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Alternative waste residue materials for passive in situ prevention of sulfide-mine tailings oxidation: A field evaluation

Journal of Hazardous Materials

By:
, , , , and
DOI: http://dx.doi.org/10.1016/j.jhazmat.2013.12.066

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Abstract

Novel solutions for sulfide-mine tailings remediation were evaluated in field-scale experiments on a former tailings repository in northern Sweden. Uncovered sulfide-tailings were compared to sewage-sludge biosolid amended tailings over 2 years. An application of a 0.2 m single-layer sewage-sludge amendment was unsuccessful at preventing oxygen ingress to underlying tailings. It merely slowed the sulfide-oxidation rate by 20%. In addition, sludge-derived metals (Cu, Ni, Fe, and Zn) migrated and precipitated at the tailings-to-sludge interface. By using an additional 0.6 m thick fly-ash sealing layer underlying the sewage sludge layer, a solution to mitigate oxygen transport to the underlying tailings and minimize sulfide-oxidation was found. The fly-ash acted as a hardened physical barrier that prevented oxygen diffusion and provided a trap for sludge-borne metals. Nevertheless, the biosolid application hampered the application, despite the advances in the effectiveness of the fly-ash layer, as sludge-borne nitrate leached through the cover system into the underlying tailings, oxidizing pyrite. This created a 0.3 m deep oxidized zone in 6-years. This study highlights that using sewage sludge in unconventional cover systems is not always a practical solution for the remediation of sulfide-bearing mine tailings to mitigate against sulfide weathering and acid rock drainage formation.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Alternative waste residue materials for passive in situ prevention of sulfide-mine tailings oxidation: A field evaluation
Series title:
Journal of Hazardous Materials
DOI:
http://dx.doi.org/10.1016/j.jhazmat.2013.12.066
Volume
267
Year Published:
2014
Language:
English
Publisher:
Elsevier
Contributing office(s):
Crustal Geophysics and Geochemistry Science Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Hazardous Materials
First page:
245
Last page:
254
Country:
Sweden
City:
Skellefte�;Stockholm