Environment
H. Nikoogoftar; A. Hezarkhani
Abstract
In this paper, we aim to achieve two specific objectives. The first one is to examine the applicability of the Artificial Neural Networks (ANNs) technique in ore grade estimation. Different training algorithms and numbers of hidden neurons are applied to estimate Cu grade of borehole data in the hypogene ...
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In this paper, we aim to achieve two specific objectives. The first one is to examine the applicability of the Artificial Neural Networks (ANNs) technique in ore grade estimation. Different training algorithms and numbers of hidden neurons are applied to estimate Cu grade of borehole data in the hypogene zone of porphyry copper-gold deposit, Masjed-Daghi, East Azerbaijan Province (Iran). The efficacy of ANNs in function-learning and estimation is compared with ordinary kriging (OK). As the kriging algorithms smooth the data, their applicability in the pre-processing of data for fractal analysis is not conducive. ANNs can be introduced as an alternative for this kind of problem. Secondly, we aim to delineate the potassic and phyllic alteration regions in the hypogene zone of Cu-Au porphyry deposit based on the estimation obtained by the ANNs and OK methods, and utilize the Concentration-Volume (C-V) fractal model. In this regard, at first, C-V log-log is generated based on the ANN results. The plots are then used to determine the Cu threshold values for the alteration zones. To investigate the correlation between the geological model and C-V fractal results, the log ratio matrix is applied. The results obtained show that Cu values less than 0.38% from ANNs have more overlapped voxels with phyllic alteration zone by an overall accuracy of 0.72. Spatial correlation between the potassic alteration zones resulting from 3D geological modeling and high concentration zones in C-V fractal model show that Cu values greater than 0.38% have more voxels overlapped with the potassic alteration zone by an overall accuracy of 0.76. Generally, the results obtained show that a combination of the ANNs and C-V fractal methods can be a suitable and robust tool for quantitative modeling of alteration zones instead of the qualitative methods.
Exploration
Ashraf Ismael; Abdelrahem Khalefa Embaby; Faissal Ali; Hussin Farag; Sayed Gomaa; Mohamed Elwageeh; Bahaa Mousa
Abstract
The mineral resource estimation process necessitates a precise prediction of the grade based on limited drilling data. Grade is crucial factor in the selection of various mining projects for investment and development. When stationary requirements are not met, geo-statistical approaches for reserve estimation ...
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The mineral resource estimation process necessitates a precise prediction of the grade based on limited drilling data. Grade is crucial factor in the selection of various mining projects for investment and development. When stationary requirements are not met, geo-statistical approaches for reserve estimation are challenging to apply. Artificial Neural Networks (ANNs) are a better alternative to geo-statistical techniques since they take less processing time to create and apply. For forecasting the iron ore grade at El-Gezera region in El- Baharya Oasis, Western Desert of Egypt, a novel Artificial Neural Network (ANN) model, geo-statistical methods (Variograms and Ordinary kriging), and Triangulation Irregular Network (TIN) were employed in this study. The geo-statistical models and TIN technique revealed a distinct distribution of iron ore elements in the studied area. Initially, the tan sigmoid and logistic sigmoid functions at various numbers of neurons were compared to choose the best ANN model of one and two hidden layers using the Levenberg-Marquardt pure-linear output function. The presented ANN model estimates the iron ore as a function of the grades of Cl%, SiO2%, and MnO% with a correlation factor of 0.94. The proposed ANN model can be applied to any other dataset within the range with acceptable accuracy.
K. Sultan shah; M. H. bin Mohd Hashim; H. Rehman; K. S. bin Ariffin
Abstract
Indirect tensile testing is used in order to investigate the effect of particle morphology (shape and size) on the various weathering grade sandstone fracture characteristics. Several fracture characteristics are discussed in depth in this work including the fracture length (FL), fracture deviation area ...
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Indirect tensile testing is used in order to investigate the effect of particle morphology (shape and size) on the various weathering grade sandstone fracture characteristics. Several fracture characteristics are discussed in depth in this work including the fracture length (FL), fracture deviation area (FDA), fracture angle (FA), and fracture maximum deviation distance (FMDD). A tabletop microscope (TTM) is used to measure the particle morphology. The image analysis techniques induce the uncertainty-related particle shape and size. Therefore, the Monte Carlo simulation (MCS) is used in order to incorporate the inherent uncertainties-related particle morphology. The results obtained reveal that the sandstone fracture angle presents an unclear relationship with the particle shape and size. The effect of particle size on FL is completely obvious, and FL increases with the particle size. In contrast, the particle shape and size have an unclear relationship with the fracture characteristics. Furthermore, the sandstone porosity affects the fracture characteristics, which increase with the weathering grade. Moreover, the findings reveal that the Monte Carlo simulation is a viable tool for integrating the inherent uncertainties associated with the particle shape and size.
