Subjects -> MINES AND MINING INDUSTRY (Total: 82 journals)
Showing 1 - 42 of 42 Journals sorted alphabetically
Applied Earth Science : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Archives of Mining Sciences     Open Access   (Followers: 1)
BHM Berg- und Hüttenmännische Monatshefte     Hybrid Journal   (Followers: 1)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
CIM Journal     Hybrid Journal  
Clay Minerals     Hybrid Journal   (Followers: 8)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 11)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 2)
European Journal of Mineralogy     Hybrid Journal   (Followers: 12)
Extractive Industries and Society     Hybrid Journal   (Followers: 2)
Gems & Gemology     Full-text available via subscription   (Followers: 1)
Geology of Ore Deposits     Hybrid Journal   (Followers: 3)
Geomaterials     Open Access   (Followers: 2)
Geotechnical and Geological Engineering     Hybrid Journal   (Followers: 8)
Ghana Mining Journal     Full-text available via subscription   (Followers: 3)
Gold Bulletin     Hybrid Journal  
International Journal of Coal Geology     Hybrid Journal   (Followers: 2)
International Journal of Coal Preparation and Utilization     Hybrid Journal   (Followers: 1)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Hospitality & Tourism Administration     Hybrid Journal   (Followers: 14)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 8)
International Journal of Mining and Geo-Engineering     Open Access  
International Journal of Mining and Mineral Engineering     Hybrid Journal   (Followers: 5)
International Journal of Mining Engineering and Mineral Processing     Open Access   (Followers: 5)
International Journal of Mining Science and Technology     Open Access   (Followers: 4)
International Journal of Mining, Reclamation and Environment     Hybrid Journal   (Followers: 4)
International Journal of Rock Mechanics and Mining Sciences     Hybrid Journal   (Followers: 6)
Journal of Analytical and Numerical Methods in Mining Engineering     Open Access  
Journal of Applied Geophysics     Hybrid Journal   (Followers: 15)
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of China Coal Society     Open Access  
Journal of Convention & Event Tourism     Hybrid Journal   (Followers: 4)
Journal of Geology and Mining Research     Open Access   (Followers: 11)
Journal of Human Resources in Hospitality & Tourism     Hybrid Journal   (Followers: 8)
Journal of Materials Research and Technology     Open Access   (Followers: 2)
Journal of Metamorphic Geology     Hybrid Journal   (Followers: 15)
Journal of Mining Institute     Open Access  
Journal of Mining Science     Hybrid Journal   (Followers: 2)
Journal of Quality Assurance in Hospitality & Tourism     Hybrid Journal   (Followers: 5)
Journal of Sustainable Mining     Open Access   (Followers: 2)
Journal of the Southern African Institute of Mining and Metallurgy     Open Access   (Followers: 5)
Lithology and Mineral Resources     Hybrid Journal   (Followers: 3)
Lithos     Hybrid Journal   (Followers: 9)
Mine Water and the Environment     Hybrid Journal   (Followers: 4)
Mineral Economics     Hybrid Journal  
Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 11)
Mineral Processing and Extractive Metallurgy Review     Hybrid Journal   (Followers: 4)
Mineralium Deposita     Hybrid Journal   (Followers: 4)
Mineralogia     Open Access   (Followers: 2)
Mineralogical Magazine     Hybrid Journal   (Followers: 1)
Mineralogy and Petrology     Hybrid Journal   (Followers: 2)
Minerals     Open Access  
Minerals & Energy - Raw Materials Report     Hybrid Journal  
Minerals Engineering     Hybrid Journal   (Followers: 9)
Mining Engineering     Full-text available via subscription   (Followers: 5)
Mining Journal     Full-text available via subscription   (Followers: 3)
Mining Report     Hybrid Journal   (Followers: 2)
Mining Technology : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 2)
Mining, Metallurgy & Exploration     Hybrid Journal  
Natural Resources & Engineering     Hybrid Journal  
Natural Resources Research     Hybrid Journal   (Followers: 8)
Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Minerals     Hybrid Journal   (Followers: 4)
Podzemni Radovi     Open Access  
Rangeland Journal     Hybrid Journal   (Followers: 1)
Réalités industrielles     Full-text available via subscription  
Resources Policy     Hybrid Journal   (Followers: 4)
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 4)
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 6)
Rocks & Minerals     Hybrid Journal   (Followers: 2)
Rudarsko-geološko-naftni Zbornik     Open Access  
Stainless Steel World     Full-text available via subscription   (Followers: 17)
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 9)
Similar Journals
Journal Cover
Journal of Analytical and Numerical Methods in Mining Engineering
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2251-6565 - ISSN (Online) 2676-6795
Published by Yazd University Homepage  [1 journal]
  • Design of the most probable pit limit of open pit mines considering price
           uncertainty

    • Abstract: Open pit design and production scheduling considering the commodity price uncertainty is one of the important issues in the field of open pit mining, so that mine design and planning regardless of price uncertainty leads to erroneous assessments and non-operational production scheduling which itself increases the investment risk. The amount of reserve that can be extracted and the location of surface facilities directly depends on final pit limit. To solve this problem, heuristic, meta-heuristic and exact mathematical methods have been employed; but these methods have been less able to lead to the presentation of the most stable pit, in the in the presence of uncertainty of the final product price. In this paper, a mathematical algorithm based on Monte Carlo Simulation and Lerch and Grossman algorithm is presented, which is able to calculate the expected value of blocks based on the metal price history and estimating its distribution function and get the most likely final pit limit. This pit can be the basis of long-term mine production planning as well as a criterion for locating surface facilities.Open pit design and production scheduling considering the commodity price uncertainty is one of the important issues in the field of open pit mining, so that mine design and planning regardless of price uncertainty leads to erroneous assessments and non-operational production scheduling which itself increases the investment risk. The amount of reserve that can be extracted and the location of surface facilities directly depends on final pit limit. To solve this problem, heuristic, meta-heuristic and exact mathematical methods have been employed; but these methods have been less able to lead to the presentation of the most stable pit, in the in the presence of uncertainty of the final product price. In this paper, a mathematical algorithm based on Monte Carlo Simulation and Lerch and Grossman algorithm is presented, which is able to calculate the expected value of blocks based on the metal price history and estimating its distribution function and get the most likely final pit limit. This pit can be the basis of long-term mine production planning as well as a criterion for locating surface facilities.
       
  • Signal processing of acoustic emission test in determining the point of
           effect of Kaiser of rocks using discrete wavelet transform

    • Abstract: One of the geomechanical parameters that is very important in the design and analysis of various rock engineering projects is the in situ stress state of the rock mass. In this regard,, direct and in situ stress measurement methods are the best and most accurate methods of measuring the in situ stress., However, these methods are very expensive,, time consuming and costly. Therefore, today's, laboratory and indirect rock core-based methods for estimating in situ stress have been taken into consideration. One of the laboratory methods is acoustic emission method based on Kaiser effect. In this method, determining the Kaiser effect point is usually done by the parameters of acoustic emission signals, which in some cases, determining the Kaiser effect point by parametric method are ambiguous and do not have sufficient clarity. In this research, acoustic emission signal processing has been used to determine the Kaiser effect point of the experimental data on the phyllite rock by discrete wavelet transform method. The results show that according to the parameters of correlation coefficient and noise to signal ratio and the type of acoustic signals the mother wave db6 was suitable for analysis. Among the parameters that can be used for analysis, the maximum approximation coefficient parameter is also selected as a suitable feature for analysis. Also, the results of the discrete wavelet transform method were in good agreement with the results of the parametric method, so that the occurrence times of the Kaiser effect obtained from the two methods are mutually acceptable.
       
  • Faults Localization Based on Joints Distribution by Fisher's
           constant coefficient(K)

    • Abstract: Fault and some major geological structures often act as the natural boundaries of a tectonic block, and depending on the scale, they can bring together areas with different joint characteristics. In geometric modeling of rock mass discontinuities, an attempt is made to identify such major geological structures in order to recognize statistically homogeneous areas with almost similar joint properties. The system of joints as homogeneous statistical assemblies limited to large tectonic structures (faults, folds, etc.), are the best indicators of separation of these areas. Numerous geometric parameters such as dip, dip direction, spacing and extension of joints are effective for detecting faults. The constant coefficient of the Fisher distribution function (K) indicates how the joints are distributed and is considered as an indicator parameter for the geometric behavior of discontinuities. Based on the evidence, the orientation of the joint system is disrupted near the tectonic structures and is regulated by distance from them. This issue was considered as the hypothesis of this study and Fisher coefficient was used as the main factor in the diagnosis and separation of the joint system. In order to validate the hypothesis, using geometric data of discontinuities taken from four mines of Sehchaoon, Meiduk and Esphordi and Choghart, the distribution of K coefficient was achieved in these mines and the contour lines of Fisher coefficient were also drawn. Thus, areas with high concentration of K coefficient in each mine were determined as the center of the joint system. Comparing the enclosed tectonic blocks between the faults of each mine and its relative adaptation to the separated areas by the proposed method, the efficiency of this method was possible to detect the joint system and estimate the location of large tectonic structures.
       
  • A comparative study on the application of Regression-PSO and ANN methods
           to predict backbreak in open pit mines

    • Abstract: • One of the most challenging safety problems in open pit mines is backbreak during blasting operation, and its prediction is very important for a technically and economically successful mining operation. To avoid backbreak, different parameters such as physicomechanical properties of rock mass, explosives properties and geometrical features of the blasting pattern should be considered. This paper presents a new solution of multiple linear regression (MLR), particle swarm optimization algorithm (PSO) and artificial neural networks (ANNs) to estimate the backbreak induced by bench blasting, based on major controllable blasting parameters. To this aim, Angouran mine in Iran was considered and blasting pattern parameters for 73 operations were collected. In addition, back-break was measured in each operation. Considering the previous investigations and also collected data from the mine, burden, spacing, hole length, stemming, charge per delay, RQD, number of row and powder factor were selected as input parameters. In order to find the better solutions, the constructed models were implemented in PSO algorithms. Also, the prediction of backbreak was investigated using ANNs. According to the obtained results, the PSO algorithm is a suitable tool for optimizing models and obtaining more accurate prediction of backbreak. Among the presented empirical models, the optimized exponential model with PSO algorithm with a RMSE (0.31) and R2 (0.87) shows the better results in prediction of backbreak and it is suitable for practical use in Angouran mine. Considering the sensitivity analysis, among the input parameters, length of stemming and charge per delay have shown the most and the least effect on the backbreak, respectively. The results of ANNs show that multilayer networks are more powerful and efficient than single-layer in prediction of backbreak.
       
