The Witwatersrand Basin, South Africa: Geological framework and mineralization processes

Robb, L. J.; Meyer, Franz Michael

doi:10.1016/0169-1368(95)00011-9

Cited by 194 publications

(100 citation statements)

References 52 publications

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“…Cr is hosted in phyllosilicates, and a similar moderate enrichment has been recorded by Craw, Windle, and Angus (1999). U enrichment in tailings dumps may be explained by the enhanced uranium content of the Dominion Reef (one of the gold-bearing horizons mined on the Witwatersrand) (Robb and Meyer, 1995). Pb indicates a moderate enrichment, which can be explained by the fact that galena (PbS) is one of minerals associated with gold ore. Pb occurs also as the end-member of the uranium radioactive decay series.…”

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confidence: 92%

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Health risk posed by enriched heavy metals (As, Cd, and Cr) in airborne particles from Witwatersrand gold tailings

Maseki

Annegarn

Spiers

2017

J. South. Afr. Inst. Min. Metall.

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Severe episodes of windblown dust from mine tailings storage facilities (TSFs) are a common phenomenon on the Witwatersrand, especially during the spring windy season. For communities around TSFs, such events pose health and environmental challenges. This paper reports on health risk assessment using US Environmental Protection Agency (US EPA) risk assessment methods for heavy metal elements in windblown dust from TSFs on the central and east Witwatersrand. Samples of surface material from these TSFs were analysed for heavy metal content using inductively coupled plasma-mass spectrometry (ICP-MS). From a range of 30 heavy metals analysed, only As, Cd, Cr, Pb, and U were enriched by a factor of two or more above the average crustal composition and at concentrations that could be of possible health concern-elements present in the range of a few parts per billion (ppb) or lower were ignored. As, Cd, Cr, Pb and U were selected for a comprehensive risk assessment from exposure through airborne routes, mainly considering inhalation and ingestion. Ambient exposures were based on a worst-case measured episode of 540 μg m -3 (24-hour average), which was projected over each day of an annual exposure for the hours for which the wind speed was above the threshold for dust generation. US EPA risk assessment methods were used to determine the inhalation and ingestion hazard quotients and hazard indices for adults and children. The sum of the hazard indices was assessed to be below the non-cancer benchmark (hazard indices 1.0) considered to be acceptable for a lifetime exposure. The total risk for both exposures (inhalation and the ingestion) was within the range of 1 per 1 000 000 to 100 per 1 000 000-taken as 'acceptable risk' by the US EPA for adults and children. These results represent the first quantitative health risk assessment of the hazard posed by heavy metals in windblown mine tailings dust on the Witwatersrand goldfield. mine tailings, dust, airborne particles, health risk, inhalation, ingestion heavy metals, arsenic, cadmium, chromium.

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confidence: 92%

“…Concentrations of elements below the Earth crustal average, including K, Mn, Zn, Fe, are not surprising for the gold tailings material (a silica-rich mineral matrix) (Frimmel and Minter, 2002;Robb and Meyer, 1995).…”

mentioning

confidence: 99%

Health risk posed by enriched heavy metals (As, Cd, and Cr) in airborne particles from Witwatersrand gold tailings

Maseki

Annegarn

Spiers

2017

J. South. Afr. Inst. Min. Metall.

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“…The Ventersdorp bimodal volcanic association of felsic to mafic lavas and pyroclastics with subordinate basal komatiites (2.71 Ga) overlies the Witwatersrand succession. It was suggested by Robb and Meyer [1995] that both the Dominion and the Ventersdorp volcanics were erupted during periods of extensional tectonic activity and that the main stage of the Witwatersrand basin evolution was linked with collision of the Zimbabwe and Kaapvaal cratons. A more recent model [Catuneanu, 2001] supports a complex flexural foreland basin evolution resulting from collision of two oceandisplaced arc terranes [de Wit et al, 1992] with the Kaapvaal cratonic nucleus.…”

Section: The Intracontinental Development Beyond Lauroscandiamentioning

confidence: 99%

Age and isotopic geochemical characteristics of Archean carbonatites and alkaline rocks of the Baltic shield