Abderrahim Ayad; Saad Bakkali
Abstract
In Sidi Chennane, Central Morocco, the cost of phosphate mining is often influenced by problems bound to the existence of sterile bodies called derangements. These bodies consisting of a waste rocky material affect the sedimentary phosphate series, and thus disturb the phosphate extraction process. In ...
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In Sidi Chennane, Central Morocco, the cost of phosphate mining is often influenced by problems bound to the existence of sterile bodies called derangements. These bodies consisting of a waste rocky material affect the sedimentary phosphate series, and thus disturb the phosphate extraction process. In this work, we attempt to analyze and quantify the economic impact of these sterile bodies on the cost of phosphate mining in Sidi Chennane. The work is carried out through a prototype model prepared as a real mining trench, using data collected during our internships in the Sidi Chennane mining field. The results of this work show that the cost of removing derangements increases the cost of phosphate mining for the entire cycle of production, drilling, blasting, ripping, dozing, loading, and hauling. It is concluded, therefore, that the outcomes of this work are of great importance for obtaining an accurate understanding of phosphate mining when confronted derangements. This can be adapted to analyze and interpret such similar structures in phosphate mines around the world (e.g. Taïba phosphate mine in Senegal).
A. Ghanizadeh Zarghami; K. Shahriar; K. Goshtasbi; A. Akbari Dehkharghani
Abstract
Calculation of the specific charge and specific drilling before a blasting operation plays a significant role in the design of a blasting pattern and the reduction of the final extraction cost of minerals. In this work, the information from the Sungun, Miduk and Chah-Firouzeh copper mines in Iran was ...
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Calculation of the specific charge and specific drilling before a blasting operation plays a significant role in the design of a blasting pattern and the reduction of the final extraction cost of minerals. In this work, the information from the Sungun, Miduk and Chah-Firouzeh copper mines in Iran was assessed, and it was found that there was a significant relationship between the specific charge and specific drilling and the hole diameter, bench height, uniaxial compressive strength and joint set orientation. After finding a technical and economic model to calculate the specific charge and specific drilling, this model was tested on the Sungun copper mine. Due to the insufficient consideration during the design of a blast pattern and because of the high hardness of the rocks in some parts of the mine, lots of destructive events such as boulders, back break, bench toe, high specific charge and high specific drilling, fly rock, and ground vibration in the blast operations were observed. The specific charge and specific drilling were found to be the most important technical and economic parameters involved in designing a blasting pattern, and they were found to play an important role in reducing the blasting cost. The blasting cost could be largely controlled by the accurate examination and computation of these parameters. An increase in the rock strength and the angle between the bench face and the main joint set would increase the specific charge and specific drilling. On the other hand, a specific charge and a specific drilling would decrease when the hole diameter increased in every range of the uniaxial compressive strength.
Exploitation
Babatunde Adebayo; Blessing Olamide Taiwo; BUSUYI THOMAS AFENI; Aderoju Oluwadolapo Raymond; Joshua Oluwaseyi Faluyi
Abstract
The quarry operators and managers are having a running battle in determining with precision the rate of deterioration of the button of the drill bit as well as its consumption. Therefore, this study is set to find the best-performing model for predicting the drill bit button's wear rate during rock drilling. ...
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The quarry operators and managers are having a running battle in determining with precision the rate of deterioration of the button of the drill bit as well as its consumption. Therefore, this study is set to find the best-performing model for predicting the drill bit button's wear rate during rock drilling. Also, the rate at which drill bit buttons wear out during rock drilling in Ile-Ife, Osogbo, Osun State, and Ibadan, Oyo State, Southwest, Nigeria was investigated. Artificial Neural Network (ANN), Adaptive Neuro-Fuzzy Inference System (ANFIS), and adaptive moment Estimation-based Long Short-Term Memory (LSTM) machine learning approaches were used to create models for estimating the bit wear rate based on circularity factor, rock grain size, equivalent quartz content, uniaxial compressive strength, porosity, and abrasive properties of the rock. The performance of the models was measured using a new error estimation index and four other convectional performance estimators. The analysis of performance shows that the adaptive moment estimation algorithm-based LSTM model did better and more accurately than the other models. Thus, the LSTM models presented can be used to improve drilling operations in real-life situations.
Environment
Ahmed Amara Konate; Djénébou Bourama Sangare; Baba Faradji N'diaye; N'dji dit Jack Dembele
Abstract
Artisanal gold mining (AGM) is one of Mali's most significant economic activities. This activity become a serious environmental concern because of the chemicals used for AGM. The artisanal gold processing method uses a significant amount of water. The operating waste, often toxic by chemical mercury, ...
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Artisanal gold mining (AGM) is one of Mali's most significant economic activities. This activity become a serious environmental concern because of the chemicals used for AGM. The artisanal gold processing method uses a significant amount of water. The operating waste, often toxic by chemical mercury, is discharged or drained into watercourses. This study describes the main actors and the different methods of exploration, extraction, and processing of gold by artisanal miners, as well as their perception of environmental impacts. The methodology adopted is based on surveys and observations conducted at the Lollè and Sinty sites. The results show that no mining legislative rules were applied. Still, non-standard customary rules for a very long time. AGM has a particular organizational chart that actors manage. This study shows that AGM can cause health and environmental problems, especially with the use of chemicals, contamination of water resources, land degradation, and destruction of fauna and flora. Analysis of water samples shows that the mercury concentration at Lollè exceeds the WHO standard, while most mercury concentrations at Sinty are below this standard. The geomorphology of the study area shows a watershed with an area of 88.40 km2 with four orders of the hydrographic network in Lollè and 404.02 km2 with five orders in Sinty. While the slopes range from very weak to strong, and the study areas are practically flat. This study will provide accurate information to policy-makers for implementing environmental management strategies in a manner that miners can understand and evaluate.
Rock Mechanics
Tanya Thakur; Kanwarpreet Singh; Abhishek Sharma
Abstract
Landslides affecting life and property losses has become a serious threat in various countries worldwide which highlights the importance of slope stability and mitigation. The methods and tools employed for slope stability analysis, ranging from traditional limit equilibrium methods to worldly-wise numerical ...
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Landslides affecting life and property losses has become a serious threat in various countries worldwide which highlights the importance of slope stability and mitigation. The methods and tools employed for slope stability analysis, ranging from traditional limit equilibrium methods to worldly-wise numerical modeling techniques. It focuses on the importance of accurate and reliable data collection, including geotechnical investigations, in developing precise slope stability assessments. Further, it also addresses challenges associated with predicting and mitigating slope failures, particularly in dynamic and complex environments. Mitigation strategies for unstable slopes were systematically reviewed of different researchers, encompassing both traditional and innovative measures. Traditional methods, such as retaining walls and drainage systems, the mitigation strategies were explored, emphasizing both preventive measures and remedial interventions. These include the implementation of engineering solutions such as slope structures, and Matrix Laboratory (MATLAB) techniques along with the comprehensive analysis of four prominent slope stability assessment tools: Rock Mass Rating (RMR), Slope Mass Rating (SMR), and the Limit Equilibrium Method (LEM). The comparative analysis of these tools highlights their respective strengths, limitations, and areas of application, providing researchers, authors, and practitioners with valuable insights to make informed choices based on project-specific requirements. To ensure the safety and sustainability of civil infrastructure, a thorough understanding of geological, geotechnical, and environmental factors in combination with cutting-edge technologies is required. Furthermore, it highlights the important role that slope stability assessment and mitigation play a major role in civil engineering for infrastructure development and mitigation strategies.
Rock Mechanics
Manthri Rakesh; Ashish Kumar Dash; Sunny Murmu
Abstract
India's growing energy demand has intensified the need for efficient and safe coal extraction methods, particularly in underground mining, where mechanized depillaring using Continuous Miner (CM) technology has gained prominence. This study explores the critical role of Cut-Out Distance (COD) in optimizing ...
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India's growing energy demand has intensified the need for efficient and safe coal extraction methods, particularly in underground mining, where mechanized depillaring using Continuous Miner (CM) technology has gained prominence. This study explores the critical role of Cut-Out Distance (COD) in optimizing production and ensuring safety during mechanized depillaring operations. COD, defined as the stable drivage length that can be cut without support, directly impacts productivity, roof stability, and operational safety. Despite its importance, there are no standardized guidelines for determining COD in Indian coal mines, leading to trial-and-error practices that compromise efficiency and safety. This paper reviews global and domestic practices, highlighting the inadequacies in existing methods for COD estimation. It identifies key factors influencing COD, including Rock Mass Rating (RMR), roof elasticity, geological conditions, and machinery capabilities. The work also examines case studies of strata control failures in Indian coal mines, highlighting the consequences of improper strata assessment in mines. The research work advocates for the development of standardized guidelines tailored to Indian mining conditions by integrating numerical simulations and machine learning tools for precise COD estimation. A flow chart of methodology for the development of guidelines is proposed; the findings aim to enhance safety, reduce accidents, and improve productivity, paving the way for sustainable growth in India's underground coal mining sector.
Mineral Processing
Sajad Kolahi; Mohammad Jahani Chegeni; Asghar Azizi
Abstract
In Part 2 of this research work, five types of liners, i.e. wave, step, step@, ship-lap, and ship-lap@, are examined. These liners all have similar connected lifters with different volumes. Their difference is in the width, height, and type of the lifter profile. All the five liner types, from 8 to 64 ...
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In Part 2 of this research work, five types of liners, i.e. wave, step, step@, ship-lap, and ship-lap@, are examined. These liners all have similar connected lifters with different volumes. Their difference is in the width, height, and type of the lifter profile. All the five liner types, from 8 to 64 lifters, are simulated using the Discrete Element Method (DEM). In this research work, for the first time, data from the sum of the kinetic and potential energies of individual balls (79,553 particles) are used to find the appropriate range for the number of lifters. In other words, the kinetic and potential energies of all particles within the system (inside the ball mill) are the basis for determining the appropriate number of lifters. The results suggest that for the wave liner, the appropriate range of the number of lifters is between 8 and 16, for the step, step@, and ship-lap liners; it is between 12 and 20, and for the ship-lap@ liner, it is between 8 and 20. In fact, using the data on the kinetic and potential energies of the balls inside the mill, it is possible to determine the appropriate range of the number of lifters, which is done for the first time in this study. In general, it is suggested that the data on the kinetic and potential energies of the balls can be used to determine the number of mill lifters, and unlike what has been done. So far, by other researchers, the number of mill lifters should not be determined solely by using its diameter or the dimensions of the lifters. Also the effect of mill-rotation direction on the values of kinetic and potential energies in step and ship-lap liners is investigated. It is shown that the step@ and ship-lap@ liners transfer more energy to the balls than the step and ship-lap liners, and have a suitable direction of rotation.
M. Kor; E. Abkhoshk; Kh. Gharibie; S. Z. Shafaei
Abstract
An attempt has been made in this paper to investigate the effect of particle size distribution on coal flotation kinetics. The effect of particle size (Ps) on kinetics constant (k) and maximum theoretical flotation recovery (RI) was investigated while other operational parameters were kept constant. ...
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An attempt has been made in this paper to investigate the effect of particle size distribution on coal flotation kinetics. The effect of particle size (Ps) on kinetics constant (k) and maximum theoretical flotation recovery (RI) was investigated while other operational parameters were kept constant. The relationship between flotation kinetics constant and theoretical flotation recovery with particle size was estimated with nonlinear equations. Analysis of variance showed that the effect of particle size on the kinetics constant was statistically significant at 95% confidence level. However, it was not significant on maximum theoretical flotation recovery (RI). Different regression methods were conducted in order to model the effect of coal particle size on flotation kinetics. Results indicated that the quadric regression method gave better prediction of the cumulative recovery for different particle size fractions. The correlation coefficient (R2) values of this model were 0.99, 0.996, 0.98, 0.98 and 0.97 for average of particle sizes of 37.5 µm, 112.5 µm, 225 µm, 400 µm and 625 µm respectively.
A. H. Ansari; K. Alamdar
Abstract
Potential field methods such as gravity and magnetic methods are among the most applied geophysical methods in
mineral exploration. A high-resolution technique is developed to image geologic boundaries such as contacts and faults.
Potential field derivatives are the basis of many ...
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Potential field methods such as gravity and magnetic methods are among the most applied geophysical methods in
mineral exploration. A high-resolution technique is developed to image geologic boundaries such as contacts and faults.
Potential field derivatives are the basis of many interpretation techniques. In boundary detection, the analytic signal
quantity is defined by combining the values of horizontal and vertical derivatives. The outlines of the geologic
boundaries can be determined by tracing the maximum amplitudes of analytic signal. However, due to superposition
effects, in some cases that a variety of sources are adjacent, the detected boundaries are blurred. To overcome this
problem, this study used enhanced analytic signal composed of the nth- order vertical derivative of analytic signal. The
locations of its maximum amplitudes are independent of magnetization direction and geomagnetic parameters. This
technique is particularly suitable when interference effects are considerable and when remanent magnetization is not
negligible. In this paper this technique has been applied to gravity data of southwest England. Using this method, five
granites outcrops and their separating faults are enhanced accurately.
P. Masoudi; B. Tokhmechi; A. Zahedi; M. Ansari Jafari
Abstract
Distinguishing productive zones of a drilled oil well plays a very important role for petroleum engineers to decide where to perforate to produce oil. Conventionally, net pay zones are determined by applying a set of cut-offs on perophysical logs. As a result, the conventional method finds productive ...
