Mineral Processing and Extractive Metallurgy, Sep 5, 2016
The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingl... more The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingly faced with the necessity to process low grade ores and waste tailings, from current mining operations. The economic extraction of copper from low-grade ores requires low-cost processing methods such as biohydrometallurgy. This study looks at a general panorama of copper mining in Zambia and discusses biohydrometallurgy as a novel and economically viable process for copper extraction. It also presents future prospects of this technology in Zambia. Since early 1930s, the copper mining industry has been the economic and social pillar of Zambia with about 80% contribution to the total export earnings and about 13% Gross Domestic Product (GDP). Mineralisation in the Zambian Copperbelt is dominantly sulphide, comprising of chalcopyrite, bornite and chalcocite among others with grades of the ore deposits generally in the range of 3-4% copper and 0.1-0.2% cobalt. Huge low grade copper deposits (~0.67% Cu) which are dominantly sulphides (chalcopyrite) were recently discovered in Lumwana area in the Northwestern Zambia and are currently being exploited. Reports show that more than one billion tons of ore (c.2.7% Cu) has so far been mined from the mines on the Copperbelt Province of Zambia and conservative estimates suggest that a further two billion tons await exploitation. This provides considerable opportunities for further exploration and mining in Zambia. However, there is currently no commercial copper processing plants in operation on a large-scale in Zambia via biohydrometallurgical process. In order for Zambian mining industry to considerably improve recoveries at inherently lower capital cost, there is need to focus effort on research in this innovative technology and its application.
Mineral Processing and Extractive Metallurgy, 2016
The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingl... more The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingly faced with the necessity to process low grade ores and waste tailings, from current mining operations. The economic extraction of copper from low-grade ores requires low-cost processing methods such as biohydrometallurgy. This study looks at a general panorama of copper mining in Zambia and discusses biohydrometallurgy as a novel and economically viable process for copper extraction. It also presents future prospects of this technology in Zambia. Since early 1930s, the copper mining industry has been the economic and social pillar of Zambia with about 80% contribution to the total export earnings and about 13% Gross Domestic Product (GDP). Mineralisation in the Zambian Copperbelt is dominantly sulphide, comprising of chalcopyrite, bornite and chalcocite among others with grades of the ore deposits generally in the range of 3 - 4% copper and 0.1 - 0.2% cobalt. Huge low grade copper depo...
American Journal of Environmental Protection, 2016
The Nchanga tailings dam, a reservoir of mine waste from Konkola Copper Mines (KCM) operations in... more The Nchanga tailings dam, a reservoir of mine waste from Konkola Copper Mines (KCM) operations in Zambia, discharges its effluent into the local Muntimpa stream. The Muntimpa stream, a possible source of drinking and domestic water for the local population, flows into Mwambashi stream which subsequently discharges into Kafue river. The Kafue river is a significant support of economic development in Zambia and is a source of 40% of drinking water for the cities with about 50% of the population living in the catchment. This study looks at an overview of the operations of Nchanga tailings dam and assesses the levels of pH, TSS, TDS, Cu, Mn, Co and SO 4 in the effluent discharged in rainy and dry seasons. It also provides possible methods that could be used to lower pollutant levels to below recommended Zambia Environmental Management Agency (ZEMA) limits. To determine the pollutant concentrations, sixty (60) samples were collected from the tailings dam spillway in rainy season (April) and dry season (October) of 2015 and analysed on a daily basis. The results indicated that the average pH, TSS and Cu levels in the samples from both wet and dry seasons were within the permissible range of 6.0-9.0, below 100 mg/l and 1.0 mg/l respectively. The TDS average figure (2658±331 mg/l) recorded in April was less than the allowable limit while significantly higher value (4783±86.6 mg/l) was obtained in October. The concentrations of Mn and Co were significantly high and above ZEMA limits with mean values of 79±22.1 mg/l and 11±5.9 mg/l for rainy season and 189±19.2 mg/l and 19±1.3 mg/l for dry season respectively. The SO 4 content was observed to be high in both seasons with average figures of 2071±240 mg/l in April and 3628±261 mg/l in October. It was observed that the levels of all the parameters analysed (with exception of Cu) showed seasonal variations attributed to evaporative effects. To minimise contaminants levels in the effluent, it is recommended that the discharged effluent should be restricted in dry season until the levels of dissolved pollutants are sufficiently low in wet season. Recycling of water from the decantation pond of the tailings impoundment back to the main plant is an effective alternative that would eliminate pollution of water bodies. Other methods that could be employed involve the use of chemical and biological treatment technologies.
