Original Research Paper
Blessing Olamide Taiwo
Abstract
Assessment of blast results is a significant approach for the improvement of mining operations. The different procedures for investigating rock fragmentation have their limitations, causing different variation prediction errors. Thus every technique is site-explicit, and applicable for a few explicit ...
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Assessment of blast results is a significant approach for the improvement of mining operations. The different procedures for investigating rock fragmentation have their limitations, causing different variation prediction errors. Thus every technique is site-explicit, and applicable for a few explicit purposes. This work evaluates the existing empirical blast fragmentation model predictions in the case study of small-scale dolomite quarries. An attempt is made to compare the prediction accuracy of the modified Kuz-Ram model, Lawal 2021 model, and Kuznetsov-Cunningham-Ouchterlony (KCO) model with the WipFrag© analysis result and proposed artificial neural network (ANN) models. The prediction error analysis of the current models and that of the new proposed ANN models is evaluated using the three model assessment indices. The assessment indices uncover that the KCO model when compared to the modified Kuz-Ram model has the least error for most blast round percentage passing size predicted. However, the proposed artificial neural network models show high prediction exactness in predicting blast fragment mean size than the existing empirical models. Therefore, the proposed ANN models can be used to improve the productivity of small-scale dolomite blasting operation results for practical purposes.
Original Research Paper
Morteza Karami; Shokrollah Zare; Jamal Rostami
Abstract
One of the important cost items in mechanized tunneling is the cost of repairing or replacing the disc cutters that have suffered from normal wear during the boring of the hard abrasive rocks. For inspecting the health of the disc cutters, the boring operation shall be stopped, and after checking, the ...
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One of the important cost items in mechanized tunneling is the cost of repairing or replacing the disc cutters that have suffered from normal wear during the boring of the hard abrasive rocks. For inspecting the health of the disc cutters, the boring operation shall be stopped, and after checking, the worn disc cutters may be replaced. In this work, the dynamic process of the TBM boring in the jointed rocks is simulated using a real-scale numerical analysis based on the rock fracturing factor using the discrete element method (DEM). The stress distributions induced within the disc cutters as well as the development of the plastic zones in the rock are investigated and compared with the actual results recorded in the Kerman water conveyance tunnel (KWCT). The numerical results indicate that the increase in the rock fracturing causes a decrease in the induced stresses and an increase in the size of the plastic zone. In other words, a higher penetration rate as well as more lifetime for disc cutters can be achieved in highly fractured rocks. Moreover, the average von Misses stress in the disc cutters in the highly fractured rocks is predicted about 16-23% less than stress induced in the slightly fractured rocks. Due to the TBM tunneling, the volume of the plastic zone as well as the actual penetration depth in the highly fracturing rocks are also about 40% and 42% higher than in the slightly fractured rocks under applying the same TBM parameters, respectively.
Case Study
SURYA PRATAP SINGH; Amrit Kumar Roy
Abstract
The Himalayan mountain range is susceptible to slope instability in numerous areas due to its complicated topography, because of the existing natural conditions and human influence and intervenes. National Highway-05 is considered in this work. The area under investigation located in Rampur, district ...
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The Himalayan mountain range is susceptible to slope instability in numerous areas due to its complicated topography, because of the existing natural conditions and human influence and intervenes. National Highway-05 is considered in this work. The area under investigation located in Rampur, district Shimla, Himachal Pradesh is evaluated for slope stability. The primary purpose of this work is to maintain the slope's stability in order to protect NH-05 and the neighboring three-sided residential structures. Following the site visit, the geotechnical investigations in the form of bore holes and laboratory tests are conducted. Analysis of slope stability is commenced after interpreting the geotechnical study report. For an analytic slope stability, the studied area is divided into three sections, labelled A1-A1', B1-B1', and C1-C1'. Taking into account the geotechnical aspects of the specified research region, the mitigation design parameters for the area and the circular slip failure are calculated using the numerical modeling techniques. The software computes the safety factor for both the static and dynamic situations. As a result, preventative measures and a few improvements are suggested.
Original Research Paper
Afrodita Zendelska; Adrijana Trajanova; Mirjana Golomeova; Blagoj Golomeov; Dejan Mirakovski; Nikolinka Doneva; Marija Hadzi-Nikolova
Abstract
The treatment of acid mine drainages is usually based on two basic technologies, active and passive treatment technologies. Whichever acid mine drainage (AMD) treatment method is employed, a neutralizing procedure that raises the water's pH over 7.0 using alkaline agents is required prior to discharge. ...
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The treatment of acid mine drainages is usually based on two basic technologies, active and passive treatment technologies. Whichever acid mine drainage (AMD) treatment method is employed, a neutralizing procedure that raises the water's pH over 7.0 using alkaline agents is required prior to discharge. A comparison of eight different agents (BaCO3, Na2CO3, NaOH, KOH, K2CO3, MgO, CaCO3, and Ba(OH)2) was performed in order to choose the most effective neutralizing agent for acid mine drainage treatment. The experiments were performed using a multi-component synthetic aqueous solution with an initial concentration of 10 mg/L of the Cu, Mn, Zn, Fe, and Pb ions and an initial pH value of 1.9. According to the research, the most effective neutralizing agent for the removal of heavy metals from a multi-component aqueous solution is MgO, while the least effective agent was Na2CO3. The obtained series of effective neutralizing agents for the removal of heavy metals from a multi-component aqueous solution are presented in the work. The effect of the studied concentration of neutralizing agents depends on the neutralizing agents and heavy metals that are used. The percentage of heavy metals removed from aqueous solutions increases along with rising pH values. The consumption of the neutralizing agent decreases as the concentration of the neutralizing agent is increased. In addition, the time taken to achieve pH depends on the agent concentration. In particular, as the concentration of the neutralizing agent increases, the time to reach the pH decreases.
Original Research Paper
Reza Mikaeil; Mostafa Piri; Sina Shaffiee Haghshenas; Nicola Careddu; Hamid Hashemolhosseini
Abstract
The noise of drilling in the dimension stone business is unbearable for both the workplace and the people who work there. In order to reduce the negative effects drilling has on the health of the environment, the drilling noise has to be measured, assessed, and controlled. The main purpose of this work ...
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The noise of drilling in the dimension stone business is unbearable for both the workplace and the people who work there. In order to reduce the negative effects drilling has on the health of the environment, the drilling noise has to be measured, assessed, and controlled. The main purpose of this work is to investigate an experimental-intelligent method to predict the noise value of drilling in the dimension stone industry. For this purpose,135 laboratory tests are designed on five types of rocks (four types of hard rock and one type of soft rock), and their results are measured in the first step. In the second step, due to the unpredicted and uncertain issues in this case, artificial intelligence (AI) approaches are applied, and the modeling is conducted using three intelligent systems (IS), namely an adaptive neuro-fuzzy inference system-SCM (ANFIS-SCM), an adaptive neuro-fuzzy inference system-FCM (ANFIS-FCM), and the radial basis function network (RBF) neural network. 75% of the samples are considered for training, and the rest for testing. Several models are constructed, and the results indicate that although there is no significant difference between the models according to the performance indices, the proposed construction of ANFIS-SCM can be considered as an efficient tool in the evaluation of drilling noise. Finally, several scenarios are designed with different input modes, and the results obtained prove that the types of rock and the drill bits are more important than the operational characteristics of the machine.
Case Study
Sina Shaffiee Haghshenas; akbar Esmaeilzadeh; Reza Mikaeil; Giuseppe Guido; Roohollah Shirani Faradonbeh; Roozbeh Abbasi Azghan; Amir Jafarpour; Shadi Taghizadeh
Abstract
Iran is one of the countries with the largest number of quarry mines in the world. Diamond cutting wire is usually used in quarries to cut dimension stone cubes, which is accompanied by hazardous events. Therefore, detecting and investigating the possible quarry risks is crucial to have a safe and sustainable ...
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Iran is one of the countries with the largest number of quarry mines in the world. Diamond cutting wire is usually used in quarries to cut dimension stone cubes, which is accompanied by hazardous events. Therefore, detecting and investigating the possible quarry risks is crucial to have a safe and sustainable mining operation. In mine exploitation, maintaining the safety of vehicles and increasing the knowledge of personnel regarding safety issues can considerably mitigate the number or radius of effect of hazards. Hence, the incidents and risks in the West-Azerbaijan quarries in Iran are investigated in this work. To do so, a list of the hazards and their descriptions are first prepared. Then the hazard risk rating is conducted using the Failure Modes and Effects Analysis (FMEA) method. The number of priorities is calculated for each incident based on probability, intensity, and risk detection probability. Finally, the main causes of risks in the studies quarries are identified. The results obtained show that the most likely dangers in dimensional stone mines in West Azerbaijan are diamond cutting wire breaking, rock-fall, and car accidents, with the priority numbers of 216, 180, and 135, respectively. These hazards can be mitigated by applying some preservative activities such as timely cutting wire replacement, utilizing an intelligent system for cutting tool control, necessary personal training, and considering some preservative points.
Original Research Paper
Jinwei Fu; Mohammad Reza Safaei; Hadi Haeri; vahab sarfarazi; Mohammad Fatehi Marji; Leige Xu; Ali Arefnia
Abstract
In this work, the mechanical behavior of strata deformation due to drilling and surface loading is investigated using a 3D physical model. For this purpose, a scaled-down physical model is first designed. Then the tunnel drilling and support system are built. The subsidence experiments performed due ...
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In this work, the mechanical behavior of strata deformation due to drilling and surface loading is investigated using a 3D physical model. For this purpose, a scaled-down physical model is first designed. Then the tunnel drilling and support system are built. The subsidence experiments performed due to tunnel excavation and loading in a very dense and loose soil are performed. Soil is clayey sand (SC), and the percentages of its components are as sand (S = 1. 41%), gravel (G = 25%), and clay (C = 9.33%). Unstable tunnel support experiments are also carried out using physical simulation. Finally, deformations of soil surface and subsidence of strata are observed and recorded. In the tunnel with segmental support, 18.75% more load is applied than in the unsupported tunnel, and the total subsidence of the strata is reduced by 36.2%. The area of the deformed inner layers is decreased by 74.2%, and the length of the affected area in the largest layer is decreased by 48%. The depth of the cavity created at the surface is 46.66% less.
Original Research Paper
Serhii Hryhorovych Nehrii; Tetiana Oleksandrivna Nehrii; Oksana Viktorivna Zolotarova; Valentyn Anatolyovich Glyva; Andrii Mykolaiovych Surzhenko; Oksana Mykolaivna Tykhenko; Nataliia Burdeina
Abstract
The studies of risk factors on which the safety of miners depends are relevant. These factors include temperature and air velocity within roadways, relative air humidity, dust, noise and vibration, lighting, clutter, limited working space, the difficulty of work, and the collapse of roof rocks. Their ...
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The studies of risk factors on which the safety of miners depends are relevant. These factors include temperature and air velocity within roadways, relative air humidity, dust, noise and vibration, lighting, clutter, limited working space, the difficulty of work, and the collapse of roof rocks. Their greatest concentration is in the technological zones of longwalls, so it is important to determine the priority of taking into account the risk factors in certain zones for planning measures for labor protection in underground coal mining. Therefore, a matrix of priority of risk factors for technological zone longwalls is proposed. The matrix is based on a survey of experienced and well-informed scientists and engineers of coal mines (experts). Fifty experts are involved in the survey.The matrix assesses the priority of risk factors, and considers the technological zones of the longwalls for the planning labor protection measures. The zones of operation of the excavation machines and the end-sections of longwalls are defined as the most safety-critical. Less safety-critical, but also dangerous, are the zones of protection means and the zones of connection of the longwalls with the roadways. The level of a certain risk factor is determined for each zone. The highest priority should be given to the collapse of roofs, dust, clutter of the working space, and the severity of the miners' work. For each risk factor included in the matrix, the technical and organizational measures for labor protection are proposed to reduce the level of injuries for miners.
Case Study
Alankrit Walia; Amrit Kumar Roy
Abstract
The complex geography of the Himalayan mountain range, along with the natural circumstances that already exist and the ways in which people have influenced and intervened in the region- makes various regions of the range vulnerable to slope instability. The slope stability of the area that is the subject ...
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The complex geography of the Himalayan mountain range, along with the natural circumstances that already exist and the ways in which people have influenced and intervened in the region- makes various regions of the range vulnerable to slope instability. The slope stability of the area that is the subject of this work is evaluated in Palampur, which is in the Kangra district of Himachal Pradesh. The primary objective of this work is to ensure that the slope remains stable so that the nearby three-sided residential structures and the highway remain protected. After the site visit, the geo-technical studies, which include testing in the form of bore holes and in the laboratory, are carried out. After evaluating the geo-technical technical report, the next step in the process is to begin the analysis of the slope's stability. In order to do an analytical analysis of the slope stability, the area has been subdivided into three portions, and labelled A-A, B-B, and C-C, respectively. Using the numerical modelling approaches, the mitigation design parameters for the area and the circular slip failure are computed. These calculations are based on the geo-technical characteristics of the studied area that have been specified. The factor of safety is calculated for both the natural and stable scenarios by the program. Because of this, some preventative steps and a few improvements are suggested.
Original Research Paper
Hafeezur Rehman; Wahid Ali; Kausar sultan Shah; Mohd Hazizan bin Mohd Hashim; Naseer Muhammad Khan; Muhammad Ali; Muhammad Kamran; Muhammad Junaid
Abstract
Support design is the main goal of the Q and rock mass rating (RMR) systems. An assessment of the Q and RMR system application in tunnelling involving high-stress ground conditions shows that the first system is more appropriate due to the stress reduction factor. Recently, these two systems have been ...
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Support design is the main goal of the Q and rock mass rating (RMR) systems. An assessment of the Q and RMR system application in tunnelling involving high-stress ground conditions shows that the first system is more appropriate due to the stress reduction factor. Recently, these two systems have been empirically modified for designing the excavation support pattern in jointed and highly stressed rock-mass conditions. This research work aims to highlight the significance of the numerical modelling, and numerically evaluate the empirically suggested support design for tunnelling in such an environment. A typical horse-shoe-shaped headrace tunnel at the Bunji hydropower project site is selected for this work. The borehole coring data reveal that amphibolite and Iskere Gneiss are the main rock mass units along the tunnel route. An evaluation of the proposed support based on the modified empirical systems indicate that the modified systems suggest heavy support compared to the original empirical systems. The intact and mass rock properties of the rock units are used as the input for numerical modelling. From numerical modelling, the axial stresses on rock bolts, thrust bending moment of shotcrete, and rock load from modified RMR and Q-systems are compared with the previous studies. The results obtained indicate that the support system designed based on modified version of the empirical systems produce better results in terms of tunnel stability in high-stress fractured rock mass conditions.
Original Research Paper
Ajay Kumar; Aditya Gupta; Yadvendra Pratap Singh; Monu Bhagat
Abstract
Land use (LU) is one of the most imperative pieces of cartographic information used for monitoring the mining environment. The extraction of land use data sets from remotely sensed satellite images has garnered significant interest in the mining region community. However, classification of LUs from satellite ...
