Ali Dadkhah Tehrani; Reza Shirinabadi
Abstract
The soil's physical and mechanical properties are obtained through laboratory or in-situ tests. The dilatometer is an in-situ tool in rock mechanics and geotechnical engineering, and is widely used in developed countries. In the advanced version of this device, a geophone receives ground vibration. Thus ...
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The soil's physical and mechanical properties are obtained through laboratory or in-situ tests. The dilatometer is an in-situ tool in rock mechanics and geotechnical engineering, and is widely used in developed countries. In the advanced version of this device, a geophone receives ground vibration. Thus Vs [1] could be obtained at the depth of the blade. This research work investigates the feasibility and performance of the first electronic seismic sensor due to its lower cost, more life span, more sensitivity instead of the geophone, and the ability to transfer signal. These changes make it an online tool connected to Arduino[2], a platform so the digital or analog result could be transferred automatically. The test is carried out under construction of Bahar Shiraz station of Tehran Metro Line 6 at the depth of 30 m. The hammer generates a shear wave, and after amplification, the received signals are measured with the software. The shear wave velocity at the test site is obtained at 504 m/s. The result compared to Vs reported geotechnical investigation done by “Darya-Khak-Pey consulting engineers” for Metro line 6 shows a 10% deviation. It is suggested to conduct more comparative tests to check the results and calibrate. Using an 801-S sensor with more life span (of more than 60 million times) and the ability to connect to the internet with an Arduino board is the innovation applied to introduce a new generation of this tool in the engineering world.
Exploration
Abdallah Atef; Ahmed A. Madani; Adel A. Surour; Mokhles K. Azer
Abstract
This study reports the application of remote sensing data and knowledge-driven GIS modeling to provide favorability maps for gold and copper mineralized areas. The South Gabal Um Monqul (SGUM) and the Gabal Al Kharaza (GKZ) prospects located in the northern Eastern Desert of Egypt are the targets for ...
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This study reports the application of remote sensing data and knowledge-driven GIS modeling to provide favorability maps for gold and copper mineralized areas. The South Gabal Um Monqul (SGUM) and the Gabal Al Kharaza (GKZ) prospects located in the northern Eastern Desert of Egypt are the targets for the present study. Four thematic layers (lithology maps, old trenches buffer analysis, lineament density maps, and alteration zone maps) were prepared and used as inputs for a weighted overlay GIS model. Combined results from false color composite images, particularly the RGB parameters (PC2, PC1, and PC3) and the RGB parameters (MNF1, MNF2, and MNF3) classified the host rocks in both prospects. PCA-based extraction of lineaments was considered using line algorithm of PCI Geomatica. QuickBird band math (G+B), (R+G), and (G-B) for RGB was successful in delineating ancient workings within the mineralized zones. Old trenches layers were buffered to 20 m wide bands extending in all directions. Landsat-8 band ratios imagery (6/5 * 4/5, 6/7, and 6/2) in red, green, and blue (RGB) is potent in defining alteration zones that host gold and copper mineralizations. Acceptable scores of 30%, 30%, 20%, and 20% were assigned for the alteration zone maps, ancient workings buffer analysis, lithology maps and lineament density maps, respectively. Two favorability maps for mineralizations were generated for the SGUM and GKZ prospects. Validation of these maps and their potential application to detect new mineralization sites in the northern Eastern Desert were discussed.
Environment
Zakirah Raihani Ya’la; Triyani Dewi; Ali Husni; Tri Joko Santoso; Samliok Ndobe; Eka Rosyida; Maemunah Maemunah; Marhawati Mappatoba; Muhammad Saleh Nurdin
Abstract
This study was conducted to determine heavy metal concentrations in sediments, assess the level of contamination using a contamination index, and identify potential sources of heavy metal contamination using multivariate analysis. This study employed contamination indices to evaluate sediment pollution ...
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This study was conducted to determine heavy metal concentrations in sediments, assess the level of contamination using a contamination index, and identify potential sources of heavy metal contamination using multivariate analysis. This study employed contamination indices to evaluate sediment pollution levels. Heavy metal concentrations were analyzed statistically by determining the minimum, maximum, mean, and standard deviation (SD) values. According to the contamination factor (Cf), Cd showed very high contamination levels, whereas Sn, Ni, and Pb indicated moderate contamination. Hg, As, Cr, and Cu were classified as having low levels of contamination. The degree of contamination (Cdeg) ranged from low to high across the sampled sites, reflecting the varied levels of pollution severity. Multivariate statistical analyses, including Principal Component Analysis (PCA), Pearson correlation matrix, and Cluster Analysis (CA), were used to identify potential sources of heavy metal contamination. Cu, Sn, Ni, Hg, and Cr are attributed to natural geological processes, whereas Pb, Cd, and As are linked to anthropogenic activities, likely originating from the nickel mining industry. In conclusion, this study underscores the complex environmental impact of nickel mining in Morowali, highlighting the need for stringent environmental management practices to mitigate further degradation and safeguard the coastal ecosystems in Central Sulawesi.