The aim of this study is to assess the quality of the groundwater currently supplied to the rural... more The aim of this study is to assess the quality of the groundwater currently supplied to the rural communities of the North West Province. Groundwater samples collected from 100 boreholes in these rural areas were subjected to culture-based methods using selective media for the isolation of faecal and total coliform bacteria. Molecular analysis targeting 16S rRNA gene, and the restriction fragmentlength polymorphism (RFLP) and sequence analysis of amplified gene for differentiating between species and strains of bacteria, were applied to selected coliform isolates. The physico-chemical parameters such as pH, temperature, total dissolved solids (TDS), turbidity and concentrations of chloride, sulphates, nitrate, fluoride, magnesium, sodium and calcium were also determined. The results revealed that 83% of the boreholes did not comply with the fluoride limit of SANS 241 (0 to 1 mg/l), 40% did not comply with the nitrate limit (0 to 6 mg/l as N), 45% did not comply with the magnesium limit (0 to 30 mg/l as Mg), 43% did not comply with the calcium limit (0 to 32 mg/l as Ca), 31% did not comply with TDS and 47% did not comply with the turbidity limit (<1 NTU). The results also indicated that 23 and 86% of the boreholes did not comply with the limits set by the national guidelines (SANS 241 and DWAF) in terms of faecal (0 cfu/100 ml) and total coliforms (0 to 5 cfu/100 ml), respectively. The results of the molecular study revealed that out of 100 boreholes, 51% tested positive for Citrobacter freundii, 28% for Serratia marcescens, 12% for Morganella morganii, 8% for Salmonella enterica, 7% for Aeromonas veronii, 5% for Bacillus cereus, 2% for Enterobacter cloacae and 1% for Escherichia coli and Shigella dysenteriae. The findings of this study showed convincing evidence that some groundwater supplies in rural areas of North West pose a serious health risk to consumers.
Chinese Journal of Chemical Engineering, May 1, 2019
Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dep... more Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dependence of the transition velocity on several factors including measurement methods and interpretation of results. In this work, numerical simulations using the two fluid model (TFM) are performed in an attempt to predict the regime change reported by Gopalan et al. (2016) in a small scale pseudo-2D gas-solid fluidized bed containing Geldart D particles. Various time and frequency domain analyses were applied on predicted absolute and differential pressure time series data to reveal the bed dynamics. Numerical predictions of the transition velocity, U c are in reasonably good agreement with experimental results from the small scale challenge problem. The literature correlations completely fail to predict the transition velocity for the system considered in this work. This work thus provides a different approach for validating the CFD model against experimental measurements.
Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dep... more Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dependence of the transition velocity on several factors including measurement methods and interpretation of results. In this work, numerical simulations using the two fluid model (TFM) are performed in an attempt to predict the regime change reported by Gopalan et al. (2016) in a small scale pseudo-2D gas-solid fluidized bed containing Geldart D particles. Various time and frequency domain analyses were applied on predicted absolute and differential pressure time series data to reveal the bed dynamics. Numerical predictions of the transition velocity, U c are in reasonably good agreement with experimental results from the small scale challenge problem. The literature correlations completely fail to predict the transition velocity for the system considered in this work. This work thus provides a different approach for validating the CFD model against experimental measurements.
Electrospun multicomposite nanofibers synthesized from extracts of Moringa oleifera (M. oleifera)... more Electrospun multicomposite nanofibers synthesized from extracts of Moringa oleifera (M. oleifera) seed biomass blended with metal oxide nanoparticles (MONPs) and polyacrylonitrile (PAN) were investigated as potential adsorbents. The materials were characterized using SEM, XRD, FTIR, BET and TGA. The specific surface area of MONPs ranged between 29.75 and 60.92 m2/g and their incorporation in the PAN/M. oleifera composite blend resulted in increased surface coarseness and larger nanofiber diameters (268 ± 21–317 ± 27 nm). The application of PAN/M. oleifera/MONPs for Pb(II) removal from aqueous solution via batch adsorption experiments was investigated based on the parameters: solution pH, contact time and initial Pb(II) ion concentration. Experimental results better fitted the Langmuir isotherm model and pseudo-second-order kinetics. Adsorption capacities ranged between 172.4 and 227.3 mg/g. These results demonstrate that low-cost indigenous materials have significance and applicabil...
