The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform

Georgesivo E Ekosse - One of the best experts on this subject based on the ideXlab platform.

  • heavy metals concentrations in the biophysical environment around the ni cu mine and the smelter Concentrator Plant selebi phikwe botswana
    Global Journal of Environmental Sciences, 2006
    Co-Authors: Georgesivo E Ekosse
    Abstract:

    The present work involves the study of heavy metals concentrations in the biophysical environment of a Ni-Cu mining and smelting area in Botswana, Africa. Samples of tailings dump, soils, particulate air matter (PAM), Imbrasia belina , and Colophospermum mopane were analysed for concentrations of heavy metals. Elements analysed were those associated with Ni-Cu mining and smelting included Cd, Cr, Co, Cu, Fe, Ni, Se and Zn, which were likely to be found in Ni-Cu orebodies and released into the biophysical environment through mining and smelting activities. Results depicted higher concentration levels of heavy metals in samples obtained close to the mine and the Concentrator/smelter Plant compared to samples obtained further away from where mining and smelting activities are being carried out. It is anticipated that these findings may be useful in interpreting biophysical environments where Ni-Cu mining and smelting activities are being conducted. Keywords : Selebi Phikwe, biophysical, heavy metals, environment Global Journal of Environmental Sciences Vol. 4(2) 2005: 97–110

  • Heavy metals concentrations in the biophysical environment around the Ni-Cu mine and the smelter/Concentrator Plant, Selebi Phikwe, Botswana
    Global Journal of Environmental Sciences, 2006
    Co-Authors: Georgesivo E Ekosse
    Abstract:

    The present work involves the study of heavy metals concentrations in the biophysical environment of a Ni-Cu mining and smelting area in Botswana, Africa. Samples of tailings dump, soils, particulate air matter (PAM), Imbrasia belina , and Colophospermum mopane were analysed for concentrations of heavy metals. Elements analysed were those associated with Ni-Cu mining and smelting included Cd, Cr, Co, Cu, Fe, Ni, Se and Zn, which were likely to be found in Ni-Cu orebodies and released into the biophysical environment through mining and smelting activities. Results depicted higher concentration levels of heavy metals in samples obtained close to the mine and the Concentrator/smelter Plant compared to samples obtained further away from where mining and smelting activities are being carried out. It is anticipated that these findings may be useful in interpreting biophysical environments where Ni-Cu mining and smelting activities are being conducted. Keywords : Selebi Phikwe, biophysical, heavy metals, environment Global Journal of Environmental Sciences Vol. 4(2) 2005: 97–110

  • multivariate analyses of heavy metals in soils and colophospermum mopane leaves around the selebi phikwe nickel copper mine and smelter Concentrator Plant area botswana
    Journal of Applied Sciences and Environmental Management, 2005
    Co-Authors: Georgesivo E Ekosse, Catherine J Ngila, Ntonghanwah Forcheh
    Abstract:

    This study was conducted in order to ascertain levels of concentrations and areal distribution of heavy metals in the surface soils and vegetation around the Selebi Phikwe Ni-Cu mine and smelter/Concentrator Plant, Botswana. One hundred and forty samples each of soil and Colophospermum mopane leaves obtained from ten sites, were analyzed by atomic absorption spectrometry (AAS) technique for their concentration levels of Cu, Ni, Fe, Cr, Co, Cd, Zn and Se. Data analysis was done mainly using the statistical package for social science (SPSS). Multivariate analysis was used to determine the distribution of metals within the study area. Concentration values obtained for analysed soil samples were as follows: Cd ranged from 0.01 to 0.05 ppm; Co from 1.0 to 28 ppm, Cr from 0.03 to 14 ppm; Cu from 11 to 116 ppm; Fe from 31 to 430 ppm; Ni from 19 to 120 ppm; Se from 0.01 to 0.03 ppm, and Zn from 17 to 68 ppm. The concentration values obtained for analysed mopane leaves were as follows: Cd was between 0.01 and 0.05 ppm, Co ranged from 1.0 to 28 ppm; Cr from 0.03 to 11 ppm; Cu from 4 to 116 ppm; Fe from 31 to 430 ppm; Ni from 19 to 120 ppm; Se was between 0.01 and 0.03 ppm, and Zn was between 17 and 79 ppm. In general heavy metals concentrations in both soils and vegetation depended on the site and proximity of the sampling locations to the mine. The findings of the study depicted that concentrations of heavy metals in soils and leaves of colophospermum mopane decreased with increase in distance from the mine and smelter/concentration Plant. Journal of Applied Sciences and Environmental Management Vol. 9(1) 2005: 177-185

