Abstract Developing efficient inhibitors based on eco-friendly compounds for steel protection is ... more Abstract Developing efficient inhibitors based on eco-friendly compounds for steel protection is crucially important. Here the synthesis and characterization of a new hybrid inhibitor based on intercalation of 6-aminohexanoic acid (6-AHA) in layered aluminum tri-polyphosphate (ATP) are reported. ATP and the inorganic-organic hybrid inhibitor system ATP-6-AHA are characterized by XRD, thermal gravimetric analysis (TGA), SEM, IR and Raman spectroscopy. The interlayer space of ATP is expanded by 10.1 A, with 6-AHA planes arranged in bilayers. Corrosion efficiency of ATP-6-AHA was evaluated in 0.1 M and 3.5 % NaCl using electrochemical impedance spectroscopy (EIS) and showed a significantly reduced corrosion for steel S235.
Phosphate mining generates large quantities of waste rock and sludge annually, resulting in signi... more Phosphate mining generates large quantities of waste rock and sludge annually, resulting in significant environmental issues. The large areas of mine sites used to store these wastes limit the availability of usable and agricultural land, alter the topography of the land, and degrade the landscape’s aesthetics. In this study, the acid activation of phosphate by-products to enhance their reactivity and suitability for the development of geopolymer-based thermal insulation materials was investigated. Four formulations of geopolymers were developed using varying ratios of calcined clay by-product and metakaolin as aluminosilicate sources. The activation of precursors was accomplished using a 5M concentration of phosphoric acid (H3PO4). Several analytical techniques, including mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and X-ray fluorescence (XRF), were carried out to characterize both the raw clays...
Jerada coal mine is located in north east of Morocco, and closed in late 2001.Today the quantity ... more Jerada coal mine is located in north east of Morocco, and closed in late 2001.Today the quantity stored is about 15 to 20 million tonnes. These releases contain significant levels of accompanying elements or secondary minerals such as iron sulfides (pyrite) and their oxidation products.Monitor the groundwater quality was developed in the region in order to assess the quality of these waters and to estimate the risk of contamination. The study focused on 35 wells spread to cover almost all of the study area.Two main sampling campaigns were conducted, the first one in October 2010, the second in July 2011.The pH of the different measuring points is generally between 6 and alkaline tending 8 show groundwater level in the region.The results obtained by ion chromatography show an average sulphate concentration of about 700mg/l.These concentrations are much higher in the wet season than the dry season. The average nitrate levels are in the range of 300mg/l while those chlorides are of the...
The Kettara site (Morocco) is an abandoned pyrrhotite ore mine in a semi-arid environment. The si... more The Kettara site (Morocco) is an abandoned pyrrhotite ore mine in a semi-arid environment. The site contains more than 3 million tons of mine waste that were deposited on the surface without concern for environmental consequences. Tailings were stockpiled in a pond, in a dyke, and in piles over an area of approximately 16 ha and have generated acid mine drainage (AMD) for more than 29 years. Geophysical methods have been used at the Kettara mine site to determine the nature of the geological substrate of the tailings pond, the internal structure of the mine wastes, and to investigate the pollution zones associated with sulphide waste dumps. Electrical resistivity tomography (ERT) and seismic refraction data were acquired, processed, and interpreted; the results from ERT and seismic refraction were complementary. A topographical survey of the tailings disposal area was also undertaken to estimate the volume of wastes and quantify the AMD process. Two-dimensional inverse models were used to investigate the geophysical data and indicated alteration zones at depth. It was determined that the material could be classified into three categories: tailings, with low resistivity (5-15 X m) and low velocity (500-1,800 m/s); altered, black shales, with intermediate resistivity (20-60 X m) and velocity (2,000-3,500 m/s), and; materials with high resistivity and velocity ([60 X m and [4,000 m/s, respectively), including unaltered shales associated with quartzite seams. The low-resistivity zone generates AMD, which migrates downward through fractures and microfractures. The substrate is composed of broken and altered shale, which facilitates AMD infiltration.
