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- Holmström, Henning, et al.
(författare)
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Secondary copper enrichment in tailings at the Laver mine, northern Sweden
- 1999
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Ingår i: Environmental Geology. - : Springer Science and Business Media LLC. - 0943-0105 .- 1432-0495. ; 38:4, s. 327-342
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Tidskriftsartikel (refereegranskat)abstract
- Field and laboratory studies of the sulphide-bearing tailings at Laver, northern Sweden, show that the present release of metals from the tailings is low, especially with regard to Cu. A large part of the Cu released by sulphide oxidation is enriched in a distinct zone just below the oxidation front. The enrichment zone occurs almost all over the tailings area except in areas with a shallow groundwater table. The Cu enrichment is caused by formation of covellite and adsorption onto mineral surfaces. The transport of Zn, Co, Cd, Ni and S seems to be controlled mainly by adsorption. No secondary zone or secondary minerals containing these metals have been found. Just below the groundwater table, metals are released into solution when the enrichment zone reaches the groundwater due to the low pH. An increased release of metals, especially Cu, can be expected in the future, since the enrichment zone is moving towards the groundwater table.
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- Ljungberg, Johan
(författare)
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The geochemical dynamics of mine tailings at Laver and Stekenjokk, Northern Sweden
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents geochemical studies of tailings and waters sampled at two closed mines; the Laver mine in Norrbotten where the tailings have not been remediated, and the Stekenjokk mine in Västerbotten where the tailings have been flooded. Oxidation of sulfide minerals in the tailings at Laver has led to the development of a distinct chemical zonation with an oxidised zone above the unoxidised tailings. Metals released from oxidation and weathering of sulfide minerals are retained within the tailings impoundment. This retention mechanism is today very efficient and only 5-10 % of the released masses of metals reaches the surface water system. Areas of the tailings deposit with shallow groundwater table are at present the main source of metal release. The water column of the water cover at Stekenjokk was sampled four times at various stations. The pond water contains higher concentrations of Ca, S (as sulfate), Cd and Zn than local background. The flow of Ca, S, Cd and Zn to the water column from the pore water of the tailings is an effect of both in-situ oxidation and buffering in the uppermost part of the tailings, and the fact that some parts of the tailings material were oxidised prior to the remediation with water cover. Resuspension of sulfides from the tailings surface itself is insignificant. Flooding as remediation method works well at Stekenjokk.
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