R. Norouzi Masir; R. Khalokakaie; M. Ataei; S. Mohammadi
Abstract
Mining can become more sustainable by developing and integrating economic, environmental, and social components. Among the mining industries, coal mining requires paying a serious attention to the aspects of sustainable development. Therefore, in this work, we investigate the impacting factors involved ...
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Mining can become more sustainable by developing and integrating economic, environmental, and social components. Among the mining industries, coal mining requires paying a serious attention to the aspects of sustainable development. Therefore, in this work, we investigate the impacting factors involved in the sustainable development of underground coal mining from the structural viewpoint. For this purpose, the decision-making trial and evaluation laboratory (DEMATEL) technique, which is a graph-based method, is utilized. To do so, at first, twenty effective factors are determined for three components. Then the hierarchical structure and the systematic approach are used to determine the total exerted influence or total received influence of the components. The results obtained show that the environmental and social components are the most important, and the economic components are the least important among them.
Rock Mechanics
M. Nikkhah; M. A. Ghasvareh; N. Farzaneh Bahalgardi
Abstract
In general, underground spaces are associated with high risks because of their high uncertainty in geotechnical environments. Since most accidents and incidents in these structures are often associated with uncertainty, the development of risk analysis and management methods and prevention of accidents ...
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In general, underground spaces are associated with high risks because of their high uncertainty in geotechnical environments. Since most accidents and incidents in these structures are often associated with uncertainty, the development of risk analysis and management methods and prevention of accidents are essential. A deeper recognition of the factors affecting the implementation process can pave the way for this purpose. Risk rating of projects is a key part of the risk assessment stage in the risk management process of each project. Various multi-criteria decision-making methods, as quantitative approaches, are used to allow them to be used in the risk rating issue of each project. In this work, a new model is provided for risk management of Mashhad Urban Railway Line 3 using the game theory and multi-criteria decision-making methods. Based on the answers of the specialists and experts to the prepared questionnaires, various risk groups identified using the TOPSIS and AHP multi-criteria decision-making methods are ranked. Accordingly, the group of economic risks, as the most important risk and social risk group, is ranked as the least significant in both methods. In the following, the appropriate response to the main risks of the ratings is proposed based on the modeling of the game theory, and ranked in terms of importance. Also the worst risk scenario in the project is identified, and the appropriate responses for this state are also expressed in order of importance. The results obtained indicate that the risk of financing problems is the most significant risk, and other risks are ranked in terms of importance in the next ranks. Additionally, the use of new financing methods at times of credit scarcity and project financial problems is also considered as the most important response to the risk in this project.
M. Ibrahim; N. Mohammad; Z. Ahmad; Sh. Bacha; N. Muhammad Khan; M. Iftikhar Khan
Abstract
In this work, we focus on the up-gradation of the copper ore of Qilla Saifullah in Pakistan through the froth flotation technique. The chemical analysis of the head copper ore sample reveal the presence of 2.85% Cu, 22% Fe2O3, 52.9% SiO2, and other minor minerals. The optimum grinding time and ...
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In this work, we focus on the up-gradation of the copper ore of Qilla Saifullah in Pakistan through the froth flotation technique. The chemical analysis of the head copper ore sample reveal the presence of 2.85% Cu, 22% Fe2O3, 52.9% SiO2, and other minor minerals. The optimum grinding time and liberation size of the copper ore have been determined as 30 minutes and +149-105 µm, respectively, for further processing. The chemical reagents are optimized in order to get a maximum grade and recovery of the copper ore. After comparisons and analysis of the results obtained, it can be concluded that the maximum grade and recovery of the copper ore are achieved at the dosage 300 (g/t) of the collector potassium amyl xanthate (C6H11KOS2), 250 g/t of pine oil, 250 g/t of a depressant (Na2SiO3), conditioning time of 10 minutes for a collector, flotation time of 6 and 10 minutes, and pH of 10 using the froth flotation technique.
S. Pratap Singh; A. Kumar Roy
Abstract
The Himalayan mountain range is susceptible to slope instability in numerous areas due to its complicated topography, because of the existing natural conditions and human influence and intervenes. National Highway-05 is considered in this work. The area under investigation located in Rampur, district ...
