Rock Mechanics
M. Lotfi; B. Tokhmechi
Abstract
Nowadays, Barton’s Joint Roughness Coefficients (JRC) are widely used as the index for roughness and as a challenging fracture property. When JRC ranking is the goal, deriving JRC from different fractal/wavelet procedures can be conflicting. Complexity increases when various rankings outcome from ...
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Nowadays, Barton’s Joint Roughness Coefficients (JRC) are widely used as the index for roughness and as a challenging fracture property. When JRC ranking is the goal, deriving JRC from different fractal/wavelet procedures can be conflicting. Complexity increases when various rankings outcome from different calculation methods. Therefore, using Barton’s JRC, we cannot make a decision based on the proven mathematical theories because each method has a different rank. Ideally, these rankings must be equal but, in practice, they are different for each method. To solve this problem and to achieve a robust and valid ranking for JRC, Condorcetand Borda count methods have been used. These methods have been proposed as fusion approaches. Re-ranking of JRC using different methods integrated with Condorcet showed confusion in ranking of the JRC4, JRC5, and JRC6 profiles. This ambiguity is equal to equalizing decision conditions about all the three at the examination of the winners, losers, and draws in pairwise matrices. Therefore, Borda Count was applied and resulted in robust rankings. In fact, a new approach for a roughness measurement is presented. A new JRC ranking called JRCN is introduced. This new ranking shows a lower sum of squared errors (0.00390) in comparison with the original JRC ranking method (0.00410) and ranked JRCN1 to JRCN10. Thus it is proposed to consider JRCN as a new and improved version of JRC rankings.
Rock Mechanics
Aref Jaberi; Shokroallah Zare
Abstract
Unlike the mechanical properties of intact rock, which can be obtained on a laboratory scale, estimating the mechanical properties of the jointed rock mass is very difficult due to the presence of different joints and the complexity of the joints. Therefore, to calculate the mechanical parameters of ...
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Unlike the mechanical properties of intact rock, which can be obtained on a laboratory scale, estimating the mechanical properties of the jointed rock mass is very difficult due to the presence of different joints and the complexity of the joints. Therefore, to calculate the mechanical parameters of the jointed rock mass and use the continuous media theory of the jointed rock mass, it is necessary to calculate the Representative Element Volume (REV) of the rock mass. In this study, the Discrete Element Method (DEM) and the mechanical index of strength were used to investigate the effect of persistent and non-persistent joint angles, as well as model size on the REV in x, y, and z directions. The numerical results showed that by changing the joint angles and side length, both the strength and the REV of the rock mass were affected. The maximum representative side length for the persistent joint in the x and z directions occurred at angles of 60° and 75°, respectively. The minimum strength was obtained for joints in the x and z directions at a 45° angle. Finally, the REV for persistent and non-persistent joints is calculated as 10*0.5*8m and 4*0.5*4m, respectively.
Rock Mechanics
Ali Kazempour Osalou; Sayfoddin Moosazadeh; Ali Nouri Qarahasanlou; Mohammad-Reza Baghban Golpasand
Abstract
Nowadays, tunnel excavation plays a major role in the development of countries. Due to the complex and challenging ground conditions, a comprehensive study and analysis must be done before, during, and after the excavation of tunnels. Hence, the importance of study and evaluation of ground settlement ...
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Nowadays, tunnel excavation plays a major role in the development of countries. Due to the complex and challenging ground conditions, a comprehensive study and analysis must be done before, during, and after the excavation of tunnels. Hence, the importance of study and evaluation of ground settlement is dramatically increased since many tunnel projects are performed in urban areas, where there are plenty of constructions, buildings, and facilities. For this reason, the control and prediction of ground settlement is one of the complicated topics in the field of risk engineering. Therefore, in this paper, the proportional hazard model (PHM) is used to analyze and study the ground settlement induced by Tabriz Metro Line 2 (TML2) tunneling. The PHM method is a semi-parametric regression method that can enter environmental conditions or factors affecting settlement probability. These influential factors are used as risk factors in the analysis. After establishing a database for a case study and using a proportional hazard model for surface settlement analysis, and then by evaluating the effect of environmental conditions on the ground surface settlement, it has been found that the risk factors of grouting pressure behind the segment, the ratio of tunnel depth to groundwater level, and drained cohesion strength at a significant level of 5% have a direct effect on the probability of settlement. The results also showed that the effect of grout injection pressure on ground subsidence is more than other parameters, and with increasing injection pressure, the probability of exceeding safe subsidence values decreases. In addition, it has been found that increasing the risk factor for the ratio of tunnel depth to groundwater level reduces the probability of exceeding the safe ground settlement. Finally, increasing the number of risk factors for drained cohesion strength increases the probability of exceeding safe settlement.