Exploitation
Meisam Saleki; Reza Khaloo Kakaie; Mohammad Ataei; Ali Nouri Qarahasanlou
Abstract
One of the most critical designs in open-pit mining is the ultimate pit limit (UPL). The UPL is frequently computed initially through profit-maximizing algorithms like the Lerchs-Grossman (LG). Then, in order to optimize net present value (NPV), production planning is executed for the blocks that ...
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One of the most critical designs in open-pit mining is the ultimate pit limit (UPL). The UPL is frequently computed initially through profit-maximizing algorithms like the Lerchs-Grossman (LG). Then, in order to optimize net present value (NPV), production planning is executed for the blocks that fall within the designated pit limit. This paper presents a mathematical model of the UPL with NPV maximization, enabling simultaneous determination of the UPL and long-term production planning. Model behavior is nonlinear. Thus, in order to achieve model linearization, the model has been partitioned into two linear sub-problems. The procedure facilitates the model solution and the strategy by decreasing the number of decision variables. Naturally, the model is NP-Hard. As a result, in order to address the issue, the Dynamic Pit Tracker (DPT) heuristic algorithm was devised, accepting economic block models as input. A comparison is made between the economic values and positional weights of blocks throughout the steps in order to identify the most appropriate block. The outcomes of the mathematical model, LG, and Latorre-Golosinski (LAGO) algorithms were assessed in relation to the DPT on a two-dimensional block model. Comparative analysis revealed that the UPLs generated by these algorithms are consistent in this instance. Utilizing the new algorithm to determine UPL for a 3D block model revealed that the final pit profit matched LG UPL by 97.95%.
Exploration
reza Shahnavehsi; Farnusch Hajizadeh
Abstract
The present work is mainly about a method for illustrating the relation between the raw data in the same time; clustering is a key procedure to solve the problem of data division; also illustrating the connection among the elements of the research area simultaneously is important. Therefore, we propose ...
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The present work is mainly about a method for illustrating the relation between the raw data in the same time; clustering is a key procedure to solve the problem of data division; also illustrating the connection among the elements of the research area simultaneously is important. Therefore, we propose a novel kind of clustering for data mining in the gravity field to reach the presenting connection among all elements in the same time. For this research work, 867 gravity surveying points were collected in the southern part of Iran (near diapir of Larestan) with a range of absolute gravity from 978579.672 to 978981.186. In this paper, clustering by self-organizing- maps, by utilizing scatter plot matrix is utilized for detecting the relation between the easting, northing, elevation, and absolute gravity simultaneously. In the proposed method, the relations between arrays, two by two, are defined, and like matrix, each raw and column has different i and j values, which represent elements of the studied area, instead of number; for example, array A23 is data division between i = 2 or raw two (in our case northing) and j = 3 or column, three (in our case elevation). In this algorithm, firstly, by using self-organizing maps, clustering is done, and this processing is generated to all arrays by scatter plot matrix, and in all arrays, three clusters are proposed; the result of this clustering shows that in arrays A12, A13, A14, A21, A23, A24, A31, A32, A41, A42, clustering is performed perfectly, and the relationship between the parameters of the studied area near Larestan salt, diaper, can be useful in notifying the properties of this salt diapir.
Ali Entezari; Mohammad Karamoozian; M Eskandari Nasab
Abstract
The possibility of selective leaching process was investigated during molybdenite flue dust leaching to recover its rhenium content. The results show that addition of alcohols to water makes the medium less favorable for molybdenum transfer into aqueous phase. On the other hand, addition of small amounts ...
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The possibility of selective leaching process was investigated during molybdenite flue dust leaching to recover its rhenium content. The results show that addition of alcohols to water makes the medium less favorable for molybdenum transfer into aqueous phase. On the other hand, addition of small amounts of alcohols (5-15%) makes a noticeable separation of rhenium over molybdenum, but by increasing the alcohol content recovery of both metals decreases. More than 90% of Re transferred into leach solution but the corresponding amount for Mo was only about 0.5%.
K. Barani; H. Esmaili
Abstract
In this work, the waste stone sludge obtained from the granite and marble stone processing factories was used for the manufacture of artificial stones using vibratory compaction in a vacuum environment. The results obtained showed that water absorption and density increased, and the flexure, ...
