Exploitation
A. Aryafar; H. Moeini
Abstract
Anomaly separation using stream sediment geochemical data has an essential role in regional exploration. Many different techniques have been proposed to distinguish anomalous from study area. In this research, a continuous restricted Boltzmann machine (CRBM), which is a generative stochastic artificial ...
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Anomaly separation using stream sediment geochemical data has an essential role in regional exploration. Many different techniques have been proposed to distinguish anomalous from study area. In this research, a continuous restricted Boltzmann machine (CRBM), which is a generative stochastic artificial neural network, was used to recognize the mineral potential area in Korit 1:100000 sheet, located 15 km south of Tabas, South Khorasan Province (East of Iran). For this purpose, 470 geochemical stream sediment samples were collected from the study area and analyzed for 36 elements. In order to achieve the goal, in the first step, the robust factor analysis on compositional data was applied to reduce the data dimension and to limit the multivariate analysis by selecting the main components of mineralization. In this procedure, the third factor (out of 6) consisting of Cu, Pb, Zn, Sn, and Sb, related to the metallogenic properties, was considered as the input set in CRBM. In continuation, the CRBM structure with the best efficiency after trying different parameters was stabilized. High-identified error values or anomalies were exteracted using two different thresholds (ASC and ASE) after training with the whole data and reconstructing it by CRBM. The anomalies were then mapped. These indicated the promissing areas. The field studies and existing mining indices confirmly demonestrated the results obtained by CRBM.
Rock Mechanics
N. Aziz; A. Mirzaghorbanali; G. Yang; S. Khaleghparast; H. Resekh
Abstract
There is an increasing need to determine accurately the strength properties of tendons for an effective ground control on mines and underground structures as well as on modelling simulations. The strength properties of cables, used as cable bolts, have been evaluated mainly by their ultimate tensile ...
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There is an increasing need to determine accurately the strength properties of tendons for an effective ground control on mines and underground structures as well as on modelling simulations. The strength properties of cables, used as cable bolts, have been evaluated mainly by their ultimate tensile strength, as this kind of test can be carried out in the field as well as in the laboratory. Only recently, there has been a growing interest in cable bolt failures in shear because of the documented field failure evidence. Accordingly, this paper reports various methods of shear testing of rock bolts and cables using different shear testing rigs, some have been developed by the rock bolting research team at the University of Wollongong. A programme of shear testing of a variety of cable bolts marketed in Australia was undertaken, the results of which were reported and conclusions were drawn. It was concluded that plain cable bolts were de-bonded during shearing when compared to spiral cables under the same testing conditions. In addition, both the single shear and double shear testing methodologies will result in the same outcome if there is no de-bonding, and a proper confinement is applied.
Mineral Processing
P. Karimi; A. Khodadadi Darban; Z. Mansourpour
Abstract
Low-intensity magnetic separators are widely used in the research works and the industry. Advancement in the magnetic separation techniques has led to an expansion in the application of this method in different fields such as enrichment of magnetic mineral, wastewater treatment, and medicine transfer ...
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Low-intensity magnetic separators are widely used in the research works and the industry. Advancement in the magnetic separation techniques has led to an expansion in the application of this method in different fields such as enrichment of magnetic mineral, wastewater treatment, and medicine transfer in the human body. In the mineral processing industry, the main application of wet magnetic separation is via drum separators. The design of this separator is based on drum rotation inside a tank media, where a permanent magnet placed inside the drum as an angle form produces a magnetic field. In the present work, the magnetic variables involved (magnetic flux density, intensity of magnetic field, and gradient of magnetic field intensity) were simulated in the drum wet low-intensity magnetic separator using the finite element method and a COMSOL Multiphysics simulator; these variables were further validated through the measured data. A comparison between the simulation and laboratory measurements (of the magnetic field) showed that the mean value of the simulation error in 94 points in 2 sections was equal to 9.6%. Furthermore, the maximum simulation error in the middle of the magnets, as the most important part of the magnetic field distribution in the process of magnetic separation, was in the 6th direction and equal to 7.8%. Therefore, the performed simulation can be applied as a first step to design and construct more advanced magnetics separators.