  • Determining the optimal dimensions of the pillars under static and dynamic
           loads in room and pillar mines (Case study: Tabas central coal mine)

    • Abstract: Pillar dimension in room and pillar mining method has been always a technical and economical issue for mining and rock mechanic engineers. The strength of the pillars is usually determined by empirical relationships, which have been determined by experience and by the data collected from the coal mines of the United States, South Africa, and China, and which, except in one case, have never considered seismic loads. This study aims to define the optimum pillar dimension based on the pillar strength derived from a new approach implemented into the numerical modeling by gradually applying an increasing load on the pillar and monitoring its displacement, using Central section of Tabas coal mine data. The results are compared with the ones from Salamon and Monroe (1967) method as one of the most commonly used empirical methods. This comparison shows that the strength obtained from the numerical method for pillar widths of less than 15 m is well consistent with the empirical Salamon-Monroe method, whereas the difference between the results of the two methods increases progressively with pillar width increment. The safety factor of the pillar is then defined by dividing the obtained pillar strength and monitored critical stresses, under static and dynamic conditions. Tabas (1978) earthquake with 7.4 magnitude is used for dynamic analyses. The results show that the optimal width of the pillar in the static and dynamic states are 12 and 15 meters, respectively. Moreover, curve fitting with high regression to the results obtained in both static and dynamic states, relations in terms of width to height ratio were presented for use in other areas of the mine with similar geomechanical conditions.
       
  • Qualitative evolving rockfall hazard assessment for dolomite's
           highwalls in Golbini7 mine, Jajarm Bauxite mines complex

    • Abstract: Shape of Rock failure depend on strength condition and dip of bedding planes, discontinuities direction, condition of discontinuities (filling, roughness, spacing and weathering), face geometry and area condition. Slopes can be divided to homogeneous and non- homogeneous based on rock structure. In homogeneous slopes, failure is circular shape and in non- homogeneous slopes, failure is plane, wedge and toppling failure or combined failure. The aim of this study is slope stability analysis of the dolomite wall of Golbini 7 mine. footwall in this mine is extremely faulted. Strike of faults in Golbini 7 mine is vertical to strike of bedding planes and dip direction of faults is in the opposite direction of dip direction of bedding planes except to some reverse faults and toppling failure is possible. One of the basic methods for stability analysis of the dolomite wall, especially on rock slopes, is rockfall hazard Assessment. In this method, based on visual monitoring system, the unstable blocks will be recognized and Rockfall hazard will be evaluated. In the study, the dolomite wall was divided into 13 different zones and in each zone, blocks prone to instability were identified. The total number of evaluated blocks is 46 cases. According to the results, the blocks related to zone 8 have a medium to high risk level and all blocks related to zone 13 have a high hazard level. No block is at the low hazard level. Only 2% of the assessed blocks are in the low to medium hazard level. 9% are at the medium hazard level, 50% are at the medium to high hazard level and 39% are at the high hazard level. The rockfall distance from the toe of the face determined by the Evolving rockfall hazard Assessment method and the results were compared with the modeling results by Rocfall software. The maximum difference between the results is 25%.
       
  • Numerical modeling of the effect of acidizing on the permeability of rock
           joints during shear displacement.

    • Abstract: Acidizing of rock joints performs to increase the permeability productivity of reservoirs. For this purpose, various laboratory and numerical studies have been conducted to investigate the effect of acidizing on the hydraulic behavior of joints. At the same time, due to the displacement of the joints of the rocks, the pattern of fluid flow and amount of flow through the degraded joints changes, which has not been attempted in previous studies and is the main purpose of this study. In this research, various natural joint samples were prepared by indirect tensile method of Asmari limestone, which is the reservoir rock of oil fields in south-west of Iran. After acidizing using the developed acidizing reactor, flow rate of the fluid in the initial conditions was measured. A numerical code based on finite element method in MATLAB software has been developed for numerical investigation about the effect of joint shearing rate on hydraulic behavior of joints in pre/post-acidizing conditions. The numerical results has been verified with laboratory test results. The results show that with increasing the shearing rate in both conditions before and after acidizing, the flow rate has an increasing trend. Also, the flow pattern of the fluid goes towards canalization with increasing shear rate. After acidizing of the joint surface, the difference between the roughness coefficient and the linear roughness of the two fracture surfaces increases, which increases the initial hydraulic conductivity of the fracture and flow changes have a lower slope than similar conditions in the pre-acid state. In some cases, the trend of discharge rates in the conditions after acidizing does not follow the general pattern of discharge rates.
       
  • Estimation of Groutability of granular soils using laboratory data and
           several intelligent classification methods

    • Abstract: In this study, in order to construct and validate several classification models, a set of laboratory data was used in the grouting operations in several literature. Classification models include Artificial Neural Network, Support Vector Machine, K-Nearest Neighbor, Random Forest and Naive Bayes. Orange software has been used in this regard. The results showed that the models have high accuracy in estimating groutability and among them the artificial neural network method with 0.86% precision has better performance than other methods. In addition, in examining the importance of input variables based on scoring indices, variables N2 and N1 are the most influential variables in the process of correctly predicting groutability.The output variable is a property of groutability, which as a binary variable has two states of zero meaning nongroutable and 1 meaning groutable. Input variables also include the ratio of water cement in the grout or viscosity (W / C), the relative density of the soil (Dr), grouting pressure (P), the percentage of the soil particles passing through a 0.6 mm sieve (FC), N1 = D15soil / D85 grout and N2 = D10 soil / D95 grout. The values of the evaluation criteria for the methods are almost close to each other. According to the AUC index, the random forest is the best model and the k-nearest neighbor method has the lowest value of this index. But in terms of other criteria, the artificial neural network is higher than other methods and the k-nearest neighbor method is very close to it. On the other hand, random forest model has the lowest value of criteria. Ignoring the AUC criteria, ANN and KNN methods are the best methods.
       