  • heavy metals concentrations in imbrasia belina phane caterpillar around the selebi phikwe ni cu mine and smelter Concentrator Plant botswana
    Global Journal of Pure and Applied Sciences, 2005
    Co-Authors: Georgesivo E Ekosse, Dawid J Van Den Heever, Linda De Jager, Otlogetswe Totolo
    Abstract:

    Samples of Imbrasia belina (phane caterpillar) obtained from around the Selebi Phikwe Ni-Cu mine and smelter/Concentrator Plant, Botswana were investigated for their heavy metals concentrations. The samples were obtained from 10 sampling sites, which included a chosen control site located 56 km from Selebi Phikwe. Chemical analyses for Cd, Co, Cr, Cu, Fe, Ni, Se and Zn concentrations in the samples of Imbrasia belina were measured using atomic absorption spectrometry. Concentration values obtained for heavy metals in Imbrasia belina were as follows: Cd was between 0.01 ppm and 0.05 ppm, Co was between 0.01 ppm and 0.6 ppm, Cr was between 0.03 ppm and 1.03 ppm, Cu was between 1.3 ppm and 9.79 ppm, Fe was between 1 ppm and 13.5 ppm, Ni was between 1.2 ppm and 4.20 ppm, Se was between 0.01 ppm and 0.03 ppm, and Zn was between 0.6 ppm and 5.79 ppm. The correlation coefficients between heavy metals in Imbrasia belina were generally average. Strong correlations included Fe/Cu, Ni/Cr, Se/Co, Zn/Cu and Zn/Ni. The lowest correlation coefficient was at 0.03 with Ni/Fe. The worms close to the Plant; more specifically sites four, five and six were the most contaminated. Results from this baseline study calls for the need to further investigate the possible effects on human health due to the consumption of Imbrasia belina . Keywords : heavy metals, Imbrasia belina , concentrations, linear trend, nickel-copper Global Journal of Pure and Applied Sciences Vol. 11(4) 2005: 553-559

  • Heavy metals concentrations in Imbrasia belina (phane caterpillar) around the Selebi Phikwe Ni-Cu mine and smelter/Concentrator Plant, Botswana
    Global Journal of Pure and Applied Sciences, 2005
    Co-Authors: Georgesivo E Ekosse, Dawid J Van Den Heever, Linda De Jager, Otlogetswe Totolo
    Abstract:

    Samples of Imbrasia belina (phane caterpillar) obtained from around the Selebi Phikwe Ni-Cu mine and smelter/Concentrator Plant, Botswana were investigated for their heavy metals concentrations. The samples were obtained from 10 sampling sites, which included a chosen control site located 56 km from Selebi Phikwe. Chemical analyses for Cd, Co, Cr, Cu, Fe, Ni, Se and Zn concentrations in the samples of Imbrasia belina were measured using atomic absorption spectrometry. Concentration values obtained for heavy metals in Imbrasia belina were as follows: Cd was between 0.01 ppm and 0.05 ppm, Co was between 0.01 ppm and 0.6 ppm, Cr was between 0.03 ppm and 1.03 ppm, Cu was between 1.3 ppm and 9.79 ppm, Fe was between 1 ppm and 13.5 ppm, Ni was between 1.2 ppm and 4.20 ppm, Se was between 0.01 ppm and 0.03 ppm, and Zn was between 0.6 ppm and 5.79 ppm. The correlation coefficients between heavy metals in Imbrasia belina were generally average. Strong correlations included Fe/Cu, Ni/Cr, Se/Co, Zn/Cu and Zn/Ni. The lowest correlation coefficient was at 0.03 with Ni/Fe. The worms close to the Plant; more specifically sites four, five and six were the most contaminated. Results from this baseline study calls for the need to further investigate the possible effects on human health due to the consumption of Imbrasia belina . Keywords : heavy metals, Imbrasia belina , concentrations, linear trend, nickel-copper Global Journal of Pure and Applied Sciences Vol. 11(4) 2005: 553-559

