Mineralogy and trace element relative solubility p

Authors: George M Blackwood Evan N Edinger

Publish Date: 2006/10/25

Volume: 52, Issue: 4, Pages: 803-818

PDF Link

Abstract

Shallow marine sediments of the BuyatRatototok district of North Sulawesi Indonesia are affected by submarine disposal of industrial gold mine tailings and smallscale gold mining using mercury amalgamation Industrial mine tailings contained 590–660 ppm arsenic 490–580 ppm antimony and 08–58 ppm mercury Electron microprobe survey found both colloidal iron–arsenicphases without sulphur and arsenian pyrite in tailings and sites to which tailings had dispersed but only arsenopyrite in sediments affected by artisanal mining Antimony in tailings was present as antimony oxides colloidal iron–antimony phases colloidal iron–antimony phases and stibnite in sediments affected by both types of mining A sequential extraction found that 2 of arsenic held in tailings and tailingscontaminated sediments was exchangeable 20–30 was labile including weakly adsorbed carbonate and arsenate bound 20–30 was metastable probably incorporated into iron or manganese oxyhydroxides or strongly adsorbed to silicate minerals and 40–48 was relatively insoluble probably incorporated into sulphides or silicates Arsenic in sediments affected by artisanal gold mining was 75–95 relatively insoluble Antimony in all sediments was 90 relatively insoluble Relative solubility patterns of most other metals did not differ between industrial tailingsaffected artisanalmining affected areas and fluvial sediments Results suggest that submarine tailings disposal is not suitable for refractory Carlinlike gold deposits because ore processing converts arsenic to forms unstable in anoxic marine sedimentsWe thank the people of Buyat Pantai for hospitality and assistance in the field particularly Mansur Lombonaung and family Bayu Suwarno Kelola assisted with 2002 field work and Dr Hanny Tioho Sam Ratulangi University assisted with 2004 field work Pam King and Lakhmali Hewa ran ICPMS analyses Michael Schaeffer assisted with electron microprobe analysis and Helen Gillespie assisted with grain size carbonate content and organic content analysis Charlie Conway produced final maps The manuscript benefited from comments by M Parsons J Rendell O Sherwood P Sylvester and an anonymous reviewer Funded by Memorial University of Newfoundland internal grants an NSERC Discovery grant to EE and a Geological Association of Canada environmental geology student award to GMB Dedicated to the memories of Kasey Allen and Baby Andini

Keywords: