J. Jurković; E. Babajić; T. Muhić – Šarac; M. Kolar; A. Kazlagić
Abstract
Oxidation of sulfide-containing ores is the main cause of Acid Mine Drainage (AMD), which is an environmental problem associated with both the abandoned and active mines. Iron-bearing sulfide minerals can be oxidized and form mine waters with high sulfate content, low pH, high electrical conductivity, ...
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Oxidation of sulfide-containing ores is the main cause of Acid Mine Drainage (AMD), which is an environmental problem associated with both the abandoned and active mines. Iron-bearing sulfide minerals can be oxidized and form mine waters with high sulfate content, low pH, high electrical conductivity, high redox potential, and high concentrations of iron, aluminum, and other heavy metals. In the process of AMD, precipitation of poorly crystalized oxy-hydroxides of iron with a large active surface can occur. On the surface of iron oxy-hydroxide, the precipitated particulate matter, anions, and cations (metals) could be adsorbed. Mine waters can contain a certain amount of precious metals that can also be adsorbed onto an iron particulate matter surface, which is investigated in this research work. In this work, the samples of iron oxy-hydroxide particulate matter at abandoned gold mine waste in Bakovići (Central Bosnia and Herzegovina) are used. Several parameters including pH, water content, particle size distribution, sulfate content, electrical conductivity, redox potential, and amounts of gold, silver, and iron are measured on the selected mine waste samples. The results obtained indicate that significant amounts of gold (average: 6.8 mg/kg) and silver (average: 7.13 mg/kg) are present in the iron precipitate. Adsorption of precious metals onto the iron oxy-hydroxide surface is strongly pH-dependent. At a very low pH value, desorption of precious metals is favorite. Thus, precious metals are only partially adsorbed onto the iron oxy-hydroxide surface.
F. Ghadimi; A. Hajati; A. Sabzian
Abstract
The Mighan playa/lake is characterized as a closed catchment. In the recent years, the rapid industrialization and urbanization has resulted in a pollution area in the city of Arak. In this work, we focus on six regions around the playa/lake to study the distribution of heavy metals in the waters and ...
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The Mighan playa/lake is characterized as a closed catchment. In the recent years, the rapid industrialization and urbanization has resulted in a pollution area in the city of Arak. In this work, we focus on six regions around the playa/lake to study the distribution of heavy metals in the waters and their contamination risk. A total of 32 water samples are analyzed to determine the contamination degree of heavy metals, i.e. Hg, As, Cd, Cr, Cu, Pb, and Zn. The heavy metal pollution index, heavy metal evaluation index, and degree of contamination are utilized to assess the pollution extent of these metals. The spatial distribution patterns reveal that the waters in different areas of playa/lake are in a good condition. The island, lake in playa, and the Wastewater Mineral Salts Company are most seriously polluted with Pb, being higher than the standard of drinking water quality limit. Water in the wastewater treatment plant is polluted with Hg and As. The correlation matrix, factor analysis, and cluster analysis are used to support the idea that Pb may be mainly derived from the atmospheric input, and As and Hg from the wastewater treatment plant, agricultural lands, and domestic waste. Many native and migratory birds live in the Mighan playa, which is exposed to heavy metals. Therefore, it is required to monitor heavy metals in the Arak playa and to manage the municipal, industrial, and agricultural activities around it and to reduce them.
F. Sadough Abbasian; B. Rezai; A. R. Azadmehr; H. Hamidian
Abstract
In this work, two clay-based composites are prepared for the adsorptive removal of the chloride ions from aqueous solutions. These composites are characterized through Fourier transform-infrared spectroscopy, scanning electron microscopy, X-ray fluorescence spectroscopy, and X-ray diffraction analysis. ...
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In this work, two clay-based composites are prepared for the adsorptive removal of the chloride ions from aqueous solutions. These composites are characterized through Fourier transform-infrared spectroscopy, scanning electron microscopy, X-ray fluorescence spectroscopy, and X-ray diffraction analysis. The effects of different parameters such as the contact time, amount of adsorbent, chloride concentration, temperature, and pH are studied by batch experiments. Also the isotherm, kinetic, and thermodynamic of the adsorptive removal of the chloride ions from these two composites are investigated. According to the results obtained, the adsorptive removal of chloride ions is initially rapid, and the equilibrium time is reached after 30 min. The optimal pH value is 7.0 for a better adsorption, and the maximum capacity can be achieved, which is 60.2 mg/g with 1000 mg/L of the initial chloride concentration. The Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich adsorption models are applied to describe the equilibrium isotherms at different chloride concentrations. According to the equilibrium isotherms and the correlation coefficients (R2CDC: 0.9424, R2LDC: 0.996), the process can be described by the Langmuir model, and exhibits the highest removal rate of 97.24% (24.31 mg/g) with 250 mg/L of the initial chloride concentration. The pseudo-first-order and pseudo-second-order, intra-particle diffusion, and mass transfer kinetics models are used to identify the mechanism of the adsorptive removal of the chloride ions. The pseudo-second order model due the correlation coefficients (R2CDC: 0.9217-0.9852, R2LDC: 0.9227-0.9926) can be fitted to the kinetic calculations, and it is applicable for the adsorptive removal of chloride ions by the adsorbents. The thermodynamic calculations show that in a low chloride concentration, the sorption is spontaneous, associative, and endothermic; and in a high concentration, it is unspontaneous, dissociative, and endothermic. The calculated value of free energy (E) for adsorption onto the adsorbents suggests that the reaction rate controls the adsorptive removal of the chloride process rather than diffusion. It can be concluded that these two composites can be used as effective and applicable adsorbents for the adsorptive removal of chloride ions.