Alejandro Weinstein - One of the best experts on this subject based on the ideXlab platform.

  • Novel 20-MW downhill conveyor system using three-level converters
    IEEE Transactions on Industrial Electronics, 2002
    Co-Authors: Jose Rodriguez, Gerardo Alzamora, Norbert Becker, Ottomar Einenkel, Jorge Pontt, Alejandro Weinstein
    Abstract:

    This paper presents a very new drive system used to transport ore from the mine down to the Concentrator Plant in the copper mine "Los Pelambres". Eight 2500-kW motors are driven by three-level inverters with gate-turn-off thyristors (GTOs). A three-level active front end is used at the input side of each inverter. A GTO chopper is used to provide controlled electrical braking in case of line loss. The paper presents the requirements and alternatives for the drive system and the control strategies for the converters and the belt. A novel application of the selective harmonic elimination method is used to reduce the input current harmonics. Special attention is dedicated to the interaction with the electrical network. The most relevant features of the system are: (1) fuseless operation; (2) adjustable power factor; (3) reduced input current harmonics; (4) smooth transition between motoring and regenerating modes; and (5) 15 MW of regenerated power with more than six months of successful operation.

  • "Novel 20 MW downhill conveyor system using three-level converters"
    Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248), 2001
    Co-Authors: A.j.r. F, Gerardo Alzamora, Norbert Becker, Ottomar Einenkel, Jorge Pontt, J. Rodriguez, J.l. Cornet, Alejandro Weinstein
    Abstract:

    This paper presents a very new drive system used to transport ore from the mine down to the Concentrator Plant in the copper mine Los Pelambres. Eight 2500 kW motors are driven by three-level inverters with GTOs. A three-level active front end (AFE) is used at the input side of each inverter. A GTO chopper is used to provide controlled electrical braking in case of line loss. The paper presents the requirements and alternatives for the drive system and the control strategies for the converters and the belt. A novel application of the selective harmonic elimination method is used to reduce the input current harmonics. Special attention is dedicated to the interaction with the electrical network. The most relevant features of the system are: (i) fuseless operation; (ii) adjustable power factor; (iii) reduced input current harmonics; and (iv) smooth transition between motoring and regenerating modes and 15 MW of regenerated power with more than six months of successful operation.

Gerardo Alzamora - One of the best experts on this subject based on the ideXlab platform.

  • Technical evaluation and practical experience of high-power grinding mill drives in mining applications
    IEEE Transactions on Industry Applications, 2005
    Co-Authors: J.r. Rodriguez, Jorge Pontt, P. Newman, R. Musalem, H. Miranda, L. Moran, Gerardo Alzamora
    Abstract:

    Grinding mill drives play an important role in the mining industry. Almost 60% of the electrical energy consumed by modern Concentrator Plants goes to grinding mill drives. Different technologies are used in grinding systems presenting special characteristics from the electrical and process points of view. This paper presents a technical evaluation and practical experience of two different technologies used in high-power grinding mill drives. The analysis is focused on the static power converter and associated control scheme required to drive the motor. Cycloconverters and load-commutated inverters are analyzed in terms of power grid interaction, motor interaction, and the required control scheme. The evaluation is supported with practical results obtained in different Concentrator Plant facilities.