2007

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Paradoxically, the lists of "proxies" of both plate-and plume-related settings are devoid of even a mention of the high-grade metamorphic rocks (granulite, amphibolite and high-temperature eclogite facies). However, the granulite-gneiss belts and areas which contain these rocks, have a regional distribution in both the Precambrian and the Phanerozoic records. The origin and evolution of the granulite-gneiss belts correspond to the activity of plumes expressed in vigorous heating of the continental crust; intraplate magmatism; formation of rift depressions filled with sediments, juvenile lavas, and pyroclastic flow deposits; and metamorphism of lower and middle crustal complexes under conditions of granulite and high-temperature amphibolite facies that spreads over the fill of rift depressions also. Granulite-gneiss complexes of the East European Craton form one of the main components of the large oval intracontinental tectonic terranes of regional or continental rank. Inclusion of the granulite-gneiss complexes from Eastern Europe, North and South America, Africa, India, China and Australia in discussion of the problem indicated in the title to this paper, suggests consideration of a significant change in existing views on the relations between the plate-and plume-tectonic processes in geological history, as well as in supercontinent assembly and decay. The East European and North American cratons are fragments of the long-lived supercontinent Lauroscandia. After its appearance at ~2.8 Ga, the crust of this supercontinent evolved under the influence of the sequence of powerful mantle plumes (superplumes) up to ~0.85 Ga. During this time Lauroscandia was subjected to rifting, partial breakup and the following reconstruction of the continent. The processes of plate-tectonic type (rifting with the transition to spreading and closing of the short-lived ocean with subduction) within Lauroscandia were controlled by the superplumes. Revision of the nature of the granulite-gneiss complexes has led to a fundamental new understanding of: a more important role than envisaged previously for mantle-plume processes in the juvenile additions to the continental crust, especially during the Neoarchaean-Proterozoic; the existence of the supercontinent Lauroscandia from ~2.80 to 0.85 Ga; the leading role of mantle plumes in the interaction of plate-and plume-tectonics in the Neoarchaean-Proterozoic history of Lauroscandia and perhaps of the continental crust as a whole. We propose that the evolution of the geodynamic settings of the Earth's crust origin can be represented as a spiral sequence: the interaction of mantle-plume processes and embryonic microplate tectonics during the Palaeo-Mezoarchaean (~3.8-2.8 Ga) → plume-tectonics and local plume-driven plate-tectonics (~2.80-0.55 Ga) → Phanerozoic plate tectonics along with a reduced role of mantle plumes.Key words: Precambrian; plate-tectonics; plume-tectonics; granulite-gneiss belts; supercontinent; intracontinent oval orogenRecommended by E.V. Sklyarov Аннотация: Ка...

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“…The presence of fine particles of loaded activated carbon in cyanidation tailings such as the material treated in this present work is not unusual. Secondly, literature has shown that most Witwatersrand ores contain carbonaceous matter known as openUP (March 2008) kerogen, which is sometimes associated with gold and uranium ( [Simpson and Bowles, 1977], [Anhaeusser et al, 1987], [Robb and Meyer, 1995] and [Parnell, 2001]). Both activated carbon and kerogen are organic and possess natural hydrophobicity so that they are likely to influence gold and uranium flotation recoveries.…”

Section: Effect Of Sibx/c12 Ttc Mixtures On Auriferous Pyrite Flotationmentioning

confidence: 99%

The flotation of auriferous pyrite with a mixture of collectors

Makanza¹,

Vermaak²,

Davidtz³

2008

International Journal of Mineral Processing

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Dithiocarbonates (xanthates) have been the most widely used collectors in sulphide mineral flotation. More recently, research has resulted in the use of trithiocarbonate (TTC) collectors. The present study focuses on the effect of mixtures of C 12 trithiocarbonate (C 12 TTC) and sodium iso-butyl xanthate (SIBX) in the flotation of auriferous pyrite and the associated gold and uranium from cyanidation tailings.Improved gold and uranium flotation responses were observed with collector mixtures than with SIBX alone. Sulphur recoveries were not affected. Mineralogical analysis of flotation concentrates showed that gold and uranium were also hosted by kerogen. It was therefore proposed that the improved recoveries could have been mostly due to higher kerogen recovery rather than synergism in pyrite flotation. This mechanism opens possibilities into maximising uranium recoveries in auriferous flotation circuits where low recoveries are common.

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The Witwatersrand Basin, South Africa: Geological framework and mineralization processes

Cited by 194 publications

References 52 publications

Health risk posed by enriched heavy metals (As, Cd, and Cr) in airborne particles from Witwatersrand gold tailings

Health risk posed by enriched heavy metals (As, Cd, and Cr) in airborne particles from Witwatersrand gold tailings

Age and isotopic geochemical characteristics of Archean carbonatites and alkaline rocks of the Baltic shield

The flotation of auriferous pyrite with a mixture of collectors

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