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In this work, the waste stone sludge obtained from the granite and marble stone processing factories was used for the manufacture of artificial stones using vibratory compaction in a vacuum environment. The results obtained showed that water absorption and density increased, and the flexure, compressive, and tensile strengths decreased with increase in the content of the waste stone sludge. These results also demonstrated that by combining 50% of stone sludge, 12% of ground quartz, 25% of waste glass, and 13% of resin at a compaction pressure of 12 MPa, a vibration frequency of 30 Hz, and vacuum conditions at 50 mm Hg, artificial stone slabs with a water absorption less than 0.64, a density less than 2.68, a flexure strength more than 45 MPa, a compressive strength more than 90 MPa, and a tensile strength more than 35 MPa can be obtained. The artificial stone slabs obtained in this research work had good density and water absorption, and flexure, compressive, and tensile strengths compared to the natural stones, and thus they can be regarded as the ideal construction materials for covering walls or paving floors.
Rock Mechanics
M. Rezaei
Abstract
Estimation of the height of caved and fractured zones above a longwall panel along with the stability conditions of the goaf area are very crucial to determine the abutment stresses, ground subsidence, and face support as well as designing the surrounding gates and intervening pillars. In this work, ...
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Estimation of the height of caved and fractured zones above a longwall panel along with the stability conditions of the goaf area are very crucial to determine the abutment stresses, ground subsidence, and face support as well as designing the surrounding gates and intervening pillars. In this work, the height of caving-fracturing zone above the mined panel is considered as the height of destressed zone (HDZ). The long-term estimation of this height plays a key role in the accurate determination of maximum ground surface subsidence and the amount of transferred loads towards the neighbouring solid sections. This paper presents a new stability analysis model of caved material system in the goaf area. For this aim, a theoretical energy-based model of HDZ determination in long-term condition is developed. Then the stability condition of the caved material system is investigated using the principle of minimum potential energy. On the basis of the actual data gathered from the literature, the unstable time period of the caved material system is also calculated. Moreover, the effects of time- and temperature-related parameters and constant coefficients as well as their inherent relations with HDZ are evaluated. Furthermore, sensitivity analysis shows that the two temperature-related constants material constant and time are the most effective variables in HDZ, and the slope of material hardening is the least effective one. The estimated HDZ and the stability time of the caved materials can be successfully applied to determine the induced stress and the maximum surface subsidence, respectively, due to longwall mining.
A. Rezaei; H. Hassani; P. Moarefvand; A. Golmohammadi
Abstract
Ground Penetrating Radar (GPR) is an effective and practical geophysical imaging tool, with a wide set of applications in geological mapping of subsurface information. This research study aims at determination of the geophysical parameter differences in the subsurface geological structures and construction ...
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Ground Penetrating Radar (GPR) is an effective and practical geophysical imaging tool, with a wide set of applications in geological mapping of subsurface information. This research study aims at determination of the geophysical parameter differences in the subsurface geological structures and construction of a 3D fracture model. GPR and resistivity methods were applied to detect the unstable tectonic zones in the C-North deposit. Structural geology investigations were, first, surveyed to detect the faults and fractures in the study area. Based on the structural features, the survey was conducted over an area of 1 km2 with a total of 30 profiles and low-resistivity zones in the C-North deposit which is a great help in reducing their impacts in slope stability studies. GPR sections were, then, obtained from low and high frequency antennas (10 and 50 MHz) to detect fractures and water content zones. The obtained data results demonstrated that the major structural trends in the study area were W–E, NE–SW, and NW–SE while fault zones that can create pathways for groundwater inflow into the deposit in the future. Information obtained from geological and GPR studies were also integrated with drill hole data. The geological information from structures are in good agreement with the actual geological situation. Method and results of this study could be useful in solving problems related to subsurface structures in mining engineering.
N. R. Ahmadi; P. Afzal; A. B. Yasrebi
Abstract
This work aims to classify the gas content zones for coking coal deposits using a Number-Size (N-S) fractal modeling considering the explosive and free gas data. The case study is the C1 coking coal seam in the Parvadeh-4 coal deposit in the central Iran. Following this, the N-S log-log plots are created, ...
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This work aims to classify the gas content zones for coking coal deposits using a Number-Size (N-S) fractal modeling considering the explosive and free gas data. The case study is the C1 coking coal seam in the Parvadeh-4 coal deposit in the central Iran. Following this, the N-S log-log plots are created, which indicate three populations regarding both the explosive and gas data exist. Proper zones for both data in the C1 coking coal seam have explosive and free gas contents lower than 9.5 m3/ton and 1.3 m3/ton, respectively. The low-value gas content zone is located in the western part of the studied area, which is in the lowest depth of this coal seam. In addition, a high-value content zone exists in the E, NE, and SW parts of this area with explosive and free gas contents higher than 13.8 m3/ton and 2.2 m3/ton, respectively. These parts of the C1 seam are dangerous due to a high volume of gas content. Moreover, the explosive and free gas contents have a positive correlation with high risk gas volume based on the famous standards.