M. J. Sajid; N. Shahani; M. Ali
Abstract
Mining is among the oldest industries. It is the primary source of raw materials for most of the sectors. Little is known about the complex inter-sectoral carbon linkages of the mining industry. In this work, we estimate the inter- and intra-sectoral carbon linkage impacts of the mining sector across ...
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Mining is among the oldest industries. It is the primary source of raw materials for most of the sectors. Little is known about the complex inter-sectoral carbon linkages of the mining industry. In this work, we estimate the inter- and intra-sectoral carbon linkage impacts of the mining sector across ten major economies by applying an input-output model, and the hypothetical extraction method and its modified version. The hypothetical extraction method removes an industrial block from an economic system, and afterwards, it makes a comparison between the before and after removal values. China with 195.47 Mt has the highest mining emissions, followed by USA, India, and Canada with 110.99 Mt, 108.79 Mt, and 76.92 Mt, respectively. The India’s mining sector with 26.33 t/104 $ is the most carbon-intensive, followed by Japan and Canada with 6.84 t/104 $ and 5.22 t/104 $, respectively. China’s carbon emissions with -11.56% and -11.28%, respectively, have been affected the most by the total extraction of mining sector and forward carbon linkages, while for the backward carbon linkage, Canada with -1.33% has been affected the most. Canada has the highest mixed and internal emissions of 0.42 Mt and 47.88 Mt, respectively. However, China has the highest net-backward and net-forward emissions of 16.91 Mt and 189.22 Mt, respectively. For all nations, the mining sector is a net exporter of emissions to other industries. Based on the numerical findings, in this work, we discuss the mitigation measures for both the direct and indirect mining emissions.
O.E. Ifelola
Abstract
Metals are ubiquitous within the earth crust. However, the exceptional high-level concentration of heavy metals in the soil due to natural or anthropogenic activities and the chemical forms in which they exist determine the level of risk they portend to the environment. This work was aimed at determining ...
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Metals are ubiquitous within the earth crust. However, the exceptional high-level concentration of heavy metals in the soil due to natural or anthropogenic activities and the chemical forms in which they exist determine the level of risk they portend to the environment. This work was aimed at determining the background level of the presence of seven priority toxic metals (Cr, Ni, Pb, As, Cd, Cu, Zn) in the chemical phases of the overburden topsoil of a bituminous deposit prior to mining activities through the speciation analysis. The grab samples of overburden topsoil were initially obtained and homogenized to composites based on locations for the subsequent sequential extraction procedure (SEP). The specific physico-chemical properties of the sampled soils were simultaneously determined to complement the SEP inferential analysis. The results obtained showed that most metals were spatially bounded to the Fe-Mn oxides (reducible phase) followed by the organic (oxidizable) and the carbonates phases, respectively. Fractionally, the dominant soil texture in the studied area was sand (55.45%); however, the colloidal organic matter and Fe-Mn oxide phases played the dominant roles in the sorption activities of the selected metals. The soil chemical phase with the least metal pool was the exchangeable (water/salt) soluble fraction. The overall assessment revealed that the geogenic heavy metals in the topsoil posed no threats since a marginal fraction of the metals existed in the bio-available form in non-toxic concentrations in the order of Pb > Zn > Cu, while the potential mobility of metals showed that Zn was preferentially higher than Pb and Cu, respectively.
Z. Rezaei; M. Ataee-pour; H. Madani
Abstract
Providing a fresh and cool airflow in underground mines is one of the main concerns during mining. Destruction of support systems, the presence of undesirable objects in the airway and distortion of airflow are the parameters involved that would result in pressure loss, which would affect the ventilation ...
