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Reclamation of copper mine tailings using sewage sludge

Stjernman Forsberg, Lovisa (2008). Reclamation of copper mine tailings using sewage sludge. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2008:88
ISBN 978-91-86195-21-2
[Doctoral thesis]

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Tailings are the fine-grained fraction of waste produced during mining operations. This work was carried out on tailings from the Aitik copper mine in northern Sweden. Establishment of vegetation on the Aitik mine tailings deposit is planned to take place at closure of the mine, using sewage sludge as fertiliser. However, the tailings contain traces of metal sulphides, e.g. pyrite, FeS2, and chalcopyrite, CuFeS2. When the sulphides are oxidised, they start to weather and release metals and strong acid, affecting the plant establishment. This thesis investigated physical and chemical growing conditions for plants in tailings with and without sewage sludge, and how these conditions changed when the tailings were oxidised. Studies on tailings properties were related to growth and metal uptake by barley (Hordeum vulgare) and red fescue (Festuca rubra) cultivated on the tailings. Fine sand particles (diameter 0.06-0.2 mm) and moderately large pores (diameter 30-300 μm) dominated the tailings. Oxidation processes resulted in a slightly higher percentage of fine pores (diameter ≤5μm) due to the formation of aggregating iron(III)hydroxide and in a pH decrease due to the acid produced as sulphides oxidised. As oxidation proceeded and pH decreased from neutral to 4.5, Al, Cd, Cu, Pb and Zn concentrations in tailings solution increased by 2-3 orders of magnitude. Compared with mineral fertiliser, sewage sludge consistently increased plant biomass production, due to the contribution of nutrients and organic matter, and increased the percentage of large pores (30-300 μm) and fine pores (<5 μm). The effect of the sludge on pH was generally limited. In the field trial, higher levels of Al, As, Cr, Cu, Pb and Zn were found in red fescue grown in sludge-treated tailings compared with tailings treated with mineral fertiliser. In the climate chamber experiment, sludge effects on Cu in tailings and plants depended on the degree of oxidation of the material. In unoxidised tailings, sewage sludge slightly increased Cu levels in solutions and fescue shoots, but in oxidised tailings the opposite occurred. In general, the sewage sludge did not counteract the toxic conditions caused by sulphide oxidation, but had beneficial effects on plant growth irrespective of oxidation degree of the tailings material.

Authors/Creators:Stjernman Forsberg, Lovisa
Title:Reclamation of copper mine tailings using sewage sludge
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2008
Number of Pages:65
ALLI. Stjernman Forsberg, L. & Ledin, S. 2003. Effects of iron precipitation and organic amendments on porosity and penetrability in sulphide mine tailings. Water, Air and Soil Pollution, 142, 395-408. II. Stjernman Forsberg, L. & Ledin, S. 2006. Effects of sewage sludge on pH and plant availability of metals in oxidising sulphide mine tailings. Science of the Total Environment, 358, 21-35. III. Stjernman Forsberg, L., Gustafsson, J-P., Berggren Kleja, D. & Ledin, S. 2008. Leaching of metals from oxidising sulphide mine tailings with and without sewage sludge application. Water, Air and Soil Pollution, 194, 331-341. IV. Stjernman Forsberg, L., Berggren Kleja, D., Greger, M. & Ledin, S. Effects of sewage sludge on solution chemistry and plant uptake of Cu in sulphide mine tailings at different weathering stages. Accepted by Applied Geochemistry with minor revision.
Place of Publication:Uppsala
ISBN for printed version:978-91-86195-21-2
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:mine spoil, reclamation, copper, sulphides, oxidation, hordeum vulgare, festuca rubra, sewage sludge, soil chemicophysical properties, plant soil relations, nutrient uptake, porosity, soil organic matter, metals, sweden
Keywords:mine tailings, sewage sludge, sulphide oxidation, porosity, metals, DOC, plant uptake
Permanent URL:
ID Code:1874
Department:(NL, NJ) > Dept. of Soil and Environment
(S) > Dept. of Soil and Environment
Deposited By: Lovisa Stjernman Forsberg
Deposited On:12 Nov 2008 00:00
Metadata Last Modified:02 Dec 2014 10:14

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