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Land use (LU) is one of the most imperative pieces of cartographic information used for monitoring the mining environment. The extraction of land use data sets from remotely sensed satellite images has garnered significant interest in the mining region community. However, classification of LUs from satellite images remains a tedious task due to the lack of availability of efficient coal mining related datasets. Deep learning methods provide great leverage to extract meaningful information from high-resolution satellite images. Moreover, the performance of a deep learning classification approach significantly depends on the quality of the datasets. The present work attempts to demonstrate the generation of satellite-based datasets for the performance analysis of different deep neural network (DNN)-based learning algorithms in the LU classifications of mining regions. The mining regions are broadly classified into distinct regions based on visual inspection, namely barren land, built-up areas, waterbody, vegetation, and active coal mines. In our experimental work, a patch of 100 spatial samples for each of the five features is generated on three scales, as [1 × 1 × 3], [5 × 5 × 3], and [10 × 10 × 3]. Moreover, the effects of different scalabilities of the dataset on classification performances are also analyzed. Furthermore, this case study is implemented for the large-scale benchmark of satellite image datasets for mining regions. In the future, this work can be used to classify LU in the relevant study regions in real time.
Original Research Paper
Azadeh Agah; Faramarz Doulati Ardejani; Mohammad Javad Azinfar
Abstract
This work investigates the reactive transport of volatile hydrocarbons in the unconfined aquifer system of Tehran oil refinery and the industrial area of Ray, Tehran. A 2D finite volume model is presented to predict the soil gas contamination caused by LNAPL traveling on the phreatic surface through ...
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This work investigates the reactive transport of volatile hydrocarbons in the unconfined aquifer system of Tehran oil refinery and the industrial area of Ray, Tehran. A 2D finite volume model is presented to predict the soil gas contamination caused by LNAPL traveling on the phreatic surface through the vadose zone of the aquifer incorporating physical, chemical, and biological processes. A multi-purpose commercial software called PHOENICS is modified by incorporating extra codes to solve the model equations numerically. The model predictions closely agree with the field measurements, showing that the LNAPL migration is typically affected by the volatilization process. LNAPLs represent a potential long-term source of soil and groundwater contamination in the studied site. A comparison of the simulation results in a time step of 36 years with the results of field studies shows that the presented numerical model can simulate the reaction transfer of evaporated hydrocarbons in the unsaturated region. The concentrations have decreased in the time step of 36 years compared to the values shown in the time step of 50 years. This decrease in the hydrocarbon gas-phase concentrations in the unsaturated zone is due to excavations at the site for field studies. Through these excavations, a significant volume of the gaseous phase trapped below the earth's surface is released into the atmosphere, which reduces the accumulation of volatile gases beneath the earth's surface.
Original Research Paper
hossein Mahdiyanfar; Amir Salimi
Abstract
This work aims to investigate the geochemical signatures of the Cu porphyry deposit in the Dalli area using the geochemical soil samples. At the first step, the geochemical data was opened using the Centered Log-Ratio (CLR) transform method. Then those outlier samples that reduce the accuracy of the ...
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This work aims to investigate the geochemical signatures of the Cu porphyry deposit in the Dalli area using the geochemical soil samples. At the first step, the geochemical data was opened using the Centered Log-Ratio (CLR) transform method. Then those outlier samples that reduce the accuracy of the geochemical models were detected and removed using the Mahalanobis Distance (MD) method. We applied the Principal Component Analysis (PCA) and Geochemical Mineralization Prospectivity Index (GMPI) methods on the cleaned transformed geochemical dataset. The PCA method identified five principal components (PCs), from which PC1 including Cu, Au, and Mo, are specified as the mineralization factor (MF). The GMPI approach can improve the multivariate geochemical signature in geochemical mapping. Hence, the GMPI values of the samples were calculated based on the score values of MF (Cu, Au, Mo). The results convey that the large values of GMPI (MF) (Cu, Au, Mo) strongly correlate with the quartz diorite porphyry rocks and potassic alteration zones. The GMPI (MF (Cu, Au, Mo)) index was modeled using the Concentration-Number (C-N) fractal method. The C-N fractal model identified four geochemical populations based on the different fractal dimensions. The geochemical anomaly map of GMPI (MF) (Cu, Au, Mo) was delineated using these classified populations. The obtained promising areas were validated adequately by more detailed exploration works and deep drilled boreholes as well. The Cu-Au mineralization potential parts are appropriately mapped by this hybrid method. The results obtained demonstrate that this scenario can be adequately used for geochemical mapping on local scales.
