmite, hematite, goethite, diaspore and Fe Oxide Other REE anatase [45]...Fe oxide mineral phasesphases are likely to be goethite hematite; theseused were in analysed using SEM-EDS...REE could be hosted in iron oxide phases, e.g. goethite [8,50]. As the differences were small and only...2019, 236, 436–445. [CrossRef] Johnson, D.B.; du Plessis, C.A. Biomining in reverse gear: Using bacteria... 2–5. [CrossRef] Hallberg, K.B.; Grail, B.M.; Plessis, C.A.d.; Johnson, D.B. Reductive dissolution of |  | Soh Tamehe, Landry, Chongtao, Wei, Ganno, Sylvestre, Simon, Shaamu Jeremia, Kouankap Nono, Gus Djibril, Nzenti, Jean Paul, Lemdjou, Yanick Brice, Lin, Naing Htun (2019) Geology of the Gouap iron deposit, Congo craton, southern Cameroon: Implications for iron ore exploration. Ore Geology Reviews, 107. 1097-1128 doi:10.1016/j.oregeorev.2019.03.034 | Journal (article/letter/editorial) | | hematite−martite BIF (Fig. 5a) and consists of a mixture of goethite, limonite, magnetite and hematite. Weathered magnetite−hematite...floats of banded magnetite, massive magnetite and goethite−limonite were recognized at the western part of...magnetite to secondary minerals (hematite, martite, goethite, limonite) and leaching of silica gangue minerals...mainly composed of iron hydroxide minerals such as goethite and limonite. The data in Figure 16 show that...exploration targets for iron ore deposits (e.g., Du Plessis et al., 1997; Morrissey et al., 2016). Based on |  | Aiglsperger, Thomas, Proenza, Joaquin A., Lewis, John F., Labrador, Manuel, Svojtka, Martin, Rojas-Purón, Arturo, Longo, Francisco, Ďurišová, Jana (2016) Critical metals (REE, Sc, PGE) in Ni laterites from Cuba and the Dominican Republic. Ore Geology Reviews, 73. 127-147 doi:10.1016/j.oregeorev.2015.10.010 | Journal (article/letter/editorial) | | ACCEPTED MANUSCRIPT The ore minerals are mainly goethite (1.4 wt.% Ni), minor maghemite (up to 8 wt.%...ISTEEM (Universite´ Montpellier II, Montpellier, France; see Marchesi et al., 2006 for details on the applied...lizardite replacing AC primary olivine grains with goethite and chromian spinel as minor mineral phases. The...The oxide ore consists mainly of goethite (>50 wt.%) with minor maghemite, hematite and gibbsite. Original...parent rock are not preserved and locally some goethite grains show replacement by hematite. Maghemite |  | | Journal (article/letter/editorial) | | solution pH 2–5, transforms to goethite (reaction (3)) [43,44]. Goethite (FeIIIOOH): Formation is favoured...crystalline and unstable and transforms to either goethite (reaction (4)) [45,50] or jarosite (reaction (5))...iron(III) reduction and accelerate the dissolution of goethite in mildly acidic medium [116]. CuFeS2 + 2Fe2(SO4)3...hydroxide (FeIII(OH)3), akaganeite (β-FeIIIO(OH,Cl)), goethite or jarosite [115]. In the case of schwertmannite...Czech Republic Pyrenées, France Eastern Pyrenées, France Dauphiné Basin, France Selwyn Basin, YT, Canada |  | | Journal (article/letter/editorial) | | extractions were increased for laterites containing low goethite and moderate smectite content. Quast et al. [11]...rapidly in H2 SO4 compared with the more refractory goethite. Other studies have investigated the potential...and quartz (CaCO ) and cryptomelane (KMn O3), goethite (FeO(OH)), and quartz(SiO (SiO2 2),), while while...crystalline water and OH− group from the structure of goethite as well as the formation of hematite [44]. This...probably due to the higher degree of crystallinity of goethite [45]. The peaks at 530 and 570 ◦ C (Figure 4a |  | | Journal (article/letter/editorial) | | oxidized massive CE P hematite, limonite and goethite, and vein quartz breccia. 4.2.3.3. Mineralization...University‟s Central Analytical Facilities and Anton du Plessis for the use of their advanced nano-CT scanner....heterogeneous metasedimentary multilayer sequence (Brittany, France). Geofluids, 8, 143-158. SC R during progressive...the northern Variscan front zone (Bettrechies, France). Journal of Structural Geology, 22, 598–602. ...quartz veins. d) Highly altered gneiss exposed in quarry showing pervasive limonite and hematite CE P |  | | Journal (article/letter/editorial) | | indicators Eight disturbed samples were sent to BM du Plessis Civil Engineering labs for grading and Atterberg...