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Distinguishing productive zones of a drilled oil well plays a very important role for petroleum engineers to decide where to perforate to produce oil. Conventionally, net pay zones are determined by applying a set of cut-offs on perophysical logs. As a result, the conventional method finds productive intervals crisply. In this investigation, a net index value is proposed, then; diffusivity equation is utilized to calculate the proposed index value. The new net determination method is applied on the interval of Sarvak Formation of two datasets of two nearby wells. The best advantage of this newly developed net determination method is its fuzzy output. Fuzzy net pay determination is valuable in grading pay zones and not classifying all productive zones in a single class. Another advantage of the proposed net determination method is its higher accuracy in identifying productive zones in comparison with cut-off based method.
Exploitation
feng yang; pengjie li; qiang Sun
Abstract
Large coal pillars result in significant resource waste. The high stress concentration within these pillars also creates safety hazards for the working face. To address this, a cooperative mining method for section coal pillars is proposed. This method is designed for seams with large inclination angles ...
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Large coal pillars result in significant resource waste. The high stress concentration within these pillars also creates safety hazards for the working face. To address this, a cooperative mining method for section coal pillars is proposed. This method is designed for seams with large inclination angles and that are extremely close to overlying pillars. The technical principles are explained. First, FLAC3D simulation software was used to investigate the effect of the spacing between the lower roadway and the section coal pillar, which determined the optimal roadway position. Then, a coupled FLAC-PFC method was employed to optimize the coal drawing process parameters. The optimal scheme was analyzed to characterize roof deformation, stress distribution, and hydraulic support loads. An engineering case study demonstrates that a spacing greater than 18 m minimizes the influence of concentrated stress, resulting in limited deformation and improved roadway stability. The study investigates coal drawing under different sequences, port widths, and methods. The optimal process was identified as downward drawing, with a 1.5 m coal drawing port width and a two-wheel sequential method. This process achieves a drawing rate of 85.62% and a gangue content of 4.61%. Analysis shows that during the pillar drawing process, the concentrated stress on the roof plate is significantly reduced, with a maximum stress decrease of 21.1 MPa, effectively alleviating stress concentration. The total force on the section hydraulic support in fully mechanized caving is 1.6×10⁴ kN, while the force in the fully mechanized mining section is 1.4×10⁴ kN.
A Igder; Ali Akbar Rahmani; Ali Fazlavi; Mohammad Hossein Ahmadi; Mohammad Hossein Ahmadi Azqhandi; Mohammad Hassan Omidi
Abstract
The main objective of the present study is to investigate the feasibility of using Carboxymethyl chitosan magnetic nanoparticles (CCMN) for the adsorption of Cd2+. The study also reports important parameters, which affect the adsorption process, i.e., pH, adsorbent dose, contact time and concentration ...
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The main objective of the present study is to investigate the feasibility of using Carboxymethyl chitosan magnetic nanoparticles (CCMN) for the adsorption of Cd2+. The study also reports important parameters, which affect the adsorption process, i.e., pH, adsorbent dose, contact time and concentration of Cd2+, using Box-Behnken designs. Firstly, functional carboxymethyl chitosan magnetic nanoparticles (about 33 nm) was prepared by chemical coprecipitating and characterized by means of scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR). Then, CCMN was used as the adsorbent for the treatment of effluent. The ANOVA result of the full model shows that pH, adsorbent dosage and metal concentration had a significant effect on metal removal. In addition, this parameters indicates which contact time variable does not have a significant effect (p>0.05).
Saeed Alishahi; Ahmad Darban; Mahmood Abdollahi
Abstract
Since a high toxicity of cyanide which use as a reagent in the gold processing plant, thiosulfate has been recognized as a environmental friendly reagent for leaching of gold from ore. After gold leaching process it's important for recovery of gold from solution using adsorption or extraction methods, ...
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Since a high toxicity of cyanide which use as a reagent in the gold processing plant, thiosulfate has been recognized as a environmental friendly reagent for leaching of gold from ore. After gold leaching process it's important for recovery of gold from solution using adsorption or extraction methods, One of these methods is activated carbon.The loading of gold from industrial thiosulfate solution that obtained from Zarshuran gold plant-Takab-Iran, onto activated carbon have been investigated. The affecting variables of the adsorption of gold on the carbon included, temperature, concentration of gold, size of activated carbon, pH and the ratio of amount of activated carbon to the volume of solution. The results have shown that at low concentration of gold, effective loading can be achieved at pH 10.5. The size of activated carbon has a significant effect on the loading of gold. In this research the recovery of gold on activated carbon has been predicted using artificial neural network. For this purpose temperature, pH, the proportion of solution volume to weight of activated carbon, gold concentration and time of adsorption were taken as input parameters, whereas, the recovery of gold on activated carbon from thiosulfate solution was considered as an output parameter. The network with LMBP algorithm with two hidden layer were used and the topology 5-4-13-1 showed the best ability for prediction.Moreover sensitive analyze were indicated parameters pH and temperature have substantial influence on adsorption.