  • Evaluation of hydrocarbon generation in source rock using geochemical
           studies and 1D basin modeling in in Kish field, northeast Persian Gulf

    • Abstract: Summary The Kish structure is a huge gas field located in the eastern part of the Persian Gulf. It a significant amounts of gas in the Kangan and Dalan reservoirs. This work studies burial and thermal history, and the hydrocarbon generation potential of probable source rocks in the Kish gas field. Accordingly, a 58 rock samples collection was analyzed for pyrolysis of Rock Eval 6 and vitrinte reflection. Moreover, the deepest well was modeled to reconstruct burial and thermal history. The results indicate that the Sarchahan Fromation is the main source rock in the field, and has produced 95% of its potential so far.IntroductionThe Persian Gulf basin is one of the most important regions in terms of hydrocarbon resources in the world. The Kish gas field lies in the eastern part of the Persian Gulf. The purpose of this paper is to assess the hydrocarbon generation potential and model the burial and thermal history of source rocks in this gas field using Rock Eval pyrolysis, vitrinite reflection and 1D model. Methodology and ApproachesIn this study, 58 rock samples were selected from layers with high natural gamma ray in Pabdeh, Gurpi, Ilam, Lafan, Sarvak, Kazhdumi, Dariyan, Gadvan, Fahliyan, Surmeh, Neyriz, Dashtak, Dalan and Faraghan Formations for Rock Eval pyrolysis and vitrinite reflection. In addition, one-dimensional modeling of burial and thermal history was performed using PetroMod software (2011-Schlumberger) on well B of the Kish field. Results and ConclusionThe TOC and S1+S2 values vary from 0.16 to 1.59%, and from 0.08 to 4.16 mg HC/g Rock, respectively. Most of the samples have low hydrocarbon potential, only a limited numbers from Gurpi and Pabdeh show fair hydrocarbon generation potential. The samples with fair potential have kerogen type III and II/III with the low level of maturity. The one-dimensional modeling was performed to Pabdeh, Gurpi and Sarchahan source rocks. The thermal model was calibrated with corrected down-hole temperatures and vitrinite reflections. According to model, Pabdeh and Gurpi are immature, while the Sarchahan is currently in the gas window. It has reached the oil and gas window since 160 and 120 million years ago, and produced 95% of its potential so far.
       
  • Finite element analysis of wellbore stability and optimum drilling
           direction and applying NYZA method for a safe mud weight window

    • Abstract: Abstract :Wellbore stability analysis, selecting the optimum drilling direction, and determining the safe and stable mud weight windows are among the major geo-mechanical challenges in the oil and gas industries. In this study, the wellbore stability analysis and the optimal drilling direction have been numerically modelled by finite element method (FEM) considering the importance of wellbore stability and recognizing instabilities using the data of Sivand oil field. The numerical modeling of wells behaviors has been performed in two modes of elastic and elastoplastic deformations using ABAQUS software. The numerical results have been done using the two failure criteria, namely Mohr-Coulomb and Drucker-Prager and compared together, considering the effect of intermediate principal stress, Drucker-Prager failure criterion has been selected as a suitable failure criterion for this study. In addition, the numerical results have shown that the vertical well is the optimal drilling direction. Then, by applying the NYZA method, the safe mud weight window has been determined. The validity of the proposed mud window for a vertical well has been approved by applying the Mohr-Coulomb analytical method. Finally, the safe and stable mud window for the vertical wellbore has been proposed.Introduction:Previous studies for wellbore stability have been emphasizing the importance of this problem. In addition, many oil and gas reservoirs are located in the anisotropic environment that require to analyze wellbore stability comprehensively. Therefore, in this study, the wellbore stability and selection of the optimal drilling direction have been presented by applying the numerical modeling based on finite element method. In addition, the importance of the normalized yield zone area method in determining the safe mud window based on the available information from one of the oil fields in southern Iran has been discussed. The following steps have been made in this research: first, the numerical modeling of the studied well has been performed using ABAQUS software based on two modes of elastic and elastoplastic analysis. Then, the verification of numerical models in the elastic state has been done by comparing the results with the analytical relationships. The elastoplastic analysis has been presented based on the Drucker-Prager and Mohr-Coulomb criteria. Next, according to the numerical results, the appropriate yield criterion for the next analysis, such as optimal drilling direction has been chosen. Then, the safe mud window has been determined using numerical results by considering the normalized yield zone area method. Afterwards, the validation of the safe mud window for a vertical well has been evaluated using the Mohr-Coulomb analytical method. Finally, the safe and stable mud window for the vertical wellbore has been presented.
       
  • A 2D semi-analytical analysis of the time-dependent settlement of a
           shallow foundation placed near the soil slope

    •  
  • An Integrated Mathematical Model to Optimize Truck Assignment and
           Dispatching in Open Pit Mines

    • Abstract: SummarySince a significant part of mine operating cost belongs to hauling operation, optimizing the allocation and scheduling of trucks in a dynamic system is essential and it significantly affects the production efficiency. So far, different models and methods have been proposed for optimizing of haulage scheduling. In this paper, scheduling models have been reviewed, and a flow-shop model has been developed to optimize truck dispatching systems in open-pit mines. The proposed model has been implemented on a small-scale example, driven from a real-world case study, and the results have been discussed. Numerical investigation demonstrates that this model is a powerful tool for optimizing truck scheduling and it can result in an enhancement in the productivity of mining operations. The most crucial challenge that must be addressed in future work is the development of fast solution techniques to solve real-scale instances of the developed model. IntroductionHauling operation is responsible for a significant portion of the operating cost in an open pit mine operation. Therefore, as the main hauling machine, trucks' optimum scheduling is crucial and can dramatically affect mine production productivity. Conventionally, assignment and dispatching the trucks are defined as two main optimization problems in scheduling hauling operation. Simulation and stepwise mathematical programming have been proposed in the literature to solve these two problems. However, a dynamic and integrated optimization model is required to optimize hauling operation since the state-of-the-art revolution in data collection systems, computational capacity, and the necessity of real-time decision-making. Therefore, this study aims to develop an integrated and single-stage optimization model to optimize truck scheduling problem. Methodology and ApproachesIn this study, the truck dispatching problem has been discussed, and a flow-shop scheduling model has been suggested as the best model to be considered for modeling of open-pit hauling operation. In a flow shop problem, a set of jobs flow through several stages in the same machine order. The proposed flow shop model has been evaluated using an example from a real case study data. Results and ConclusionsThe results show that the use of job scheduling models for truck optimization can optimize haulage scheduling and truck dispatching in open-pit mines. Using the developed flow shop model, incorporate different mining KPI’s such as reducing production time, increase production productivity and improving fuel consumption is possible. This model can also provide a prototype tool for real time scheduling. Future work will focus on developing fast and reliable metaheuristic solution techniques for the large instances of this problem.
       