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Providing a fresh and cool airflow in underground mines is one of the main concerns during mining. Destruction of support systems, the presence of undesirable objects in the airway and distortion of airflow are the parameters involved that would result in pressure loss, which would affect the ventilation network. There are a lot of research works about the ventilation network planning that consider the confidence in the planning but how reliable are these designs? These questions can be answered using the quantitative reliability evaluation. For the reliability evaluation of mine ventilation network, tunnel resistance and flow rate changes for all branches are considered as the reliability indices and criteria. This paper describes a stepwise method for evaluation of the underground coal mine network reliability associated with major losses using the cut set method. The reliability of the entire network is achieved by the reliability of every single component. The proposed model is implemented by the Takht coal mine. The Takht mine ventilation network probability of failure is in the range of 19-100% so reliability is in the range of 0-81% for the entire ventilation network.
A. Hasanzadeh_Sablouei; Seyed M. Moosavirad
Abstract
The electrocoagulation/flotation process is a novel approach in mining industry that is implemented to return Cu metal to the production cycle, which improves copper recovery and reduces waste water. In this research work, the response surface methodology was applied to optimize the factors effective ...
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The electrocoagulation/flotation process is a novel approach in mining industry that is implemented to return Cu metal to the production cycle, which improves copper recovery and reduces waste water. In this research work, the response surface methodology was applied to optimize the factors effective in Cu metal recovery and sludge volume produced from thickener overflow. To this end, the D-optimal experimental design was utilized. The influences of four independent parameters including the electrolysis time, initial pH, current density, and electrodes type were studied to investigate the initial Cu grade percentage (28%) and sludge volume produced from thickener overflow. All these parameters were found to have important effects on the Cu metal recovery and the sludge volume produced. The linear and quadratic models were utilized for the Cu grade and sludge volume, respectively. The importance of the independent variables and the interaction between them was assessed by ANOVA. The optimum operating conditions with 27.22% Cu grade were taken to be: electrolysis time: 6.5 min, initial pH: 6.7, current density: 50.2 A/m2, and electrode type: Fe-Al. Similarly, for the produced sludge volume of 861 cm3, the following conditions were found: electrolysis time: 15 min, initial pH: 4.1, current density: 48.7, and electrode type: Fe-Al. The outcomes underscored a practical viewpoint of electrocoagulation, known as an acceptable method for Cu recovery from mine industrials, especially in mineral processing plants.
F. Mohajer-Moghari; K. Seifpanahi Shabani; M. Karamouzian
Abstract
This researchdescribe wastewater pre-treatment that contaminated with Methylene Blue dye (MB) and Ni(II) ion by Athelia Bombacina fungus dead biomass (ABFDB). Researches finding on ABFDB characterization by SEM, XRD, CHNS and FT-IR analysis show that ABFDB can be used as efficient sorbent, because ABFDB ...
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This researchdescribe wastewater pre-treatment that contaminated with Methylene Blue dye (MB) and Ni(II) ion by Athelia Bombacina fungus dead biomass (ABFDB). Researches finding on ABFDB characterization by SEM, XRD, CHNS and FT-IR analysis show that ABFDB can be used as efficient sorbent, because ABFDB cellular wall consist of Chitin, β-Glucan and Cellulose biopolymers, generally. Results show that removal of MB and Ni(II) ion by ABFDB sorbent is more than 86.41 and 66.2%, respectively. So, after parameters investigation of MB and Ni(II) ion sorption process by ABFDB, the response surface method was employed for optimization and study the interaction of operational parameters on the sorption of pollutants. This low-cost and natural environmental friendly biosorbent can be utilized for pretreatment process in the first step of wastewater treatment project.
R. Morla; Sh. Karekal; A. Godbole
Abstract
Diesel-operated Load Haul Dumper (LHD) vehicles are commonly used in underground coal mines. Despite their value as utility vehicles, the main drawback of these vehicles is that they generate diesel particulate matter (DPM), a known carcinogenic agent. In this work, an attempt is made to model DPM flows ...
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Diesel-operated Load Haul Dumper (LHD) vehicles are commonly used in underground coal mines. Despite their value as utility vehicles, the main drawback of these vehicles is that they generate diesel particulate matter (DPM), a known carcinogenic agent. In this work, an attempt is made to model DPM flows generated by LHDs in an underground coal mine environment for different DPM flow and intake air flow directions. The field experiments are conducted and used to validate the computational fluid dynamics (CFD) models and used to map the DPM flow patterns. The results obtained show that if DPM and the intake air co-flow (flow in the same direction), DPM is confined predominantly in the middle of the roadway. To the contrary, if the DPM and intake air counter-flow (flow in the opposite directions), the DPM spread occurs throughout the entire cross-section of the roadway. In the latter case, the operator will be more susceptible to exposure to high concentrations of DPM. Overall, the DPM concentration decreases with an increase in the intake air velocities. For co-flow for intake air velocities of 2 m/s, 3 m/s, and 4 m/s, the DPM concentrations at 50 m downstream of the vehicles are 39 µg/m3, 23 µg/m3, and 19 µg/ m3, respectively. The DPM concentration is also influenced by the DPM temperature at the source. For the DPM temperatures of 30 oC, 40 oC, 50 oC, and 60 oC, the DPM concentrations at 50 m downstream of the source are 43 µg/m3, 34 µg/m3, 12 µg/m3, and 9 µg/m3, respectively.