Mineral Processing and Extractive Metallurgy, Sep 5, 2016
The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingl... more The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingly faced with the necessity to process low grade ores and waste tailings, from current mining operations. The economic extraction of copper from low-grade ores requires low-cost processing methods such as biohydrometallurgy. This study looks at a general panorama of copper mining in Zambia and discusses biohydrometallurgy as a novel and economically viable process for copper extraction. It also presents future prospects of this technology in Zambia. Since early 1930s, the copper mining industry has been the economic and social pillar of Zambia with about 80% contribution to the total export earnings and about 13% Gross Domestic Product (GDP). Mineralisation in the Zambian Copperbelt is dominantly sulphide, comprising of chalcopyrite, bornite and chalcocite among others with grades of the ore deposits generally in the range of 3-4% copper and 0.1-0.2% cobalt. Huge low grade copper deposits (~0.67% Cu) which are dominantly sulphides (chalcopyrite) were recently discovered in Lumwana area in the Northwestern Zambia and are currently being exploited. Reports show that more than one billion tons of ore (c.2.7% Cu) has so far been mined from the mines on the Copperbelt Province of Zambia and conservative estimates suggest that a further two billion tons await exploitation. This provides considerable opportunities for further exploration and mining in Zambia. However, there is currently no commercial copper processing plants in operation on a large-scale in Zambia via biohydrometallurgical process. In order for Zambian mining industry to considerably improve recoveries at inherently lower capital cost, there is need to focus effort on research in this innovative technology and its application.
Mineral Processing and Extractive Metallurgy, 2016
The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingl... more The consumption of copper worldwide has grown fast since 2000; the mining industry is increasingly faced with the necessity to process low grade ores and waste tailings, from current mining operations. The economic extraction of copper from low-grade ores requires low-cost processing methods such as biohydrometallurgy. This study looks at a general panorama of copper mining in Zambia and discusses biohydrometallurgy as a novel and economically viable process for copper extraction. It also presents future prospects of this technology in Zambia. Since early 1930s, the copper mining industry has been the economic and social pillar of Zambia with about 80% contribution to the total export earnings and about 13% Gross Domestic Product (GDP). Mineralisation in the Zambian Copperbelt is dominantly sulphide, comprising of chalcopyrite, bornite and chalcocite among others with grades of the ore deposits generally in the range of 3 - 4% copper and 0.1 - 0.2% cobalt. Huge low grade copper depo...
American Journal of Environmental Protection, 2016
The Nchanga tailings dam, a reservoir of mine waste from Konkola Copper Mines (KCM) operations in... more The Nchanga tailings dam, a reservoir of mine waste from Konkola Copper Mines (KCM) operations in Zambia, discharges its effluent into the local Muntimpa stream. The Muntimpa stream, a possible source of drinking and domestic water for the local population, flows into Mwambashi stream which subsequently discharges into Kafue river. The Kafue river is a significant support of economic development in Zambia and is a source of 40% of drinking water for the cities with about 50% of the population living in the catchment. This study looks at an overview of the operations of Nchanga tailings dam and assesses the levels of pH, TSS, TDS, Cu, Mn, Co and SO 4 in the effluent discharged in rainy and dry seasons. It also provides possible methods that could be used to lower pollutant levels to below recommended Zambia Environmental Management Agency (ZEMA) limits. To determine the pollutant concentrations, sixty (60) samples were collected from the tailings dam spillway in rainy season (April) and dry season (October) of 2015 and analysed on a daily basis. The results indicated that the average pH, TSS and Cu levels in the samples from both wet and dry seasons were within the permissible range of 6.0-9.0, below 100 mg/l and 1.0 mg/l respectively. The TDS average figure (2658±331 mg/l) recorded in April was less than the allowable limit while significantly higher value (4783±86.6 mg/l) was obtained in October. The concentrations of Mn and Co were significantly high and above ZEMA limits with mean values of 79±22.1 mg/l and 11±5.9 mg/l for rainy season and 189±19.2 mg/l and 19±1.3 mg/l for dry season respectively. The SO 4 content was observed to be high in both seasons with average figures of 2071±240 mg/l in April and 3628±261 mg/l in October. It was observed that the levels of all the parameters analysed (with exception of Cu) showed seasonal variations attributed to evaporative effects. To minimise contaminants levels in the effluent, it is recommended that the discharged effluent should be restricted in dry season until the levels of dissolved pollutants are sufficiently low in wet season. Recycling of water from the decantation pond of the tailings impoundment back to the main plant is an effective alternative that would eliminate pollution of water bodies. Other methods that could be employed involve the use of chemical and biological treatment technologies.
