Journal of Mining and EnvironmentJournal of Mining and Environment
http://jme.shahroodut.ac.ir/
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Feed provided by Journal of Mining and Environment. Click to visit.Development of geometallurgical indexes (GI) for semi-autogenous milling at Sarcheshmeh ...
http://jme.shahroodut.ac.ir/article_1669_0.html
Geometallurgy tries to predict the instability of process behavior of the ores caused by variability of geological settings, and to optimize the minerals value chain. Understanding the ore variability and subsequently process response are considered to be the most important functions of an accurate geometallurgical study. In this paper geometallurgical index is presented as a new tool to optimize mining activities. Geometallurgical index is described as any geological feature which makes a footprint on the process performance of ores. In a comprehensive research at Sarcheshmeh porphyry copper mine, geological features, which affect the main process include product’s grade and recovery, and plant’s throughput, were subjected to investigate. In the current report, the rock hardness variability, in terms of semi-autogenous grinding (SAG) power index (SPI) and its effects on the mill throughput and energy consumption are presented. Ninety samples were collected based on geological features including lithology, hydrothermal alteration, and geological structures. The samples were characterized using XRD, XRF, and electron and optical microscopy. The Starkey laboratory mill, commercialized by Minnovex, was used to perform the SPI comminution test. The results of SPI showed a wide range of hardness, varies from 12 to 473 minutes. The correlation between the SPI results and the geological features showed that the lithology is the key geological feature that defines the hardness variability. In addition the hydrothermal alteration would be an effective parameter in the period that the plant is fed with a single lithology.Mon, 27 Jan 2020 20:30:00 +0100A New Stability Approach using Probabilistic Profile along Direction of Excavation
http://jme.shahroodut.ac.ir/article_1671_195.html
Estimation of the possible instability that may be encountered in the excavation slope(s) during the planning and application steps of the rock excavation processes is an important issue in geoengineering. In this paper, a modelling method is presented for assessing the probability of wedge failure involving new permanent or temporary slope(s) along the planned excavation direction. The geostructural rock slopes including wedge blocks are determined geometrically in the first step. Here, a structural data analysis system that includes a series of filterings, sortings, and linear equations used to reveal the necessary geometric conditions for the wedge form is developed and used. The second step involves the 3D visualization and Factor of Safety (FS) using the limit equilibrium analysis of wedges on both the actual and planned new excavation surfaces. The last step is the Monte Carlo simulation, which is used in assessing the instabilities on the actual and planned new excavation surfaces. These new slope surfaces that have not yet been excavated are called the virtual structures. As a result of this work, the mean and probabilistic FS variations in the planned excavation direction are obtained as profiles. We suggest the preliminary guidelines for the mean and probability of the wedge failure in the excavation direction. The model is tested on a motorway cut slope. The FS results obtained from the Monte Carlo simulation calculations are compared with the mean results and the changes are revealed with the reasons.Tue, 31 Dec 2019 20:30:00 +0100Modeling and Optimization of Truck-Shovel Allocation to Mining Faces in Cement Quarry
http://jme.shahroodut.ac.ir/article_1652_195.html
Truck and shovel are the most common raw material transportation system used in the cement quarry operations. One of the major challenges associated with the cement quarry operations is the efficient allocation of truck and shovel to the mining faces. In order to minimize the truck and shovel operating cost, subject to quantity and quality constraints, the mixed integer linear programing (MILP) model for truck and shovel allocation to mining faces for cement quarry is presented. This model is implemented using the optimization IDE tool GUSEK (GLPK under SciTE Extended Kit) and the GLPK (GNU Linear Programming Kit) standalone solver. The MILP model is applied to an existing cement quarry operation, the Kohat cement quarry located at Kohat (Pakistan) as a case study. The analysis of the results of the relating case study reveals that significant gains are achievable through employing the MILP model. The results obtained not only show a significant cost reduction but also help in achieving a better coordination among the quarry and quality department.Tue, 31 Dec 2019 20:30:00 +0100An investigation on the effect of shell liner type on performance of industrial SAG mills using DEM
http://jme.shahroodut.ac.ir/article_1677_0.html
The shell liner type, rotation speed, and ball filling percent are the key factors influencing the charge behavior inside the SAG mills, and consequently, their performance. In this work, the milling operation of industrial SAG mills is investigated using the Discrete Element Method (DEM). First, an industrial SAG mill with dimensions of 9.50 m × 4.42 m that has a Smooth-type liner is simulated. Then by changing the liner types, i.e. Wave, Rib, Ship-lap, Lorain, Osborn, and Step liners, six other independent simulations are performed. In order to investigate the impact mechanism and improve the mill performance, two new parameters called ‘head height’ and ‘impact zone length’ are introduced. Then the effects of the mill shell liner type on those parameters at two different mill speeds, i.e. 70% and 80% of its critical speed (CS), are evaluated. Also for validation of the simulation results, a laboratory-scale SAG mill with dimensions of 57.3 cm × 16.0 cm is simulated. The results obtained indicate that the Osborn liner, due to the angularity of its lifters and their proper number and thickness, performs best because it increases both parameters more than the other liners. Thus this liner is recommended as the best and optimal liner in this research work and is suggested for installation inside the industrial SAG mills. Also the Wave liner, due to its specific geometrical shape and its wavy lifters as well as their low number and inadequate thickness, provides the lowest charge ‘head height’. Therefore, it is not recommended to install this liner inside the industrial SAG mills. Meanwhile, comparison of the simulations related to the laboratory-scale SAG mill with the experimental results demonstrates a good agreement that validates the DEM simulations and the software used.Sun, 09 Feb 2020 20:30:00 +0100A review of Rock Burst’s Experimental Progress, Warning, Prediction, Control and Damage ...