  • The effect of technical parameters of cross-measure boreholes methane
           drainage method on the amount of exhaust gas (Case study: Tabas Parvadeh
           Coal mine No.1)

    • Abstract: High emissions of methane from the active extraction longwall as well as from the surrounding rocks of the extracted coal seam can affect the safety and productivity of underground coal mines. Especially the methane hazard causes very serious accidents and can be the reason of methane or methane and coal dust explosions. Because ventilation alone may not be sufficient to control methane levels in the longwall mining environment, standard methane control options such as methane drainage occur. Therefore, the use of different methane drainage methods can reduce methane emissions to the longwall environment and reduce the risk of explosion, and ultimately increase safety and production. This research deals mainly with the degassing method with cross-measure boreholes in the longitudinal front extraction method. It takes place at stations with different distances along the extraction panel. Therefore, determining the appropriate values of different parameters of methane drainage boreholes is necessary to increase efficiency. These parameters include the length of the methane drainage boreholes, the angle of the boreholes relative to the axis of the tail gate, and inclination of the boreholes. Accordingly, the analysis of operational data obtained from the methane drainage of the E4 panel has shown that with increasing the dip of the panel, the angle of boreholes relative to the axis of the tail gate should be considered less. Also, typically, the exhaust gas flow of methane drainage stations starts to increase at a distance of 15 to 25 meters from the edge of the face, so the length of methane drainage boreholes should not be considered more than 45 meters.
       
  • Predicting the coal production rate of shearer device based on the gas
           properties and coal Strength in Tabas No 1 Parvade coal mine

    • Abstract: To increase production in coal mining panels along with the use of other equipment, the use of coal machines (shearers) is very beneficial. Predicting the shearer rate and determining the effective parameters in it plays an essential role in estimating costs. Full knowledge of the Strength and properties of coal gas and evaluation of the performance of shearer loader devices causes increase the speed of the loader and coal-rock production. Therefore, in order to achieve high production efficiency in the extraction of coal seams, it is necessary to predict the shearer rate and determine the effective parameters in it. In this paper, the shear rate prediction in relation to the Strength and gas bitumen properties of coal is investigated with the help of statistical analysis.For this purpose, 1260 types of coal cutting were done by coal machine (shearer) in E3 Tabas extraction panel No. 1 of Parvadeh coal mine. In the first stage, after harvesting and recording the shearer rate of each cut, information about degassing was done at three points along the entire length of the panel. These three points include the percentage of methane gases emitted in sensor number 88 and the input sensor (TG) and the sensor installed on the armored face conveyor (AFC). Then, using the strength properties such as coal hardness and methane degassing system, the shearer rate prediction was investigated. Using statistical studies, Shearer rate prediction was performed with three models of linear and nonlinear multivariate regression (exponential and logarithmic). To develop the predicted models, 70% of the data (882 data) were used as educational data and 30% of the data (378 data) as test data. Among the three regression models performed, the results show that the linear multivariate regression model has a more accurate prediction than the other two methods. Therefore, using the linear multivariate regression model, the amount of shearer rate in the coal mine number one of parvadeh Tabas can be predicted with good accuracy.
       
  • Numerical simulation of the effect of particle size distribution and
           boundary conditions on the behavior of stone columns using DEM

    • Abstract: One of the common methods to improvement the behavior of problematic soils is the use of stone columns. These columns increase the bearing capacity. Stone columns gain their bearing capacity by the confining created by the surrounding soil. In the soft soils, the induced lateral pressure applied to the column is not sufficient and the stone column undergoes lateral buckling due to the applied loads. Numerical modeling of this phenomenon has been done using numerical methods based on the continuum mechanics. However according to the dis-continuum nature of the stone columns, the continuum-based numerical methods are not able to accurately model the lateral buckling created in the stone column. But the numerical approach based on the mechanics of discrete environments examines the problem on a small scale and applies a relatively simple behavioral model such as the force-displacement law to each particle. Due to the behavior of stone column aggregates that are discrete, in this study, using the discrete element method that has a good ability to simulate the mechanical behavior of discrete environments, the bearing capacity of the column and the lateral buckling created in the loose soils has been investigated. In this study, after simulating the stone column, the parameters affecting the bearing capacity of the stone column such as grain size, diameter and end boundary conditions of the stone column have been evaluated. The results of this simulation have been validated with the results of theory, which shows that the discrete element method has the necessary capability in simulating a stone column. The results show that increasing the diameter of the stone column increases the bearing capacity and the trapped stone column has between 25 to 30% more bearing capacity than the floating stone column. The simulation results show that reducing the grain size has limited effects on reducing the bearing capacity of the loose soil-stone column complex. Because by increasing the number of particles per unit area and subsequently by increasing the number of contacts, more particles participate in the bearing and if the particle located in the main bearing chain deviates from the path, the force is redistributed and the overall buckling of the force chains do not occur.
       