R. Alizadeh; M. Fatehi Marji; A. Abdollahipour; M. Pourghasemi Sagand
Abstract
In this work, an effective methodology is introduced for modeling the fatigue crack propagation in linear elastic brittle media. The displacement discontinuity method is used to accomplish the analysis, and the boundaries are discretized with quadratic elements in order to predict the stress intensity ...
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In this work, an effective methodology is introduced for modeling the fatigue crack propagation in linear elastic brittle media. The displacement discontinuity method is used to accomplish the analysis, and the boundaries are discretized with quadratic elements in order to predict the stress intensity factors near the crack tips. This procedure is implemented through 2D linear elastic fracture mechanics. The normal and shear displacement discontinuity around the crack tip is applied to compute the mixed-mode stress intensity factors. The crack growth is incremental, and for each increment of extension, there is no need to use a re-meshing procedure. This method has benefits over the finite element method due to its simplicity in meshing. The crack growth direction is assessed using the maximum principal stress theory. In these analyses, a repetition method is used in order to estimate the correct path of crack propagation. Therefore, the different lengths of incremental growth do not affect the crack growth path analysis. The results are exhibited for several examples with different geometries to demonstrate the efficiency of the approach for analyzing the fatigue crack growth. The accuracy represents that this formulation is ideal for describing the fatigue crack growth problems under the mixed-mode conditions.
H. Sarfaraz
Abstract
One of the most conventional toppling instabilities is the block-flexural toppling failure that occurs in civil and mining engineering projects. In this kind of failure, some rock columns are broken due to tensile bending stresses, and the others are overturned due to their weights, and finally, all ...
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One of the most conventional toppling instabilities is the block-flexural toppling failure that occurs in civil and mining engineering projects. In this kind of failure, some rock columns are broken due to tensile bending stresses, and the others are overturned due to their weights, and finally, all of the blocks topple together. A specific feature of spheroidal weathering is the rounding of the rock column edges. In the mode of flexural toppling failure, rounding of edges happens only at the upper corners of the block but in the block toppling failure mode, due to the presence of cross-joints at the base of the block, rounding of edges also occurs at the base of the block. In this work, a theoretical model is offered to block-flexural toppling failure regarding the erosion phenomenon. The suggested methodology is evaluated through a typical example and a case study. The results of this research work illustrate that in the stable slopes with rectangular prismatic blocks, where the safety factor value is close to one, the slope is subjected to failure due to erosion. Also the results obtained show that the recommended approach is conservative in analyzing the block-flexural toppling failure, and this approach can be applied to evaluate this failure.
Saeed Saadat
Abstract
In this work, the results of nearly 1400 stream sediment sample analysis are processed to better understand environmental pollution caused by mining activities in Eastern Iran. The stream sediment samples are analyzed for As, Sb, Fe, Cr, Ni, Co, Cu, Zn, Pb, Sr, and Hg. The mean concentration of these ...
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In this work, the results of nearly 1400 stream sediment sample analysis are processed to better understand environmental pollution caused by mining activities in Eastern Iran. The stream sediment samples are analyzed for As, Sb, Fe, Cr, Ni, Co, Cu, Zn, Pb, Sr, and Hg. The mean concentration of these elements follows the decreasing order of Fe > Sr > Zn > Cr > Cu > Ni > Co > Pb > As > Sb > Hg. Based on the assessment of pollution, extremely severe enrichment factor Co (EF > 25), and high enrichment of Sb, Hg, Cr, and Sr (EF > 10) are detected. Specifically, Cr and Ni in southern stream sediments show significantly elevated concentrations compared to the others. The range of the contamination factor varies from CF < 1 to CF > 6 for most elements. Geo-accumulation index shows high contamination levels by Cr and Co and high to severe contamination by Sb. The risk indices are low for all elements except for As and Co in the eastern part of the studied area. Principal component analysis, Spearman correlation coefficient, and cluster analysis are used to demonstrate similarities and differences between the elements. Pollution indices show that contaminations in some samples are the consequence of gold mineralization. The high correlation of Cu, Zn, and Sb is due to the sulfide mineralization of gold. The high correlation of Cr and Ni corresponds to ultramafic rocks and ophiolitic series. This study focuses on the impact of mining activities, even at early stages on the dispersion of some heavy metals in stream sediments. Based on the results presented here, while most contamination in the target area is rooted in geochemical and mineralization processes, mining activity also contributes to soil pollution for certain elements such as Cu and Zn. The most affected stream sediments are those within the vicinity of mining areas and attention should be paid to potential risks to the environment particularly during gold mining activities.
Rock Mechanics
Sajjad Rezaei; Ramin Rafiee; Mohammad Ataei; Morteza Javadi
Abstract
The stability of waste dumps is a significant and at times critical issue in the development of surface mines. Due to insufficient space for waste disposal, environmental concerns, and various other factors, Mine No. 4 at Golgohar Sirjan is not capable of establishing a new waste dump. Given the existing ...