V. Sarfarazi; K. Asgari; Sh. Mohamadi Bolban Abad
Abstract
In this work, we investigate the interaction between tunnel and surface foundation in two dimensions by the particle flow code. At the first stage, the PFC calibration is conducted using the experimental test results rendered by a biaxial test. Then the simulation of a biaxial test is performed by confining ...
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In this work, we investigate the interaction between tunnel and surface foundation in two dimensions by the particle flow code. At the first stage, the PFC calibration is conducted using the experimental test results rendered by a biaxial test. Then the simulation of a biaxial test is performed by confining a rectangular sample inside four walls. The walls are located at the top and bottom simulated loading plates and the adjacent walls are located at the left and right simulated sample side confinement. The velocities of the top and bottom walls are determined, and they are used for loading the sample in a strain-controlled mode. The respond of the material is evaluated by following the diverse stress and strain quantities. The axial deviatoric stress versus the axial strain for biaxial test on the bonded granular material is drawn, and then the Mohr's circle is drawn in order to reach the failure envelope of laboratory. Secondly, a rectangular model with dimensions of 10 m 10 m containing a central tunnel and a surface foundation is built. The tunnel is situated in sixteen different positions below the foundation. The foundation moves downward with a velocity of 0.016 mm/s. The results obtained show the position of the tunnel controlling the failure volume. Also the vertical displacement at the roof of the tunnel decreases by increasing the vertical spacing between tunnel and foundation. The settlement beneath the foundation increases by reducing the vertical spacing between the tunnel and the foundation. The settlement beneath the foundation decreases by augmenting the horizontal spacing between the tunnel and the foundation.
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.
R. Satari; A. Akbari Dehkharghani; K. Ahangari
Abstract
Within the last few decades, copper has been identified as one of the most applicable metals by many researchers. These researchers have also been enthusiastic to predict the price of this valuable metal. These days, the available technical analysis methods have been highly applied in the financial markets. ...
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Within the last few decades, copper has been identified as one of the most applicable metals by many researchers. These researchers have also been enthusiastic to predict the price of this valuable metal. These days, the available technical analysis methods have been highly applied in the financial markets. Moreover, the researchers have used these methods to predict the suitable price trends. In the present work, some technical analysis tools including the Fibonacci series, Elliott waves, and Ichimuko clouds were practiced to scrutinize the price changes and predict the copper price. All copper prices from 2008 to 2016 were considered. Regarding the fractal property of these methods, the relations among prices were obtained within an eight-year time sequence. Since 2016, the copper price has been gradually deviated from its previous trend. Using the wave count and Elliott waves has specified that the wave number 1 and wave number 2 have been completed. Now, the time has come to develop the wave number 3. According to the relations introduced by the Elliott waves and the clouds made by Ichimiku, it was determined that the copper price would be almost $16000 per ton in 2022.
Ataallah Bahrami; Reza Hassanpour Kashani; Mirsaleh Mirmohammadi; Fatemeh Kazemi; Ahmad Fathzadeh; Yousef Ghorbani
Abstract
Due to anthropogenic activities of arsenic, its contamination has been widely recognized as one of the most consequential environmental pollutants. This study aims to investigate the possible controlling factors in the amount of arsenic in copper concentrate of the Sungun processing plant – located ...
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Due to anthropogenic activities of arsenic, its contamination has been widely recognized as one of the most consequential environmental pollutants. This study aims to investigate the possible controlling factors in the amount of arsenic in copper concentrate of the Sungun processing plant – located in northwestern Iran. For this purpose, via utilization of process mineralogy approach, an attempt is made to provide a mineralogical-based approach to reduce or remove As from copper concentrate. Chemical analysis of flotation circuit products shows changes of 0.13-1.00% for As in concentrate, and up to 0.003% for tailings. Arsenic is recovered to concentrate in the form of sulfosalt minerals including tennantite and enargite, along with copper sulfides. In order to reduce the arsenic in copper concentrate, flotation tests are performed in Eh values of +300, +200, +100, 0, -100, -200, and -300 mV. Based on the results, a re-flotation step on copper concentrate with a pulp potential range of -300 to +300 mV is conducted as an effective and optimal solution to reduce the amount of As. At a potential of -100 mV, Cu-As minerals (tennantite and enargite) tend to be depressed, and at +300 mV, these minerals tend to float. During the processing circuit, via flotation of particles with a size of -25 μm and adjusting the pulp potential to +300 mV, it is possible to produce two copper concentrates with low arsenic content (< 0.2%) and high arsenic content (> 0.2%). The first concentrate, which is flotation tailings, can be sold in the same way. The second one can be sold after complete removal of arsenic by leaching and then collection of harmful gases.