http://jme.shahroodut.ac.ir/article_1655_195.html
Rock burst is the most attractive and hot research area in geomechanics, mining, and civil engineering due to the increasing depth of mines and construction of deep underground structures. It has also been a severe problem in ground control measures in the last few decades. Many studies have been done by different researchers in order to minimize the hazards of rock burst and to provide a safe mining/working environment. It is important to review the current advancement of rock burst prediction and its preventive measures. This paper reviews the experimental progress of rock burst warning, prediction, control measures, and potential damage measures. Different effective methods of rock burst prediction and control are also described.Tue, 31 Dec 2019 20:30:00 +0100Investigating alteration zone mapping using EO-1 Hyperion imagery and airborne geophysics data
http://jme.shahroodut.ac.ir/article_1684_0.html
Hyperspectral remote sensing records reflectance or emittance data in a large sum of contiguous and narrow spectral bands, and thus has many information in detecting and mapping the mineral zones. On the other hand, the geological and geophysical data gives us some other fruitful information about the physical characteristics of soil and minerals that have been recorded from the surface. The Sarcheshmeh mining area located in the NW-trending Uromieh-Dokhtar magmatic belt within Central Iran is mainly of porphyry type, and is associated with extensive hydrothermal alterations. Due to the semi-arid type of climate with abundant rock exposure, this area is suitable for application of remote sensing techniques. In this work, we focus on generating the alteration maps around Cu porphyry copper deposits using the spectral angle mapper algorithm on Hyperion data by applying two filters named reduction to pole and analytical signal on a total magnetic intensity map and generating the Kd map from radiometry data. What is clear is the high importance of applying the adequate pre-processing on Hyperion data because of low signal-to-noise ratio. By comparing the known deposits in the region with the results obtained by applying the mentioned methods, it is revealed that not all the higher K radiometric values are entirely associated with the hydrothermal alteration zones, and in contrast, the potassic alteration map extracted from Hyperion imagery successfully corresponds to the alteration zones around the Sarcheshmeh mining area. Finally, the results particularly obtained from processing the Hyperion data are confirmed by indices of Cu porphyry deposits in the region.Sun, 23 Feb 2020 20:30:00 +0100A Comparative Study of SVM and RF Methods for Classification of Alteration Zones Using Remotely ...
http://jme.shahroodut.ac.ir/article_1513_195.html
Identification and mapping of the significant alterations are the main objectives of the exploration geochemical surveys. The field study is time-consuming and costly to produce the classified maps. Therefore, the processing of remotely sensed data, which provide timely and multi-band (multi-layer) data, can be substituted for the field study. In this study, the ASTER imagery is used for alteration classification by applying two new methods of machine learning, including Random Forest and Support Vector Machine. The 14 band ASTER and 19 derivative data layers extracted from ASTER including band ratio and PC imagery, are used as training datasets for improving the results. Comparison of analytical results achieved from the two mentioned methods confirmed that the SVM model has sufficient accuracy and more powerful performance than RF model for alteration classification in the study area.Tue, 31 Dec 2019 20:30:00 +0100On the Analytic Solutions of Elastic Net Displacements around A Circular Tunnel
http://jme.shahroodut.ac.ir/article_1685_0.html
Displacements around a tunnel, occurring as a result of excavation, consist elastic and plastic parts. This paper discusses the elastic part of displacements as a result of excavation, called net displacement. In general, the previous analytical solutions presented for determining the displacements around a circular tunnel in elastic medium do not give the net displacements directly. The well-known Kirsch solution is the most widely used method for determining induced stresses and net displacements around a circular opening in a bi-axially loaded plate of homogeneous, isotropic, continuous, linearly elastic material. However, the complete solution for obtaining the net displacements is not presented or highlighted in available literature. Using linear elasticity, this paper reviews and presents three different analytical methods for determining net displacements directly as well as induced stresses around a circular tunnel. The three solution methods are Lame' method, airy stress function method, and complex variable method. The tunnel is assumed to be situated in elastic, continuum and isotropic medium in plane strain condition. The solutions are presented for both hydrostatic and non-hydrostatic in situ stresses in 2-Dimentional biaxial loading condition along with an internal pressure. Loading and unloading in tunnelling occurring as a result of excavation and stress differences between induced and initial ones have been considered to evaluate net displacements directly. Finally some examples are given to demonstrate the complete solution and show the difference between net elastic displacements as a result of excavation and total elastic displacements which are not real.Sun, 23 Feb 2020 20:30:00 +0100Bayesian Data Fusion: a Reliable Approach for Descriptive Modeling of Ore Deposits
http://jme.shahroodut.ac.ir/article_1449_195.html
Recognition of ore deposit genesis is still a controversial challenge for economic geologists. Here, this task was addressed by the virtue of Bayesian data fusion (BDF) implementing available proofs: semi-schematic examples with two (Cu and Pb + Zn) and three (Cu, Pb + Zn and Ag) evidences. The data, in current paper are just concentrations of indicated elements, were collected from Angouran’s deposit in Iran at prospecting and general exploration stages. BDF was used for discrimination between three geneses of Massive Sulfide, Mississippi and SEDEX types. Better genesis recognition with clear discrimination between the geneses was achieved by BDF as compared with earlier studies. The results showed that uncertainties were reduced from 50% to less than 30% and deposit recognition was improved greatly. Furthermore, we believe that using more properties can have a beneficial effect on the overall outcome. The comparison made between 2 and 3 properties showed that the amount of probable belonging values to any type of deposit was greater in 3 properties. It was also confirmed that using the completed information from the various stages of exploration progress can be amplified and be used for genesis recognition via BDF.Tue, 31 Dec 2019 20:30:00 +0100Study of damage zone around a circular opening using acoustic emission technique
http://jme.shahroodut.ac.ir/article_1682_0.html
One of the methods used to investigate the damaged zone in rock structure is the acoustic emission method. This method is based on receiving the elastic waves that are produced by deformation and cracking of the rock mass around the underground excavation. In this research, a study is conducted on the rock samples by a numerical method to investigate the damaged zone caused by the excavation of circular space on it. For this purpose, 33 cube samples of three different material types including sandstone, concrete, and cement-plaster mortar are prepared. A circular hole is drilled in the center of each sample. The hole diameter is 20 or 25 mm. The samples are loaded uniaxially or biaxially with different stress rates. It is tried to study the acoustic events occurring in the samples during the test, and their locations are investigated. Then the experiments are evaluated by a numerical method using the FLAC3D software and some developed codes. The relation between the sample damaged zone where the acoustic events have occurred during the loading period and the numerical elements that reach a degree of tensile and shear yield is studied. The results obtained show that the amount of cumulative acoustic parameters in cement-plaster mortar specimens is more than the others. In fact, the finer grains, the more amounts of energy and counts will be produced. Also, the results show that with increase in the lateral pressure and loading rate, the amount of cumulative energy and counts decreases.Wed, 19 Feb 2020 20:30:00 +0100Stability Analysis of Salt Cavern Gas Storage Using 2D Thermo-Hydro-Mechanical Finite-Element ...