The abandoned Azegour mine is located in the High Atlas Mountains of Marrakesh (Morocco), and was... more The abandoned Azegour mine is located in the High Atlas Mountains of Marrakesh (Morocco), and was mined for Cu, Mo, and W. About 850,000 t of waste rocks and tailings were deposited on the surface and have been exposed to weathering for 40 years. The remaining acid-producing potential (AP), acid-neutralizing potential, and geochemical behavior of the Azegour Cu-and Mo-rich tailings were investigated. The tailings were found to contain 9.6-19 wt% sulfur, mostly as sulfate (gypsum, anhydrite, and jarosite) while the waste rocks contain less (1.25-6.58 wt%) sulfur. The waste rocks and tailings contain 0.21-9.24 wt% Mo and 0.003-2.78 wt% Cu. The gangue is mostly composed of quartz, talc, chlorite, pyrophyllite, actonolite, clinoptilolite, and alusite. Lead, zinc, cobalt, arsenic, titanium, and nickel are also present. The calcium, which is mainly expressed as calcite, gypsum, scheelite, and powellite, is present at higher concentrations in the waste rocks (18-22 wt% Ca) than in the tailings (4.7-8.6 wt% Ca). Static ABA determinations showed that the Azegour mine wastes still have high AP, 38-205 kg CaCO 3 /t in the waste rocks and 46-387.7 kg CaCO 3 /t in the tailings. This was confirmed in weathering cell tests, where the Azegour tailings leachate had a pH range of 1.98-3.19 and high concentrations of SO 4 (468-45,400 mg/L), Ca (230-675 mg/L), Fe (3-55,900 mg/L), Mn (0.1-1,430 mg/L), and Cu (2.3-9,000 mg/L). The Mo concentrations were high (35 mg/L) during the two first weeks of kinetics tests; W concentrations were below the 0.005 mg/L detection limit.
Les rejets sulfurés de la mine abandonnée de Kettara, située à 30 km au Nord-Nord-Ouest de Marrak... more Les rejets sulfurés de la mine abandonnée de Kettara, située à 30 km au Nord-Nord-Ouest de Marrakech, sont directement entreposés sur un substratum schisto-gréseux fracturé. D'une superficie d'environ 16 ha, ils constituent une réelle source de pollution pour l'écosystème local en particulier à cause du Drainage Minier Acide (DMA) vers les eaux de surface et de la nappe phréatique. Le projet de réhabilitation du site minier de Kettara prévoit dans l'un de ses axes de minimiser l'effet DMA par neutralisation à l'aide de dépôts stériles riches en carbonates issus de l'extraction des phosphates de la mine de Youssoufia voisine. Ces derniers seront utilisés à la fois comme amendement des rejets miniers acides et comme couverture évapo-transpirante (barrière capillaire). Notre étude a permis d'une part, de mieux appréhender la nature et la structure du parc à résidus et de son substratum et d'autre part, de caractériser l'impact de ces résidus sur la qualité des ressources en eau souterraine. Les résultats issus de cette étude vont contribuer à la réussite du projet de réhabilitation du site.
A field study was conducted at the Kettara mine site located in arid climatic conditions in Moroc... more A field study was conducted at the Kettara mine site located in arid climatic conditions in Morocco. The goal was to assess the performance of an inclined store-and-release (SR) cover made with phosphate mine wastes to reduce water infiltration and control acid mine drainage (AMD). The SR cover was constructed using phosphate mine wastes (0.8 m) placed over a capillary break layer (CBL) made of coarse-grained materials. The SR cover had a slope inclination of 14.5°. The cover performance was monitored for a period of 1 year under natural and artificial conditions representing important rainfall events for the climatic conditions at the Kettara mine site. Performance was monitored using volumetric lysimeters, suction sensors, and volumetric water content sensors installed at four stations and at different depths. Under natural climatic conditions, the inclined SR cover limited water percolation by diverting and releasing water to the atmosphere through evaporation. However, the cover...