M. Hosseini; A.R. Dolatshahi; E. Ramezani
Abstract
Concrete is among the widely used materials in all industries and mineral and civil activities worldwide, highlighting its significance. Most natural and non-natural phenomena can influence the concrete's physical and mechanical properties, causing many irreparable damages. Acid rain is a natural inevitable ...
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Concrete is among the widely used materials in all industries and mineral and civil activities worldwide, highlighting its significance. Most natural and non-natural phenomena can influence the concrete's physical and mechanical properties, causing many irreparable damages. Acid rain is a natural inevitable phenomenon, particularly in industrial zones with high pollution percentages.This work investigates the effect of acid rain on the concrete specimens containing micro-silica and limestone powder. To this end, the concrete specimens are divided into six groups. Throughout this paper, CN represents the concrete without micro-silica and limestone powder under no-rain conditions, CO is the concrete without micro-silica and limestone powder under normal rain conditions, CA is the concrete without micro-silica and limestone powder under acid rain conditions, CMLN is the concrete containing micro-silica and limestone powder under no-rain conditions, CMLO is the concrete containing micro-silica and limestone powder under normal rain conditions, and CMLA shows the concrete containing micro-silica and limestone powder under acid rain conditions. The measured physical properties are the effective porosity, dry density, water absorption, and velocity of longitudinal waves. The mechanical properties including the Brazilian tensile strength, uniaxial compressive strength, triaxial compressive strength, cohesion, and internal friction angle are also measured. For the samples of CN and CMLN, they are tested under no rainfall conditions, whereas the samples of CA and CMLA are tested after 20 cycles of acid rain (pH = 2). The samples of CO and CMLO are also tested after undergoing 20 normal rain cycles (urban water with pH = 7). In each test cycle, there is 1 hour of rain and 1 hour of no rain. The results obtained show that adding micro-silica and limestone powder improves its properties so that the decrease in the effective porosity, longitudinal wave velocity, dry unit weight, water absorption, Brazilian tensile strength, uniaxial compressive strength, cohesion, and internal friction angle of the specimens of CMLA is less than those for the specimens of CA.
H. Yousefian; M. Fatehi Marji; H. Soltanian; A. Abdollahipour; Y. Pourmazaheri
Abstract
Determination of the borehole and fracture initiation positions is the main aim of a borehole stability analysis. A wellbore trajectory optimization with the help of the mud pressure may be unreasonable since the mud pressure can only reflect the degree of difficulty for the initial damage to occur at ...
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Determination of the borehole and fracture initiation positions is the main aim of a borehole stability analysis. A wellbore trajectory optimization with the help of the mud pressure may be unreasonable since the mud pressure can only reflect the degree of difficulty for the initial damage to occur at the wellbore rather than the extent of the wellbore damage. In this work, we investigate the failure extension in different arbitrary inclination boreholes under different in-situ stress regimes. Assuming the plane strain condition, the Mohr-Coulomb, Mogi-Coulomb, and Modified Lade rock failure criteria are utilized. We present an analytical equation to determine the optimum drilling trajectory of an Iranian oilfield. In order to predict the degree of wellbore damage, the initial shear failure location, failure width, and failure depth of arbitrary wellbores are determined. Then a new model is derived to calculate the initial failure area of a directional wellbore because it is more efficient in a wellbore stability analysis. The results obtained show that in the target oilfield, the vertical and low-deviated direction is the optimum drilling path. According to the results of this work, optimization of the wellbore trajectory based on the estimated failure zone is a reasonable method if a considerable failure zone takes place around the borehole wall.
Leila Nikakhtar; Shokroallah Zare; Hossein Mirzaei
Abstract
Surface settlement induced by tunneling is one of the most crucial problems in urban environments. Hence, accurate prediction of soil geotechnical properties is an important prerequisite in the minimization of it. In this research work, the amount of surface settlement is predicted using three-dimensional ...
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Surface settlement induced by tunneling is one of the most crucial problems in urban environments. Hence, accurate prediction of soil geotechnical properties is an important prerequisite in the minimization of it. In this research work, the amount of surface settlement is predicted using three-dimensional numerical simulation in the finite difference method and Artificial Neural Network (ANN). In order to determine the real geotechnical properties of soil layers around the tunnel; back-analysis is carried out using the optimization algorithm and monitoring data. Among the different optimization methods, genetic algorithm (GA) and particle swarm optimization (PSO) are selected, and their performance is compared. The results obtained show that the artificial neural network has a high ability with the amounts of R=0.99, RMSE=0.0117, and MSE= 0.000138 in predicting the surface settlement obtained from 150 simulations from randomly generated data. Comparing the results of back-analysis using the optimization algorithm, the genetic algorithm shows less error than the particle swarm algorithm in different initial populations. In all cases of analysis, the calculation time for both algorithms lasts about 5 minutes, which indicates the applicability of both algorithms in optimizing the parameters in mechanized tunneling in a short time.