http://jme.shahroodut.ac.ir/article_1624_195.html
Ensuring the stability and integrity of underground gas storage salt caverns is a very complicated subject due to the non-linear and time-dependent behavior of rock salts under complicated thermal and mechanical loading conditions. For this reason, pressure and temperature fluctuations in the caverns and their surrounding strata must be integrated into the analysis and the numerical tools that are used for this purpose. LOCAS, a 2D axisymmetric finite-element code, dedicated to the stability analysis of underground salt spaces, was applied to assess the effects of various operating and geometrical parameters on the cavern behavior. In this paper, we aimed to give an overall assessment of the behavior of the salt caverns used for natural gas storage. In this work, some specific loading scenarios were considered first, followed by thorough parametric and sensitivity analyses to reveal the impacts of the geometrical parameters and operational parameters involved on the behavior of salt caverns using the modern stability criteria. The findings showed that the onset of dilation was more likely to happen within the first cavern life cycle when pressure dropped to the minimum level. As for the potential of tension occurrence in the surrounding rock, this is more likely to happen by increasing the number of operation cycles, especially in the upper one-third of the cavern wall. Finally, it was seen that the cavern depth and minimum cavern internal pressure had even more important influences than the others on the salt cavern behavior.Tue, 31 Dec 2019 20:30:00 +0100Gold, Silver and Iron in Iron Oxy-hydroxide Precipitate Formed in Process of Acid Mine Drainage
http://jme.shahroodut.ac.ir/article_1689_0.html
Oxidation of sulfide containing ores is main cause of Acid mine drainage (AMD), which is environmental problem associated with both abandoned and active mines. Iron-bearing sulfide minerals can be oxidized and form mine waters with high sulfate content, low pH, high electrical conductivity, high redox potential and high concentrations of iron, aluminum and other heavy metals. In the process of acid mine drainage precipitation of poorly crystalized oxy-hydroxides of iron with large active surface can occur. On the surface of iron oxy-hydroxide precipitated particulate matter, anions and cations (metals) could be adsorbed. Mine waters can contain a certain amount of precious metals, which could also be adsorbed onto iron particulate matter surface, which was investigated in this research. In this study, samples of iron oxy-hydroxide particulate matter at abandoned gold mine waste in Bakovići (Central Bosnia and Herzegovina) were used. Several parameters were measured on the selected mine waste samples: pH, water content, particle size distribution, sulfate content, electrical conductivity, redox potential, and amounts of gold, silver and iron. The results indicate that significant amount of gold (average: 6.8 mg/kg), and silver (average: 7.13 mg/kg) are present in iron precipitate. Adsorption of precious metals onto iron oxy-hydroxide surface is strongly pH dependent. At very low pH which was found in investigated samples, desorption of precious metals is favorited. Thus, precious metals are only partially adsorbed onto iron oxy-hydroxide surface.Thu, 27 Feb 2020 20:30:00 +0100Identification of Geochemical Anomalies Using Fractal and LOLIMOT Neuro-Fuzzy modeling in Mial ...
http://jme.shahroodut.ac.ir/article_1625_195.html
The Urumieh-Dokhtar Magmatic Arc (UDMA) is recognized as an important porphyry, disseminated, vein-type and polymetallic mineralization arc. The aim of this study is to identify and subsequently determine geochemical anomalies for exploration of Pb, Zn and Cu mineralization in Mial district situated in UDMA. Factor analysis, Concentration-Number (C-N) fractal model and Local Linear Model Tree (LOLIMOT) algorithm used for this purpose. Factor analysis utilized in recognition of the correlation between elements and their classification. This classified data used for training the LOLIMOT algorithm based on relevant elements. The results of the LOLIMOT algorithm represent anomalies in areas with no lithogeochemical samples. Although, the C-N log-log plot for target elements were generated based on stream sediment and lithogeochemical samples which could be delineated mineral potential maps of the target elements. Results obtained by the LOLIMOT and fractal modeling show that the SW and the Eastern parts of the area are proper for further exploration of Cu, Pb, and Zn.Tue, 31 Dec 2019 20:30:00 +0100Investigation of the effect of the number of lifters on performance of pilot-scale SAG mills ...
http://jme.shahroodut.ac.ir/article_1688_0.html
The number of lifters of mill shell liners, mill rotation speed, and filling percentage of grinding media are three of the most important parameters influencing the charge behavior and the trajectory of ball motion inside the SAG mills, consequently their performance. In this paper, milling operation of pilot-scale SAG mills using Discrete Element Method (DEM) is investigated. First, a pilot-scale SAG mill with dimensions of 3.0 m × 1.5 m with no lifter is simulated. Then, by adding respectively one, two, four, eight, sixteen, and thirty-two rectangle lifter(s), six other independent simulations are performed. Effects of the number of lifters on two new parameters introduced by the authors i.e. ‘head height’ and ‘impact zone length’ at two different mill speeds, i.e. 70% and 80% of its critical speed (NC) are evaluated. Also, in order to validate simulation results, a laboratory-scale SAG mill is simulated. The results indicate that the optimum number of lifters for pilot-scale SAG mills is between 16 and 32 lifters with medium thickness. Liners with the number of lifters in this range require less mill speed to create cataract motions. But liners, with the number of lifters less than this range, need a higher mill speed. Also, liners with a number of lifters beyond this range need less mill speed and they can cause centrifugal motions in the balls. Comparison of the simulations related to the laboratory-scale SAG mill with experimental results demonstrates a good agreement which validates the DEM simulations and the software used.Tue, 25 Feb 2020 20:30:00 +0100Application of Sequential Gaussian Conditional Simulation into Underground Mine Design Under ...
http://jme.shahroodut.ac.ir/article_1540_0.html
In mining projects, all uncertainties associated with the project must be considered to determine the feasibility study. Grade uncertainty is one of the major components of technical uncertainty that affects the variability of the project. Geostatistical simulation as a reliable approach is the most widely used method to quantify risk analysis to overcome the drawbacks of estimation methods entire an ore-body. In this paper, all developed algorithms by numerous researchers for optimization of underground stope layout were reviewed. After that, a computer program called Stope Layout Optimizer 3D (SLO3D) was developed based on a new heuristic algorithm in order to incorporate the influence of grade variability in final stope layout. Utilizing Sequential Gaussian Conditional Simulation (SGS), 50 simulations and a kriging model were constructed for an underground copper vein deposit situated in the southwest of Iran and final stope layout was carried out separately. It was observed that geostatistical simulation can effectively cope with the weakness of kriging model. Final results showed that the frequency of economic value for all realizations varies between 6.7M$ and 30.7M$. This range of variation helps designers to make a better and lower risk decision under different conditions.Tue, 03 Sep 2019 19:30:00 +0100Effects of Flocculant, Surfactant, Coagulant, and Filter Aid on Efficiency of Filtration ...