M. Fakhrerad; A. Nejati Kalateh; S. Ghomi
Abstract
Coastal Fars gravimetry project in Fars province was carried out to find the buried salt domes and to determine characteristics of faults in this area. The Lavarestan structure was covered by 4203 gravimetry stations in a regular grid of 1000*250 m. Depth structural model of this anticline made in previous ...
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Coastal Fars gravimetry project in Fars province was carried out to find the buried salt domes and to determine characteristics of faults in this area. The Lavarestan structure was covered by 4203 gravimetry stations in a regular grid of 1000*250 m. Depth structural model of this anticline made in previous studies was based on geological evidences and structural geology measurements. In order to have a complete coverage of Lavarestan anticline, 4 profiles with appropriate intervals were selected on gravity data for further processing and interpretation. 2D inverse modeling was performed on these profiles using Encome Modelvision and Encome PA software. Geometrical and physical parameters of each layer were changed step by step and forward gravity calculations were repeated until we reached a desirable fitting between observed and calculated gravity anomaly. The results of 2D gravity modeling were focused on Lower Paleozoic and Kazerun (cap rock) top horizon, also the underground contour map was extracted from seismic data after interpretation. The results show appropriate correlation between the underground contour map of 2D gravity modeling and interpretation of seismic data.
Gh. Mojarradi; R. Rezaei; A. Ketabi
Abstract
This descriptive analytical survey was aimed to study the negative impacts of mine exploitations carried out in the rural regions of the Tekab Township located in Iran. The statistical population of the studied areas consisted of all the heads of the rural households in the villages located in the vicinity ...
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This descriptive analytical survey was aimed to study the negative impacts of mine exploitations carried out in the rural regions of the Tekab Township located in Iran. The statistical population of the studied areas consisted of all the heads of the rural households in the villages located in the vicinity of the mines in the Tekab Township (N=2680). According to the Cochran formula, a sample size of 220 was selected using a stratified random sampling technique (n=220). A questionnaire was used to collect the data required. The validity of the questionnaire used was confirmed by a panel of experts. A pilot study was conducted to establish the reliability of the instrument used. The Cronbach’s alpha coefficient for the main scale of the questionnaire including the negative effects of the mine exploitations was equal to 0.94. The results obtained from the factor analysis revealed that five factors including the environmental, social, economic, cultural, and hygiene factors explained 60.19% of the total variances of the negative impacts of the mine exploitations in the rural regions of the Tekab Township.
Rock Mechanics
M. T. Hamzaban; H. Memarian; J. Rostami
Abstract
Rock abrasivity is an essential factor for selecting cutting tools, estimating tool wear and life, and ultimately, matching various mechanized excavation systems with a given geologic condition. It also assists engineers to determine economic limits of different cutting tools and machines used in civil ...
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Rock abrasivity is an essential factor for selecting cutting tools, estimating tool wear and life, and ultimately, matching various mechanized excavation systems with a given geologic condition. It also assists engineers to determine economic limits of different cutting tools and machines used in civil and mining projects. The Cerchar abrasion test is a simple and most widely used method for rock abrasivity assessments. However, it has some shortcomings to describe the steel-rock interaction during the cutting process. In this work, two new parameters are used to describe the pin-rock interaction in the Cerchar abrasion test and to evaluate the efficiency of the rock scratching process. A set of 41 different rock samples are tested by a newly developed testing device. The device provides a more precise control of the testing operational parameters, and measures the applied frictional force on the pin and its horizontal and vertical displacements on the sample surface. The results obtained are used to calculate the Modified Cerchar Abrasion Index (MCAI) and the Scratch Energy Index (SEi), as two newly developed parameters. The accuracy of the calculated parameters is discussed. Our investigations show that MCAI has closer correlations with rock mechanical parameters than CAI, and therefore, has a higher potential to estimate the rock cutting tool wear in tunneling applications. Also SEi shows sensible correlations with sample hardness and mechanical properties. The results obtained show that SEi can be used to compare the efficiency of various pin hardnesses to create scratches on various rock samples, and could be used as a determinative parameter in selecting the cutting tool hardness.
M. Rezaee Rad; Sh. Shahhoseini; M. Janfada; H. A. Mirzaee; P. Kelidari
Abstract
Low grade diasporic bauxite in the Jajarm mine with an A/S (Al2O3/SiO2) ratio of 2.3 is not usable in the Bayer process at Jajarm Alumina Complex. Due to the severe interlocking effect between the diaspore and aluminosilicate minerals (Chamosite and Kaolinite) and iron-containing minerals in a microcrystal ...