Rock Mechanics
H. Fattahi; N. Babanouri; Z. Varmaziyari
Abstract
The dynamic response of slopes against earthquake is commonly characterized by the earthquake-induced displacement of slope (EIDS). The EIDS value is a function of several variables such as the material properties, slope geometry, and earthquake acceleration. This work is aimed at the prediction of EIDS ...
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The dynamic response of slopes against earthquake is commonly characterized by the earthquake-induced displacement of slope (EIDS). The EIDS value is a function of several variables such as the material properties, slope geometry, and earthquake acceleration. This work is aimed at the prediction of EIDS using the Monte Carlo simulation method (MCSM). Hence, the parameters height, unit specific weight, cohesion, friction angle, vibration duration, and maximum horizontal acceleration are used to predict the EIDS values. To do this, a multiple non-linear regression relationship is first derived between EIDS and the independent variables. Then MCSM is performed based on the developed regression equation. The results obtained demonstrate that the stochastic approach used is able to successfully reproduce the EIDS values and calculate the confidence intervals. The average of the measured and simulated values for EIDS was 4.34 cm and 4.48 cm, respectively. Eventually, the results of a performed correlation sensitivity analysis revealed that the maximum horizontal acceleration had the greatest impact on EIDS.
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.
Rock Mechanics
Ehsan Taheri; Reza Mohammadpour; Mohammad Hossein Mokhtarzadeh
Abstract
In recent years, the demand for new trenchless methods has dramatically risen. Pipe jacking is a trenchless method widely used in recent years. Ground deformation is one of the significant parameters that may lead to unrepairable harm to facilities and even people. So, ground deformation analysis is ...
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In recent years, the demand for new trenchless methods has dramatically risen. Pipe jacking is a trenchless method widely used in recent years. Ground deformation is one of the significant parameters that may lead to unrepairable harm to facilities and even people. So, ground deformation analysis is necessary for safety and design reasons. The present study analyzes the factors affecting ground deformation during pipe jacking. This is a descriptive-interventional study. Pipe jacking causes soil displacement in three dimensions (3-D). Therefore, 3-D numerical methods were applied for analysis. In this study, numerical simulation was performed using PLAXIS finite element numerical software, taking the case study into account. The effect of each parameter on the ground deformation pattern was studied in three directions; the uplift and their exact position were then analyzed. It should be noted that displacement analyses were performed in two areas: pipe crown and ground surface. Also, the relation of each parameter was estimated with the ground subsidence. Finally, the effect of each different factor and their sensitivity index were determined using sensitivity analysis. The highest subsidence occurs at the end of the shield due to stress relaxation. Considering the results, it was found that the relationship between the internal friction angle and subsidence is linear and direct. The relationship between the elastic modulus and subsidence is also linear but indirect. The results indicate that the most sensitive factor of ground deformation is the diameter, but the least sensitive factor is the face pressure.
Environment
Morteza Niromand; Reza Mikaeil; Mehran Advay; Masoud Zare Naghadehi
Abstract
Slope instability can occur due to external loads such as earthquakes, explosions, and pore pressures. In addition, under natural conditions, slope instability can be caused by factors such as the erosion of some parts of the slope due to water or wind currents and the gradual rise of groundwater levels. ...