http://jme.shahroodut.ac.ir/article_1649_195.html
In the recent decades, water scarcity has become a major challenge for many reasons, especially the inadequate use of water resources. The mineral processing plant is among the most important water-consuming industries. Filtration, as one of the important processes in water recovery, is a process in which the solid-suspended particles are removed from the liquid. In the present work, the effect of the additives affecting the filtration process upon the responses including the resistance to filter cloth (R), specific cake resistance (α), moisture content, water recovery rate, and cake formation rate by the vacuum top-feed method is investigated. The experiments are performed by two methodologies: one-factor-at-a-time and statistical analysis. The additives are the flocculant, coagulant, surfactant, and filter aid. According to the one-factor-at-a-time methodology, the optimal type and dosage of the variables are as follow: flocculant A25 with a concentration of 15 g/L, perlite as the filter aid with an amount of 2.5%, surfactant cop 20-101 with a concentration of 3 cc/L, and the coagulant CaCl2.2H­2O with a concentration of 2.5 g/L. The usage of the flocculant, surfactant, and filter aid at the same time is also statistically analyzed with the aim of maximizing the cake formation rate and minimizing the moisture content of the filter cake. Under the optimal conditions and taking into account 11.68 g/t of the flocculant A25, 3.8% of perlite as the filter aid, and2.92 cc/L of the surfactant cop 20-101, the cake formation rate and the moisture content were obtained to be 0.297 mm/s and 12.7 %, respectively.Tue, 31 Dec 2019 20:30:00 +0100Geostatistical Modeling of Electrical Resistivity Tomography for Imaging Porphyry Cu ...
http://jme.shahroodut.ac.ir/article_1603_195.html
This work presents the application of a geostatistical-based modeling approach for building up electrical properties acquired from a geophysical electrical tomography survey deployed for the purpose of porphyry Cu exploration at the Takht-e-Gonbad deposit, in the central domain of Iran. Electrical data were inverted in 2D along several profiles across the main favorable zones of Cu-bearing mineralization to image electrical resistivity and chargeability properties. Upon tight spatial correlation of these geophysical properties and Cu mineralization (i.e. Cu grade), electrical models were constructed in 3D through geostatistical interpolation of 2D inverted data to provide insights into the geometry of probable ore mineralization. Anomalous geophysical zone that was coincident simultaneously with higher values of electrical chargeability and resistivity, was in accordance with the main body of high Cu grades generated from exploratory drillings. It reveals that the porphyry-type Cu mineralization system in this area has strong geophysical footprints controlled mainly by rock types and alterations. Note that these physical models supply valuable pieces of information for designing the layout of further exploratory drillings, constructing geological characteristics, separating non-mineralized form mineralized zones, and resource modeling.Tue, 31 Dec 2019 20:30:00 +0100Dilution risk ranking in underground metal mines using Multi-Attributive Approximation area ...
http://jme.shahroodut.ac.ir/article_1650_0.html
The contamination of ore with wastes or materials of lower than cut-off grade is referred to as dilution. Dilution is an undesirable phenomenon that, reduces product grade and, consequently, reduces sales prices and, on the other hand, adds extra cost to waste production. Therefore, the studying and evaluating the risk of dilution is important in mining and especially in underground mining. In this paper, using a powerful decision-making method, Multi-Attributive Approximation area Comparison (MABAC), the risk of dilution and ranking it in underground mines has been assessed. For this purpose, firstly, the most important parameters affecting the dilution in 10 mines of Venarch manganese mines were identified, and then weighed using the Fuzzy Delphi Analytical Hierarchy Analysis (FDAHP) method. Then, using the MABAC method, the dilution risk score for each mine was estimated, and subsequently, various mines were ranked in dilution risk. Then, with the implementation of the Cavity Monitoring System (CMS), and the measurement of the actual values of the dilution, the mines are ranked in dilution. The correct matching of the results of these two rankings indicates that the MABAC method is highly effective in the ranking of the risk. In the end, the risk ranking of the mines was done using the TOPSIS method, and the lack of full compliance with the results of this method with actual values indicates that the MABAC method is preferable to the above method.Tue, 24 Dec 2019 20:30:00 +0100Investigation of Bishop’s and Janbu’s Models Capabilities on Slope Stability Problems with ...
http://jme.shahroodut.ac.ir/article_1623_195.html
One of the most effective parameters in economics of open-pit mines is the pit slope angle, so that the slope angle more than the optimum value increases the probability of a large failure in the pit wall and the slope angle less than the optimum value leads to increasing stripping ratio and reducing net present value of mine. Therefore, in this paper, considering the limit equilibrium methods of modified Bishop and modified Janbu and numerical models of the slope stability analysis, the effect of overall slope angle on the Economics of open pit mines was investigated. In addition, it was shown that selecting the overall slope angle less than the optimum value leads to reducing the depth of open-pit mining (the ultimate pit depth) and consequently, reducing the net present value of mine. Finally, in homogenous and Isotropic media, the results of Bishop and Janbu and numerical modeling are close together.Tue, 31 Dec 2019 20:30:00 +0100Risk assessment of flyrock in surface mines using FFTA-MCDMs combination
http://jme.shahroodut.ac.ir/article_1666_0.html
Drilling and blasting method is the first choice for rock breakage in surface or underground mines due to the high flexibility against variations and low investment costs. However, any method has own advantages and disadvantages. Flyrock phenomenon is one of the drilling and blasting disadvantages that mining engineers have always conflicted with it in the surface mines blasting operations. Flyrock may lead to fatality and destroying of mine equipment and structures then its risk assessment is very essential. For flyrock risk assessment, the causing events that lead to flyrock along with their probabilities and severities should be identified. For this aim, the combination of fuzzy fault tree analysis (FFTA) and multi-criteria decision-making (MCDM) methods have been used. Based on the results, the relevant causing events of flyrock in surface mines were categorized into three major groups: design error, human error, and natural error. Finally, using obtained probabilities and severities for these three groups the risk matrix has been constructed. Based on the risk matrix, the risk number of flyrock occurrence due to the design errors, human errors and natural influence are 12, 6 and 2, respectively. Hence, in order to minimize the risk of flyrock, it is very vital for engineers to select appropriate values for the design events of blasting pattern such as burden, spacing, delays, hole diameter etc.Wed, 22 Jan 2020 20:30:00 +0100Assessment of Heavy Metal Contamination in Waters due to Mineral Salts Company from Mighan ...