In arid and semiarid climates, acid mine drainage (AMD; also called acid rock drainage, ARD) gene... more In arid and semiarid climates, acid mine drainage (AMD; also called acid rock drainage, ARD) generated by mine tailings can be controlled by reducing water percolation. The use of store-andrelease (SR) covers with capillary barrier effect is emerging as the most effective way to prevent water percolation through tailings under these climates. Four instrumented experimental cells made of phosphate wastes, as SR covers, were constructed on top (flat surface) of the abandoned Kettara mine site (near Marrakech, Morocco). Results confirmed the potential of phosphate mine waste as SR cover material to control water percolation. However, significant uncertainties remain about the influence of inclined conditions on the hydrogeological behavior of a SR cover at the mine, as the mine wastes at Kettara mine site are retained by dykes that reach a height of 10 m. Due to the slope inclination, water can accumulate above the tilt interface during extreme precipitation events, which could create a breakthrough of the capillary barrier; at this location, the cover is no longer effective to control water infiltration into the mine wastes. A field investigation was conducted to evaluate the influence of the slope on the Kettara SR cover's performance. An experimental field cell (10 m wide by 8 m long) inclined at an angle of 14.5 degrees was constructed on-site. The SR cover retained is made of 0.8 m of phosphate waste, placed over a capillary break layer made of coarse-grained materials. Cover performance was monitored using lysimeters, Tensiometers, suction and soil moisture sensors installed at four stations and at different depths. The paper presents the design, the construction and the instrumentation of an inclined SR covert. Preliminary results of the monitored parameters under natural conditions are also included. The field test showed that the slope influences water distribution in the cover with more water at the bottom of the slope. The inclined SR cover still effectively limited water percolation under natural conditions.
LiCo2/3Ni1/6Mn1/6O2 layered oxide was synthesized by the combustion method that led to a crystall... more LiCo2/3Ni1/6Mn1/6O2 layered oxide was synthesized by the combustion method that led to a crystalline phase with good homogeneity and low particles size. The structural properties of the prepared positive electrode material were investigated by performing XRD Rietveld refinement. Practically no Li/Ni mixing was detected evidencing that the studied compound adopts almost an ideal α-NaFeO2 type structure. The Li||LiCo2/3Ni1/6Mn1/6O2 cell showed
A field investigation was conducted to evaluate the effectiveness of store-and-release (SR) cover... more A field investigation was conducted to evaluate the effectiveness of store-and-release (SR) covers made with different phosphate mine wastes in reducing water infiltration (system inclination and surface runoff were neglected) and controlling acid rock drainage (ARD) generation. Four instrumented experimental cells were constructed with different SR layer configurations (two thicknesses and three materials) placed over a capillary break layer. To assess the hydrogeological behaviour of these cover systems, volumetric water content, matric suction, and meteorological monitoring time trends were studied for a period of 1.5 years under actual and extreme conditions typical of an arid climate. Under natural climatic conditions, all net infiltration was released to the atmosphere by the physical process of evaporation (regardless of SR layer thickness and type). Although high surface matric suction (>3000 kPa) decreased the evaporation rate (or release capacity) during the drying period, field tests showed that the studied scenarios limited deep water infiltration even under extreme rainfall events. The release capacity of the SR layer was slightly lower for cover systems made with the finer-grained mine waste (phosphate limestone tailings). This study showed that, for a one-dimensional (1D) condition, the tested phosphate mine wastes have the appropriate hydrogeological properties to be used as components of SR covers under conditions at the Kettara mine site, located near Marrakech, Morocco.
Valorisation des rejets miniers du district pb-zn de Touissit-boubker (région orientale-maroc) 15... more Valorisation des rejets miniers du district pb-zn de Touissit-boubker (région orientale-maroc) 15 Introduction
ABSTRACT The reuse of some industrial by-products in the construction industry saves natural reso... more ABSTRACT The reuse of some industrial by-products in the construction industry saves natural resources and energy, while at the same time reduces environmental problems related to their surface disposal. Mine tailings are currently among the largest industrial by-products in the world, and yet, only limited studies have been conducted to evaluate their reuse potential. Moreover, abandoned base-metal tailings are increasingly used in some developing countries for the manufacture of mortars without any control, engineering basis or environmental concern. In this study, an experimental program using mechanical tests, mineralogical investigations and leaching tests is presented to assess the use of low sulfide base-metal tailings, with varying properties, as fine aggregates for rendering and masonry mortars. An authentic case study illustrating their use in Moroccan construction is additionally presented. Overall, it was observed that the main properties affecting the performances of these tailings-based mortars are the residual Pb-Zn concentrations and the fine content of each tailing. The Pb-Zn fraction, when using the appropriate substitution level, may serve as an active set retardant improving mortars setting time. The leaching of metals was also successfully stabilized in mortars.