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Slope instability can occur due to external loads such as earthquakes, explosions, and pore pressures. In addition, under natural conditions, slope instability can be caused by factors such as the erosion of some parts of the slope due to water or wind currents and the gradual rise of groundwater levels. Another factor leading to slope instability is human activities involving various types of loading and unloading on the slope. The instability of slopes may be associated with limited or large displacements, which either can cause problems or damage structures on the slope. Therefore, this phenomenon needs due care at all slope design and implementation stages. In general, slope stability is influenced by natural factors such as rock type (lithology), tectonic conditions of the area, rock mass joint conditions, and climatic conditions of the area. Furthermore, it is a function of design factors such as dip, height, explosive pattern, and explosion method. The present study offers a multi-factorial fuzzy classification system using the multi-criteria fuzzy approach to evaluate the slope stability. The evaluation is performed in five classes, namely “high stability”, “stable”, “relatively stable”, “unstable”, and “highly unstable”. Next, the viability of 28 slopes of 8 large open-pit mines in different parts of the world was evaluated. According to the fuzzy classification results, 4 and 6 slopes were evaluated in relatively stable and unstable conditions, respectively, with the other slopes classified as stable class. Afterward, the developed fuzzy classification system was assessed based on the actual behavior of the slopes. The results revealed a general large and local failure in most slopes in unstable and relatively stable conditions. Hence, a non-linear multi-factorial fuzzy classification system with good reliability can be used to evaluate the stability of the slopes.
L. Daneshvar Saein
Abstract
The purpose for this research is to define the gold mineralization potentials by the concentration-number fractal and staged factor analysis modeling based on rock samples at the Bardaskan area (NE Iran). Two main gold mineralization types are epithermal and disseminated systems in this district. First, ...
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The purpose for this research is to define the gold mineralization potentials by the concentration-number fractal and staged factor analysis modeling based on rock samples at the Bardaskan area (NE Iran). Two main gold mineralization types are epithermal and disseminated systems in this district. First, the staged factor analysis is carried out at four stages. The stepwise factor analysis was applied in three stages to remove noise elements. Moreover, staged factor analysis was applied in the fourth step based on metallic elements including Au, Ag, Cu, As, Fe, Mo, Bi, La, S, Zn, and Cd were grouped. These elements are grouped at four factors, and related factors for gold mineralization are F1-4 (first factor in the fourth stage) which is consisting of As, Mo, S and Fe and F3-4 (third factor in the fourth stage) includes Au and Ag. The concentration-number log–log plots for factor scores of F1-4 and F3-4 were generated, and their threshold values were calculated to create the factor score’s geochemical maps. Based on these results, the gold mineralization potentials are positioned in the NE, northern and SE sections of the district, which indicate a correlation among alteration zones, including chloritization, sericitization, and silicification alteration zones and faults and fault’s intersections. Main Au mineralization occurred in silicified-sulfidic veins/veinlets in NE and northern portions of the region. However, high grade F3-4 anomalies are located in intersection of faults and neighboring fault zones especially at the northern part of this district. Moreover, Samples with Au≥ 100 ppb were situated in major anomalous parts of F3-4 (Au-Ag) and marginal parts of the F1-4, which include pathfinder of gold mineralization.
A. Shokry; Z. Ghazizadeh; Sh. Piroozfar; H. Tohidi
Abstract
Business logic is one of the most important logics based on the decision matrix. However, using this logic alone and environmental uncertainty leads to problems such as low accuracy and integrity in strategic planning. In this work, we use an intelligent model based on the neural-fuzzy approach aiming ...
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Business logic is one of the most important logics based on the decision matrix. However, using this logic alone and environmental uncertainty leads to problems such as low accuracy and integrity in strategic planning. In this work, we use an intelligent model based on the neural-fuzzy approach aiming at a desired decision-making and reducing the uncertainty in the strategic planning in mineral holdings. Here, the strategies are presented based on three logics, namely business, added value, and capital market. After extracting the primary indices, the final indices of the three logics are selected by consulting with the mineral holding experts. Modelling of the indices is accomplished by the Matlab software, and the model computation is done by the root mean square error for the test data and train data. The case study (Shahab-sang holding) findings show that by a combination of these three logics, the proposed strategies include more integration and accuracy, which lead to a lower uncertainty and more speed in the strategy formulation. Also the test result indicates the validity of all the extracted strategies.
Amirmohammad Nasrollahzadeh; Mohammad Jahani Chegeni; Ahmad Moghooeinejad; Zahra Manafi
Abstract
Due to the increasing consumption of lime in the flotation process to increase the pH of the system and create an alkaline environment, as well as its gradual increase in cost, the attention of researchers has been drawn to perform flotation operations in a neutral environment. Halophilic bacteria have ...