Rock Mechanics
Vahab Sarfarazi; Lei Zhou; Hadi Haeri; Parastou Salehipour; Ali Elahi; Ali Moayer; Mohammad Fatehi Marji
Abstract
The mechanical behavior of rock-rock bolt interface considering the effects of indents’ shape and their number was numerically simulated based on discrete element method using the two-dimensional particle flow code. The conventional and standard uniaxial compressive and Brazilian tensile strengths ...
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The mechanical behavior of rock-rock bolt interface considering the effects of indents’ shape and their number was numerically simulated based on discrete element method using the two-dimensional particle flow code. The conventional and standard uniaxial compressive and Brazilian tensile strengths tests were used to calibrate the modelled samples with 100 cm 100 cm in dimension. The numerical models were prepared such that different indent shape and number were inserted in the cable bolts arrangements during the rock reinforcement process. The effects of confining pressure 3.7 MPa and different shear failure loads were modeled for the punch shear test of the concrete specimens. The results of this study showed that the dominant failure mode of the rock-cable bolt interface was of tensile mode and the shape and number of cable indents significantly affected the strength and mechanical behavior of the modelled samples. It has also been showed that the indent dimensions and number affected the shear strength of the interfaces.
Environment
Masoud Rabieian; Farhad Qaderi
Abstract
Offshore produced water (OPW), a type of wastewater rich in hazardous compounds such as polycyclic aromatic hydrocarbons (PAHs), requires effective treatment. This study presents a novel methodology utilizing TiO2 nanoparticles, ultraviolet (UV) lamps, and ozonation for the degradation of phenanthrene ...
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Offshore produced water (OPW), a type of wastewater rich in hazardous compounds such as polycyclic aromatic hydrocarbons (PAHs), requires effective treatment. This study presents a novel methodology utilizing TiO2 nanoparticles, ultraviolet (UV) lamps, and ozonation for the degradation of phenanthrene (PHE) from OPW. Various factors including UV lamp power (10W-50W), ozone dose (0.1 mg/L-0.5 mg/L), TiO2 concentration (0.5 g/m²-2.1 g/m²), ethanol fraction (25%-85%), pH (4.5-10.5), PHE initial concentration (5 mg/L-25 mg/L), and treatment time (15 min-45 min) were systematically investigated to understand their impact on PAH degradation in the OPW. The study employs Response Surface Methodology (RSM) for modeling and optimizing PHE removal efficiency. The results contribute to the development of a mathematical model, and through optimization, optimal conditions are proposed to maximize PHE removal efficiency. Experimental implementation of the optimized conditions in a physical model resulted in an impressive 98% PHE removal efficiency. The identified optimal conditions include UV lamp power of 40 W, ozone dose of 0.5 mg/L, TiO2 concentration of 2 g/m², ethanol fraction of 25%, pH of 5.2, initial PHE concentration of 15 mg/L, and a treatment time of 40 min. This optimized approach provides valuable insights for efficient and environmentally friendly treatment of PAHs in OPW, emphasizing on the potential for practical application in soil washing effluent treatment.
R. Dabiri; M. Bakhshi Mazdeh; H. Mollai
Abstract
The aim of this study was to determine the extent of metal pollutions and the identification of their major sources in the vicinity of the Sangan iron mine occurring in NE Iran. Soil samples were collected from the vicinity of the mine site and analyzed for heavy metals. In addition, the chemical speciation ...
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The aim of this study was to determine the extent of metal pollutions and the identification of their major sources in the vicinity of the Sangan iron mine occurring in NE Iran. Soil samples were collected from the vicinity of the mine site and analyzed for heavy metals. In addition, the chemical speciation of these metals was investigated by means of the sequential extraction procedure. The statistical and spatial variability of the metal concentrations and other soil parameters were also analyzed by the multivariate statistical methods (principal component analysis and cluster analysis). Contaminant Factor (CF) and Enrichment Factor (EF) were used to evaluate soil pollution in the samples. By this study, one can conclude that a notable enrichment of heavy metals happened in the margin of the mining area. The data obtained reveal that soils in the area are contaminated, showing higher levels of Fe, Sn, Co, Cu, Sb, S, and Cd in comparison with their normal distributions. The results of sequential extraction analysis and multivariate (geo)statistical methods show that the variability of Fe, Sn, Co, Cu, Sb, S, and Cd is predominately controlled by the anthropogenic source (mining activity), whereas Pb, Cr, and Zn are mainly of natural (geogenic) origin.