  • Three-dimensional numerical modeling of hydraulic fracturing:
           Investigation of the influence of time, injection rate and fluid viscosity
           

    • Abstract: Hydraulic fracturing as one of the most important technologies for reservoir stimulation has particular complexities. Since the operation is expensive and sensitive, accurate treatment design is critical and prerequisites are recognizing fracture growth conditions in different injection rates and fracture geometries in different conditions. Therefore three- dimensional modeling is the way to attain these unknowns with the accepted precision. In this research a three dimensional coupled nonlinear fluid-solid finite element model based on the cohesive zone method established by finite element software ABAQUS. The operation is simulated in a vertical well by this model. In the creation of this model, technical reports as well as laboratory and in situ tests were used in the reservoir and well in question. One of the features of this modeling is its field scale. After fluid injection, the fracture geometry was studied at different rates and viscosities of the injected fluid. According to the results, as the injection duration and the pumping rate increase, the fracture length increases and the maximum length created is about 22 meters by applying a fluid with a viscosity of one centipoise during 5 minutes injection time and the rate of 35 barrels per minute or similarly by the same fluid with 18 minutes injection time and the rate of 10 barrels per minute. Moreover, the maximum fracture opening is about 9 mm. Increased fluid viscosity increases the opening and the fracture length. Finally, after fracture initiation and propagation in different fluid injection rate and different fluid viscosity, fracture geometry was studied.
       
  • Investigating the three-dimensional effect of spatial variability of Young
           modulus based on the probabilistic analysis of surface settlement in NATM
           tunneling (Case study)

    • Abstract: One of the problems with NATM tunneling in urban areas is the risk of excessive surface settlement during excavation operations. For real analysis and detailed study of surface settlement, it is necessary to pay attention to the real soil conditions. However, the conventional methods are always deterministic, rather than taking the natural spatial variability of soil properties into account. Therefore, in this study, an attempt has been made to model the real soil conditions by the spatial variability of the soil young modulus based on a three-dimensional random field. By combining finite difference analysis with random field theory, preliminary investigation has been performed into the surface settlement with spatially random Young modules. For this purpose, a combination of finite difference numerical method, random field and Monte Carlo simulation is used which is known as the random finite difference method (RFDM). The procedure used is re-implemented by the authors in MATLAB environment in order to combine it with The FLAC3D program and a series of parametric analyses were conducted to study the effects of uncertainty due to the variability of soil Young’s modulus on ground movements. Results show that the mean value and coefficient of variation (COV) related to the maximum surface settlement (Smax) increase with increasing the Scale of fluctuation (SOF) from 28 mm to 31 mm and from 0.02 to 0.35, respectively. Also, the variability of soil properties is effective in both size and distribution of land deformation in three dimensions, and ignoring it leads to minimizing the risk of excessive subsidence.
       
  • 3D Zonation model of primary haloes and geochemical prospecting pattern of
           Aliabad Cu-Mo deposit, Yazd, Central Iran

    • Abstract: Most of hydrothermal ore deposits are controlled by geological structures and they are often a product of multistage hydrothermal activities, as a result, primary alteration haloes usually overlap in the vertical direction. By distinguishing the hydrothermal stages associated with ore-forming processes, one can determine the timings of hydrothermal activities and use the results as a method to identify blind mineralization. In order to explore probable blind mineralized zones of the Aliabad deposit, it is necessary to evaluate the element concentrations towards depth or margins of the deposit. Modelling primary geochemical haloes could be useful in this stage. The Aliabad porphyry Cu-Mo deposit, located in the southern segment of the Central Iran and adjacent to the northern border of the Urmia-Dokhtar volcanic belt and east of Dehshir fault. Ore bodies at the Aliabad deposit are primarily controlled by structural features, which provide an opportunity to investigate the zonality in primary halos in this copper-molybdenum porphyry deposit. The primary geochemical characteristics of the mineral deposit were studied based on geochemical analysis of 1559 core samples from 24 drill holes. The formation of the primary geochemical haloes, which joins the ore body up to the surface, can be associated with hydrothermal fluid diffusion through fracture (fissures) zone developed in the rocks of the folding axis in the mining area. Along the vertical direction, the concentrations of Cu, Ag and Fe shows an increasing trend from surface to the ore body, at all boreholes; while the concentration of Pb, Mn and Bi are decreased with depth at the same environment. A detailed zonality sequence of indicator elements is obtained using the variability index of these elements: Pb → (Bi, Mn, Mo) → Cr → Ni → (Sb, V, Zn) → (Ag, Co, Cu, Fe, S) → P. According to this zonality, indexes such as Vz4=Pb×Mn/Cu×Ag and Vz5=Pb×Mn/Cu×Ag×Co can be constructed and considered as a significant criterion for predicting the Cu potential at a particular depth. Studying the distribution of the zoning indexes at different levels revealed high values of proposed indexes in the northwest and south of the area. It can be concluded that copper mineralization will continue to deeper and unexplored parts of the deposit at northwest of the study area. Consequently, it is suggested that further investigations concentrate on geophysical operations and it is highly recommended to drill additional boreholes at these areas. It is noteworthy that new drillings of the north western part must continue deeper than current boreholes (>150 m); because geochemical zonality indexes are extended to deeper parts. This extension is not observed for the southern part, so, additional drillings at the southern part can be shallower than 150 m.
       