http://jme.shahroodut.ac.ir/article_1653_195.html
The Mighan playa/lake is characterized as a closed catchment. In the recent years, the rapid industrialization and urbanization has resulted in a pollution area in the city of Arak. In this work, we focus on six regions around the playa/lake to study the distribution of heavy metals in the waters and their contamination risk. A total of 32 water samples are analyzed to determine the contamination degree of heavy metals, i.e. Hg, As, Cd, Cr, Cu, Pb, and Zn. The heavy metal pollution index, heavy metal evaluation index, and degree of contamination are utilized to assess the pollution extent of these metals. The spatial distribution patterns reveal that the waters in different areas of playa/lake are in a good condition. The island, lake in playa, and the Wastewater Mineral Salts Company are most seriously polluted with Pb, being higher than the standard of drinking water quality limit. Water in the wastewater treatment plant is polluted with Hg and As. The correlation matrix, factor analysis, and cluster analysis are used to support the idea that Pb may be mainly derived from the atmospheric input, and As and Hg from the wastewater treatment plant, agricultural lands, and domestic waste. Many native and migratory birds live in the Mighan playa, which is exposed to heavy metals. Therefore, it is required to monitor heavy metals in the Arak playa and to manage the municipal, industrial, and agricultural activities around it and to reduce them.Tue, 31 Dec 2019 20:30:00 +0100Detection of zones based on ore and gangue using fractal and multivariate analysis in Chah Gaz ...
http://jme.shahroodut.ac.ir/article_1691_0.html
Detection of mineralized zones based on ores and gangues is important for mine planning and excavation operation. Major goal of this research is determination of zones based on ores and gangues by combination of fractal and factor analysis in Chah Gaz iron ore (Central Iran). Concentration-Volume (C-V) fractal method was carried out for Fe and S which indicates the main mineralized zones consist of Fe, S and P values ≥57%, ≤0.4% and ≤0.3%, respectively. Factor analysis categorized variables in two groups including factor 1 (F1) and factor 2 (F2) for ore and gangue, respectively. The C-V fractal modeling on the derived factors shows four zones for the F1 and F2. Based on the correlation among results of fractal modeling on the elements and factors, first and second zones of F1 are proper for exploitation. Furthermore, the last and first zones of F1 and F2 can be assumed as main waste for mining excavation.Tue, 03 Mar 2020 20:30:00 +0100A Mathematical Model to Optimize Allocation Sequence in Dispatching Problem
http://jme.shahroodut.ac.ir/article_1582_195.html
Truck-Shovel fleet, as the most common transportation system in open-pit mines, has a significant part of mining costs, for which optimal management can lead to substantial cost reductions. Among the available dispatch mathematical models, the multi-stage approach is well suited for allocating trucks to respected shovels in a dynamic dispatching program. However, with this kind of modeling sequencing of the allocated trucks is not possible though it is important to find out the best solution so that getting the minimum accrued cost. To comply with the shortcoming of the traditional model, in this paper, a new hybrid model is developed and applied in Copper Mine of Iran, in which for each truck an allocation matrix is considered as input to the genetic algorithm implemented to determine the best solution. According to the obtained results, the optimal sequencing of the trucks can result in a significant (31%) cost reduction in a shift.Tue, 31 Dec 2019 20:30:00 +0100A 3D discrete element analysis of the failure mechanism of shallow foundations in rocks
http://jme.shahroodut.ac.ir/article_1692_0.html
In this research, a three-dimensional numerical modeling technic based on the three-dimensional particle flow code (PFC3D) is proposed to investigate the failure mechanism of rock foundations. Two series of footings with different geometries and areas have been considered in this study. The failure mechanism obtained in this study is similar to that of the Terzaghi’s but there is a negligible difference in between. Lastly, one equation was presented to calculate the bearing capacity based on the results achieved from the numerical model and the Mohr-Coulomb theory. The sensitivity analyses were performed on friction angle, cohesion and footing width. The results obtained from this equation was compared with the corresponding results given by equations of Terzaghi and Meyerhof. This comparison demonstrates a good agreement between them. In the friction angle sensitive analysis, the amounts of the bearing capacity diagram are very close to Meyerhof’s, which overlap each other.Wed, 04 Mar 2020 20:30:00 +0100Wellbore Trajectory Optimization of an Iranian Oilfield Based on Mud Pressure and Failure Zone
http://jme.shahroodut.ac.ir/article_1668_195.html
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.Tue, 31 Dec 2019 20:30:00 +0100Optimum selection of simulated geological models by multi-point geostatistics and ...
http://jme.shahroodut.ac.ir/article_1693_0.html
An accurate modeling of sophisticated geological units has a substantial impact on designing a mine extraction plan. Geostatistical simulation approaches, via defining a variogram model or incorporating a training image (TI), can tackle the construction of various geological units when a sparse pattern of drilling is available. The variogram-based techniques (derived from two-point geostatistics) usually suffer from reproducing complex and non-linear geological units as dyke. However, multipoint geostatistics (MPS) resolves this issue by incorporating a training image from a prior geological information. This work deals with the multi-step Single Normal Equation Simulation (SNESIM) algorithm of dyke structures in the Sungun Porphyry-Cu system, NW Iran. In order to perform a multi-step SNESIM algorithm, the multi-criteria decision-making and MPS approaches are used in a combined form. To this end, two TIs are considered, one for simulating dyke structures in the shallow depth, and two for simulating dyke structures in a deeper depth. In the first step, a TI is produced using geological map, which has been mined out during the previous exploration operations. After producing TI, the 35 realizations are simulated for the shallow depth of deposit in the area under study. To select the best realization (as a TI for the next step) of the simulation results, several statistical criteria are used and the results obtained are compared. To this end, a hybrid multi-criteria decision-making is designed on the basis of a group of statistical criteria. In the next step, the dyke structures in the deeper depth are also simulated by the new TIThu, 05 Mar 2020 20:30:00 +0100Comparison between Helical and Elliptical Static Mixers Performance in Column Flotation of ...