Mineral Processing
M. Mohseni; M. Abdollahy; R. Poursalehi; M. R. Khalesi
Abstract
The reactivity of the protonated and hydroxylated sphalerite (1 1 0) surface with xanthate was simulated using the density functional theory (DFT). The difference between the energy of the lowest unoccupied molecular orbital of the sphalerite surface and the energy of the highest occupied molecular orbital ...
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The reactivity of the protonated and hydroxylated sphalerite (1 1 0) surface with xanthate was simulated using the density functional theory (DFT). The difference between the energy of the lowest unoccupied molecular orbital of the sphalerite surface and the energy of the highest occupied molecular orbital of xanthate ( was used to compare the reaction capability of xanthate with fresh and functionalized surfaces. The Mulliken atomic charge analysis was used to provide an in-depth insight into the effects of –H+ and –OH- groups on the reactivity of Zn atoms at the sphalerite surface. The values for different systems showed that the protonated surfaces exposed a higher reactivity with xanthate than the fresh and hydroxylated surfaces. The results of the Mulliken atomic charge analysis demonstrated that after the formation of –H+ and –OH- contained groups on the sphalerite surface, the surface atoms found a new charge due to the reduction and oxidation mechanism. In addition, the results obtained revealed that the electrophilicity of Zn atoms after the ion adsorption could be considered as a key factor in the reactivity of the sphalerite surface with xanthate. The DFT-based calculations also showed that different alkyl groups of xanthate had no significant influence on the reactivity of their head groups. The findings of this research work provided insights into the reactions of the sphalerite surface with xanthate.
Rock Mechanics
E. Bakhshi; V. Rasouli; A. Ghorbani; M. Fatehi Marji
Abstract
In this work, we used a grain-based numerical model based on the concept of lattice. The modelling was done to simulate the lab experiments carried out on the mortar samples. Also the analytical solutions corresponding to the viscosity-dominated regime were used to estimate the fracture length and width, ...
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In this work, we used a grain-based numerical model based on the concept of lattice. The modelling was done to simulate the lab experiments carried out on the mortar samples. Also the analytical solutions corresponding to the viscosity-dominated regime were used to estimate the fracture length and width, and the results obtained were compared with the numerical simulations. As the analytical solutions are proposed for a penny-shaped fracture with no presence of any obstacle such as natural interfaces, in this work, we presented the results of lattice simulations for hydraulic fracturing in the cement sample, similar to the lab, but with no natural fractures, and compared the results obtained with analytical solutions. The results indicated that in the case of a continuous medium, the analytical solutions may present a reasonable estimation of the fracture geometry. Also the viscosity-dominated leak-off model showed a better match between the analytical solutions and the numerical simulation results, confirmed by observing fluid loss into the sample in the lab post-experiment. In the case of assuming leak-off, the results indicated that the fracture width and length would reduce. However, it should be noted that in real cases, rock formations exhibit fractures and inhomogeneity at different scales so that the applications of the analytical solutions are limited.
M. Hosseini Nasab; M. Noaparast; H. Abdollahi
Abstract
In this research work, the bio-leaching of Co and Ni from an iron-rich laterite ore is assessed using the acidophilic heterotrophic (Delftia acidovorans)and autotrophic (Acidithiobacillus ferrooxidans) bacteria. The metabolic products of the acidophilic bacteria play an important role in bio-leaching. ...
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In this research work, the bio-leaching of Co and Ni from an iron-rich laterite ore is assessed using the acidophilic heterotrophic (Delftia acidovorans)and autotrophic (Acidithiobacillus ferrooxidans) bacteria. The metabolic products of the acidophilic bacteria play an important role in bio-leaching. The results obtained from the indirect bio-leaching indicate the highest nickel recoveries of up to 83.65% and 80.18%, respectively, by the supernatants of Acidithiobacillus ferrooxidans and Delftia acidovorans, both measured at 90 °C for 3 h with a stirring speed of 370 rpm and S/L of 0.1, while the corresponding cobalt recovery rates have reached 86.93% and 83.94%, respectively. The iron dissolution rates in these conditions for the two studied bacteria are 64.34% and 54.41%, respectively. The nickel and cobalt extractions by the indirect bio-leaching of Delftia acidovorans are, respectively, 29.84% and 23.75% higher than those for the direct bio-leaching, performed at 30 °C and 150 rpm of an incubator shaker for 30 days. For the indirect bio-leaching, the chemical control has a larger influence on the dissolution rate of the iron-rich laterite compared to the diffusion control. The activation energies of nickel and cobalt in the chemical control model are 40.07 and 39.08 kJ/mol, respectively.
Exploitation
A. Hosseini; M. Najafi; Seyed A. Shojaatlhosseini; R. Rafiee
Abstract
The longwall mining method is one of the most applied methods in extracting low-inclined to high-inclined coal seams. Selection of the most suitable extraction equipment is very important in the economical, safety, and productivity aspects of mining operations. There are a lot of parameters affecting ...