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Low grade diasporic bauxite in the Jajarm mine with an A/S (Al2O3/SiO2) ratio of 2.3 is not usable in the Bayer process at Jajarm Alumina Complex. Due to the severe interlocking effect between the diaspore and aluminosilicate minerals (Chamosite and Kaolinite) and iron-containing minerals in a microcrystal matrix, the thermo-chemical treatment, which is independent from micro-mineralogy, was chosen for bauxite desilication. Five parameters affecting the process and their interactions were investigated using the Taguchi experimental design method. The results obtained showed that there was an interaction between the furnace temperature and the leaching time. Moreover, the optimum values for the parameters involved in the thermo-chemical treatment were determined to be a furnace temperature of 950 °C, a furnace residence time of 90 min, a leaching agent (soda) concentration of 150 g L-1, and a leaching time of 120 min, where the solid content (in leaching) had no effect. Moreover, a model was proposed using the Dx7 software to predict the A/S ratio. The ratio was predicted to be 7.52 at the optimum conditions, whereas in the experiments carried out under the same conditions, it was obtained to be 6.96 ± 0.2, which means a 59% decrease in silica and an increase in the A/S ratio of up to 3 times with 80% weight recovery.
Rock Mechanics
A. Asgari; A. Ramezanzadeh; Seyed M. E. Jalali; B. Brouard
Abstract
Ensuring the stability and integrity of underground gas storage salt caverns is a very complicated subject due to the non-linear and time-dependent behavior of rock salts under complicated thermal and mechanical loading conditions. For this reason, pressure and temperature fluctuations in the caverns ...
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Ensuring the stability and integrity of underground gas storage salt caverns is a very complicated subject due to the non-linear and time-dependent behavior of rock salts under complicated thermal and mechanical loading conditions. For this reason, pressure and temperature fluctuations in the caverns and their surrounding strata must be integrated into the analysis and the numerical tools that are used for this purpose. LOCAS, a 2D axisymmetric finite-element code, dedicated to the stability analysis of underground salt spaces, was applied to assess the effects of various operating and geometrical parameters on the cavern behavior. In this paper, we aimed to give an overall assessment of the behavior of the salt caverns used for natural gas storage. In this work, some specific loading scenarios were considered first, followed by thorough parametric and sensitivity analyses to reveal the impacts of the geometrical parameters and operational parameters involved on the behavior of salt caverns using the modern stability criteria. The findings showed that the onset of dilation was more likely to happen within the first cavern life cycle when pressure dropped to the minimum level. As for the potential of tension occurrence in the surrounding rock, this is more likely to happen by increasing the number of operation cycles, especially in the upper one-third of the cavern wall. Finally, it was seen that the cavern depth and minimum cavern internal pressure had even more important influences than the others on the salt cavern behavior.
N. M. Shahani; M. J. Sajid; I. M. Jiskani; B. Ullah; A. R. Qureshi
Abstract
In this work, we employ the fuzzy logic technique to achieve and present, for the first time, a proper analysis of the actual intensity of the increase in the coal miners’ fatality rates in Pakistan from 2010 to 2018, compared with China and India, with an objective to minimize the impact of incidents ...
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In this work, we employ the fuzzy logic technique to achieve and present, for the first time, a proper analysis of the actual intensity of the increase in the coal miners’ fatality rates in Pakistan from 2010 to 2018, compared with China and India, with an objective to minimize the impact of incidents on the miners’ fatalities. The average and yearwise fatality rates in Pakistan, compared with China and India, are used for the fuzzy logic technique in order to calculate the actual degree of flexibility for the surging fatalities. The findings show that both the average (2010-2018) and yearwise fatality rates in 2011, 2015, and 2018 are 2.44, 1.74, and 1.6, respectively. In the fuzzy logic technique, the variables whose membership function (µ) values are ≥ 1 represent the absolute truth. The membership function values for the years 2011, 2015, and 2018 are alarmingly high for the fatalities of coal miners. Similarly, except for 2014 and 2010, where 0 represents the absolute falseness, the results for the remaining years indicate high fatality rates with a flexibility (or small extent) of its corresponding membership function (µ) values such as 0.623, 0.739, 0.219, 0.173 and 0.115, and 0.714, 0.24, 0.01, 0.324 and 0.317 using the average and yearwise analysis, respectively, compared with China. Likewise, the fuzzy logic membership function (µ) values compared with India in the remaining years are 0.704, 0.795, 0.386, 0.159, 0.352 and 0.306, and 0.675, 0.795, 0.386, 0.186, 0.321 and 0.322, respectively. The proposed fuzzy logic analysis has been founded based on the theory of fuzzy sets to properly identify the miners’ fatalities, and also to suggest the implementation of appropriate recommendations to reduce the fatalities in the coal mines in Pakistan.
