MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching microorganisms
| dc.contributor.author | Fagan, Marijke A | |
| dc.contributor.author | Ngoma, I. Emmanuel | |
| dc.contributor.author | Chiume, Rebecca Angela | |
| dc.contributor.author | Minnaar, Sanet | |
| dc.contributor.author | Sederman, Andrew J | |
| dc.contributor.author | Johns, Michael L | |
| dc.contributor.author | Harrison, Sue | |
| dc.date.accessioned | 2015-04-29T09:12:26Z | |
| dc.date.available | 2015-04-29T09:12:26Z | |
| dc.date.issued | 2014-12 | |
| dc.description.abstract | Heap bioleaching performance is dependent on the contacting of the leach solution with the ore bed, hence on the system hydrodynamics. In this study two experimental setups were used to examine hydrodynamics associated with irrigation from a single drip emitter, one of the most common methods of heap irrigation. A specialist magnetic resonance imaging (MRI) method which is insensitive to the metal content of the ore was used to examine the liquid flow into an ore bed in the immediate vicinity of an irrigation point. The distribution of liquid in, microbial colonisation of and mineral recovery from a bioleach of a large scale 132 kg “ore slice” were subsequently monitored using sample ports positioned along the breadth and height of the reactor. In both systems the lateral movement of the liquid increased with bed depth, though preferential flow was evident. The majority of the liquid flow was in the region directly below the irrigation point and almost no liquid exchange occurred in the areas of lowest liquid content at the upper corners of the bed in which fluid exchange was driven by capillary action. The MRI studies revealed that the liquid distribution was unchanging following an initial settling of the ore bed and that, at steady state, the majority (~60%) of the liquid flowed directly into established large channels. The limited lateral movement of the liquid had a significant impact on the local leaching efficiencies and microbial colonisation of the ore with cell concentrations in the regions of lowest liquid content lying below the detection limit. Hence poor lateral liquid distribution with drip irrigation, and the associated impact on colonisation was identified as a significant disadvantage of this irrigation approach. Further, the need to optimise fluid exchange throughout the ore bed was identified as key for optimisation of leaching performance. | en_ZA |
| dc.identifier.apacitation | Fagan, M. A., Ngoma, I. Emmanuel., Chiume, R. A., Minnaar, S., Sederman, A. J., Johns, M. L., & Harrison, S. (2014). MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching microorganisms. <i>Hydrometallurgy</i>, http://hdl.handle.net/11427/12699 | en_ZA |
| dc.identifier.chicagocitation | Fagan, Marijke A, I. Emmanuel Ngoma, Rebecca Angela Chiume, Sanet Minnaar, Andrew J Sederman, Michael L Johns, and Sue Harrison "MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching microorganisms." <i>Hydrometallurgy</i> (2014) http://hdl.handle.net/11427/12699 | en_ZA |
| dc.identifier.citation | Fagan MA, Ngoma IE, Chiume RA, Minnaar SH, Sederman AJ, Johns ML and Harrison STL. (2014). MRI and gravimetric studies of hydrology in drip irricated heaps and its effect on the propagation of bioleaching micro-organisms. Hydrometallurgy, 150: 210-221. http://dx.doi.org/10.1016/j.hydromet.2014.04.022 | en_ZA |
| dc.identifier.ris | TY - Journal Article AU - Fagan, Marijke A AU - Ngoma, I. Emmanuel AU - Chiume, Rebecca Angela AU - Minnaar, Sanet AU - Sederman, Andrew J AU - Johns, Michael L AU - Harrison, Sue AB - Heap bioleaching performance is dependent on the contacting of the leach solution with the ore bed, hence on the system hydrodynamics. In this study two experimental setups were used to examine hydrodynamics associated with irrigation from a single drip emitter, one of the most common methods of heap irrigation. A specialist magnetic resonance imaging (MRI) method which is insensitive to the metal content of the ore was used to examine the liquid flow into an ore bed in the immediate vicinity of an irrigation point. The distribution of liquid in, microbial colonisation of and mineral recovery from a bioleach of a large scale 132 kg “ore slice” were subsequently monitored using sample ports positioned along the breadth and height of the reactor. In both systems the lateral movement of the liquid increased with bed depth, though preferential flow was evident. The majority of the liquid flow was in the region directly below the irrigation point and almost no liquid exchange occurred in the areas of lowest liquid content at the upper corners of the bed in which fluid exchange was driven by capillary action. The MRI studies revealed that the liquid distribution was unchanging following an initial settling of the ore bed and that, at steady state, the majority (~60%) of the liquid flowed directly into established large channels. The limited lateral movement of the liquid had a significant impact on the local leaching efficiencies and microbial colonisation of the ore with cell concentrations in the regions of lowest liquid content lying below the detection limit. Hence poor lateral liquid distribution with drip irrigation, and the associated impact on colonisation was identified as a significant disadvantage of this irrigation approach. Further, the need to optimise fluid exchange throughout the ore bed was identified as key for optimisation of leaching performance. DA - 2014-12 DB - OpenUCT DO - 10.1016/j.hydromet.2014.04.022 DP - University of Cape Town J1 - Hydrometallurgy LK - https://open.uct.ac.za PB - University of Cape Town PY - 2014 T1 - MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching microorganisms TI - MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching microorganisms UR - http://hdl.handle.net/11427/12699 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/12699 | |
| dc.identifier.uri | http://dx.doi.org/10.1016/j.hydromet.2014.04.022 | |
| dc.identifier.vancouvercitation | Fagan MA, Ngoma I Emmanuel, Chiume RA, Minnaar S, Sederman AJ, Johns ML, et al. MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching microorganisms. Hydrometallurgy. 2014; http://hdl.handle.net/11427/12699. | en_ZA |
| dc.language | eng | en_ZA |
| dc.publisher | Elsevier | en_ZA |
| dc.publisher.department | Centre for Bioprocess Engineering Research | |
| dc.publisher.faculty | Faculty of Engineering and the Built Environment | |
| dc.publisher.institution | University of Cape Town | |
| dc.rights | Creative Commons Attribution 4.0 International (CC BY 4.0) | * |
| dc.rights.uri | http://creativecommons.org/licenses/by/4.0/ | en_ZA |
| dc.source | Hydrometallurgy | en_ZA |
| dc.source.uri | http://www.journals.elsevier.com/hydrometallurgy/ | |
| dc.title | MRI and gravimetric studies of hydrology in drip irrigated heaps and its effect on the propagation of bioleaching microorganisms | en_ZA |
| dc.type | Journal Article | en_ZA |
| uct.subject.keywords | Bioleaching | en_ZA |
| uct.subject.keywords | hydrology | en_ZA |
| uct.subject.keywords | irrigation | en_ZA |
| uct.subject.keywords | MRI | en_ZA |
| uct.subject.keywords | sulfide ores | en_ZA |
| uct.type.filetype | Text | |
| uct.type.filetype | Image | |
| uct.type.publication | Research | en_ZA |
| uct.type.resource | Article | en_ZA |