  • Technical evaluation and practical experience of high power grinding mill drives in mining applications
    38th IAS Annual Meeting on Conference Record of the Industry Applications Conference 2003., 2003
    Co-Authors: J. Rodriguez, P. Newman, Jorge Pontt, L. Moran, Gerardo Alzamora
    Abstract:

    Grinding mill drives play an important role in the mining industry. Close to 60% of the electrical energy consumed by modern Concentrator Plants goes to grinding mill drives. Different technologies are used in grinding systems presenting special characteristics from the electrical and process points of view. This paper presents a technical evaluation and practical experience of two different technologies used in high power grinding mill drives. The analysis is focused on the static power converter and associated control scheme required to drive the motor. Cycloconverters and load commutated inverters are analyzed in terms of the interaction with the power grid, the motor, and the required control scheme. The evaluation is supported with practical results obtained in different Concentrator Plant facilities.

  • Novel 20-MW downhill conveyor system using three-level converters
    IEEE Transactions on Industrial Electronics, 2002
    Co-Authors: Jose Rodriguez, Gerardo Alzamora, Norbert Becker, Ottomar Einenkel, Jorge Pontt, Alejandro Weinstein
    Abstract:

    This paper presents a very new drive system used to transport ore from the mine down to the Concentrator Plant in the copper mine "Los Pelambres". Eight 2500-kW motors are driven by three-level inverters with gate-turn-off thyristors (GTOs). A three-level active front end is used at the input side of each inverter. A GTO chopper is used to provide controlled electrical braking in case of line loss. The paper presents the requirements and alternatives for the drive system and the control strategies for the converters and the belt. A novel application of the selective harmonic elimination method is used to reduce the input current harmonics. Special attention is dedicated to the interaction with the electrical network. The most relevant features of the system are: (1) fuseless operation; (2) adjustable power factor; (3) reduced input current harmonics; (4) smooth transition between motoring and regenerating modes; and (5) 15 MW of regenerated power with more than six months of successful operation.

  • "Novel 20 MW downhill conveyor system using three-level converters"
    Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248), 2001
    Co-Authors: A.j.r. F, Gerardo Alzamora, Norbert Becker, Ottomar Einenkel, Jorge Pontt, J. Rodriguez, J.l. Cornet, Alejandro Weinstein
    Abstract:

    This paper presents a very new drive system used to transport ore from the mine down to the Concentrator Plant in the copper mine Los Pelambres. Eight 2500 kW motors are driven by three-level inverters with GTOs. A three-level active front end (AFE) is used at the input side of each inverter. A GTO chopper is used to provide controlled electrical braking in case of line loss. The paper presents the requirements and alternatives for the drive system and the control strategies for the converters and the belt. A novel application of the selective harmonic elimination method is used to reduce the input current harmonics. Special attention is dedicated to the interaction with the electrical network. The most relevant features of the system are: (i) fuseless operation; (ii) adjustable power factor; (iii) reduced input current harmonics; and (iv) smooth transition between motoring and regenerating modes and 15 MW of regenerated power with more than six months of successful operation.

Jorge Pontt - One of the best experts on this subject based on the ideXlab platform.

  • Technical evaluation and practical experience of high-power grinding mill drives in mining applications
    IEEE Transactions on Industry Applications, 2005
    Co-Authors: J.r. Rodriguez, Jorge Pontt, P. Newman, R. Musalem, H. Miranda, L. Moran, Gerardo Alzamora
    Abstract:

    Grinding mill drives play an important role in the mining industry. Almost 60% of the electrical energy consumed by modern Concentrator Plants goes to grinding mill drives. Different technologies are used in grinding systems presenting special characteristics from the electrical and process points of view. This paper presents a technical evaluation and practical experience of two different technologies used in high-power grinding mill drives. The analysis is focused on the static power converter and associated control scheme required to drive the motor. Cycloconverters and load-commutated inverters are analyzed in terms of power grid interaction, motor interaction, and the required control scheme. The evaluation is supported with practical results obtained in different Concentrator Plant facilities.