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The stability of waste dumps is a significant and at times critical issue in the development of surface mines. Due to insufficient space for waste disposal, environmental concerns, and various other factors, Mine No. 4 at Golgohar Sirjan is not capable of establishing a new waste dump. Given the existing limitations of the mine, the investigation has focused on increasing the dump capacity through the implementation of benches. In this research work, the stability of the waste dump has been investigated using the limit equilibrium method with the Slide3D software, along with a Monte Carlo simulation approach for probabilistic analysis. The results obtained from these methods have been compared with each other. The acceptable safety factor considered for this assessment ranges from 1.15 to 1.2. By adding benches to the eastern waste dump of the mine, a displaced volume equivalent to 36,715.565 cubic meters has been added to the capacity. The constructed model is based on the topography of the area, with dimensions of 1850 meters in length, 1750 meters in width, and 160 meters in height. The results indicate that the safety factor of the waste dump has been calculated as follows using the Spencer, Janbu, and Bishop methods respectively: 1.26, 1.199, and 1.226. Mine No. 4 needs to extract 983.58 million tons of waste to produce 73 million tons of iron ore. In total, by discharging 428 million tons of waste in the northeastern and eastern dumps and adding a bench, a volume of 555.571 million tons of waste is available for disposing of the remaining waste. Considering the remaining waste volume, space must be allocated for waste disposal to Mine No. 4.
Exploitation
Hossein Mirzaei Nasir Abad; Mehrnaz Mohtasham; Farshad Rahimzadeh-Nanekaran
Abstract
Transportation of materials is the most cost-intensive component in open-pit mining operations. The aim of the allocation models is to manage and optimize transportation activities, leading to reduced wasted time, and ultimately, increasing profitability while reducing operational costs. Given that the ...
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Transportation of materials is the most cost-intensive component in open-pit mining operations. The aim of the allocation models is to manage and optimize transportation activities, leading to reduced wasted time, and ultimately, increasing profitability while reducing operational costs. Given that the implementation of allocation models is one of the essential requirements in Iranian mining operations, this research work focuses on the transportation system in the Sungun copper mine, one of the largest mines in Iran, and highlights the challenges faced by the fixed allocation approach. The aim is to develop and implement a mathematical model to evaluate its performance, and suggest improvements. The allocation model attempts to optimize truck capacity utilization and maximize mining production. Implementing the model in the mine results in a 13.42% increase in total production compared to the conventional method, with a cost increase of 14.7%. The model shows the potential to meet operational and technical constraints to achieve optimal production. Overall, the developed model, with optimized management and improved fleet efficiency, outperforms the traditional haulage method in the mine.
Exploration
Mojtaba Bazargani Golshan; Mehran Arian; Peyman Afzal; Lili Daneshvar Saein; Mohsen Aleali
Abstract
The purpose of this research is application of the Concentration-Number and Concentration-Area fractal models for determining the distribution pattern of REEs and lithium in mining area of the North Kochakali coal deposit. According to the Concentration-Area and Concentration-Number fractal graphs, four ...
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The purpose of this research is application of the Concentration-Number and Concentration-Area fractal models for determining the distribution pattern of REEs and lithium in mining area of the North Kochakali coal deposit. According to the Concentration-Area and Concentration-Number fractal graphs, four different geochemical groups were obtained for REEs and lithium in the mining area of North Kochakali coal deposit. The comparison of the threshold values and the models obtained based on the Concentration-Area and Concentration-Number fractal models indicate that the Concentration-Area Fractal model has performed better in determining different geochemical groups and separating anomalies from the background for REEs and lithium in North Kochakali coal deposit. Based on the fractal models in the mining area, the southeastern and western parts have the highest concentrations of REEs and the northeastern parts have the highest concentrations of lithium. These parts should be considered in mining operations due to their higher economic value. The locations of the REEs anomalies are consistent with the location of right-lateral faults with a normal component, since these faults are young and have operated after the formation of coal seams, so the mineralization of REEs in North Kochakali coal deposit is epigenetic.
K. Tanguturi; R. Balusu
Abstract
Fundamental understanding of the goaf gas distribution in a gassy coal mine is necessary for developing effective goaf gas drainage strategies in the longwall coal mine. The goaf gas was subjected to the surface and body forces that were classified depending upon whether they acted on the surface area ...
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Fundamental understanding of the goaf gas distribution in a gassy coal mine is necessary for developing effective goaf gas drainage strategies in the longwall coal mine. The goaf gas was subjected to the surface and body forces that were classified depending upon whether they acted on the surface area or the volume of the gas element. Of these forces, the body forces were more predominant in displacing the goaf gas present in the underground mine. The buoyancy forces were classified as the body forces; they are the predominant forces acting on the goaf gas. The buoyancy forces depend mainly upon the density variation in the gas species and the panel orientation or panel geometry. If the temperature variations are neglected, the buoyancy forces that cause the displacement of the goaf gas depend mainly upon the panel orientation. In this work, numerical investigations were carried out using the computational fluid dynamics (CFD) techniques for the fundamental understanding of the goaf gas displacement for various panel orientations. The numerical results obtained for various panel orientations indicated that the goaf gas is displaced towards the tailgate (TG) side when the maingate (MG) was downdip, towards the MG side when MG was updip, towards the start-up of the panel when the face was downdip, and towards the face when the face was updip.