A. Aryafar; R. Mikaeil; F. Doulati Ardejani; S. Shaffiee Haghshenas; A. Jafarpour
Abstract
The process of pollutant adsorption from industrial wastewaters is a multivariate problem. This process is affected by many factors including the contact time (T), pH, adsorbent weight (m), and solution concentration (ppm). The main target of this work is to model and evaluate the process of pollutant ...
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The process of pollutant adsorption from industrial wastewaters is a multivariate problem. This process is affected by many factors including the contact time (T), pH, adsorbent weight (m), and solution concentration (ppm). The main target of this work is to model and evaluate the process of pollutant adsorption from industrial wastewaters using the non-linear multivariate regression and intelligent computation techniques. In order to achieve this goal, 54 industrial wastewater samples gathered by Institute of Color Science & Technology of Iran (ICSTI) were studied. Based on the laboratory conditions, the data was divided into 4 groups (A-1, A-2, A-3, and A-4). For each group, a non-linear regression model was made. The statistical results obtained showed that two developed equations from the A-3 and A-4 groups were the best models with R2 being 0.84 and 0.74. In these models, the contact time and solution concentration were the main effective factors influencing the adsorption process. The extracted models were validated using the t-test and F-value test. The hybrid PSO-based ANN model (particle swarm optimization and artificial neural network algorithms) was constructed for modelling the pollutant adsorption process under different laboratory conditions. Based on this hybrid modeling, the performance indices were estimated. The hybrid model results showed that the best value belonged to the data group A-4 with R2 of 0.91. Both the non-linear regression and hybrid PSO-ANN models were found to be helpful tools for modeling the process of pollutant adsorption from industrial wastewaters.
M. Samadi; S. Torbati; S. Alipour
Abstract
Heavy metal(loid) contamination in the environment of mining areas has become an important problem. Cheshemeh-Konan is one of the main copper deposits in NW Iran that is currently abandoned. In the present work, the intensity of some metal(loid) pollutions in the soil of the mining area was assessed ...
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Heavy metal(loid) contamination in the environment of mining areas has become an important problem. Cheshemeh-Konan is one of the main copper deposits in NW Iran that is currently abandoned. In the present work, the intensity of some metal(loid) pollutions in the soil of the mining area was assessed using three reliable indices. In addition, the potential of Sonchus oleraceus L., as the dominant plant grown in the area, in the uptake of some metal(loid)s from the soil was evaluated. The plant and soil samples were collected from the mining area and analyzed by inductively coupled plasma-mass spectrometry (ICP-MS). The results obtained revealed that the soil of the studied mining area was considerably contaminated by As (CF = 3.1), Cr (CF = 3.8), and Ni (CF = 4.07). It was confirmed that S. oleraceus had a good ability to accumulate Cd (0.74 mg/kg), Mo (0.67 mg/kg), Sr (285.80 mg/kg), Sn (161.10 mg/kg), and Sc (30.35 mg/kg) when mean concentrations of these metals in the soil were 0.14, 0.12, 161.05, 1.94, and 17.9 mg/kg, respectively. The plant biological absorption coefficient for these 5 elements was more than 1. The correlations between the Mo and Sr contents in the soil and plant were significantly positive. According to the results obtained, the present work provides some geochemical findings about the substrate, and leads to the increasing information about the relationship between the element concentrations in the plants and different soils.
Seyedeh M. Ehsani; M. Unesi; R. Tamartash
Abstract
Changes in the tailing properties (increasing clay mineral content and fine particles) and poor operation of the dewatering systems have negative impacts on the Tailing Storage Facilities (TSF) of the Shahrbabak copper complex. The design solid concentration of the thickened tailings is 63 wt.% in the ...
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Changes in the tailing properties (increasing clay mineral content and fine particles) and poor operation of the dewatering systems have negative impacts on the Tailing Storage Facilities (TSF) of the Shahrbabak copper complex. The design solid concentration of the thickened tailings is 63 wt.% in the Shahrbabak paste plant but it is well below the design value right now (approx. 55 wt.%). The aim of this work is to find the effects of the clay mineral and dewatering operations on the water recovery and tailing dam capacity. The understudied samples were taken from the thickener underflow and prepared at the required solid concentrations (55, 60, 65, and 70 wt.%). The results obtained showed that the initial settled density varied from 1.044 to 1.146 t/m3 by increasing the solid concentrations from 55 to 63 wt.%. Furthermore, the shrinkage limit density of the two solid concentrations was recorded at 1.52 and 1.62 t/m3, and the crack volume was estimated at 6.3% and 7.2% of the final sample volume. Also the sub-aerial tailing beach slope in the upper quarter and the remainder of TSF was too low and exhibited 2.0% and 1.0%, respectively. However, it is far from the design values (3.5%, 2.5%, and 1.7% from head of the beach to the end). Thus it is clear that the clay minerals and fine particles hold more water in their inner network and occupy a more TSF volume. Nevertheless, the beach slope can be increased by improving the thickener performance and removing the leakage and other periodic water, although it seems impractical to achieve the design value due to the changes in the tailing properties.