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The Himalayan mountain range is susceptible to slope instability in numerous areas due to its complicated topography, because of the existing natural conditions and human influence and intervenes. National Highway-05 is considered in this work. The area under investigation located in Rampur, district Shimla, Himachal Pradesh is evaluated for slope stability. The primary purpose of this work is to maintain the slope's stability in order to protect NH-05 and the neighboring three-sided residential structures. Following the site visit, the geotechnical investigations in the form of bore holes and laboratory tests are conducted. Analysis of slope stability is commenced after interpreting the geotechnical study report. For an analytic slope stability, the studied area is divided into three sections, labelled A1-A1', B1-B1', and C1-C1'. Taking into account the geotechnical aspects of the specified research region, the mitigation design parameters for the area and the circular slip failure are calculated using the numerical modeling techniques. The software computes the safety factor for both the static and dynamic situations. As a result, preventative measures and a few improvements are suggested.
Mineral Processing
S. Kolahi; M. Jahani Chegeni
Abstract
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, and consequently, their performance. In this paper, the milling ...
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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, and consequently, their performance. In this paper, the milling operation of pilot-scale SAG mills using the 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. The effects of the number of lifters on the two new parameters introduced by the authors, i.e. ‘head height’ and ‘impact zone length’ as well as on creation of cascading, cataracting, and centrifuging motions for balls at two different mill speeds, i.e. 70% and 80% of its critical speed (NC), are evaluated. Also in order to validate the simulation results, a laboratory-scale SAG mill is simulated. The results obtained 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. However, liners with the number of lifters less than this range require a higher mill speed. Also liners with the number of lifters beyond this range require less mill speed, and 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.
Mineral Processing
S. Razmjooei; M. Abdollahy; M. R. Khalesi
Abstract
Flotation process in mechanical cells is carried out in highly turbulent conditions. In this work, the impact of impeller speed on four characteristics of the quiescent zone, i.e. zone height, turbulence, solid percentage, and gas holdup, and their relationship with the entrainment is investigated, and ...
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Flotation process in mechanical cells is carried out in highly turbulent conditions. In this work, the impact of impeller speed on four characteristics of the quiescent zone, i.e. zone height, turbulence, solid percentage, and gas holdup, and their relationship with the entrainment is investigated, and it is shown why at a higher impeller speed, entrainment is not significant. The height of the quiescent zone and its turbulence are measured using a piezoelectric sensor, while an electrical conductivity sensor measures the gas hold-up. A peristaltic pump is applied to take samples from the pulp to measure the solid percentage. The results obtained showed that with increase in the impeller speed from 750 to 1100 rpm, the entrainment value changed from 2.01% to 5.69%. However, the variations in entrainment were not significant at speeds higher than 1100 rpm. It was found that the height of the quiescent zone was independent from the impeller speed, while raising the impeller speed, as long as the solid percentage, turbulence, and gas hold-up are increased, caused a drastic increase in entrainment. Despite the increase in the solid percentage and turbulence, the gas hold-up decreased at impeller speeds higher than 1100 rpm due to the variation in the bubble distribution pattern, so the entrainment raised with a smaller slope. Finally, a model is presented for the entrainment as a function of the three correlated variables using the Ridge regression. The entrainment is then correlated to the impeller speed, explaining the contradictory results from the literature on the effect of impeller speed on the entrainment.
M. J. Sajid; N. Shahani; M. Ali
Abstract
Mining is among the oldest industries. It is the primary source of raw materials for most of the sectors. Little is known about the complex inter-sectoral carbon linkages of the mining industry. In this work, we estimate the inter- and intra-sectoral carbon linkage impacts of the mining sector across ...
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Mining is among the oldest industries. It is the primary source of raw materials for most of the sectors. Little is known about the complex inter-sectoral carbon linkages of the mining industry. In this work, we estimate the inter- and intra-sectoral carbon linkage impacts of the mining sector across ten major economies by applying an input-output model, and the hypothetical extraction method and its modified version. The hypothetical extraction method removes an industrial block from an economic system, and afterwards, it makes a comparison between the before and after removal values. China with 195.47 Mt has the highest mining emissions, followed by USA, India, and Canada with 110.99 Mt, 108.79 Mt, and 76.92 Mt, respectively. The India’s mining sector with 26.33 t/104 $ is the most carbon-intensive, followed by Japan and Canada with 6.84 t/104 $ and 5.22 t/104 $, respectively. China’s carbon emissions with -11.56% and -11.28%, respectively, have been affected the most by the total extraction of mining sector and forward carbon linkages, while for the backward carbon linkage, Canada with -1.33% has been affected the most. Canada has the highest mixed and internal emissions of 0.42 Mt and 47.88 Mt, respectively. However, China has the highest net-backward and net-forward emissions of 16.91 Mt and 189.22 Mt, respectively. For all nations, the mining sector is a net exporter of emissions to other industries. Based on the numerical findings, in this work, we discuss the mitigation measures for both the direct and indirect mining emissions.