The aim of this study is to assess the quality of the groundwater currently supplied to the rural... more The aim of this study is to assess the quality of the groundwater currently supplied to the rural communities of the North West Province. Groundwater samples collected from 100 boreholes in these rural areas were subjected to culture-based methods using selective media for the isolation of faecal and total coliform bacteria. Molecular analysis targeting 16S rRNA gene, and the restriction fragmentlength polymorphism (RFLP) and sequence analysis of amplified gene for differentiating between species and strains of bacteria, were applied to selected coliform isolates. The physico-chemical parameters such as pH, temperature, total dissolved solids (TDS), turbidity and concentrations of chloride, sulphates, nitrate, fluoride, magnesium, sodium and calcium were also determined. The results revealed that 83% of the boreholes did not comply with the fluoride limit of SANS 241 (0 to 1 mg/l), 40% did not comply with the nitrate limit (0 to 6 mg/l as N), 45% did not comply with the magnesium limit (0 to 30 mg/l as Mg), 43% did not comply with the calcium limit (0 to 32 mg/l as Ca), 31% did not comply with TDS and 47% did not comply with the turbidity limit (<1 NTU). The results also indicated that 23 and 86% of the boreholes did not comply with the limits set by the national guidelines (SANS 241 and DWAF) in terms of faecal (0 cfu/100 ml) and total coliforms (0 to 5 cfu/100 ml), respectively. The results of the molecular study revealed that out of 100 boreholes, 51% tested positive for Citrobacter freundii, 28% for Serratia marcescens, 12% for Morganella morganii, 8% for Salmonella enterica, 7% for Aeromonas veronii, 5% for Bacillus cereus, 2% for Enterobacter cloacae and 1% for Escherichia coli and Shigella dysenteriae. The findings of this study showed convincing evidence that some groundwater supplies in rural areas of North West pose a serious health risk to consumers.
Chinese Journal of Chemical Engineering, May 1, 2019
Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dep... more Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dependence of the transition velocity on several factors including measurement methods and interpretation of results. In this work, numerical simulations using the two fluid model (TFM) are performed in an attempt to predict the regime change reported by Gopalan et al. (2016) in a small scale pseudo-2D gas-solid fluidized bed containing Geldart D particles. Various time and frequency domain analyses were applied on predicted absolute and differential pressure time series data to reveal the bed dynamics. Numerical predictions of the transition velocity, U c are in reasonably good agreement with experimental results from the small scale challenge problem. The literature correlations completely fail to predict the transition velocity for the system considered in this work. This work thus provides a different approach for validating the CFD model against experimental measurements.
Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dep... more Accurate prediction of the onset of turbulent fluidization still remains elusive owing to the dependence of the transition velocity on several factors including measurement methods and interpretation of results. In this work, numerical simulations using the two fluid model (TFM) are performed in an attempt to predict the regime change reported by Gopalan et al. (2016) in a small scale pseudo-2D gas-solid fluidized bed containing Geldart D particles. Various time and frequency domain analyses were applied on predicted absolute and differential pressure time series data to reveal the bed dynamics. Numerical predictions of the transition velocity, U c are in reasonably good agreement with experimental results from the small scale challenge problem. The literature correlations completely fail to predict the transition velocity for the system considered in this work. This work thus provides a different approach for validating the CFD model against experimental measurements.
Electrospun multicomposite nanofibers synthesized from extracts of Moringa oleifera (M. oleifera)... more Electrospun multicomposite nanofibers synthesized from extracts of Moringa oleifera (M. oleifera) seed biomass blended with metal oxide nanoparticles (MONPs) and polyacrylonitrile (PAN) were investigated as potential adsorbents. The materials were characterized using SEM, XRD, FTIR, BET and TGA. The specific surface area of MONPs ranged between 29.75 and 60.92 m2/g and their incorporation in the PAN/M. oleifera composite blend resulted in increased surface coarseness and larger nanofiber diameters (268 ± 21–317 ± 27 nm). The application of PAN/M. oleifera/MONPs for Pb(II) removal from aqueous solution via batch adsorption experiments was investigated based on the parameters: solution pH, contact time and initial Pb(II) ion concentration. Experimental results better fitted the Langmuir isotherm model and pseudo-second-order kinetics. Adsorption capacities ranged between 172.4 and 227.3 mg/g. These results demonstrate that low-cost indigenous materials have significance and applicabil...
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