Mineral Processing
S. Nazari; Seyed Ziaedin Shafaei; M. Gharabaghi; R. Ahmadi; B. Shahbazi
Abstract
In this work, the effects of the types of frother (MIBC, pine oil, and A65) and operational parameters (impeller speed and air flow rate) on the flotation of quartz coarse particles was investigated using nano bubbles (NBs). Quartz particles of the size of -425+106 mm and three types of frother were ...
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In this work, the effects of the types of frother (MIBC, pine oil, and A65) and operational parameters (impeller speed and air flow rate) on the flotation of quartz coarse particles was investigated using nano bubbles (NBs). Quartz particles of the size of -425+106 mm and three types of frother were used for the flotation experiments. Also the impeller speed was 600 to 1300 rpm, and the air flow rates were 30 and 60 L/h. In the absence of NBs, the maximum recovery was achieved with the pine oil frother, an impeller speed of 1000 rpm, and an air flow rate of 60 L/h. In the presence of NBs, the maximum recovery was achieved using pine oil at an impeller speed of 900 rpm and an air flow rate of 30 L/h. However, increasing the recovery in the presence of NBs, compared to the absence of NBs for MIBC, was more than the other two frothers, and the recovery using this frother to increase up to 25% but using pine oil, the recovery increased up to 23%. The lowest recovery in the presence of NBs was obtained using A65. Also the use of NBs increased recovery in all the three fractions compared to the absence of NBs but the presence of NBs increased the recovery of particles with size of -212+106 mm more than the particle size in the ranges of -300+212 and -425+300 mm.
Exploitation
Behnam Alipenhani; Mehran Jalilian; Abbas Majdi; Hassan Bakhshandeh Amnieh; Mohammad Hossein Khosravi
Abstract
The paper presents the effect of the dip of joints, joint spacing, and the undercutting method on the height of the caving in block caving. The obtained results show that among the three investigated parameters, respectively, the dip of joints, undercutting method, and joint spacing have the greatest ...
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The paper presents the effect of the dip of joints, joint spacing, and the undercutting method on the height of the caving in block caving. The obtained results show that among the three investigated parameters, respectively, the dip of joints, undercutting method, and joint spacing have the greatest effect on increasing the height of the caving zone. Comparing the data obtained from physical and numerical modeling shows a 97% match. Also, by increasing the joint spacing from 4 to 6 cm, 14%, from 6 to 8 cm, about 35%, and from 8 to 10, about 50%, the height of the caving zone has decreased. Regarding the dip of the joint, with the dip increasing from 30 to 45 degrees, about 3% of the caving height decreases. By increasing the dip of the joint from 45 to 60 degrees, the caving height has decreased by 42%. By increasing this value from 60 to 75 degrees, the caving height has increased by 50%. Also, changing the undercutting method from symmetric to advanced undercutting has increased the caving height by 40%. Additionally, three mathematical models have been proposed based on the shape of the caving zone in physical modeling.
Exploration
Shirin Jahanmirir; Ali Aalianvari; Hossein Ebrahimpour-Komleh
Abstract
This paper introduces the Human Mental Search (HMS) algorithm as a novel and superior optimization technique for predicting groundwater seepage in tunnel environments. Traditional methods for predicting such seepage often struggle with the complexities of subterranean water flow, particularly in heterogeneous ...
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This paper introduces the Human Mental Search (HMS) algorithm as a novel and superior optimization technique for predicting groundwater seepage in tunnel environments. Traditional methods for predicting such seepage often struggle with the complexities of subterranean water flow, particularly in heterogeneous geological conditions, and while machine learning approaches have offered improvements, they often require significant computational resources. The HMS algorithm, inspired by human cognitive processes, employs memory recall, adaptive clustering, and strategic selection to efficiently refine solutions. Our results demonstrate that HMS significantly outperforms established algorithms in predicting groundwater seepage, achieving an R² value of 0.9988, a Mean Squared Error (MSE) of 0.0002, and a Root Mean Squared Error (RMSE) of 0.0137. In comparison, the Whale Optimization Algorithm (WOA) achieved an R² of 0.9951 with much higher MSE and RMSE, and other methods, like Genetic Programming and ANN-PSO, show higher error values. The HMS algorithm also showed a Variance Accounted for (VAF) of 99.88% and a Mean Absolute Error (MAE) of 0.0041, further validating its high predictive accuracy. This study highlights the HMS algorithm’s superior performance and computational efficiency for optimizing groundwater seepage predictions, positioning it as a powerful tool for geotechnical engineering applications, including real-time monitoring.