  • Key group analysis based on DDA method for rock slope stability analysis

    • Abstract: Inhomogeneity and discontinuities play a key role in resistance and behavior of rock masses. Today engineers have a wide range of methods to analyze the stability of rock slopes. Due to its simplicity and speed of evaluation, static analysis methods continue to play a special role in the stability assessment of jointed rock slopes. One of the most well-known static methods used in the stability analysis of rock slopes is the Key Block method (KBM), which is based on the key block finding and analyzing. In this method, if none of the key blocks are unstable, it implies that rock mass is stable. Occasionally, the combination of a number of stable blocks has led to formation a group of blocks that sometimes leads to instability. Therefore, the stability analysis of the jointed rock masses leads to study of groups of blocks that are potentially dangerous for the stability of a rock slope. The Key Group method (KGM), with its progressive approach, finds these critical groups and focuses the stability calculations on these groups. In order to increase the efficiency, accuracy and speed of this method and to develop it in three dimensions, it is decided to combine it with one of the numerical methods. The standard Discontinuous Deformation Analysis method (DDA) is an implicit method based on the finite element method. This is a sophisticated numerical method for modeling the quasi-static and dynamic behavior of rock block systems in discontinuous rock masses. The goal of this paper is to use of the potency of the numerical method of DDA to analyze the candidate key group. For this purpose, the DDA computer program was developed with Mathematica programming language and combined with the KGM software. The resulting package, after selecting the key group by the KGM method, proceeds to analyze it with the DDA method. Two examples solved illustrating the reasonable results and the efficiency of this developed method compared to that of the original KGM and SKGM. The results validated the proper accuracy and good performance of the procedure developed in this research.
       
  • Relationship between physical and mechanical properties of jointed rocks
           in Central Iran (Bafgh Block)

    • Abstract: Central Iran is one of the active mining zones of Iran and has great mining potential. Large iron mines such as Choghart, Chadormalu, Sechahoon, Chahgaz, Lake Siah, Mishdavan, etc. are located in this zone. Other metals also exist in this zone Like lead and zinc in Koushk, Chahmir and Taj-Kooh mines. Also, non-metallic deposits such as Fahraj limestone mines and building stone mines such as Bishedar marble, Taft travertine, Shirkooh granite, etc. are being extracted in this zone. Considering mineral resources and current explorations, the mines continue to develop and one of the important topics in the exploration and exploitation phase is the study of geomechanical conditions in the zone under study. The relationship between the physical and mechanical properties of rocks makes it possible to predict the strength of intact rock which can be used in preliminary designing of the mine at less cost and less time and just with some simple tests on exploratory boreholes and surface samples. It can also be used in mines under extraction to gain more comprehensive knowledge of the mechanical properties of mine rocks. In this study, mechanical properties such as uniaxial compressive strength, point load, indirect tensile strength (Brazilian) as well as physical properties of rock such as density, porosity, compressive wave velocity (P-wave) and electrical resistivity were measured on selected samples taken from Choghart, Sechahoon, Lakeh Siah, Koushk, Bishehdar marble, Taft travertine, Ravar sandstone and the cores of 5 geotechnical boreholes from the Anomaly VI of Central Iran Iron Ore and 4 geotechnical boreholes of Chahgaz iron ore mine. The purpose of these measurements is investigating the relationship between mechanical and physical properties of the samples, especially electrical resistivity. In the first step, 300 surface and depth samples were collected from the mines mentioned above. After preparing the cores, effective porosity and density were recorded according to the standards (weighing the saturated and dry sample method). Also, the electrical resistivity was calculated by measuring the voltage and electrical current in the samples. The results demonstrated that there is a high correlation between P-wave velocity and electrical resistivity in all the samples. Furthermore, both parameters of P-wave velocity and electrical resistivity are dependent on porosity, and electrical resistivity like P-wave velocity, has a good relationship with mechanical properties of sedimentary rocks and volcano-sediments. Hence, the special electrical resistivity can be used as a non-destructive test to estimate the mechanical properties of rocks. Additionally, the presence of metal ores in the samples in low percentages does not cause errors in estimating physical and mechanical parameters as long as density is less than 2.8 gr/cm3. For samples with high metal content, induced polarization measurements can reduce uncertainty of the electrical resistivity.
       
  • Numerical modeling for Selection of appropriate tunneling method for S
           station of Isfahan subway

    • Abstract: Nowadays, due to the increasing urban environments, increasing the density of surface structures and the lack of space for intra-urban transportation, the need to implement underground structures such as tunnels and subway station in urban environments has been felt more than ever. One of the important factors in the implementation of deep underground stations in urban environments is the choice of suitable excavation methods that have a significant impact on the stability of the tunnel space during excavation, surface sinking caused by drilling, and also the long-term stability of the excavated space. In this research, considering the geotechnical characteristics of the land and the geometry of the station under study, three common methods for excavation of subway station, including NATM, STM, and cut & cover methods with support systems such as shotcrete, piles and ribs, fore polling and nailing numerically modeled and have been evaluated and reviewed for the stability of the space and tunnel wall displacement. Main object of this research is finding of suitable excavation method in terms of stability. Three common methods for excavation of large tunnels, including NATM, STM, and cut & cover methods are investigated using the numerical model in finite difference method with FLAC3D software in a case study. According to the results, the maximum displacement in the environment around the station is related to cut & cover method and the minimum is related to the STM method with the nailing support system. Numerical modeling of various methods for implementing this space has been done using the finite difference method with FLAC3D software. Sensitivity analysis for changing of geometric parameters of support systems was done. According to the results, the maximum displacement in the environment around the station is related to cut & cover method and the minimum is related to the STM method with the nailing support system.
       