  • Technical evaluation and practical experience of high power grinding mill drives in mining applications
    38th IAS Annual Meeting on Conference Record of the Industry Applications Conference 2003., 2003
    Co-Authors: J. Rodriguez, P. Newman, Jorge Pontt, L. Moran, Gerardo Alzamora
    Abstract:

    Grinding mill drives play an important role in the mining industry. Close to 60% of the electrical energy consumed by modern Concentrator Plants goes to grinding mill drives. Different technologies are used in grinding systems presenting special characteristics from the electrical and process points of view. This paper presents a technical evaluation and practical experience of two different technologies used in high power grinding mill drives. The analysis is focused on the static power converter and associated control scheme required to drive the motor. Cycloconverters and load commutated inverters are analyzed in terms of the interaction with the power grid, the motor, and the required control scheme. The evaluation is supported with practical results obtained in different Concentrator Plant facilities.

  • Novel 20-MW downhill conveyor system using three-level converters
    IEEE Transactions on Industrial Electronics, 2002
    Co-Authors: Jose Rodriguez, Gerardo Alzamora, Norbert Becker, Ottomar Einenkel, Jorge Pontt, Alejandro Weinstein
    Abstract:

    This paper presents a very new drive system used to transport ore from the mine down to the Concentrator Plant in the copper mine "Los Pelambres". Eight 2500-kW motors are driven by three-level inverters with gate-turn-off thyristors (GTOs). A three-level active front end is used at the input side of each inverter. A GTO chopper is used to provide controlled electrical braking in case of line loss. The paper presents the requirements and alternatives for the drive system and the control strategies for the converters and the belt. A novel application of the selective harmonic elimination method is used to reduce the input current harmonics. Special attention is dedicated to the interaction with the electrical network. The most relevant features of the system are: (1) fuseless operation; (2) adjustable power factor; (3) reduced input current harmonics; (4) smooth transition between motoring and regenerating modes; and (5) 15 MW of regenerated power with more than six months of successful operation.

  • "Novel 20 MW downhill conveyor system using three-level converters"
    Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248), 2001
    Co-Authors: A.j.r. F, Gerardo Alzamora, Norbert Becker, Ottomar Einenkel, Jorge Pontt, J. Rodriguez, J.l. Cornet, Alejandro Weinstein
    Abstract:

    This paper presents a very new drive system used to transport ore from the mine down to the Concentrator Plant in the copper mine Los Pelambres. Eight 2500 kW motors are driven by three-level inverters with GTOs. A three-level active front end (AFE) is used at the input side of each inverter. A GTO chopper is used to provide controlled electrical braking in case of line loss. The paper presents the requirements and alternatives for the drive system and the control strategies for the converters and the belt. A novel application of the selective harmonic elimination method is used to reduce the input current harmonics. Special attention is dedicated to the interaction with the electrical network. The most relevant features of the system are: (i) fuseless operation; (ii) adjustable power factor; (iii) reduced input current harmonics; and (iv) smooth transition between motoring and regenerating modes and 15 MW of regenerated power with more than six months of successful operation.

Jose Rodriguez - One of the best experts on this subject based on the ideXlab platform.

  • Novel 20-MW downhill conveyor system using three-level converters
    IEEE Transactions on Industrial Electronics, 2002
    Co-Authors: Jose Rodriguez, Gerardo Alzamora, Norbert Becker, Ottomar Einenkel, Jorge Pontt, Alejandro Weinstein
    Abstract:

    This paper presents a very new drive system used to transport ore from the mine down to the Concentrator Plant in the copper mine "Los Pelambres". Eight 2500-kW motors are driven by three-level inverters with gate-turn-off thyristors (GTOs). A three-level active front end is used at the input side of each inverter. A GTO chopper is used to provide controlled electrical braking in case of line loss. The paper presents the requirements and alternatives for the drive system and the control strategies for the converters and the belt. A novel application of the selective harmonic elimination method is used to reduce the input current harmonics. Special attention is dedicated to the interaction with the electrical network. The most relevant features of the system are: (1) fuseless operation; (2) adjustable power factor; (3) reduced input current harmonics; (4) smooth transition between motoring and regenerating modes; and (5) 15 MW of regenerated power with more than six months of successful operation.