H. Haghnazar; B. Hashemzadeh Ansar; R. Amini; M. Saneie
Abstract
River bed sand and gravel are utilized more than mountain materials due to their availability and closeness to the transit roads and sites of usage. Excessive and non-technical extraction of gravel and sand bring a kind of interference in them, leading to many negative consequences. Therefore, presenting ...
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River bed sand and gravel are utilized more than mountain materials due to their availability and closeness to the transit roads and sites of usage. Excessive and non-technical extraction of gravel and sand bring a kind of interference in them, leading to many negative consequences. Therefore, presenting solutions to reduce these impacts and infilling mining pits are essential. In this research work, through an experimental work, locating two consequent river bed mining pits in the form of the distance between them and also their distance from the walls for the purpose of infilling and extraction management was investigated. The results obtained showed that movement of the downstream pit did not significantly affect the infilling volume and migration of the upstream pit but by movement of the pit towards the wall, the infilling volume of the upstream pit was reduced by up to 25% compared to the channel center. Concerning the downstream pit, the impact of the distance between pits depended on their distance from the wall so that if the pit was close to the channel center, the infilling volume was increased, and if it was located close to the wall, the infilling volume was increased up to a distance equal to 9 times the flow depth, and after that the infilling was reduced. In case the pits were excavated towards the channel center and the downstream pit was excavated at a distance equal to 12 times the flow depth, the best state of infilling and pit migration did occur.
A.O. Owolabi
Abstract
The vulnerability of water bodies to contamination within the neighbourhood of open mine cast environ cannot be overemphasized. Evidence of radioactive trace elements associated with the target minerals in the Plateau State (Nigeria) showed the extent of this vulnerability. In order to address this challenge, ...
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The vulnerability of water bodies to contamination within the neighbourhood of open mine cast environ cannot be overemphasized. Evidence of radioactive trace elements associated with the target minerals in the Plateau State (Nigeria) showed the extent of this vulnerability. In order to address this challenge, the radioactivity levels of water samples from mine ponds, streams, wells, and boreholes around mine sites in the Plateau State were assessed. The water samples were analysed for gross alpha and beta radiation activities using MPC 2000 radiation counter in accordance with the provisions of International Atomic Energy Agency (IAEA) at the Centre for Energy Research and Training (CERT) Zaria. The mean alpha radiation activity dose for the water samples collected from mine ponds, streams, wells, and boreholes was 0.63 + 0.1 Bq/l, 0.13 + 0.1 Bq/l, 0.34 + 0.1 Bq/l, and 0.51 + 0.2 Bq/l, respectively. The mean beta radiation activity dose for the water samples collected from mine ponds, streams, wells and boreholes was 4.1 + 1.8 Bq/l, 1.0 + 0.7Bq/l, 2.4 + 1.9 Bq/l, and 2.7 + 1.3 Bq/l, respectively. The water bodies were unwholesome for human consumption. The present use of water from the mine ponds for irrigation should be discontinued. The specific activities of alpha and beta radiations in the water samples decreased as distance from the mine increased. It is, therefore, clear that the mine sites were the sources of the high radiation values recorded in the water sources.
M.R. Shahverdi; A. Khodadadi Darban; M. Abdollahy; Yadollah Yamini
Abstract
Flotation is a common process in sulfide ore beneficiation. Due to the restrictions and lack of access to high-quality water sources for industrial purposes, recycled water plays an important role in the flotation processes. Due to the existence of various organic and inorganic substances in the process, ...
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Flotation is a common process in sulfide ore beneficiation. Due to the restrictions and lack of access to high-quality water sources for industrial purposes, recycled water plays an important role in the flotation processes. Due to the existence of various organic and inorganic substances in the process, water influences the flotation performance. In this work, the effect of accumulation of sulfate ion in processed water on galena flotation was investigated. Flotation experiments using processed water without sulfate ion led to a concentrate containing 40.7% of lead and a maximum recovery of 58.9%. The presence of higher sulfate ion levels (2000 M) in processed water caused a significant decrease in the grade and recovery of the lead concentrate. With 2000 mg/L of sulfate ion, the grade and recovery of lead decreased from 40.7 to 24.3% and from 58.9 to 32.1 %, respectively. Thermodynamic calculations showed that when the sulfate ion concentration was increased from 300 to 2000 ppm, it was more likely that lead sulfate (solid) was formed. With increase in the xanthate ion concentration from 10-6 to 10-4 M, could be substituted by . On the basis of the results obtained, it was concluded that in order to reduce the negative effects of sulfate ion accumulation in water and increase the efficiency of the galena flotation process, higher dosages of xanthates should be added to the system.