  • Crack growth properties in granite specimens consisting non-persistent
           joint under punch shear through test

    • Abstract: Experimental and numerical methods (Particle Flow Code) were used to investigate the effect of echelon notchs on the shear behaviour of joint’s bridge area in granite. A punch-through shear test was used to model the granite cracks under shear loading. Granite samples with dimension of 20 mm×150 mm×40 mm were prepared in the laboratory. Within the specimen model and near the edges, four edge notches were provided. Nine different configuration systems were prepared for notches. In these configurations, the length of each notch was taken as 3 cm, 4cm and 5 cm. Assuming a plane strain condition, special rectangular models were prepared with dimensions of 100 mm×100 mm using particle flow code in two dimensions. similar to those for joints configuration systems in the experimental tests i.e. 9 models with different rock bridge lengths and rock bridge joint angle were prepared. The axial load was applied to the punch through the central portion of the model. This testing showed that the failure process was mostly governed by the rock bridge length and rock bridge angle. The shear strengths of the specimens were related to the fracture pattern and failure mechanism of the discontinuities. It was shown that the shear behaviour of discontinuities is related to the number of the induced tensile cracks which are increased by increasing the rock bridge angle. The strength of samples decreases by increasing the joint length. The failure pattern and failure strength are similar in both methods i.e. the experimental testing and the numerical simulation methods.
       
  • An exploratory model for sediment-hosted lead and zinc deposits by using
           the fractal method in Yazd block- Central Iran

    • Abstract: Structure processes have a significant role in forming sediment-hosted lead and zinc deposits. On other words, they are formed in an individual pattern located in the related rift basins. So, the first-order, the second-order, and the third-order basins have been created. Faults operate as the conduct of ore-bearing fluid and the bounding-the second-order basins. By starting rifting, hydrothermal fluid enters a sedimentary basin and as a result of the extending faults, it creates convection cells confined by faults. Therefore, structural processes are the main control factor for these deposits. Also, factors controlling the mineralization are recognized by spatial analysis methods. In this study, to identify controlling factors and present an exploratory pattern for sediment-hosted Pb-Zn deposits in the southern part of the Yazd Block, the fractal (Box- counting) method has been used. This method was utilized to estimate the distance of sub-basins which are the host of sediment-hosted Pb and Zn mineralization for the first time. The results of this method depicted three different populations representing three factors controlling the mineralization in the studied area. These results were consistent with the basin structure which has been formed from three sub-basins. Therefore, three populations obtained from the fractal analysis showed the dimensions of three sub-basins in the studied area. The distance between mineral deposits in the third-order basin obtained about 8 Km while it is about 31 Km for the second-order basins. So, three second-order basins were recognized in which the distance between sub-basin numbers 1 and 2 is about 30 Km while it is about 60 Km between sub-basin numbers 2 and 3. Based on this exploratory model, there could be another second-order basin between sub-basin numbers 2 and 3. According to reports and literature, no other deposit has been discovered between them until now. So, based on the suggested model, there is a possibility of other deposits occurring between sub-basins numbers 2 and 3.
       
  • Optimal location of non-level tunnels using a new probabilistic approach

    • Abstract: With the development of urban subway construction and commercialization in the downtown areas, crossing metro tunnels and underground spaces are frequently encountered in geotechnical and civil engineering practice. One of the important issues in designing non-level tunnels is determining the optimal location of tunnels relative to each other. This is especially important in dense urban areas, often in the form of flat tunnels. In this research, in order to optimally locate the two factors of land subsidence and stability (safety factor) of tunnels have been used. Optimal placement of non-level tunnels in various geological conditions should use probabilistic methods and reliability. On the other hand, knowing the impact of each of the design parameters on the amount of subsidence and safety factor can reduce the damage to surface structures. In this paper, PLAXIS3D finite element software is used to study different states of non-level tunnels. Then, using the harmony search algorithm, two limit state functions are estimated separately for safety factor and maximum ground surface subsidence. Then, using the two limit state functions obtained from the previous step and the first-order reliability methods and Monte Carlo simulation in RT software, the best location for digging a new tunnel compared to the previous (existing) tunnel based on having the highest safety factor and lowest ground subsidence. The results show that the probability of failure of the first (existing) tunnel is approximately 0.3% and it will have ideal conditions in terms of stability and reaction to the optimal position of the new tunnel.
       
  • Evaluation of phosphate processing from the green rock with the existing
           Esfordi plant circuit

    • Abstract: ABSTRACT Esfordi Phosphate Mine is a deposit consisting of igneous rocks which is the most important producer of phosphate concentrate in Iran. This plant flowsheet is designed to separate phosphate from iron minerals. Green rocks are a part of the deposit containing magnesium silicate minerals as gunge which represent more than five million tons of the mine reserve with an average P2O5 grade of 7%. Nevertheless, green rock has not been used as feed for the existing processing plant. In this research, green rock processing by the current flowsheet of the factory was evaluated. Green rock samples were identified under the chemical, mineralogical, and liberation analysis. It was found that part of the iron is in the form of magnetite mineral. High-intensity magnetic experiments showed that the silicate minerals were transferred to the magnetic concentrate (10.38% MgO recovered by use of a 5000 gauss magnetic field). The results of flotation showed that the recovery and grade of P2O5 are very low(recovery 7.39% and grade 21.11%), and improved to 38.655% and 27.98% after de-sliming the feed. Low phosphate recovery and hyperstability of the froth were observed when green rock fed to the processing plant. The performance of the grinding circuit and de-sliming hydrocyclones was investigated. Some suggestions were offered to improve the efficiency of the current processing circuit for the green rock processing. KEYWORDS Phosphate, Green rock, Flotation, Processing circuit modification, Silicate mineralsABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT ABSTRACT
       
 
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