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Due to the increasing consumption of lime in the flotation process to increase the pH of the system and create an alkaline environment, as well as its gradual increase in cost, the attention of researchers has been drawn to perform flotation operations in a neutral environment. Halophilic bacteria have the potential to replace flotation reducers such as lime because flotation can be done with their help at neutral pH as well. Also, due to the buffer effect of sea water, which is the chosen medium for bio-flotation, the use of bio-flotation method reduces the use of drinking water, and also reduces the consumption of chemicals. In this research work, five types of halophilic bacteria are studied for pyrite bio-depression and chalcopyrite flotation. Bio-flotation experiments are conducted using Hallimond tubes, and the bacteria Halobacillus sp., Alkalibacillus almallahensis, and Alkalibacillus sp. had better performance in pyrite depression and chalcopyrite flotation than other bacteria. The recovery of pyrite depression when using them was 30.9, 30.3, and 34.0 %, respectively, and the recovery of chalcopyrite flotation by them was equal to 52.9, 68.6, and 55.7, respectively, which indicates the high selectivity of these bacteria in flotation. In addition to the above tests, the effect of the combination of these three types of bacteria on pyrite depression and chalcopyrite flotation was also studied. The results obtained indicate that in the combination (mix) test of all three types of bacteria (33.3% of each type), pyrite was depressed better than other tests, and its recovery was 27.5%, which was lower than the single bacteria tests. Also, the effect of the combination of these three types of bacteria on the flotation of chalcopyrite is investigated, and its recovery was 72.6%, which was higher than the single bacteria tests. On the other hand, considering that the recovery of chalcopyrite in the three-bacteria combination tests was is higher than the single-bacteria and two-bacteria tests, it can be concluded that the combination of all three bacteria can cause a better synergism and improve their performance in micro-flotation tests.
Environment
Akbar Esmaeilzadeh; Korosh Shahriar; Reza Mikaeil
Abstract
The hydraulic properties of the rock masses are of great importance in analyzing the behavior and stability of the structures constructed on or in rock mass. Permeability is key parameter among other rock mass features due to its important role in rock mass overall behavior. According to aforementioned ...
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The hydraulic properties of the rock masses are of great importance in analyzing the behavior and stability of the structures constructed on or in rock mass. Permeability is key parameter among other rock mass features due to its important role in rock mass overall behavior. According to aforementioned reason, numerous efforts have been made by researchers in the field of rock mechanics for its obtaining. To access the rock masses’ permeability, in-situ test methods and simulation techniques could be used. In-situ tests like Lugeon Test are time-consuming and costly and they provide local results. Simulation base methods calculate the permeability of the model that is generated similar to the real region indeed and the developing the results to the real condition always raises substantial challenges. according to the aforementioned reason, direct acquiring of permeability with optimum cost and time which is easily generalizable to the overall of a region would be very important. In this work using crack tensor concept, permeability tensor of Lorestan’s Rudbar dam cavern is calculated efficiently by considering rock mass structural features. Resulted permeability of the power plant’s cavern was obtained equal to that seems to be acceptable compared to the measured values which is obtained 9/87×10-7 m/s.
Environment
Feridon Ghadimi; Amirhossein Solaimani
Abstract
Chogan region is located in the west of the Urmia-Dokhtar volcanic belt and northwest of the Markazi province in Komijan City. Copper mineralization has a vein type with a length of 260 meters and an average thickness of 4 meters. Mineralization was taken in a sheared silica vein. Eighty three samples ...