A. Ghasemloonia; S. D. Butt
Abstract
Underground caverns in rock salt deposits are the most secure disposal method and a type of gas-storing facility. Gas storage plays a vital role in ensuring that a strategic relationship is secured between an established energy infrastructure provider and a midstream energy company. The Fischells Brook ...
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Underground caverns in rock salt deposits are the most secure disposal method and a type of gas-storing facility. Gas storage plays a vital role in ensuring that a strategic relationship is secured between an established energy infrastructure provider and a midstream energy company. The Fischells Brook area is a pillow-shaped body of salts located in the St. George's Bay area of southwest Newfoundland, which has three layers of salt beds, and is capable of excavating caverns for the storage purposes. The development of cavern facilities requires the stability analysis through numerical models and experimental facilities. This work was motivated to examine the engineering feasibility of the salt cavern characteristics in this area, and to investigate its stability under creep behavior. An experimental test facility was developed to investigate the constitutive parameters governing the creep of rock salt, and the constitutive parameters were implemented into a developed finite element model to investigate the stability of the cavern over a 5-year period. Also a stress-based dilatancy failure envelope was developed to interpret the results of the numerical model, and to conduct sensitivity analyses for different design scenarios. The design recommendations developed in this study will be implemented as a key part of an engineering feasibility study for underground caverns in salt deposits in western Newfoundland.
Exploration
Sepideh Ghasemi; Ali Imamalipur; Samaneh Barak
Abstract
This investigation centers on the Qarah Tappeh copper deposit, situated in the northern region of West Azerbaijan province, approximately 15 kilometers northeast of Maku city. The primary objective of the study is to comprehensively examine the study area through the analysis of 253 lithogeochemical ...
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This investigation centers on the Qarah Tappeh copper deposit, situated in the northern region of West Azerbaijan province, approximately 15 kilometers northeast of Maku city. The primary objective of the study is to comprehensively examine the study area through the analysis of 253 lithogeochemical samples, and assessing reserves utilizing ordinary kriging, guided by subsurface data obtained from 14 boreholes totaling 909.2 meters. The concentration–volume (C–V) multifractal modeling approach was employed to estimate the deposit's reserve. The findings of this research project indicate an estimated 988,604 tons of the deposit with an average grade of 0.14%. Through the analysis of log–log plots within the C–V relationship, threshold values signifying various copper (Cu) concentrations were identified. These plots revealed a pronounced power-law correlation between Cu concentrations and their corresponding volumes, with arrows denoting four specific threshold values. Utilizing this analytical methodology, mineralized zones were classified into five distinct categories: high (>0.42%), above-average (0.35-0.42%), average (0.27-0.35%), below-average (0.14-0.27%), and low (<0.14%) mineralized zones.
Exploration
Shaghayegh Esmaeilzadeh; Ali Moradzadeh; omid Asghari; Reza Mohebian
Abstract
Seismic inversion is a critical technique for estimating the spatial distribution of petro-elastic properties in the subsurface, based on the seismic reflection data. This work introduces an iterative geostatistical seismic inversion method, designed to address challenges in complex geological settings ...
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Seismic inversion is a critical technique for estimating the spatial distribution of petro-elastic properties in the subsurface, based on the seismic reflection data. This work introduces an iterative geostatistical seismic inversion method, designed to address challenges in complex geological settings by incorporating self-updating local variogram models. Unlike the conventional approaches that rely on a single global variogram or fixed local variograms, the proposed method dynamically updates the spatial continuity models at each iteration using automatic variogram modeling and clustering of variogram parameters. The optimal number of clusters is determined using three cluster validity indices: Silhouette Index (SI), Davies-Bouldin Index (DB), and Calinski-Harabasz Index (CH). The method’s effectiveness was evaluated using a three-dimensional non-stationary synthetic dataset, demonstrating robust convergence when employing the SI and CH indices, with both achieving a high global correlation coefficient of 0.9 between the predicted and true seismic data. Among these, the CH index provided the best balance between the computational efficiency and inversion accuracy. The results highlight the method’s ability to effectively capture local spatial variability, while maintaining a reasonable computational cost, making it a promising approach for seismic inversion in complex sub-surface environments.
Exploration
Hossein Mahdiyanfar; Mirmahdi Seyedrahimi-Niaraq
Abstract
In this investigation, the hybrid approach of wavelet transforms and fractal method named Wavelet-Fractal model has been utilized for geochemical contamination mapping as a novel application. For this purpose, the distribution maps of pollutant elements were transformed to the position-scale domain using ...