Valorisation des rejets miniers du district Pb-zn de Touissit-Boubker (région orientale-Maroc) 38... more Valorisation des rejets miniers du district Pb-zn de Touissit-Boubker (région orientale-Maroc) 38 RESUME Au Maroc, aucun dispositif n'a été mis en place pour gérer l'abandon des anciens sites miniers. Ces derniers sont caractérisés par la persistance d'immenses tonnages de résidus miniers dont la nocivité est à l'origine, dans de nombreux cas, d'importants impacts environnementaux. L'objectif de ce travail de recherche est d'étudier la faisabilité de valorisation des rejets abandonnés du district minier Pb-Zn de Touissit-Boubker (Maroc) comme granulats fins pour mortier de finition. L'étude consiste d'abord en une caractérisation des propriétés physiques, chimiques et minéralogiques des rejets, suivie d'une évaluation des propriétés mécaniques des mortiers confectionnés. L'étude comporte aussi une évaluation du potentiel polluant des mortiers à base de ce type de rejets. Les résultats ont mis en évidence la présence d'une grande proportion de particules fines (< 63µm) et des concentrations élevées en As, Cu, Cd, Pb et Zn dans les rejets miniers. Il a été observé que l'utilisation des rejets miniers comme agrégats, pour la confection de mortiers, engendre une importante augmentation de la demande en eau nécessaire au gâchage ainsi qu'une diminution significative des résistances mécaniques en particulier à court terme. Toutefois, la stabilisation des rejets miniers dans la matrice cimentaire est effective puisque la dissolution du Pb et du Zn s'avère très limitée.
Abstract Developing efficient inhibitors based on eco-friendly compounds for steel protection is ... more Abstract Developing efficient inhibitors based on eco-friendly compounds for steel protection is crucially important. Here the synthesis and characterization of a new hybrid inhibitor based on intercalation of 6-aminohexanoic acid (6-AHA) in layered aluminum tri-polyphosphate (ATP) are reported. ATP and the inorganic-organic hybrid inhibitor system ATP-6-AHA are characterized by XRD, thermal gravimetric analysis (TGA), SEM, IR and Raman spectroscopy. The interlayer space of ATP is expanded by 10.1 A, with 6-AHA planes arranged in bilayers. Corrosion efficiency of ATP-6-AHA was evaluated in 0.1 M and 3.5 % NaCl using electrochemical impedance spectroscopy (EIS) and showed a significantly reduced corrosion for steel S235.
Phosphate mining generates large quantities of waste rock and sludge annually, resulting in signi... more Phosphate mining generates large quantities of waste rock and sludge annually, resulting in significant environmental issues. The large areas of mine sites used to store these wastes limit the availability of usable and agricultural land, alter the topography of the land, and degrade the landscape’s aesthetics. In this study, the acid activation of phosphate by-products to enhance their reactivity and suitability for the development of geopolymer-based thermal insulation materials was investigated. Four formulations of geopolymers were developed using varying ratios of calcined clay by-product and metakaolin as aluminosilicate sources. The activation of precursors was accomplished using a 5M concentration of phosphoric acid (H3PO4). Several analytical techniques, including mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and X-ray fluorescence (XRF), were carried out to characterize both the raw clays...