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Chogan region is located in the west of the Urmia-Dokhtar volcanic belt and northwest of the Markazi province in Komijan City. Copper mineralization has a vein type with a length of 260 meters and an average thickness of 4 meters. Mineralization was taken in a sheared silica vein. Eighty three samples were taken from the surface ground, in the trenches and it determined the concentration of 10 elements such as Fe, Al, Ca, Ba, S, Mn, As, Pb, Zn, and Cu. It was determined, that S, Ba, Mn, Fe, and Cu are secondary elements in the tuffs by the method of factor and cluster analysis. The constituent mineral such as barite and malachite are vein-shaped, but iron oxides such as hematite and goethite in the form of iron gossan. Geochemical, mineralogical, and geophysical (IP/RS) indices were investigated to separate copper oxide and copper sulfide zones. Sulfur and Ba were used in barite and excess S was chosen as sulfide index (Is). Chalcopyrite and metal factor were chosen as separating oxide and sulfide zones. By combining the geochemical and metal factor, it was approximated the apparent sulfide zone depth and confirmed with actual depth in borehole and error was less than 12%.
Exploitation
Mehdi Rahmanpour; Golpari Norozi; Hassan Bakhshandeh Amnieh
Abstract
Drift-and-fill mining is a variation of cut-and-fill mining method. Drift-and-fill mining method refers to the excavation of several parallel drifts in ore. Excavation of a new drift could start when its adjacent drifts are backfilled or not excavated. The amount of ore material and its grade depends ...
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Drift-and-fill mining is a variation of cut-and-fill mining method. Drift-and-fill mining method refers to the excavation of several parallel drifts in ore. Excavation of a new drift could start when its adjacent drifts are backfilled or not excavated. The amount of ore material and its grade depends on the excavation sequence of drifts. As the number of drifts increases, one will need a model to optimize the drift excavation and backfilling sequence. This paper introduces a mathematical model to determine the optimal drift-and-fill sequence while the safety constraints, excavation, and backfilling capacities and their dependencies are satisfied. The model seeks to minimize the deviations from some predefined goals, and it handles the long-term and short-term constraints in separate and integrated scenarios. An application of the model is presented based on the data available from a lead/zinc underground mining project. There are 91 drifts in the selected level. Based on the monthly planning horizon, the integrated model leads to the slightest deviations in both the mining rate and average grade, and the deviation from the predetermined annual goals is negligible. For the case where long-term and short-term plans are determined separately, the deviation is approximately 10%.
Rock Mechanics
Sina Alizadeh; Mohammad Reza Ghassemi; Mehran Arian; Ali Solgi; Zahra Maleki; Reza Mikaeil
Abstract
One of the most significant risks for investors in the dimension stone industry is the presence of natural discontinuities in the rock mass, which affect the quality of the extracted stone blocks. These discontinuities not only reduce extraction efficiency but also hinder the optimal utilization of the ...
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One of the most significant risks for investors in the dimension stone industry is the presence of natural discontinuities in the rock mass, which affect the quality of the extracted stone blocks. These discontinuities not only reduce extraction efficiency but also hinder the optimal utilization of the quarry. Therefore, it is essential to identify and analyze discontinuities in the rock before initiating any extraction activities and to assess the optimization of the extraction direction in dimension stone quarries. This study examines the key characteristics of discontinuities and joint sets, including their coordinates, strike, dip, spacing and aperture, in the Melika marble dimension stone quarry in Kerman. The collected data are then analyzed using 3DEC software to construct a quarry block model. Additionally, the azimuth rotation of different joint sets is investigated in four categories. The results obtained from the modeling indicate that, to achieve maximum blocking, the current extraction direction should be shifted 70° westward. This adjustment increases the number of blocks to 14,550, the average block volume to 5.5 m³, and the total volume of extracted stone to 79,918.9 m³. These changes are projected to generate approximately $3,180,000 in revenue for the quarry. The study highlights a practical optimization strategy that can significantly enhance the efficiency and profitability of dimension stone quarries by improving extraction direction based on discontinuity analysis.
Saeed Mojeddifar; Hojatollah Ranjbar; Hossain Nezamabadipour
Abstract
The main problem associated with the traditional approach to image classification for the mapping of hydrothermal alteration is that materials not associated with hydrothermal alteration may be erroneously classified as hydrothermally altered due to the similar spectral properties of altered and unaltered ...