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In this investigation, the hybrid approach of wavelet transforms and fractal method named Wavelet-Fractal model has been utilized for geochemical contamination mapping as a novel application. For this purpose, the distribution maps of pollutant elements were transformed to the position-scale domain using two-dimensional discrete wavelet transformation (2DDWT). The Symlet2 and Haar mother wavelets were applied for two-dimensional signal analysis of elemental concentrations of As, Pb, and Zn based on soil samples taken from the Irankuh mining district, Central Iran. The Symlet2 and Haar wavelet coefficients of approximate and detail components were obtained at one level frequency decomposition using 2DDWT. The wavelet coefficients of approximate component (WCAC) were modeled using a fractal method for delineating the geochemical contamination populations of toxic elements. Based on the results of wavelet-fractal models, the As, pb, and Zn were classified into three and four populations. Two areas contaminated with metals have been found in the district. These areas are within the limit of mining operations and its surroundings. The wavelet-fractal proposed model has been able to separate environmental areas contaminated with toxic metals accurately. Anomalously intense pollution has spread to one kilometer outside the mining operation limit. This dispersion in the case of Pb and Zn elements is well seen in the geochemical map prepared with the Haar class.
Exploitation
Alireza Afradi; Arash Ebrahimabadi
Abstract
Rock-fragmentation is generally regarded as a crucial indicator within the mining industry for evaluating the effects of blasting operations. In this work, a database was primarily constructed using field data to predict rock fragmentation in the mines of Anguran and Sarcheshmeh. The datasets comprised ...
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Rock-fragmentation is generally regarded as a crucial indicator within the mining industry for evaluating the effects of blasting operations. In this work, a database was primarily constructed using field data to predict rock fragmentation in the mines of Anguran and Sarcheshmeh. The datasets comprised the input parameters such as Burden (m), spacing (m), powder factor (kg/m³), and stemming (m), with fragmentation (cm) as the output parameter. The analysis of these datasets was conducted using the Ant Lion Optimizer (ALO) and Crow Search Algorithm (CSA) methodologies. To assess the predictive models' accuracy, metrics including the coefficient of determination (R²), Variance Accounted For (VAF), and Root Mean Square Error (RMSE) were employed. The application of ALO and CSA to the database yielded results indicating that for ALO, R² = 0.99, RMSE = 0.005, and VAF (%) = 99.38, while for CSA, R² = 0.98, RMSE = 0.02, and VAF (%) = 98.11. Ultimately, the findings suggest that the predictive models yield satisfactory results, with ALO demonstrating a greater level of precision.
H. Shahi; R. Ghavami Riabi; A. Kamkar Ruhani; H. Asadi Haroni
Abstract
In this research work, the frequency domain (FD) of surface geochemical data was analyzed to decompose the complex geochemical patterns related to different depths of the mineral deposit. In order to predict the variation in mineralization in the depth and identify the deep geochemical anomalies and ...
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In this research work, the frequency domain (FD) of surface geochemical data was analyzed to decompose the complex geochemical patterns related to different depths of the mineral deposit. In order to predict the variation in mineralization in the depth and identify the deep geochemical anomalies and blind mineralization using the surface geochemical data for the Dalli Cu-Au porphyry deposit, a newly developed approach was proposed based on the coupling Fourier transform and principal component analysis. The surface geochemical data was transferred to FD using Fourier transformation and high and low pass filters were performed on FD. Then the principal component analysis method was employed on these frequency bands separately. This new combined approach demonstrated desirably the relationship between the high and low frequencies in the surface geochemical distribution map and the deposit depth. This new combined approach is a valuable data-processing tool and pattern-recognition technique to identify the promising anomalies, and to determine the mineralization trends in the depth without drilling. The information obtained from the exploration drillings such as boreholes confirms the results obtained from this method. The new exploratory information obtained from FD of the surface geochemical distribution map was not achieved in the spatial domain. This approach is quite inexpensive compared to the traditional exploration methods.
Mineral Processing
Ahmad Abbasi Gharaei; Bahram Rezai; Hadi Hamidian Shormasti
Abstract
This paper examines the performance of Atmospheric Leaching (AL) and High-Pressure Acid Leaching (HPAL) on nickel laterite, classified as limonite. The study, conducted on a laboratory scale, involved temperatures of 35-95°C for AL and 220-250°C for HPAL. Nickel and cobalt contents were found ...
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This paper examines the performance of Atmospheric Leaching (AL) and High-Pressure Acid Leaching (HPAL) on nickel laterite, classified as limonite. The study, conducted on a laboratory scale, involved temperatures of 35-95°C for AL and 220-250°C for HPAL. Nickel and cobalt contents were found to be 0.7% and 0.04%, respectively. AL achieved an 89% yield of Al with a pH of 0.2 and a 14-hour leaching time, while nickel and iron recoveries reached 92% and 87% after 20 hours, with an acid consumption of 1.2 kg H2SO4 per 100 kg laterite (dry) at pH 0.2. Leaching experiments at 220-250°C for 2 hours showed similar nickel recovery rates, indicating no improvement beyond 240°C. Hematite, a stable compound associated with nickel, hindered its release during HPAL due to its resistance to leaching. Nickel yields remained around 90% in both AL and HPAL tests. Iron behavior differed significantly between the two methods, with HPAL dissolving iron initially but transforming it into hematite in situ, leading to lower net acid consumption compared to AL. The leaching mechanism for iron oxides followed empirical power law kinetics of order 1.5 with activation energies of 36.23 and 25.09 kJ/mol for Ni and Fe, respectively.