Jerada coal mine is located in north east of Morocco, and closed in late 2001.Today the quantity ... more Jerada coal mine is located in north east of Morocco, and closed in late 2001.Today the quantity stored is about 15 to 20 million tonnes. These releases contain significant levels of accompanying elements or secondary minerals such as iron sulfides (pyrite) and their oxidation products.Monitor the groundwater quality was developed in the region in order to assess the quality of these waters and to estimate the risk of contamination. The study focused on 35 wells spread to cover almost all of the study area.Two main sampling campaigns were conducted, the first one in October 2010, the second in July 2011.The pH of the different measuring points is generally between 6 and alkaline tending 8 show groundwater level in the region.The results obtained by ion chromatography show an average sulphate concentration of about 700mg/l.These concentrations are much higher in the wet season than the dry season. The average nitrate levels are in the range of 300mg/l while those chlorides are of the...
The Kettara site (Morocco) is an abandoned pyrrhotite ore mine in a semi-arid environment. The si... more The Kettara site (Morocco) is an abandoned pyrrhotite ore mine in a semi-arid environment. The site contains more than 3 million tons of mine waste that were deposited on the surface without concern for environmental consequences. Tailings were stockpiled in a pond, in a dyke, and in piles over an area of approximately 16 ha and have generated acid mine drainage (AMD) for more than 29 years. Geophysical methods have been used at the Kettara mine site to determine the nature of the geological substrate of the tailings pond, the internal structure of the mine wastes, and to investigate the pollution zones associated with sulphide waste dumps. Electrical resistivity tomography (ERT) and seismic refraction data were acquired, processed, and interpreted; the results from ERT and seismic refraction were complementary. A topographical survey of the tailings disposal area was also undertaken to estimate the volume of wastes and quantify the AMD process. Two-dimensional inverse models were used to investigate the geophysical data and indicated alteration zones at depth. It was determined that the material could be classified into three categories: tailings, with low resistivity (5-15 X m) and low velocity (500-1,800 m/s); altered, black shales, with intermediate resistivity (20-60 X m) and velocity (2,000-3,500 m/s), and; materials with high resistivity and velocity ([60 X m and [4,000 m/s, respectively), including unaltered shales associated with quartzite seams. The low-resistivity zone generates AMD, which migrates downward through fractures and microfractures. The substrate is composed of broken and altered shale, which facilitates AMD infiltration.
The abandoned Azegour mine is located in the High Atlas Mountains of Marrakesh (Morocco), and was... more The abandoned Azegour mine is located in the High Atlas Mountains of Marrakesh (Morocco), and was mined for Cu, Mo, and W. About 850,000 t of waste rocks and tailings were deposited on the surface and have been exposed to weathering for 40 years. The remaining acid-producing potential (AP), acid-neutralizing potential, and geochemical behavior of the Azegour Cu-and Mo-rich tailings were investigated. The tailings were found to contain 9.6-19 wt% sulfur, mostly as sulfate (gypsum, anhydrite, and jarosite) while the waste rocks contain less (1.25-6.58 wt%) sulfur. The waste rocks and tailings contain 0.21-9.24 wt% Mo and 0.003-2.78 wt% Cu. The gangue is mostly composed of quartz, talc, chlorite, pyrophyllite, actonolite, clinoptilolite, and alusite. Lead, zinc, cobalt, arsenic, titanium, and nickel are also present. The calcium, which is mainly expressed as calcite, gypsum, scheelite, and powellite, is present at higher concentrations in the waste rocks (18-22 wt% Ca) than in the tailings (4.7-8.6 wt% Ca). Static ABA determinations showed that the Azegour mine wastes still have high AP, 38-205 kg CaCO 3 /t in the waste rocks and 46-387.7 kg CaCO 3 /t in the tailings. This was confirmed in weathering cell tests, where the Azegour tailings leachate had a pH range of 1.98-3.19 and high concentrations of SO 4 (468-45,400 mg/L), Ca (230-675 mg/L), Fe (3-55,900 mg/L), Mn (0.1-1,430 mg/L), and Cu (2.3-9,000 mg/L). The Mo concentrations were high (35 mg/L) during the two first weeks of kinetics tests; W concentrations were below the 0.005 mg/L detection limit.