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The main problem associated with the traditional approach to image classification for the mapping of hydrothermal alteration is that materials not associated with hydrothermal alteration may be erroneously classified as hydrothermally altered due to the similar spectral properties of altered and unaltered minerals. The major objective of this paper is to investigate the potential of a neuro-fuzzy system in overcoming this problem. The proposed system is applied to the northwestern part of the Kerman Cenozoic Magmatic Arc (KCMA), which hosts many areas of porphyry and vein-type copper mineralization. A software program based on an Adaptive Neuro-Fuzzy Inference System (ANFIS) was developed using the MATLAB ANFIS toolbox. The ANFIS program was used to classify Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) data based on the spectral properties of altered and unaltered rocks. The ANFIS result was then compared with other classified images based on artificial neural networks (ANN) and the maximum likelihood classifier (MLC). The verification of the results, based on field and laboratory investigations, revealed that the ANFIS method produces a more accurate map of the distribution of alteration than that obtained using ANN or MLC.
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.
Exploitation
R. Norouzi Masir; M. Ataei; A. Mottahedi
Abstract
The drilling and blasting method is the first choice for rock breakage in surface or underground mines due to its high flexibility against variations and low investment costs. However, any method has its own advantages and disadvantages. The flyrock phenomenon is one of the drilling and blasting disadvantages ...
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The drilling and blasting method is the first choice for rock breakage in surface or underground mines due to its high flexibility against variations and low investment costs. However, any method has its own advantages and disadvantages. The flyrock phenomenon is one of the drilling and blasting disadvantages that the mining engineers have always been faced with in the surface mine blasting operations. Flyrock may lead to fatality and destroy mine equipment and structures, and so its risk assessment is very essential. For a flyrock risk assessment, the causing events that lead to flyrock along with their probabilities and severities should be identified. For this aim, a combination of the fuzzy fault tree analysis and multi-criteria decision-making methods are used. Based on the results obtained, the relevant causing events of flyrock in surface mines can be categorized into three major groups: design error, human error, and natural error. Finally, using the obtained probabilities and severities for these three groups, the risk matrix is constructed. Based on the risk matrix, the risk numbers of flyrock occurrence due to the design errors, human errors, and natural influence are 12, 6, and 2, respectively. Hence, in order to minimize the flyrock risk, it is very vital for the engineers to select appropriate values for the design events of blasting pattern such as burden, spacing, delays, and hole diameter.
Mineral Processing
A. Behnamfard; E. Khaphaje
Abstract
Beneficiation of a low-grade iron ore was investigated by combination of the low-intensity magnetic separation and reverse flotation methods. The main constituents of the representative sample were 36.86% Fe, 8.1% FeO, 14.2% CaO, 13.6% SiO2, and 0.12% S based on the X-ray fluorescence, titration, and ...
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Beneficiation of a low-grade iron ore was investigated by combination of the low-intensity magnetic separation and reverse flotation methods. The main constituents of the representative sample were 36.86% Fe, 8.1% FeO, 14.2% CaO, 13.6% SiO2, and 0.12% S based on the X-ray fluorescence, titration, and Leco analysis methods. The mineralogical studies by the X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron probe micro-analyzer, and Fe/FeO titration methods showed that the ore minerals present in the representative sample were magnetite, hematite, and goethite, and the main gangue minerals were calcite and quartz. The effects of the operating parameters including the feed size, solid content, and drum rotation speed were investigated on the performance of the wet low-intensity magnetic separation (WLIMS). The optimum operating conditions of WLIMS were determined to be feed size = 135 μm, solid content = 40%, and drum rotation speed = 50 rpm. Under these conditions, a concentrate of 62.69% Fe grade and 55.99% recovery was produced. The tailing of WLIMS with an iron grade of 28.75% was upgraded by reverse flotation with fatty acids as the collector. The effects of five parameters on two levels were investigated using the 25-1 fractional factorial design in 16 experiments. The optimum flotation conditions were determined to be pH = 12; dosage of collector, 1 kg/t; dosage of Ca2+ as activator, 4 kg/t; and dosage of starch as depressant, 1 kg/t. Under these conditions, a concentrate of 53.4% Fe grade and 79.91% recovery was produced.
H. Fattahi; F. Jiryaee
Abstract
The surface settlement is an essential parameter in the operation of mechanized tunneling that should be determined before excavation. The surface settlement analysis caused by mechanized tunneling is a geo-technical problem characterized by various sources of uncertainty. Unlike the deterministic methods, ...