Exploitation
Mojtaba Dehghani Javazm; Mohammadreza Shayestehfar
Abstract
In this work, various methods for evaluating recoverable reserves including estimation techniques and conditional simulation have been compared in the Miduk copper deposit using data from 55,119 blast holes and 6,178 composite samples from exploratory drillings in the supergene and hypogene zones, with ...
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In this work, various methods for evaluating recoverable reserves including estimation techniques and conditional simulation have been compared in the Miduk copper deposit using data from 55,119 blast holes and 6,178 composite samples from exploratory drillings in the supergene and hypogene zones, with a block model constructed for the analysis. Four methods were employed: UC, LUC, DCSBG, and SGS. The correlation coefficients for UC, DCSBG, and SGS methods in the supergene zone, as well as the results from extraction drill holes (extraction blocks) at a cut-off grade of 0.15%, were 0.637, 0.527, and 0.556, and the correlation coefficient for calculating tonnage and the metal content using UC was 0.364 and 0.629, respectively. For the hypogene zone, the correlation coefficients for metal content at a cut-off grade of 0.15% were 0.778, 0.788, and 0.790 for UC, DCSBG, and SGS, and at a cut-off grade of 0.65%, they were 0.328, 0.431, and 0.458, respectively. By employing The LUC method in the supergene zone with a change in SMU and comparing the results obtained from the E-Type map, the performance of this method is higher across all cut-off grades. As the cut-off grade increases in the hypogene zone, the performance of the LUC method relative to simulation methods decreases. The LUC method can be used to observe the impact of the convergence of results obtained from this method with real data from low-grade to high-grade sections, highlighting the necessity of differentiating this zone into low and high-grade segments during the estimation process.
Rock Mechanics
Faezeh Barri; Hamid Chakeri; Mohammad Darbor; Hamed Haghkish
Abstract
Excavation with Tunnel Boring Machine (TBM) in urban environments can have risks, such as ground surface settlement. The empty space between the cutterhead and the segment should be filled with suitable grout during the excavation. Nowadays, using grout behind the segment and other fillers fill the empty ...
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Excavation with Tunnel Boring Machine (TBM) in urban environments can have risks, such as ground surface settlement. The empty space between the cutterhead and the segment should be filled with suitable grout during the excavation. Nowadays, using grout behind the segment and other fillers fill the empty space behind the segment and reduce the amount of ground surface settlement. Undoubtedly, using a grout with appropriate mechanical behavior can be a suitable substitute for excavated soil in mechanized tunneling. In this research, the mechanical behavior of the grout behind the segment during injection into the space between the soil and the segment and its mixture with the soil is studied. Also, the effect of mechanical properties of grout mixed with soil on the ground surface settlement is investigated using numerical modeling. The components of two-component grout of this study comprises Sufian type 2 cement with 28-day strength of 44 MPa and density of 3050 kg/m3, Salafchegan bentonite with density of 2132 kg/m3 and precipitator of liquid sodium silicate with density of the solution 1500 kg/m3. The results of the laboratory studies indicated that mixing the grout and soil increases the mechanical properties of grout significantly. Increasing the soil in the mixture of soil and grout up to 40% increases the uniaxial compressive strength up to 300%, the elasticity of modulus up to 156% and the cohesion of the mixture up to 100%. On the other hand, based on the results of numerical modeling, the proper injection pressure can significantly reduce the ground surface settlement. Increasing the injection pressure from 0 to 120 kPa has a 17% influence on the reduction of ground surface settlement.
Mineral Processing
Fatemeh Kazemi; Ali akbar Abdollahzadeh
Abstract
This research work aims to explore the intricate mineralogy and texture of the tailing piles of iron ore processing plants to present a particle-based prediction for magnetite recovery. Three samples were taken from different points of tailings piles of an iron ore processing plant. Davis tube tests ...