Les rejets sulfurés de la mine abandonnée de Kettara, située à 30 km au Nord-Nord-Ouest de Marrak... more Les rejets sulfurés de la mine abandonnée de Kettara, située à 30 km au Nord-Nord-Ouest de Marrakech, sont directement entreposés sur un substratum schisto-gréseux fracturé. D'une superficie d'environ 16 ha, ils constituent une réelle source de pollution pour l'écosystème local en particulier à cause du Drainage Minier Acide (DMA) vers les eaux de surface et de la nappe phréatique. Le projet de réhabilitation du site minier de Kettara prévoit dans l'un de ses axes de minimiser l'effet DMA par neutralisation à l'aide de dépôts stériles riches en carbonates issus de l'extraction des phosphates de la mine de Youssoufia voisine. Ces derniers seront utilisés à la fois comme amendement des rejets miniers acides et comme couverture évapo-transpirante (barrière capillaire). Notre étude a permis d'une part, de mieux appréhender la nature et la structure du parc à résidus et de son substratum et d'autre part, de caractériser l'impact de ces résidus sur la qualité des ressources en eau souterraine. Les résultats issus de cette étude vont contribuer à la réussite du projet de réhabilitation du site.
A field study was conducted at the Kettara mine site located in arid climatic conditions in Moroc... more A field study was conducted at the Kettara mine site located in arid climatic conditions in Morocco. The goal was to assess the performance of an inclined store-and-release (SR) cover made with phosphate mine wastes to reduce water infiltration and control acid mine drainage (AMD). The SR cover was constructed using phosphate mine wastes (0.8 m) placed over a capillary break layer (CBL) made of coarse-grained materials. The SR cover had a slope inclination of 14.5°. The cover performance was monitored for a period of 1 year under natural and artificial conditions representing important rainfall events for the climatic conditions at the Kettara mine site. Performance was monitored using volumetric lysimeters, suction sensors, and volumetric water content sensors installed at four stations and at different depths. Under natural climatic conditions, the inclined SR cover limited water percolation by diverting and releasing water to the atmosphere through evaporation. However, the cover...
In arid and semiarid climates, acid mine drainage (AMD; also called acid rock drainage, ARD) gene... more In arid and semiarid climates, acid mine drainage (AMD; also called acid rock drainage, ARD) generated by mine tailings can be controlled by reducing water percolation. The use of store-andrelease (SR) covers with capillary barrier effect is emerging as the most effective way to prevent water percolation through tailings under these climates. Four instrumented experimental cells made of phosphate wastes, as SR covers, were constructed on top (flat surface) of the abandoned Kettara mine site (near Marrakech, Morocco). Results confirmed the potential of phosphate mine waste as SR cover material to control water percolation. However, significant uncertainties remain about the influence of inclined conditions on the hydrogeological behavior of a SR cover at the mine, as the mine wastes at Kettara mine site are retained by dykes that reach a height of 10 m. Due to the slope inclination, water can accumulate above the tilt interface during extreme precipitation events, which could create a breakthrough of the capillary barrier; at this location, the cover is no longer effective to control water infiltration into the mine wastes. A field investigation was conducted to evaluate the influence of the slope on the Kettara SR cover's performance. An experimental field cell (10 m wide by 8 m long) inclined at an angle of 14.5 degrees was constructed on-site. The SR cover retained is made of 0.8 m of phosphate waste, placed over a capillary break layer made of coarse-grained materials. Cover performance was monitored using lysimeters, Tensiometers, suction and soil moisture sensors installed at four stations and at different depths. The paper presents the design, the construction and the instrumentation of an inclined SR covert. Preliminary results of the monitored parameters under natural conditions are also included. The field test showed that the slope influences water distribution in the cover with more water at the bottom of the slope. The inclined SR cover still effectively limited water percolation under natural conditions.