Deemah Saad Mahmoud; Ahmed Ali Madani; Said Mohamed Said; Mohamed Mokhtar Yehia; Tamer Nassar
Abstract
The eastern border of the Nile valley south of Cairo is distinguished by numerous springs and associated surface water bodies, e.g. Ain El-Sira, Helwan, and Atfih. Except the latter, all of them were disseminated in urban areas, and were hardly detected by remote sensing data. Thus, studying the surface ...
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The eastern border of the Nile valley south of Cairo is distinguished by numerous springs and associated surface water bodies, e.g. Ain El-Sira, Helwan, and Atfih. Except the latter, all of them were disseminated in urban areas, and were hardly detected by remote sensing data. Thus, studying the surface water of Atfih spring is key to understanding the nature of the east Nile spring system. Change in this surface water has been detected based on the integration between the spatiotemporal analysis of the multi-spectral satellite images and the Modern-Era Retrospective Analysis for Research and Applications (MERRA-2) rainfall data from 1987 to 2019, and the field investigation. The normalized differential water index analysis reveals an increase in the surface area of the Atfih water body by two to three times during the years 2016-2017. The results clarified the relationship between the appearance of the surface water of Atfih spring and rainfall amounts. Another factor controlling the Atfih water body treated in this work is the geological structures. A field survey aided by the processed satellite data revealed the presence of three fault populations: WNW-ESE, E-W to ENE-WSW, and NNE-SSW. The E-W to ENE-oriented faults are the main faults and have a right-lateral strike-slip sense of movement. This fault pattern and Pliocene shale have a substantial impact on the appearance of the Atfih water body. These faults act as a horizontal channel that allows lateral movement of meteoric water through Eocene carbonate, and water recharge occurs at the highly fractured strike-slip transfer zones.
Mineral Processing
Y. Kianinia; M. R. Khalesi; M. Abdollahy; A. Khodadadi Darban
Abstract
Processing of gold ores with high sulfide minerals is problematic as they consume cyanide and reduce gold leaching. Optimization of gold leaching and cyanide consumption requires a methodology to estimate the amount of exposed cyanicides, their leaching kinetics, and speciation of cyanide complexes that ...
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Processing of gold ores with high sulfide minerals is problematic as they consume cyanide and reduce gold leaching. Optimization of gold leaching and cyanide consumption requires a methodology to estimate the amount of exposed cyanicides, their leaching kinetics, and speciation of cyanide complexes that consume the free cyanide and compete with gold. In this paper, a physico-chemical approach is presented to estimate the liberation and exposure of cyanicides to the leaching solution, and then prediction of the speciation of all possible related species in the solution. The results obtained show that this methodology not only could successfully estimate the gold leaching and cyanide consumption based on the mineralogical data with a lower number of parameters compared to existing empirical models, but also offers the prediction of formation of all the possible complexes that could be used for optimization purposes.
M. Bahaaddini; M. Serati; M. H. Khosravi; B. Hebblewhite
Abstract
A proper understanding of the shear behaviour of rock joints and discontinuities is yet a remaining challenge in the rock engineering research works owing to the difficulties in quantitatively describing the joint surface roughness both at the field and the laboratory scales. Several instruments and ...
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A proper understanding of the shear behaviour of rock joints and discontinuities is yet a remaining challenge in the rock engineering research works owing to the difficulties in quantitatively describing the joint surface roughness both at the field and the laboratory scales. Several instruments and techniques have been developed over the years for the surface characterisation of joints at the field- and laboratory-scale investigations, amongst which the application of the photogrammetry methods has obtained a growing popularity. This work evaluates the applicability of the photogrammetry techniques for the characterisation of joint surface topography and texture at micro-scales, which has been largely understudied in the literature. Three tensile joint surfaces are digitized using photogrammetry, and the results are compared with those obtained from laser scans with a high 3D accuracy. A comprehensive statistical analysis is then undertaken on the digitized point clouds in order to assess the performance of photogrammetry in surface characterisation. The results of this work show that the height differences between the resulting point clouds from the two adopted techniques (photogrammetry and 3D laser scanning) follow the normal distribution with the mean values close to zero. The statistical analyses illustrate that the measured joint surfaces using the photogrammetry techniques are in good agreement with the laser scanning data, confirming that photogrammetry is a capable method for characterising the joint surface roughness even at micro-scales. Interestingly, the results obtained further indicate that the accuracy and preciseness of the photogrammetry techniques are independent from the joint roughness coefficient but the camera and configuration parameters remarkably control the performance of the measurement.