Original Research Paper
Seyyed Mohammad Seyyed Alizadeh Ganji; hassan vafaie
Abstract
The present work is aimed to examine the elimination of cyanide ions from the wastewater derived from the Agh-Darreh gold mine using the Caro’s acid method. The response surface modeling is utilized to evaluate and optimize the influential parameters such as the sulfuric acid/hydrogen peroxide ...
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The present work is aimed to examine the elimination of cyanide ions from the wastewater derived from the Agh-Darreh gold mine using the Caro’s acid method. The response surface modeling is utilized to evaluate and optimize the influential parameters such as the sulfuric acid/hydrogen peroxide ratio, pH, Caro’s acid concentration, and contact time on the elimination process. The results obtained indicate that the increase in the Caro’s acid concentration and contact time has a positive impact on the elimination of the free cyanide ions, while the increment in the weight ratio of sulfuric acid/hydrogen peroxide and pH higher than 9.5 demonstrate a negative impact. Also it is found that the quadratic effect of pH has the highest influence on the removal of cyanide ion, and the linear effect of the ratio of sulfuric acid/hydrogen peroxide has the lowest degree of importance. Additionally, the optimization process is carried out, and about 96.4% of the cyanide ions is eliminated from the wastewater under the optimal conditions including 2 g/L Caro’s acid concentration, 9.3 pH, 8 min contact time, and sulfuric acid to hydrogen peroxide (weight) ratio of 2.
Original Research Paper
Pooria Kianoush; Ghodratollah Mohammadi; Seyed Aliakbar Hosseini; Nasser Keshavazr Faraj Khah; Peyman Afzal
Abstract
In the seismic methods, estimation of the formation pressures is obtained by converting the seismic velocity to the pore pressure, and comparing it with the effective pressure during the well-test program. This work is a new challenge regarding the velocity study domain in an oil field in SW Iran. The ...
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In the seismic methods, estimation of the formation pressures is obtained by converting the seismic velocity to the pore pressure, and comparing it with the effective pressure during the well-test program. This work is a new challenge regarding the velocity study domain in an oil field in SW Iran. The reservoir generally consists of carbonate rocks, and contains no shale interbeds. Here, 23 well information, seismic data interpretation, compressional (Vp), and shear velocity (Vs) models are implemented. The models are determined from the combined geo-statistical methods, and the results obtained are compared with the fractal models. The final Vs cube is modeled in order to determine the formation fracture pressure using the exploratory well cores and dipole sonic imager (DSI) Vs logs with a correlation coefficient of 0.95 for the Vs data obtained from the porosity, lithology, and primary DSI data. The vertical seismic profiling (VSP) data introduce a maximum interval velocity of 2760-2900 m/s in the field related to the Gotnia formation. The final amounts of seismic acoustic impedance inversion (AI) at the bottom of the field are mostly in the range of 8000-15000 [(m/s)*(g/cm3)], which can be related to the calcareous formations. Based on the Logratio matrix obtained from the fractal velocity-volume (Vp-V) model, the maximum overall accuracy (OA) in the dominant limestone intervals is 0.74. It indicates a high correlation of the Vp cube model obtained from the combination of sequential Gaussian simulation (SGS) and co-kriging models with AI. The uncertainty studies of Vp model in blind wells are about 50%, which is acceptable considering the large well numbers.
Original Research Paper
Seyed Ahmad Mousavi; Kaveh Ahangari; Kamran Goshtasbi
Abstract
Blast and stress release create cracks, fractures, and excavation damage zone in the remaining rock mass. Bench health monitoring (BHM) is crucial regarding bench health and safety in blast dynamic loading. Several empirical criteria have been proposed for a quick estimation of different parameters of ...