LiCo2/3Ni1/6Mn1/6O2 layered oxide was synthesized by the combustion method that led to a crystall... more LiCo2/3Ni1/6Mn1/6O2 layered oxide was synthesized by the combustion method that led to a crystalline phase with good homogeneity and low particles size. The structural properties of the prepared positive electrode material were investigated by performing XRD Rietveld refinement. Practically no Li/Ni mixing was detected evidencing that the studied compound adopts almost an ideal α-NaFeO2 type structure. The Li||LiCo2/3Ni1/6Mn1/6O2 cell showed
A field investigation was conducted to evaluate the effectiveness of store-and-release (SR) cover... more A field investigation was conducted to evaluate the effectiveness of store-and-release (SR) covers made with different phosphate mine wastes in reducing water infiltration (system inclination and surface runoff were neglected) and controlling acid rock drainage (ARD) generation. Four instrumented experimental cells were constructed with different SR layer configurations (two thicknesses and three materials) placed over a capillary break layer. To assess the hydrogeological behaviour of these cover systems, volumetric water content, matric suction, and meteorological monitoring time trends were studied for a period of 1.5 years under actual and extreme conditions typical of an arid climate. Under natural climatic conditions, all net infiltration was released to the atmosphere by the physical process of evaporation (regardless of SR layer thickness and type). Although high surface matric suction (&amp;gt;3000 kPa) decreased the evaporation rate (or release capacity) during the drying period, field tests showed that the studied scenarios limited deep water infiltration even under extreme rainfall events. The release capacity of the SR layer was slightly lower for cover systems made with the finer-grained mine waste (phosphate limestone tailings). This study showed that, for a one-dimensional (1D) condition, the tested phosphate mine wastes have the appropriate hydrogeological properties to be used as components of SR covers under conditions at the Kettara mine site, located near Marrakech, Morocco.
Valorisation des rejets miniers du district pb-zn de Touissit-boubker (région orientale-maroc) 15... more Valorisation des rejets miniers du district pb-zn de Touissit-boubker (région orientale-maroc) 15 Introduction
ABSTRACT The reuse of some industrial by-products in the construction industry saves natural reso... more ABSTRACT The reuse of some industrial by-products in the construction industry saves natural resources and energy, while at the same time reduces environmental problems related to their surface disposal. Mine tailings are currently among the largest industrial by-products in the world, and yet, only limited studies have been conducted to evaluate their reuse potential. Moreover, abandoned base-metal tailings are increasingly used in some developing countries for the manufacture of mortars without any control, engineering basis or environmental concern. In this study, an experimental program using mechanical tests, mineralogical investigations and leaching tests is presented to assess the use of low sulfide base-metal tailings, with varying properties, as fine aggregates for rendering and masonry mortars. An authentic case study illustrating their use in Moroccan construction is additionally presented. Overall, it was observed that the main properties affecting the performances of these tailings-based mortars are the residual Pb-Zn concentrations and the fine content of each tailing. The Pb-Zn fraction, when using the appropriate substitution level, may serve as an active set retardant improving mortars setting time. The leaching of metals was also successfully stabilized in mortars.
Valorisation des rejets miniers du district Pb-zn de Touissit-Boubker (région orientale-Maroc) 38... more Valorisation des rejets miniers du district Pb-zn de Touissit-Boubker (région orientale-Maroc) 38 RESUME Au Maroc, aucun dispositif n'a été mis en place pour gérer l'abandon des anciens sites miniers. Ces derniers sont caractérisés par la persistance d'immenses tonnages de résidus miniers dont la nocivité est à l'origine, dans de nombreux cas, d'importants impacts environnementaux. L'objectif de ce travail de recherche est d'étudier la faisabilité de valorisation des rejets abandonnés du district minier Pb-Zn de Touissit-Boubker (Maroc) comme granulats fins pour mortier de finition. L'étude consiste d'abord en une caractérisation des propriétés physiques, chimiques et minéralogiques des rejets, suivie d'une évaluation des propriétés mécaniques des mortiers confectionnés. L'étude comporte aussi une évaluation du potentiel polluant des mortiers à base de ce type de rejets. Les résultats ont mis en évidence la présence d'une grande proportion de particules fines (< 63µm) et des concentrations élevées en As, Cu, Cd, Pb et Zn dans les rejets miniers. Il a été observé que l'utilisation des rejets miniers comme agrégats, pour la confection de mortiers, engendre une importante augmentation de la demande en eau nécessaire au gâchage ainsi qu'une diminution significative des résistances mécaniques en particulier à court terme. Toutefois, la stabilisation des rejets miniers dans la matrice cimentaire est effective puisque la dissolution du Pb et du Zn s'avère très limitée.
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