Microbial colonisation in heaps for mineral bioleaching and the influence of irrigation rate

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dc.contributor.authorChiume, R
dc.contributor.authorMinnaar, S H
dc.contributor.authorNgoma, I E
dc.contributor.authorBryan, C G
dc.contributor.authorHarrison, S T L
dc.date.accessioned2016-08-18T09:14:06Z
dc.date.available2016-08-18T09:14:06Z
dc.date.issued2012
dc.date.updated2016-08-18T09:09:10Z
dc.description.abstractMicrobial colonisation is important for mineral dissolution in heap bioleaching of low grade ore. Colonisation studies to date have focused on the microbial attachment of single species to mineral concentrates in batch and flow systems. Hydrology and soil engineering studies suggest interaction between microbial colonisation and fluid flow in porous systems that result from solution-ore and microbe-mineral contacting (Wan et al., 1994 and Yarwood et al., 2006). The effect of the irrigation rate on microbial colonisation was assessed using columns packed with acid agglomerated low grade copper-containing ore. Continuous flow, unsaturated, aerated bed reactors were inoculated by pulse irrigation with iron and sulphur oxidising mesophilic microorganisms (1012 cells/ton ore), followed by operation at irrigation rates of 2, 6 and 18 l/m2/h. A novel in-bed sampling technique allowed the extraction of ore samples from the bed during the leaching process. Novel insights regarding microbial growth, interstitial and weakly and strongly attached microbial populations were obtained. Bacterial adherence and cell number retained in the ore bed increased over the 32 day leaching period. Average specific growth rates of ore-associated micro-organisms of 0.161 ± 0.0045, 0.155 ± 0.026 and 0.120 (± 0.00) 1/h were obtained at 2, 6 and 18 L/m2/h respectively. Faster colonisation occurred at lower irrigation rates. At higher irrigation rates, higher detachment and cell removal were apparent, based on PLS cell numbers. The interstitial cells from the stagnant fluid in the ore bed formed the dominant contribution to the microbial population within all the heap systems.en_ZA
dc.identifierhttp://dx.doi.org/10.1016/j.mineng.2012.07.002
dc.identifier.apacitationChiume, R., Minnaar, S. H., Ngoma, I. E., Bryan, C. G., & Harrison, S. T. L. (2012). Microbial colonisation in heaps for mineral bioleaching and the influence of irrigation rate. <i>Minerals Engineering</i>, http://hdl.handle.net/11427/21307en_ZA
dc.identifier.chicagocitationChiume, R, S H Minnaar, I E Ngoma, C G Bryan, and S T L Harrison "Microbial colonisation in heaps for mineral bioleaching and the influence of irrigation rate." <i>Minerals Engineering</i> (2012) http://hdl.handle.net/11427/21307en_ZA
dc.identifier.citationChiume, R., Minnaar, S. H., Ngoma, I. E., Bryan, C. G., & Harrison, S. T. L. (2012). Microbial colonisation in heaps for mineral bioleaching and the influence of irrigation rate. Minerals Engineering, 39, 156-164.en_ZA
dc.identifier.issn0892-6875en_ZA
dc.identifier.ris TY - Journal Article AU - Chiume, R AU - Minnaar, S H AU - Ngoma, I E AU - Bryan, C G AU - Harrison, S T L AB - Microbial colonisation is important for mineral dissolution in heap bioleaching of low grade ore. Colonisation studies to date have focused on the microbial attachment of single species to mineral concentrates in batch and flow systems. Hydrology and soil engineering studies suggest interaction between microbial colonisation and fluid flow in porous systems that result from solution-ore and microbe-mineral contacting (Wan et al., 1994 and Yarwood et al., 2006). The effect of the irrigation rate on microbial colonisation was assessed using columns packed with acid agglomerated low grade copper-containing ore. Continuous flow, unsaturated, aerated bed reactors were inoculated by pulse irrigation with iron and sulphur oxidising mesophilic microorganisms (1012 cells/ton ore), followed by operation at irrigation rates of 2, 6 and 18 l/m2/h. A novel in-bed sampling technique allowed the extraction of ore samples from the bed during the leaching process. Novel insights regarding microbial growth, interstitial and weakly and strongly attached microbial populations were obtained. Bacterial adherence and cell number retained in the ore bed increased over the 32 day leaching period. Average specific growth rates of ore-associated micro-organisms of 0.161 ± 0.0045, 0.155 ± 0.026 and 0.120 (± 0.00) 1/h were obtained at 2, 6 and 18 L/m2/h respectively. Faster colonisation occurred at lower irrigation rates. At higher irrigation rates, higher detachment and cell removal were apparent, based on PLS cell numbers. The interstitial cells from the stagnant fluid in the ore bed formed the dominant contribution to the microbial population within all the heap systems. DA - 2012 DB - OpenUCT DP - University of Cape Town J1 - Minerals Engineering LK - https://open.uct.ac.za PB - University of Cape Town PY - 2012 SM - 0892-6875 T1 - Microbial colonisation in heaps for mineral bioleaching and the influence of irrigation rate TI - Microbial colonisation in heaps for mineral bioleaching and the influence of irrigation rate UR - http://hdl.handle.net/11427/21307 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/21307
dc.identifier.urihttp://www.sciencedirect.com/science/article/pii/S0892687512002531
dc.identifier.vancouvercitationChiume R, Minnaar SH, Ngoma IE, Bryan CG, Harrison STL. Microbial colonisation in heaps for mineral bioleaching and the influence of irrigation rate. Minerals Engineering. 2012; http://hdl.handle.net/11427/21307.en_ZA
dc.languageengen_ZA
dc.publisherElsevieren_ZA
dc.publisher.institutionUniversity of Cape Town
dc.sourceMinerals Engineeringen_ZA
dc.source.urihttp://www.sciencedirect.com/science/journal/08926875
dc.subject.otherMineral bioleaching
dc.subject.otherHeap bioleaching
dc.subject.otherSulphide ores
dc.subject.otherShear forces
dc.subject.otherColonisation
dc.subject.otherAcidophilic
dc.titleMicrobial colonisation in heaps for mineral bioleaching and the influence of irrigation rateen_ZA
dc.typeJournal Articleen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceArticleen_ZA
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