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Blast and stress release create cracks, fractures, and excavation damage zone in the remaining rock mass. Bench health monitoring (BHM) is crucial regarding bench health and safety in blast dynamic loading. Several empirical criteria have been proposed for a quick estimation of different parameters of a rock mass in the zone damaged by the blast. This work estimates the rock mass properties behind the blast hole based on the generalized Hoek-Brown failure criterion and quantitative disturbance factor (D). Considering a constant D value, either zero or one, for the entire rock mass, remarkably alters its strength and stability, resulting in very optimistic or very conservative analyses. Therefore, D is considered based on the elastic damage theory, and numerical simulation is conducted based on the finite difference software FLAC to investigate the vibration and damage threshold by monitoring the peak particle velocity (PPV) in the bench domain with different geometries. According to the numerical simulation, as the depth behind the blast hole increases, the value of D decreases from one to zero almost non-linearly, resulting in a non-linear reduction in the Hoek-Brown behavioral model properties. It is found that using various parameters of rock mass in the blast-induced damage zone behind the hole leads to thoroughly different PPV values than the constant parameters. Accordingly, the approach to using the quantified values of parameter D is of great importance in the estimation of various properties of a rock mass in the blast-induced zone, as well as calculation of the vibration.
Original Research Paper
Sima Mohammadnejad; Sina Ghasemi; Mohammad Reza Khalesi
Abstract
The adsorption of gold and copper cyanide complexes on the activated carbon is investigated using the Density Functional Theory (DFT). In order to represent the activated carbon, two fullerene-like model (presenting structural defect sites) and a simple graphene layer containing different functional ...
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The adsorption of gold and copper cyanide complexes on the activated carbon is investigated using the Density Functional Theory (DFT). In order to represent the activated carbon, two fullerene-like model (presenting structural defect sites) and a simple graphene layer containing different functional groups (presenting chemical active sites) are employed. The structural defect sites show a much lower adsorption tendency toward all the cyano complexes comparing to the chemical active sites. The interaction energy for all of the complexes with structural defect sites (concave) is very low. However, the graphene layer with unsaturated active sites displays the highest level of interaction almost for all the complexes except Cu(CN)4-3. The effect of oxygen functional groups on the graphite edges shows a crucial role in the selectivity of gold adsorption over copper complexes. It has increased adsorption energy for Cu(CN)2- in the presence of OH and COOH, and has decreased adsorption energy for Au(CN)2- by OH and increased by COOH. The study results elucidate the lower selectivity for adsorption of gold over copper cyanides by high oxygen content activated carbon. The energy levels of the HOMO and LUMO orbitals show adsorption of unpaired cyanide anions on the activated carbon surface occurs by electron transfer from the complex to the adsorbent and adsorption onto the activated carbon edges by transferring electrons from the absorbent to the complex. The result has clearly demonstrated that the functional groups increase the adsorption tendency for both the gold (only COOH) and copper complexes (OH and COOH) but deteriorate the selectivity of gold over copper cyanides.
Original Research Paper
Mohammadhossein Dehghani Firoozabadi; Mohammad Fatehi Marji; Abolfazl Abdollahipour; Alireza Yarahamdi Bafghi; Yousef Mirzaeian
Abstract
In this work, an effective methodology is introduced for simulation of the crack propagation in linear poroelastic media. The presence of pores and saturated cracks that can be accompanied by fluid flow makes the use of poroelastic media inevitable. In this work, involvement of the time parameter in ...
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In this work, an effective methodology is introduced for simulation of the crack propagation in linear poroelastic media. The presence of pores and saturated cracks that can be accompanied by fluid flow makes the use of poroelastic media inevitable. In this work, involvement of the time parameter in crack propagation is of particular importance. The order of doing the work is such that first, derives the fundamental solutions of a poroelastic higher order displacement discontinuity method (PHODDM). Then will be provided a numerical formulation and implementation for PHODDM in a code named linear element poroelastic DDM (LEP-DDM). Analytical solutions use different times to check the correctness and validity of the proposed solution and the newly developed code. The numerical results show a good agreement and coordination with the analytical results in time zero and 5000 seconds . The code is able to pursue crack-propagation in time and space. This topic is introduced and shown in an example.