R. Dabiri; E. Amiri Shiraz
Abstract
This paper describes a preliminary study of the adsorption of toxic elements from synthetic wastewater in a batch mode. Clay minerals have been highly considered as inexpensive available adsorbents that adapt with the environment due to a special level and a high potential of adsorption. In the present ...
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This paper describes a preliminary study of the adsorption of toxic elements from synthetic wastewater in a batch mode. Clay minerals have been highly considered as inexpensive available adsorbents that adapt with the environment due to a special level and a high potential of adsorption. In the present research work, low-cost natural minerals of speiolite from the Iliato mine (located in NE Iran) and zeolite from the Aftar mine (located in north of Iran) are used to remove nickel(II), antimony(III), and arsenic(V) from synthetic wastewater. The adsorption experiments are conducted by varying the initial concentrations of the elements, pH values, adsorption times, and adsorbent dosage. The experimental isotherm data is analyzed using the Langmuir and Freundlich equations. Concerning a higher Langmuir coefficient R2 in nickel and antimony, the mechanism of adsorption of these elements is mono-layer and homogenous. Based on the Freundlich model, adsorption of arsenic is multi-layer and heterogeneous. The kinetic studies show that the Ni, Sb, and As adsorption mechanism is well-described by a pseudo-second-order kinetic model. The thermodynamic parameters indicate that the adsorption process has an exothermic character and is more feasible with decreasing temperature. Based on the experimental results, it can be concluded that natural sepiolite and zeolite has the potential of application as an efficient adsorbent for the removal of toxic elements from synthetic wastewater.
K.M. Tanguturi; R.S. Balusu
Abstract
It is necessary to obtain a fundamental understanding of the goaf gas flow patterns in longwall mine in order to develop optimum goaf gas drainage and spontaneous combustion (sponcom) management strategies. The best ventilation layout for a longwall underground mine should assist in goaf gas drainage ...
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It is necessary to obtain a fundamental understanding of the goaf gas flow patterns in longwall mine in order to develop optimum goaf gas drainage and spontaneous combustion (sponcom) management strategies. The best ventilation layout for a longwall underground mine should assist in goaf gas drainage and further reduce the risk of sponcom in the goaf. Further, in the longwall panel, regulators are installed in the maingate (MG) seals to control the gas migration on the MG side and the mine operators frequently encountered with seals leakage problems leading to abnormal gas contents in the tube bundles. Extensive parametric studies were carried out to investigate the effects of ventilation layouts, regulators, and seals leakages on the goaf gas distribution using the Computational Fluid Dynamics (CFD) techniques. The results of various CFD simulations are presented and discussed in detail in this paper.
Sh. Sadat Etemadzadeh; G. Emtiazi; Z. Etemadifar
Abstract
Most studies on sulfur bioleaching from coal depend on an autotrophic microorganism with a low growth and a long leaching time. For this reason, heterotrophic heat and acidic pH-resistant Alicyclobacillus was used as the growing and resting cells for the sulfur and iron removal from coal. The results ...
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Most studies on sulfur bioleaching from coal depend on an autotrophic microorganism with a low growth and a long leaching time. For this reason, heterotrophic heat and acidic pH-resistant Alicyclobacillus was used as the growing and resting cells for the sulfur and iron removal from coal. The results obtained were analyzed by XRF. The data showed that 26.71% of sulfur was removed by Alicyclobacillus in a few days; however, 49.07% of sulfur was removed by Acidithiobacillus in 30 days. This was interesting since the leachings of zinc, strontium, titanium, and iron by Alicyclobacillus, obtained in a few days, were almost the same as the leachings by Acidithiobacillus in 30 days. The results obtained also showed that the Alicyclobacillus cells growing at 55 ˚C removed most of the coal impurities without any change in the carbon content of this fuel. To the best of our knowledge, coal leaching by Alicyclobacillus is reported for the first time.
R. Norouzi Masir; R. Khalokakaie; M. Ataei; S. Mohammadi
Abstract
Mining can become more sustainable by developing and integrating economic, environmental, and social components. Among the mining industries, coal mining requires paying a serious attention to the aspects of sustainable development. Therefore, in this work, we investigate the impacting factors involved ...
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Mining can become more sustainable by developing and integrating economic, environmental, and social components. Among the mining industries, coal mining requires paying a serious attention to the aspects of sustainable development. Therefore, in this work, we investigate the impacting factors involved in the sustainable development of underground coal mining from the structural viewpoint. For this purpose, the decision-making trial and evaluation laboratory (DEMATEL) technique, which is a graph-based method, is utilized. To do so, at first, twenty effective factors are determined for three components. Then the hierarchical structure and the systematic approach are used to determine the total exerted influence or total received influence of the components. The results obtained show that the environmental and social components are the most important, and the economic components are the least important among them.