http://jme.shahroodut.ac.ir/article_1572_195.html
The flotation circuit in Sungun copper plant consists of two column flotation cells as cleaner, having fixed-spargers system. To achieve the expected aims in flotation step, there are serious operational challenges such as: fast choking of the static mixers, boiling problem, burping phenomena and pulp overflow to concentrate lander, maintenance and control problems. An attempt was exerted by implementing new helical static mixer in one of cleaner cells instead of old elliptical type to overcome the challenges. The changes resulted in proper performance of the column whereas burping phenomena due to choking was eliminated, finer bubbles were produced, and the boiling and overflow problems were solved. Also, the static mixers life time increased to 7 months in helical column cells from one month in elliptical column cells. In addition to 40% air consumption reduction and 20% solid percent increase in final product, the grade of Cu and Mo increased by helical static mixer replacement up to about 18.7% from 16.8% (11%) and to 511.1 ppm from 263 ppm (94%) in the cleaner step, respectively. Recovery of Cu and Mo were increased about 1.5% and 0.2%, respectively. Finally, the results proved the effectiveness of finer bubble generation on grade improvement is depend on minerals hydrophobicity as Mo grade increased more than Cu.Tue, 31 Dec 2019 20:30:00 +0100Mining and Environmental Degradation: A gift bring grief scenario for mining communities in ...
http://jme.shahroodut.ac.ir/article_1694_0.html
Sierra Leone is blessed with abundant natural resources, but yet prone to environmental degradation, due to mining operations. Most often, mining communities are faced with social tensions, as a result of the possible tradeoff between expected employment impact and the cost of mining operations to the environment. This article seeks to examine both the environmental and social implication of mining operations on three mining edge communities in Sierra Leone. This paper also utilized secondary data from published articles, government’s reports, workshops and conference proceedings, policy documents of non-governmental organizations (NGO), newspapers and the like to generate this writer's view on the topic under review. The thrust of the review will be on the following: Sierra Rutile Ltd, Koidu Holdings Ltd and Shandong Iron Ore Mines. The environmental performance index and the mining impact framework were used to clearly show the impact of mining operations on the environment in Sierra Leone. As a result of mining operation, deforestation is skyrocketing, public discomfort and air pollution is worsen, social unrest is increasing as a result of some unacceptable consequences including pollution of water source without recourse to short term remedy. Literature reviewed reveals that mining activities has two faces in Sierra Leone. One is that, it serves as a resource curse. An example to this sad reality is, the outbreak of civil war, social unrest among others. On the other hand, the mining sector is one of the principal backbones of the economy. It contributes to the livelihood of the country.Thu, 05 Mar 2020 20:30:00 +0100Predicting Unconfined Compressive Strength of Intact Rock Using New Hybrid Intelligent Models
http://jme.shahroodut.ac.ir/article_1573_195.html
Bedrock unconfined compressive strength (UCS) is a key parameter in designing thegeosciences and building related projects comprising both the underground and surface rock structures. Determination of rock UCS using standard laboratory tests is a complicated, expensive, and time-consuming process, which requires fresh core specimens. However, preparing fresh cores is not always possible, especially during the drilling operation in cracked, fractured, and weak rocks. Therefore, some attempts have recently been made to develop the indirect methods, i.e. intelligent predictive models for rock UCS estimation, which require no core preparation and laboratory equipment. This work focuses on the application of new combinations of intelligent techniques including adoptive neuro-fuzzy inference system (ANFIS), genetic algorithm (GA), and particle swarm optimization (PSO) in order to predict rock UCS. These models were constructed based on the collected laboratory datasets upon 93 core specimens ranging from weak to very strong rock types. The proposed hybrid model results were compared with each other, and the real data and multiple regression (MR) results. These comparisons were made using coefficient of correlation, mean of square error, mean of absolute error, and variance account for indices. The comparison results proved that the ANFIS-GA combination had a relatively higher accuracy than the ANFIS-PSO combination, and both had a higher capability than the MR model. Furthermore, the ANFIS-GA and ANFIS-PSO model results were completely in accordance with the UCS laboratory test, and they were more accurate than the previous single/hybrid intelligent models. Lastly, a parametric study of the suggested models showed that the density and Schmidt hammer rebound had the highest influence, and porosity had the lowest influence on the output (UCS).Tue, 31 Dec 2019 20:30:00 +0100On the applicability of some indirect tests for estimation of tensile strength of anisotropic rocks
http://jme.shahroodut.ac.ir/article_1696_0.html
Tensile strength of rock plays a noteworthy role in the failure mechanism of rock and determination of that can be beneficial in optimizing the design of the rock structures. Schistose rocks due to their inherent anisotropy in different directions of foliation show diverse strength at each direction. The purpose of this study is to compare and assess the tensile strength of phyllite which obtained in direct and indirect tensile test in different directions of foliation. To this end, several phyllite specimens with different foliation angles: 0º, 30º, 45º, 60º and 90º related to the loading axis (β) were prepared. Finally, direct tensile test, diametrical and axial point load tests, Brazilian test and Schmidt hammer test were conducted on 188 samples. The results of experimental test revealed that the maximum and minimum tensile strength in direct tensile testing tension is directly related to the angle of 0º and 90º. Also, it observed that the Brazilian tensile strength overestimates the tensile strength. Furthermore, an exponential correlation between the direct tensile strength and Brazilian tensile strength is introduced.Fri, 06 Mar 2020 20:30:00 +0100Numerical Modeling of Rock Slopes with a Potential of Block-Flexural Toppling Failure
http://jme.shahroodut.ac.ir/article_1622_195.html
One of the most important instabilities of rock slopes is toppling failure. Among the types of toppling failure, block-flexural failures are more common instability which occurs in nature. In this failure, some rock blocks break because of tensile stresses, and some overturn under their weights, and next to all of them topple together. Physical and theoretical modeling of this failure is studied by Amini et al. in 2015. Due to the complexity of this failure mechanism, no appropriate numerical model has been proposed so far. In this research, first, a literature review of toppling failure is summarized. Then, using UDEC software as distinct element method (DEM), the experimental models were analyzed numerically, and Voronoi joint model was applied to simulate the failure. The results of numerical simulations are compared with the outcomes of physical models and analytical solution. The comparison illustrates that numerical modeling has good agreement with corresponding experimental tests and theoretical approach. Also, the results show that although the mechanism of block-flexural toppling failure is complicated, the numerical code is well capable to analyze of this failure.Tue, 31 Dec 2019 20:30:00 +0100A New Method for Forecasting of Uniaxial Compressive Strength of Weak Rocks
http://jme.shahroodut.ac.ir/article_1701_0.html
The uniaxial compressive strength of weak rocks (UCSWR) is between the essential parameter for the design of underground excavations, surface and underground mines, foundations in/on rock masses and oil wells as an input factor of some analytical and empirical methods such as RMR and RMi. The direct standard approaches are difficult, expensive and time-consuming, especially with highly fractured, highly porous, weak and in homogeneous rocks. Numerous endeavors have been made to develop indirect approaches of predicting UCSWR. In this research, new intelligence method, namely relevance vector regression (RVR) improved by cuckoo search (CS) and harmony search (HS) algorithms is introduced to forecast the UCSWR. The HS and CS algorithms are combined with the RVR for determining the optimal value of the RVR controlling factors. The optimized models (RVR-HS and RVR-CS) were employed to available data given in open source literature. In these models, bulk density, the Brazilian tensile strength test, point load index test, and the ultrasonic test were used as the input, while the UCSWR was the output parameter. The performances of the suggested predictive models were tested according to two performance indices, i.e., mean square error and determination coefficient. The results show that the RVR optimized by HS model can be successfully utilized for estimation of the UCSWR with R2=0.9903 and MSE=0.0031203.Mon, 09 Mar 2020 20:30:00 +0100Comparative and Competitive Study of LDH/Diatomite and Chitosan/Diatomite for Adsorptive ...