(wt %) (wt %) (wt %) (wt %) Highveld (%) Goethite 11.79 12.82 1.9 19.03 Kaolinite 2.48 4...identified lithiophorite, birnessite and todorokite and goethite, hematite and maghemite as the common Mn and Fe...Mn-oxides manganite and todorokite with respect to goethite and mica or gibbsite. Therefore, the minerals |  | López Valdivieso, A, Celedón Cervantes, T, Song, S, Robledo Cabrera, A, Laskowski, J.S (2004) Dextrin as a non-toxic depressant for pyrite in flotation with xanthates as collector. Minerals Engineering, 17 (9). 1001-1006 doi:10.1016/j.mineng.2004.04.003 | Journal (article/letter/editorial) | | spectroscopy studies, that ferric oxyhydroxide, probably goethite, is the oxidation product. Nanopatches of ferric...Santiago, Chile, pp. 283–297. Miller, J.D., Du Plessis, R., Kotylar, D.G., Zhu, X., Simmons, G.L., 2002 |  | von der Heyden, Bjorn P., Frith, Matthew G., Bernasek, Steven, Tylizszak, Tolek, Roychoudhury, Alakendra N., Myneni, Satish C.B. (2018) Geochemistry of Al and Fe in freshwater and coastal water colloids from the west coast of Southern Africa. Geochimica et Cosmochimica Acta, 241. 56-68 doi:10.1016/j.gca.2018.08.043 | Journal (article/letter/editorial) | | chemically-reactive ferrihydrite aggregates, with minor goethite and hematite also observed (Hirst et al., 2017)...4.3. Crystalline Fe oxide fraction (including goethite, akaganeite, hematite): Sediment was extracted...intensity ratio two parameter plot (Fig. 3a). Goethite is the most common soil Fe oxy-hydroxide and has...number of fluvial samples overlap with the standard goethite spectral parameter field on the plot, which may...ΔeV = 1.57 ± 0.02) partially overlap with the goethite, akaganeite and 0.1 – 5% Al substituted oxide |  | Bolaños-Benítez, Viviana, van Hullebusch, Eric, Lens, Piet, Quantin, Cécile, van de Vossenberg, Jack, Subramanian, Sankaran, Sivry, Yann (2018) (Bio)leaching Behavior of Chromite Tailings. Minerals, 8 (6) 261 doi:10.3390/min8060261 | Journal (article/letter/editorial) | | University Paris Diderot, UMR 7154, CNRS, F-75005 Paris, France; vivi.bolanos.benitez@gmail.com (V.B.-B.); sivry@ipgp...Paris-Est, EA 4508, UPEM, 77454 Marne-la-Vallée, France Department of Environmental Engineering and Water...Sud-CNRS-Université Paris Saclay, 91405 Orsay CEDEX, France; cecile.quantin@u-psud.fr Department of Materials...of chromite, hematite, lizardite, chlorite, and goethite, which are all known as Cr-bearing phases. During...are locked either within the iron ore minerals (goethite/hematite) and silicates or the chromite with inclusions |  | | Journal (article/letter/editorial) | | (SiO2 ), muscovite [(KF)2 (Al2 O3 )3 (SiO2 )6 ], goethite [FeO(OH)], and carbonate gangue minerals based...Hydrometallurgy 2018, 179, 79–93. [CrossRef] Du Plessis, C.; Lambert, H.; Gärtner, R.S.; Ingram, K.; Slabbert...and electrokinetic processes in the iron oxide (Goethite)—Oleic acid—Oleate system. J. Colloid Interface |  | | Report (chapter) | | and oxysulfates such as ferrihydrite (Fe(OH)3), goethite (FeOOH) and iron sulphate polymorphs. Secondary...Ferrihydrite Dehydration leads to instability goethite Precipitate at ambient temperature Fe (III) to...Conceptual model of a closure plan for an open pit or quarry. restrict entry of water which will in turn reduce...conditions. For example at the Roquis mine, St Salvy, France, flooding of the underground workings has limited...ferrihydrite becomes unstable and converts to goethite (Waychunas et al. 1993). Arsenical ferrihydrite |  | | Journal (article/letter/editorial) | | chalcopyrite pyrite marcasite magnetite hematite goethite gibbsite calcite dolomite quartz mica total 62...Australia, 2007; p. 18. Zanin, M.; Lambert, H.; Du Plessis, C.A. Lime use and functionality in sulphide mineral |
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