M. Anselme Kamga; S. Nzali; C. O. Olatubara; A. Adenikinju; E. A. Akintunde; M. P. Kemeng; F. W.D. Nguimatsia; E. A. Ndip; C. Fuanya
Abstract
Cameroon has a strong geological potential for a number of mineral resources that, if well managed, could support economic growth. The country contains potentially large deposits of iron ore, gold, bauxite, diamond, limestone, nickel, and gemstones, and indices of other numerous minerals and precious ...
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Cameroon has a strong geological potential for a number of mineral resources that, if well managed, could support economic growth. The country contains potentially large deposits of iron ore, gold, bauxite, diamond, limestone, nickel, and gemstones, and indices of other numerous minerals and precious metals. Despite its geological wealth, mining has never played a major role in Cameroon’s economic development. A study on the state of sustainable development and environmental challenges in the Cameroon mining sector permits the identification of key points for improvement in order to position the country towards achieving a sustainable mining industry in the future. This paper reviews the mining potential, stakeholder participation, legislation, and mining policy in Cameroon mining industry. The methodology involves a single case study focused on the review of sustainable development in the Cameroon mining industry up to date. It includes scientific studies, and reports of ministries and support organizations, national laws, and regulations related to the area of study. Also the corporate sustainability reports of mining companies and mining stakeholders are analyzed. This research work covers the latest developments in terms of the institutional and regulatory frameworks for mining and the environment in the country, history of mining in Cameroon, and evolution and issues of the Environmental and Social Impact Assessment (ESIA) system in the mining sector until 2016. The work concludes with an identification of the current challenges of implementing sustainable development in mining as well as future directions that research works on this area should take.
U. Yenial; G. Bulut
Abstract
Two common waste materials, red mud and fly ash, were used to produce a new nano-hybrid adsorbent by heat treatment with alkali addition. The new zeolitic structure formation of the hybrid adsorbent was revealed using the BET surface area, XRD, and SEM analyses. This hybrid adsorbent was utilized to ...
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Two common waste materials, red mud and fly ash, were used to produce a new nano-hybrid adsorbent by heat treatment with alkali addition. The new zeolitic structure formation of the hybrid adsorbent was revealed using the BET surface area, XRD, and SEM analyses. This hybrid adsorbent was utilized to remove arsenic from synthetic and real waste waters by batch and column adsorption experiments. The parameters such as the pH, contact time, and effect of the co-existing ions were investigated. Slightly acidic media favored arsenic adsorption by the hybrid adsorbent, the same as the individual use of fly ash and red mud. The effects of ions such as Fe3+, Cu2+, Cl-, SO42-, and PO43- were investigated as the co-existing ions. It was found that arsenic adsorption increased with cationic ions and decreased with anionic ions according to their valance charge. The intra-particle diffusion model showed that adsorption took place at three different rates depending on time. The hybrid adsorbent was formed as a pellet and utilized in a column for treatment of arsenic containing real waste water. The hybrid adsorbent derived from mineral wastes was more successful than their individual usages.
S. Torbati; S. Alipour; M. Rostami; S. Hajializadeh
Abstract
The Agh-Dareh and Zarshouran mines are two known active gold deposits in Takab, NW Iran. In the present study, the potentials of two species of Astragalus (A. microcephalus from Agh-Dareh and A. effusus from Zarshouran mines), as the dominant plants grown in these areas, were assessed for the bio-accumulation ...
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The Agh-Dareh and Zarshouran mines are two known active gold deposits in Takab, NW Iran. In the present study, the potentials of two species of Astragalus (A. microcephalus from Agh-Dareh and A. effusus from Zarshouran mines), as the dominant plants grown in these areas, were assessed for the bio-accumulation of the major, trace, and rare earth elements (REEs). The plant and soil samples were collected from the mining areas and analyzed by inductively coupled plasma-mass spectroscopy (ICP-MS). According to the results obtained, A. effusus in the Zarshouran mine passed a high ability in the accumulation of some major elements such as S, P, K, Ca, and Zn. Although the amounts of the examined trace elements in the soil samples were more than those in the shoots of both examined plants, the potential of A. microcephalus in the absorbance and translocation of Cd, U, Tl, and Pb was more than that for A. effusus. It became clear that the performance of A. microcephalus from the Agh-Dareh mine in the uptake and transportation of REEs was more than that for A. effusus from the Zarshouran mine; also both plant species absorbed and transported much more light REEs than heavy REEs did. According to the results obtained, the present study provides some geochemical findings about the substrate and leads to the increasing information about the plants as a useful indicator of metal mineralization.