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This research work aims to explore the intricate mineralogy and texture of the tailing piles of iron ore processing plants to present a particle-based prediction for magnetite recovery. Three samples were taken from different points of tailings piles of an iron ore processing plant. Davis tube tests were performed on each sample under various operating conditions. Process mineralogy studies were conducted to determine the mineralogy modal of the feed and product of each test. An Artificial Neural Network (ANN) model was used to make a model that related the grade and recovery of magnetite in the product to the mineralogy modal of the tailing piles. The magnetite grade and association index of feed, the magnetic intensity, and the water flow rate were the inputs to this network. The grade and magnetite recovery correlation coefficients were 0.954 and 0.86, respectively. The grade of magnetite in the feed emerged as a limiting factor on the grade and recovery of magnetite in concentrate. An increase of one unit in magnetite grade in the feed resulted in a 1.68 decrease in the recovery. The association index changes with the coefficients of -0.173 cause the changes in predicted magnetite recovery in the concentrate.
Exploitation
Hamid Saberi; Mohammad Golmohammadi; Mohammadali Zanjani; Yaghoub Saberi
Abstract
The Bavanapadu-Nuvvalarevu coastal sector in Andhra Pradesh, India, hosts substantial subsurface heavy mineral (HM) resources, presenting significant economic potential. This study employs ArcGIS raster techniques to estimate Total Heavy Mineral (THM) and Total Economic Heavy Mineral (TEHM) resources ...
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The Bavanapadu-Nuvvalarevu coastal sector in Andhra Pradesh, India, hosts substantial subsurface heavy mineral (HM) resources, presenting significant economic potential. This study employs ArcGIS raster techniques to estimate Total Heavy Mineral (THM) and Total Economic Heavy Mineral (TEHM) resources in a 39 square kilometers area, integrating geospatial analysis with field data from core sediment samples. The findings reveal a total of 2.681953 million tons of THM, including 2.434422 million tons of TEHM, with the highest concentration observed in the top 1-meter sea bed sediment layer (1.605286 million tons). Ilmenite, garnet, and sillimanite dominate the mineral assemblage, accompanied by smaller quantities of zircon, monazite, and rutile, offering an estimated revenue potential of $634 to $851 million USD. The application of ArcGIS methodologies, particularly inverse distance weighting (IDW) interpolation, enabled precise mapping of HM distribution, despite challenges such as wide sample spacing and shallow core penetration. While the study highlights the economic and industrial significance of the Bavanapadu sector, it also underscores environmental concerns, including habitat disruption and sediment degradation, associated with mining. Sustainable practices, such as advanced separation technologies, site rehabilitation, and comprehensive environmental impact assessments (EIAs), are essential to mitigate ecological impacts. This research demonstrates the efficacy of GIS-based techniques in resource estimation and sustainable mining, offering a replicable framework for coastal and offshore mineral resource management globally. The findings provide critical insights into balancing economic growth with environmental preservation, setting a benchmark for responsible heavy mineral extraction in dynamic coastal environments.
Rock Mechanics
Mahdi Bajolvand; Ahmad Ramezanzadeh; Amin Hekmatnejad; Mohammad Mehrad; Shadfar Davoodi; Mohammad Teimuri; Mohammad Reza Hajsaeedi; Mahya Safari
Abstract
Bit wear is one of the fundamental challenges affecting the performance and cost of drilling operations in oil, gas, and geothermal wells. Since identifying the factors influencing bit wear rate (BWR) is essential, and the ability to predict its variations during drilling operations is influenced by ...
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Bit wear is one of the fundamental challenges affecting the performance and cost of drilling operations in oil, gas, and geothermal wells. Since identifying the factors influencing bit wear rate (BWR) is essential, and the ability to predict its variations during drilling operations is influenced by environmental and operational factors, this study aims to develop an Adaptive Bit Wear Rate Predictor (ABWRP) algorithm for estimating the BWR during drilling operations for new wells. The structure of this algorithm consists of a data transmitter, data processor, deep learning-based bit wear rate estimator, and a bit wear updating module. To develop a model for the BWR estimation module, data from two wells in an oil field in southwest Iran were collected and analyzed, including petrophysical data, drilling data, and bit wear and run records. Both studied wells were drilled using PDC bits with a diameter of 8.5 inches. After preprocessing the data, the key factors affecting the bit wear rate were identified using the Wrapper method, including depth, confined compressive strength, maximum horizontal stress, bit wear percentage, weight on bit, bit rotational speed, and pump flow rate. Subsequently, seven machine learning (ML) and deep learning (DL) algorithms were used to develop the bit wear rate estimation module within the ABWRP algorithm. Among them, the convolutional neural network (CNN) model demonstrated the best performance, with Root Mean Square Error (RMSE) values of 0.0011 and 0.0017 and R-square (R²) values of 0.96 and 0.92 for the training and testing datasets, respectively. Therefore, the CNN model was selected as the most efficient model among the evaluated models. Finally, a simulation-based experiment was designed to evaluate the performance of the ABWRP algorithm. In this experiment, unseen data from one of the studied wells were used as data from a newly drilled well. The results demonstrated that the ABWRP algorithm could estimate final bit wear with a 14% error. Thus, the algorithm developed in this study can play a significant role in the design and planning of new wells, particularly in optimizing drilling parameters while considering bit wear effects.