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The longwall mining method is one of the most applied methods in extracting low-inclined to high-inclined coal seams. Selection of the most suitable extraction equipment is very important in the economical, safety, and productivity aspects of mining operations. There are a lot of parameters affecting the selection of an extraction equipment in mechanized longwall mining in steeply inclined coal seams. The important criteria involved are the geometric properties of coal seam (dip, thickness, and uniformity of coal seam), geological and hydraulic conditions (faults, fractures, joints, and underground water), and geomechanical properties of coal seam and surrounding rocks. Extraction of inclined coal seams with gradients greater than 40 degree is different from low-inclined seams, and requires a special equipment. Therefore, the influence of the above-mentioned parameters must be considered simultaneously in the selection of extraction equipment for steeply inclined seams. This paper presents an application of the Fuzzy Analytical Hierarchy Process (FAHP) method in order to select a suitable extraction equipment in the Hamkar coal mine. In the proposed FAHP model, fifteen main criteria are considered, as follow: dip of coal seam, thickness of coal seam, seam uniformity, expansion of coal seam, faults, fractures and joints, underground waters, hangingwall strength, footwall strength, coal strength, in-situ stress, equipment salvage, dilution, system flexibility, and operational costs. Among the 6 considered longwall extraction equipment system alternatives, the findings show that the most suitable extraction equipment system is shearer on footwall and a support system using hydraulic props and the transport of coal with the force of gravity.
M. M. Pourgholam; P. Afzal; A. Adib; K. Rahbar; M. Gholinejad
Abstract
Signal analysis approaches are a powerful and widely used tool in processing multi-spectral satellite images for detection of alteration zones. The main goal of this work is application of the spectrum-area fractal methodology based on the Landsat 8 OLI satellite images’ data for separation alteration ...
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Signal analysis approaches are a powerful and widely used tool in processing multi-spectral satellite images for detection of alteration zones. The main goal of this work is application of the spectrum-area fractal methodology based on the Landsat 8 OLI satellite images’ data for separation alteration zones for iron oxides at the Tarom region (NW Iran). These alteration zones, Normalized Difference Vegetation Index (NDVI), and Normalized Difference Water Index (NWDI) are detected using the band-ratio and band combination methods. Then the calculated values are categorized by Spectral Angle Mapper (SAM), k-means, and S-A fractal model. Considering a positive correlation of iron oxides alterations along with magnetite mineralization as an index of mineralization at the studied region, the promising areas are classified by a decision-making model using the TOPSIS method with an acceptable accuracy for presenting in the exploration models.
R. Siyar; F. Doulati Ardejani; M. Farahbakhsh; M. Yavarzadeh; S. Maghsoudy
Abstract
Copper smelting and refinery factories are the final stages of a pyrometallurgical processing chain, and they cause many environmental challenges around the world. One of the most common environmental problems of these factories is toxic emissions. These toxic gases have harmful effects on the vegetation, ...
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Copper smelting and refinery factories are the final stages of a pyrometallurgical processing chain, and they cause many environmental challenges around the world. One of the most common environmental problems of these factories is toxic emissions. These toxic gases have harmful effects on the vegetation, animal species, soils, and water resources around the factories. Phytoremediation can play an important role in the reduction of the adverse effects of environmental pollutions arising from copper smelting and refinery factories. In this paper, we first discuss different types of pollutions caused by copper metallurgical factories, and present the main research approaches and studies conducted on these factories. In the second part, we provide a summary and comparison of different remediation technologies used to reduce the environmental pollutions of these factories. Besides, the advantages and disadvantages of each method is also investigated. In the third part, we review the different aspects of the phytoremediation including the effective mechanisms, different types of plants, application environments, and the effective factors. The next part includes the selection of suitable plants for the phytoremediation process applied for copper metallurgical factories and investigation of the native and cultivated hyperaccumulator plants. In addition, different efficiency indices are introduced for evaluating the phytoremediation efficiency and selecting an appropriate hyperaccumulator plant. At the final stage, some appropriate plant species for various types of phytoremediation are introduced. The effects of different environmental stresses and the possibilities of integrating phytoremediation with other remediation technologies as well as the advantages and disadvantages of phytoremediation are eventually investigated.
Hadi Bejari; Jafar Khademi Hamidi
Abstract
This work aims to investigate the effect of water saturation on cutting forces and chipping efficiency by performing a series of small-scale linear cutting tests with a chisel pick on twelve low- and medium-strength rock samples. The peak and mean cutting force acting on the chisel pick are measured ...