M Mohammadiun; B. Dahrazma; Seyed F. Saghravani; A. Khodadadi Darban
Abstract
Use of nanotechnology has proven to be a promising approach toward remediation of all phases of environment. The aim of this work is to investigate the effects of different parameters on using iron III oxide nanoparticles in a continuous flow configuration for the removal of Cd2+ ionsfrom contaminated ...
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Use of nanotechnology has proven to be a promising approach toward remediation of all phases of environment. The aim of this work is to investigate the effects of different parameters on using iron III oxide nanoparticles in a continuous flow configuration for the removal of Cd2+ ionsfrom contaminated soils. Also selective sequential extraction tests are carried out to evaluate the nanoparticle tendency to remove cadmium from different fractions of soils. In order to achieve this goal, a specific flow rate of a nanoparticle solution was passed through a soil sample in a column with 3 cm diameter and 4 cm height. Up to 100% of cadmium removal was achieved by providing a nano-fluid concentration of 500 ppm, pH of 6.5, treatment duration of 24 hours, and flow rate of 0.5 mL/min. Evaluation of the results obtained showed that the tendency of the iron oxide nanoparticles to remove cadmium from different fractions of contaminated soil was in the order of exchangeable > carbonates > oxides and hydroxides > organic matter > residual. The results obtained from this work can be used to develop an appropriate remediation protocol for contaminated soils.
S. Tabasi; H. Hassani; A. R. Azadmehr
Abstract
In the present work, we aimed to focus on the identification and characterization of the heavy metal-tolerant plant species growing spontaneously at the tailings site of the Sarcheshmeh copper mine, south of Iran. Our aim was to find the plant species that were potentially useful for phytoextraction ...
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In the present work, we aimed to focus on the identification and characterization of the heavy metal-tolerant plant species growing spontaneously at the tailings site of the Sarcheshmeh copper mine, south of Iran. Our aim was to find the plant species that were potentially useful for phytoextraction purposes. The concentrations of As, Cu, Mo, Ni, Zn, and Re were analyzed in soil as well as in the shoots and roots of plant species separately by an Inductively Coupled Plasma-Optical Emission Spectrometer (ICP–OES). The mean concentrations of As, Cu, Mo, Ni, Zn, and Re in soil were found to be 18.44±13.41, 1280±500.95, 25.06±13.33, 32.9±14.39, 251.82±95.82, and 1.7±0.78 mg kg-1, respectively. The translocation factor (TF) and the bioaccumulation factor (BCF) were defined and used to assess the amount of the elements accumulated in the shoots and roots of each plant species and to evaluate their potential for phytoextraction purposes. Based upon the results obtained and using the most common criteria, T. ramosissima, C. dactylon, A. leucoclada, and Z. fabago could strongly tolerate and extremely accumulate multiple metal(loid)s. Also Salsola kali, C. dactylon, A. leucoclada, and Z. fabago could be classified as hyperaccumulators for Re with TF and BCF greater than one and ten, respectively. The results of this work should be further developed in order to confirm the potential use of these species in phytoextraction programs.
M. Sakizadeh; M. T. Sattari; H. Ghorbani
Abstract
The soil samples were collected from 170 sampling stations in an arid area in Shahrood and Damghan, characterized by prevalence of mining activity. The levels of Co, Pb, Ni, Cs, Cu, Mn, Sr, V, Zn, Cr, and Tl were recorded in each sampling location. A new method known as min/max autocorrelation factor ...
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The soil samples were collected from 170 sampling stations in an arid area in Shahrood and Damghan, characterized by prevalence of mining activity. The levels of Co, Pb, Ni, Cs, Cu, Mn, Sr, V, Zn, Cr, and Tl were recorded in each sampling location. A new method known as min/max autocorrelation factor (MAF) was applied for the first time in the environmental research works to de-correlate these elements before their geo-statistical simulation. The high cross-correlation among some elements, while poor spatial correlation among the others, could have made spectral decomposition of MAFs unstable, resulting in some negative eigenvalues, so it was decided to reduce the dimensionality of the original variables by Principal Component Analysis (PCA). The resultant 6 heavy metals (Cr, Mn, Cu, V, Ni, and Co) were converted to their respective MAFs followed by their geo-statistical simulation using Sequential Gaussian Simulation (SGS) independently. Examination of the cross-variograms of MAFs indicated that the resultant factors had been rigorously de-correlated, especially at zero lag and around ∆ lag distance. Several validation checks including reproduction of variograms in data and normal score space, close matching between distribution of MAFs versus simulated realizations, and reproduction of descriptive statistics and data histograms all confirmed that the data values had been honored by this applied method. The results obtained indicated that this method could reproduce the data values as well as the spatial continuity of heavy metals (e.g. semi-variograms) successfully. In addition, this technique is simpler and more computationally efficient than its equivalent sequential Gaussian co-simulation as fitting a linear model of co-regionalization (LMC) is not required in the data-driven MAF method.