http://jme.shahroodut.ac.ir/article_1667_195.html
In this work, two clay-based composites are prepared for the adsorptive removal of the chloride ions from aqueous solutions. These composites are characterized through Fourier transform-infrared spectroscopy, scanning electron microscopy, X-ray fluorescence spectroscopy, and X-ray diffraction analysis. The effects of different parameters such as the contact time, amount of adsorbent, chloride concentration, temperature, and pH are studied by batch experiments. Also the isotherm, kinetic, and thermodynamic of the adsorptive removal of the chloride ions from these two composites are investigated. According to the results obtained, the adsorptive removal of chloride ions is initially rapid, and the equilibrium time is reached after 30 min. The optimal pH value is 7.0 for a better adsorption, and the maximum capacity can be achieved, which is 60.2 mg/g with 1000 mg/L of the initial chloride concentration. The Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich adsorption models are applied to describe the equilibrium isotherms at different chloride concentrations. According to the equilibrium isotherms and the correlation coefficients (R2CDC: 0.9424, R2LDC: 0.996), the process can be described by the Langmuir model, and exhibits the highest removal rate of 97.24% (24.31 mg/g) with 250 mg/L of the initial chloride concentration. The pseudo-first-order and pseudo-second-order, intra-particle diffusion, and mass transfer kinetics models are used to identify the mechanism of the adsorptive removal of the chloride ions. The pseudo-second order model due the correlation coefficients (R2CDC: 0.9217-0.9852, R2LDC: 0.9227-0.9926) can be fitted to the kinetic calculations, and it is applicable for the adsorptive removal of chloride ions by the adsorbents. The thermodynamic calculations show that in a low chloride concentration, the sorption is spontaneous, associative, and endothermic; and in a high concentration, it is unspontaneous, dissociative, and endothermic. The calculated value of free energy (E) for adsorption onto the adsorbents suggests that the reaction rate controls the adsorptive removal of the chloride process rather than diffusion. It can be concluded that these two composites can be used as effective and applicable adsorbents for the adsorptive removal of chloride ions.Tue, 31 Dec 2019 20:30:00 +0100Safe and sustainable development in a hygiene and healthy company: using the decision matrix ...
http://jme.shahroodut.ac.ir/article_1714_0.html
This article describes the process of improving risk management practices in a foundry of the ALFET Company, Algeria. The proposed methodology is based on the Decision Matrix Risk Assessment (DMRA) technique. This technique allows making a risk assessment for each source of risk (machine, man, environment and management), which leads to the determination of the overall risk rate during the activity by a new concept. The latter giving a comprehensive vision of occupational health and safety and compares it with the ALARP principle to determine the acceptability of risk. The main goal of this work is to inculcate a culture on the effects of changing behaviors and attitudes, to disseminate the culture of continuous and sustainable progress within the enterprise and to ensure that a good atmosphere is maintained in the workplace. It aims to protect and promote the health and safety of workers and the working environment in order to promote a safe and sustainable development company. Our study shows that the working environment is tolerable in terms of health and safety at work. However, to promote safe and sustainable development in company, an action plan based on the evaluation of the field and feedback through priority actions is recommended for continuous improvement in OSH. Toward the workplace should be continuously monitored to detect risk factors as early as possible before they have negative effects.Fri, 13 Mar 2020 20:30:00 +0100Prediction of Blasting Cost in Limestone Mines Using Gene Expression Programming Model and ...
http://jme.shahroodut.ac.ir/article_1662_195.html
The use of blasting cost (BC) prediction to achieve optimal fragmentation is necessary in order to control the adverse consequences of blasting such as fly rock, ground vibration, and air blast in open-pit mines. In this research work, BC is predicted through collecting 146 blasting data from six limestone mines in Iran using the artificial neural networks (ANNs), gene expression programming (GEP), linear multivariate regression (LMR), and non-linear multivariate regression (NLMR) models. In all models, the ANFO value, number of detonators, Emolite value, hole number, hole length, hole diameter, burden, spacing, stemming, sub-drilling, specific gravity of rock, hardness, and uniaxial compressive strength are used as the input parameters. The ANN model results in the test stage indicating a higher correlation coefficient (0.954) and a lower root mean square error (973) compared to the other models. In addition, it has a better conformity with the real blasting costs in comparison with the other models. Although the ANNs method is regarded as one of the intelligent and powerful techniques in parameter prediction, its most important fault is its inability to provide mathematical equations for engineering operations. In contrast, the GEP model exhibits a reliable output by presenting a mathematical equation for BC prediction with a correlation coefficient of 0.933 and a root mean square error of 1088. Based on the sensitivity analysis, the spacing and ANFO values have the maximum and minimum effects on the BC function, respectively. The number of detonators, Emolite value, hole number, specific gravity, hardness, and rock uniaxial compressive strength have a positive correlation with BC, while the ANFO value, hole length, hole diameter, burden, spacing, stemming, and sub-drilling have a negative correlation with BC. Tue, 31 Dec 2019 20:30:00 +0100Application of phytoremediation to reduce environmental pollution of copper smelting and ...