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This work aims to investigate the effect of water saturation on cutting forces and chipping efficiency by performing a series of small-scale linear cutting tests with a chisel pick on twelve low- and medium-strength rock samples. The peak and mean cutting force acting on the chisel pick are measured and recorded under dry and saturated cutting conditions by the strain sensors that are embedded in the dynamometer. Also the amplitude of cutting force fluctuations in dry and saturated cutting conditions is compared by the standard deviation measurement of cutting force data, and its relationship with the size of cutting fragments is investigated. The results obtained show that the peak cutting force is reduced in saturated conditions compared to dry conditions. The mean cutting force in the synthetic sample cutting test is unchanged or in some cases increase, while in the natural samples it decreases. The relative increase in the mean cutting force in synthetic rock specimens is due to the paste state of fine materials produced from saturated cutting and chisel pick clogging. A strong correlation is found between the standard deviation of cutting force data and the average size of rock debris, indicating that the standard deviation of cutting force data is a useful measure for evaluating the chipping efficiency. The present study's findings reveal that to have an efficient excavation system in field operations, it is necessary to consider the presence of water and saturated conditions in designing the cutting machine's operating parameters and predicting the performance of mechanical excavators.
Exploitation
Shahrokh Khosravimanesh; Masoud Cheraghi Seifabad; Reza Mikaeil; Raheb Bagherpour
Abstract
Specific energy is a key indicator of drilling performance to consider in the feasibility and economic analyses of drilling projects. Any improvement in the specific energy of a drilling operation may reflect an improvement in the overall efficiency of drilling operations. This improvement can be achieved ...
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Specific energy is a key indicator of drilling performance to consider in the feasibility and economic analyses of drilling projects. Any improvement in the specific energy of a drilling operation may reflect an improvement in the overall efficiency of drilling operations. This improvement can be achieved by delivering a suitable cooling lubricant into the drilling environment. The present study examines the mechanical characteristics of the drilled rock, the physical qualities of the cooling lubricant employed, and the drilling rig operational parameters related to the drilling-specific energy (DSE). To this end, seven rock samples (granite, marble, and travertine) were drilled using water and five other fluids as the cooling lubricants. A total of 492 drilling experiments were conducted with a custom-designed and built laboratory-scale drilling rig on cuboid rock specimens. The univariate linear regression analysis of experimental results revealed a significant drop in DSE after using cooling lubricants instead of conventional cooling fluid (i.e. water). Under constant conditions in terms of mechanical properties of the rock, using Syncool with a concentration of 1:100 and soap water with a concentration of 1:120 instead of water led to 34% and 43% DSE reductions in the granite samples, 48% and 54% in the marble samples, and 41% and 50% in the travertine samples, respectively. These variations in specific energy suggest that the drilling efficiency and performance can be augmented using properly selected cooling lubricants.
Rock Mechanics
Mohammad Rezaei; Seyed Zanyar Seyed Mousavi; Kamran Esmaeili
Abstract
This study introduces a novel approach, known as Hybrid Probabilistic Slope Stability Analysis (HPSSA), tailored for Mine 4 of the Gol-E-Gohar iron complex in Iran. The mine walls are first divided into 8 separate structural zones, including A-A' to H-H' sections for slope stability analysis. Then, sufficient ...
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This study introduces a novel approach, known as Hybrid Probabilistic Slope Stability Analysis (HPSSA), tailored for Mine 4 of the Gol-E-Gohar iron complex in Iran. The mine walls are first divided into 8 separate structural zones, including A-A' to H-H' sections for slope stability analysis. Then, sufficient core specimens are prepared from 22 drilled boreholes and the required parameters for slope design, including cohesion (c), friction angle (φ), and unit weight (γ), are measured. Finally, the HPSSA approach is performed through the combination of Monte Carlo simulation (MCS), Mohr-Coulomb criterion and Bishop's technique. According to the HPSSA results, the normal distribution function is achieved as the best curve fit for c, φ and γ parameters. Also, the obtained values of mean probabilistic safety factor (SF) for defined structural zones vary from 0.93 to 1.86, with the probability of failure (PF) of 0 to 75.6%. Moreover, SF values varied from 0.68 to 1.22 (mean value of 0.93) with a PF of 75% for the A-A' section and from 0.65 to 1.24 (mean value of 0.97) with a PF of 60% for the H-H' section. Hence, it is concluded that the A-A' section and mine’s north wall are more prone to instability with PF>60%. On the other hand, SF>1.2 and PF<5% for other mine walls (sections B-B'-G-G') prove that they are highly unlikely to be unstable. Displacement monitoring of the pit walls using installed prisms confirmed that average displacements in structural zones have a similar trend with SF values of the HPSSA. The results show a good agreement between the trend of probabilistic SFs and monitored slope displacements. Lastly, comparative analysis confirmed the validity of the suggested HPSSA approach with relatively higher accuracy than most previous slope stability analysis methods.