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The surface settlement is an essential parameter in the operation of mechanized tunneling that should be determined before excavation. The surface settlement analysis caused by mechanized tunneling is a geo-technical problem characterized by various sources of uncertainty. Unlike the deterministic methods, the reliability analysis can take into account the uncertainties for the surface settlement assessment. In this work, the reliability analysis methods (second-order reliability method (SORM), Monte Carlo simulation (MCS), and first-order reliability method (FORM)) based on the genetic algorithm (GA) are utilized to build models for the reliability analysis of the surface settlement. Specifically, for large-scale projects, the limit state function (LSF) is non-linear and hard to apply based on the reliability methods. In order to resolve this problem, the GMDH (group method of data handling) neural network can estimate LSF without the need for additional assumptions about the function form. In this work, the GMDH neural network is adapted to obtain LSF. In the GMDH neural network, the tail void grouting pressure, groundwater level from tunnel invert, depth, average penetrate rate, distance from shaft, pitching angle, average face pressure, and percent tail void grout filling are used as the input parameters. At the same time, the surface settlement is the output parameter. The field data from the Bangkok subway is used in order to illustrate the capabilities of the proposed reliability methods.
Mineral Processing
B. Nemati Akhgar; A. Fathzade; B. Golizadeh; S. Hajilou
Abstract
The flotation circuit in Sungun copper plant consists of two column flotation cells as cleaner, having fixed-spargers system. To achieve the expected aims in flotation step, there are serious operational challenges such as: fast choking of the static mixers, boiling problem, burping phenomena and pulp ...
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The flotation circuit in Sungun copper plant consists of two column flotation cells as cleaner, having fixed-spargers system. To achieve the expected aims in flotation step, there are serious operational challenges such as: fast choking of the static mixers, boiling problem, burping phenomena and pulp overflow to concentrate lander, maintenance and control problems. An attempt was exerted by implementing new helical static mixer in one of cleaner cells instead of old elliptical type to overcome the challenges. The changes resulted in proper performance of the column whereas burping phenomena due to choking was eliminated, finer bubbles were produced, and the boiling and overflow problems were solved. Also, the static mixers life time increased to 7 months in helical column cells from one month in elliptical column cells. In addition to 40% air consumption reduction and 20% solid percent increase in final product, the grade of Cu and Mo increased by helical static mixer replacement up to about 18.7% from 16.8% (11%) and to 511.1 ppm from 263 ppm (94%) in the cleaner step, respectively. Recovery of Cu and Mo were increased about 1.5% and 0.2%, respectively. Finally, the results proved the effectiveness of finer bubble generation on grade improvement is depend on minerals hydrophobicity as Mo grade increased more than Cu.
Mohammad Omidi manesh; Vahab Sarfarazi; Nima Babanouri; Amir Rezaei
Abstract
This work presents the Semi-Circular Bend (SCB) test and Notched Brazilian Disc (NBD) test of shotcrete using experimental test and Particle Flow Code in two-dimensions (PFC2D) in order to determine a relation between mode I fracture toughness and the tensile strength of shotcrete. Firstly, the micro-parameters ...
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This work presents the Semi-Circular Bend (SCB) test and Notched Brazilian Disc (NBD) test of shotcrete using experimental test and Particle Flow Code in two-dimensions (PFC2D) in order to determine a relation between mode I fracture toughness and the tensile strength of shotcrete. Firstly, the micro-parameters of flat joint model are calibrated using the results of shotcrete experimental test (uniaxial compressive strength and splitting tensile test). Secondly, numerical models with edge notch (SCB model) and internal notch (NBD model) with diameter of 150 mm are prepared. Notch lengths are 20 mm, 30 mm, and 40 mm. The tests are performed by the loading rate of 0.016 mm/s. Tensile strength of shotcrete is 3.25 MPa. The results obtained show that by using the flat joint model, it is possible to determine the crack growth path and crack initiation stress similar to the experimental one. Mode I fracture toughness is constant by increasing the notch length. Mode I fracture toughness and tensile strength of shotcrete can be related to each other by the equation, σt = 6.78 KIC. The SCB test yields the lowest fracture toughness due to pure tensile stress distribution on failure surface.
