Geochemical, mineralogical and microbiological characterization of a sulphide-bearing carbonate-rich gold-mine tailings impoundment, Joutel, Québec

The results of an integrated geochemical and mineralogical study conducted at the Agnico-Eagle gold-mine tailings impoundment, Joutel, Québec, are correlated with bacterial populations determined from an enumeration of 3 groups of Thiobacilli. The tailings were determined to contain approximately 5...

Full description

Saved in:

Bibliographic Details
Published in:	Applied geochemistry Vol. 13; no. 6; pp. 687 - 705
Main Authors:	Blowes, David W., Jambor, John L., Hanton-Fong, Christine J., Lortie, Lyne, Gould, W.Douglas
Format:	Journal Article
Language:	English
Published:	Oxford Elsevier Ltd 01-08-1998 Elsevier
Subjects:	Earth sciences Earth, ocean, space Engineering and environment geology. Geothermics Exact sciences and technology Freshwater Metal geology Metallic and non-metallic deposits Pollution, environment geology Canada Quebec Eastern Canada Canada, Quebec, Joutel siderite arsenopyrite oxides bacteria biodegradation pseudomorphism pollution pyrite North America goethite gold pH tailings dams sulfides iron sulfides pyrrhotite dissolution oxidation mining carbonates migration of elements hydroxides mines prokaryotes ankerite tailings dolomite acid mine drainage
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	The results of an integrated geochemical and mineralogical study conducted at the Agnico-Eagle gold-mine tailings impoundment, Joutel, Québec, are correlated with bacterial populations determined from an enumeration of 3 groups of Thiobacilli. The tailings were determined to contain approximately 5 wt.% sulphide–S, predominantly as pyrite, and up to 30 wt.% carbonate minerals, chiefly as dolomite–ankerite and siderite. The objective of the study was to evaluate the potential for the development of acidic drainage and dissolved-metal migration in carbonate-rich tailings impoundments, and to compare the results of the geochemical and microbiological characterization of the tailings. Sulphide-oxidation reactions have proceeded to a depth of 20–100 cm below the tailings surface. Pyrrhotite consistently shows more alteration than pyrite and arsenopyrite. Pyrrhotite is altered mainly through the replacement by goethite. The most abundant Thiobacilli are neutrophilic bacteria of the Thiobacillus thioparus type. The maximum most probable number values for these bacteria occur 20–40 cm below the tailings surface, a depth that coincides with the disappearance of oxide coatings. This observation, coupled with the sharp decline in gas-phase O 2 concentration, suggests that rapid bacterially-mediated S–oxidation is occurring at this depth. The pore-water pH throughout the tailings varies between 6.5 and 8.5; no low-pH waters were observed in the impoundment. These neutral pH conditions are attributed to the effect of acid-consuming carbonate-mineral dissolution reactions, which are also indicated by increased concentrations of Mg and Ca and alkalinity in the shallow zone of the tailings. As a result of these acid-neutralization reactions, dissolved metal concentrations are low.
Bibliography:	ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 ObjectType-Article-1 ObjectType-Feature-2
ISSN:	0883-2927 1872-9134
DOI:	10.1016/S0883-2927(98)00009-2