Hostname: page-component-cd9895bd7-p9bg8 Total loading time: 0 Render date: 2024-12-23T15:21:23.121Z Has data issue: false hasContentIssue false
  • English
  • Français

Reflected-light microscope and SEM/EMP observations on the behaviour of aurostibite (AuSb2) during amalgamation

Published online by Cambridge University Press:  05 July 2018

Jacques Jedwab ,
Jose Mendes Chuva  and
Eric Poot
Jacques Jedwab
Affiliation:
Laboratoire de Géochimie et de Minéralogie Appliquée, CP 160/02, Université Libre de Bruxelles, 50 Avenue Roosevelt, B-1050 Brussels, Belgium
Jose Mendes Chuva
Affiliation:
Laboratoire de Géochimie et de Minéralogie Appliquée, CP 160/02, Université Libre de Bruxelles, 50 Avenue Roosevelt, B-1050 Brussels, Belgium
Eric Poot
Affiliation:
Société Minière et Industrielle du Kivu (SOMINKI), Kamituga (Kivu) Zaire
Get access Rights & Permissions [Opens in a new window]

Abstract

The Mobale gold mine (Kivu, Zaire) has been worked since 1923, but the presence of aurostibite in the ore was recognized only very recently. The discovery of the mineral has also led to the recognition of its heretofore unsuspected reactivity during the amalgamation ore dressing operations. At the surface of aurostibite a layer of up to 30 μm thickness forms which has an overall brown colour and a low reflectivity, and is composed of several variegated, concentric zones. These zones contain gold, mercury, antimony and oxygen, with traces of iron and arsenic. Oxygen is present with a concentration range of 2-4 wt.% (20-30 at.%). The zones form at the expense of aurostibite, according to micrographical criteria. In complex grains formed of gold-arsenopyrite-galena-aurostibite, only aurostibite is affected by the formation of the external brown zones. Later pure gold veneers are deposited on the outermost surface of the brown layers during the processing of the ore. The newly discovered features of processed aurostibite could explain some of the difficulties met with during the dressing of antirnonian gold ores.

Keywords

amalgamationaurostibiteore dressingZaire mineralogygold-mercury-antimony-oxygen compound
Type
Research Article
Information
Mineralogical Magazine , Volume 56 , Issue 385 , December 1992 , pp. 561 - 565
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Allard, D. (1989) Les mindralisations aurifères de Mobale (Kivu, Zaire) et leur valorisation rationnelle. Thesis, ULB, Brussels.Google Scholar
Coleman, L. C. (1953) Econ. Geol., 52, 400–25.CrossRefGoogle Scholar
Gamyanin, G. N., Nekrasov, I. Ya., Zhdanov, Yu. Ya., and Leskova, N. V. (1988) Dokl. Akad. Nauk SSSR, 301, 947–50.(in Russian).Google Scholar
Graham, A. R. and Kaiman, S. (1952) Am. Mineral., 37, 461–9.Google Scholar
Harris, D. C. (1990) Mineralium Deposita., 25, Suppl. S3-S7.CrossRefGoogle Scholar
Henley, K. J. (1975) Minerals Sci. and Eng., 7, (4) 289–312.Google Scholar
Mehliss, A. T. M. (1969) Geol. Soc. S. Afr. Trans., 71, Annexure: ‘Syrup. of the Rhodesian basement complex', 135-46, 3 plates.Google Scholar
Morrison, R. J. (1978) Annual Report West Austr. Dep. Mines', 118-23.Google Scholar
NOTICE EXPLICATIVE (1974) Notice explicative de la carte des gftes mindraux du Zaire. Service Géologi-que du Zaire, R6publique du Zaire, Département des Mines. BRGM, Paris.Google Scholar
Nysten, P. (1986) Mineral. Deposita, 21, 116–20.CrossRefGoogle Scholar
Pascal, P. (1957) Nouveau traitd de chimie mindrale, T.III. Masson et Cie, Paris.Google Scholar
Ramdohr, P. (1980) The ore minerals and their inter-growths, Second Edition, Pergamon Press, Oxford.Google Scholar
Sobotka, J. (1954) Rozpr. Ceskosl. Akad. Ved., 64, 43–60.Google Scholar
Swash, P. M. (1986) A mineralogical examination of an antimony-bearing gold ore and its beneficiation products. MINTEK Report No. M281, Randburg, S. Africa.Google Scholar
Wilson, W. E. (1982) Mineral. Record., 13, 394–9.Google Scholar