Fly ash as a permeable cap for tailings management : pedogenesis in bauxite residue tailings

Show simple item record Santini, Talitha C. Fey, Martin V. 2016-08-30T14:28:04Z 2016-08-30T14:28:04Z 2015-03
dc.description.abstract PURPOSE : Closure of tailings facilities typically involves either a ‘cap and store’ or ‘direct revegetation’ approach. Both have been used in the management of bauxite residue (alumina refining tailings), with mixed results. This study evaluated the merit of an intermediate approach, using a permeable cap, and examined the pedogenic trajectory of the Technosol. MATERIALS AND METHODS : Chemical, mineralogical and physical properties of samples from a Brazilian bauxite residue deposit, which had been capped with fly ash 14 years prior and supported a vegetation cover, were compared to evaluate soil formation and pedogenic trajectory of the developing Technosol according to the World Reference Base for Soil Resources. Samples were collected at three points along an elevation gradient, and from 0 to 150 cm below the surface. RESULTS AND DISCUSSION : Rainfall leaching was identified as the most important pedogenic process occurring in the tailings, lowering salinity and pH. The Technosol classification was poorly suited to describe the soil materials within the study site because two wastes (fly ash and bauxite residue) were co-disposed in discrete layers. CONCLUSIONS : The permeability of the fly ash cap is key to soil development in these tailings : it provides a suitable medium for plant growth whilst still allowing contact between the tailings and the surrounding environment. The introduction of a novel prefix qualifier,ordic, would enable more accurate description of layered Technosols. The Technosol at this site is likely to develop towards an Andosol or Ferralsol. en_ZA
dc.description.department Plant Production and Soil Science en_ZA
dc.description.librarian hb2016 en_ZA
dc.description.sponsorship Minerals and Energy Research Institute of Western Australia, Alcoa of Australia Ltd, and BHP Billiton Worsley Alumina Pty Ltd. en_ZA
dc.description.uri en_ZA
dc.identifier.citation Santini, T.C. & Fey, M.V. Fly ash as a permeable cap for tailings management : pedogenesis in bauxite residue tailings. Journal of Soils and Sediments (2015) 15: 552. doi:10.1007/s11368-014-1038-6. en_ZA
dc.identifier.issn 1439-0108 (print)
dc.identifier.issn 1614-7480 (online)
dc.identifier.other 10.1007/s11368-014-1038-6
dc.language.iso en en_ZA
dc.publisher Springer en_ZA
dc.rights © Springer-Verlag Berlin Heidelberg 2014. The original publication is available at : en_ZA
dc.subject Pedogenesis en_ZA
dc.subject Red mud en_ZA
dc.subject Remediation en_ZA
dc.subject Tailings management en_ZA
dc.subject Technosols en_ZA
dc.title Fly ash as a permeable cap for tailings management : pedogenesis in bauxite residue tailings en_ZA
dc.type Postprint Article en_ZA

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