http://jme.shahroodut.ac.ir/article_1715_0.html
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.Sat, 14 Mar 2020 20:30:00 +0100Numerical Modelling of Backfill Grouting Approaches in EPB Tunneling
http://jme.shahroodut.ac.ir/article_1661_195.html
One of the main issues involved during tunnel construction with tunnel boring machines is the tail gap grouting. This gap is between the external diameter of tunnel lining and the excavation boundary that is filled with high-pressure grouting materials. In this work, three different approaches of gap grouting modeling in the FLAC3D software are investigated with a special attention to the influence of the grout material hardening process. In the first approach, the grout is modeled as a liquid during injection, and considering the TBM advancement and its hardening time, the grout characteristics are changed to the properties of the solid grouting. In the second approach, the grouting material from the beginning of injection is considered with the properties of solid grouting in the model, and the liquid phase is ignored. In the third approach, without considering the back-filled grouting area in the model geometry, only the injection pressure is applied to the end of the shield and behind the installed segments. The validity of the approaches is evaluated with respect to the maximum ground surface settlement. All the three approaches estimate different surface settlement but the result of the first approach is closer to the monitoring data. Also as a sensitivity analysis, in this work, we investigate the effect of the elastic modulus of liquid and solid grouting materials on the amount of surface settlement that can help to gain a more accurate insight into the effect of grout mixture.Tue, 31 Dec 2019 20:30:00 +0100TBM Tunneling Construction Time with respect to the Learning Phase Period (LPP) and Normal ...
http://jme.shahroodut.ac.ir/article_1717_0.html
In every tunnel boring machine (TBM) tunneling project, there is an initial low production phase so-called the Learning Phase Period (LPP), in which low utilization is experienced and the operational parameters are adjusted to match the working conditions. LPP can be crucial in scheduling and evaluating the final project time and cost, especially for short tunnels for which it may constitute a major percentage of the total project completion time. The contractors are required to have a better understanding of the initial phase of a project to provide better estimates in the bidding documents. While evaluating and shortening of this phase of low production is important for increasing the productivity and daily advance rate of the machine, there has been limited a direct study and assessment of this period. In this work, we discuss the parameters impacting LPP, and introduce a new methodology for its evaluation. In this regard, an algorithm is introduced for estimation of the approximate extent of LPP based on some TBM tunneling case histories. On the basis of many statistical analyses conducted on the actual data and application of two different shapes of linear and polynomial for the description of LPP, a linear function is proposed for estimation of the learning phase parameters. The major parameters of this function are the learning conditions’ rating and the proportion of LPP to tunnel diameter (X1/D). Analysis of the correlation between these two parameters show a very good coefficient of determination (R2 = 92%). This function can be used for the evaluation of TBM advance rates in LPP and for adjusting the TBM utilization factor in the initial stages of a TBM tunneling project. The learning phase can affect the overall utilization rate and completion time of the tunnels, especially when their lengths are around a couple of kilometers. A true understanding of the LPP characteristics can help the contractors to come up with a more accurate bidding time and cost evaluation, and may also benefit the clients to arrange a better schedule for the final project delivery to the public.Tue, 24 Mar 2020 19:30:00 +0100Studying Relationship between Coal Intrinsic Characteristics in Spontaneous Combustion of Coal ...
http://jme.shahroodut.ac.ir/article_1495_195.html
Spontaneous combustion of coal is one of the most horrifying hazards in coal industries, especially in underground coal mines. Thus having a prior knowledge about the occurrence of this phenomenon in underground coal mines is of crucial importance in preventing this process, loss of life, huge economic loss, and environmental pollution. The aim of this work is to determine the spontaneous combustion of coal potential in the Tabas Parvadeh coal mines in Iran in order to assess the effect of coal intrinsic characteristics on its occurrence. For the purpose of this investigation, the coal samples were collected from Parvadeh I to IV, and the coal intrinsic characteristics of the samples were tested. In order to determine the spontaneous combustion of coal propensity in this case study, the Crossing Point Temperature (CPT) test was used. Then the relation between the coal intrinsic characteristics and the CPT test values was determined. The results obtained showed that the B1 seam in Parvadeh II and C1 seam in Parvadeh III had a high potential of spontaneous combustion of coal potential. These results also show that an increase in the moisture, volatile matter, pyrite, vitrinite, and liptinite contents enhance the spontaneous combustion of coal tendency in these mines. The results obtained have major outcomes for the management of this phenomenon in the Tabas Parvadeh coal mines. Therefore, evaluation of the spontaneous combustion of coal hazards in coal mines should start in the first stage of design and carried on during their whole lifecycle, even after mine closure.Tue, 31 Dec 2019 20:30:00 +0100A comprehensive study of several meta-heuristic algorithms for the open-pit mine production ...
http://jme.shahroodut.ac.ir/article_1718_0.html
It is significant to discover global optimum in problems with large dimensional scales to increase the quality of decision making in the mining operation. It is broadly confirmed that Long-term production scheduling (LTPS) problem performs a main role in mining projects to develop their performance through regarding the obtainability of constraints while making the most of the project whole profits in the period. There is a need for improving scheduling methodologies to get a good solution since production scheduling problems are Non-deterministic Polynomial-time hard. The current paper introduces hybrid models so as to solve the LTPS problem under the condition of grade uncertainty with the contribution of Lagrangian relaxation (LR), particle swarm optimization (PSO), firefly algorithm (FA), and bat algorithm (BA). In fact, the LTPS problem is solved under the condition of grade uncertainty. It is proposed to use the LR technique on the LTPS problem and develop its performance speeding up the convergence. Furthermore, PSO, FA and BA are projected to bring up-to-date the Lagrangian multipliers. The consequences of the case study specified that the LR method is more influential than traditional linearization method to clarify the large-scale problem and make an acceptable solution. The fallouts point out that better presentation is gained by LR–FA in comparison with LR-PSO, LR-BA, LR-Genetic algorithm (GA), and traditional methods in terms of average net present value. Moreover, the CPU time by the LR-FA method is approximately 16.2% upper than the other methods.Tue, 24 Mar 2020 19:30:00 +0100