V. Mwango Bowa; W. Samiselo; E. Manda; Y. Lei; W. Zhou; A. Shane; S. Chinyanta
Abstract
The influence of variable groundwater has been overlooked in the available literature. Yet, wedge failure induced by variable groundwater is still commonly experienced in sedimentary rock formation in many commercial dams, highways, and surface mine slopes around the world. In this article, a robust ...
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The influence of variable groundwater has been overlooked in the available literature. Yet, wedge failure induced by variable groundwater is still commonly experienced in sedimentary rock formation in many commercial dams, highways, and surface mine slopes around the world. In this article, a robust analytical model for stability analysis of the rock slopes subjected to wedge slope failure induced by variable groundwater is presented. This involves modifying the existing analytical model for estimating the safety factor of the rock slope subjected to wedge failure by incorporating the effects of variable groundwater. The proposed analytical model is validated using a numerical simulation model using the Fast Lagrangian Analysis of Continua in 3 Dimensions (FLAC3D) software. Furthermore, a real wedge slope instability at the Chingola Open-Pit Mine (COP F&D) induced by the presence of variable groundwater case history is studied in order to illustrate the effectiveness of the presented analytical model. The investigation results indicate that the presence of variable groundwater has a direct impact on the computed factor of safety of the rock slope subjected to wedge failure. The results obtained entail that the presented analytical model can provide a robust analytical model for the stability analyses of the rock slope subjected to wedge failure considering the presence of variable groundwater.
Ilyas Ongarbayev; Nasser Madani
Abstract
Geological modeling is an important step for the evaluation of natural resources. One option is to use a common geo-statistical modeling method such as Indicator Kriging (IK). However, there are specific problems associated with IK, the worthiest of attention is an order relation violation. Alternatively, ...
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Geological modeling is an important step for the evaluation of natural resources. One option is to use a common geo-statistical modeling method such as Indicator Kriging (IK). However, there are specific problems associated with IK, the worthiest of attention is an order relation violation. Alternatively, some studies propose to use the Inverse Distance Weighting (IDW) method. Though again, there are certain limitations associated with the IDW geo-domain modeling application. In fact, the current IDW methodology does not cover the subject of anisotropic geo-domain modeling; thus it is only applicable for the isotropic cases. Therefore, this work proposes a previously unused geo-domain modeling–Anisotropic IDW, which underlies the concept of indicator variogram, allowing one to consider the spatial correlation of the domains. The experimental part in this work includes the comparison of anisotropic IDW, IK, and traditional IDW over the synthetic case study, which imitates a highly anisotropic geological behavior, and a more complicated real case study over a vein-type gold deposit from Kazakhstan. The case studies’ results illustrate that the anisotropic IDW can model the geo-domains more accurately than IK and the traditional IDW.
K. Sultan Shah; I. Mithal Jiskani; N. Muhammad Shahani; H. Ur Rehman; N. Muhammad Khan; S. Hussain
Abstract
In the mining sector, the barrier to obtain an efficient safety management system is the unavailability of future information regarding the accidents. This paper aims to use the auto-regressive integrated moving average (ARIMA) model, for the first time, to evaluate the underlying causes that affect ...
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In the mining sector, the barrier to obtain an efficient safety management system is the unavailability of future information regarding the accidents. This paper aims to use the auto-regressive integrated moving average (ARIMA) model, for the first time, to evaluate the underlying causes that affect the safety management system corresponding to the number of accidents and fatalities in the surface and underground mining in Pakistan. The original application of the ARIMA model provides that how the number of accidents and fatalities is influenced by the implementation of various approaches to promote an effective safety management system. The ARIMA model requires the data series of the predicted elements with a random pattern over time and produce an equation. After the model identification, it may forecast the future pattern of the events based on its existing and future values. In this research work, the accident data for the period of 2006-2019-is collected from Inspectorate of Mines and Minerals (Pakistan), Mine Workers Federation, and newspapers in order to evaluate the long-term forecast. The results obtained reveal that ARIMA (2, 1, 0) is a suitable model for both the mining accidents and the workers’ fatalities. The number of accidents and fatalities are forecasted from 2020 to 2025. The results obtained suggest that the policy-makers should take a systematic consideration by evaluating the possible risks associated with an increased number of accidents and fatalities, and develop a safe and effective working platform.
M. Ziaii; A. Abedi; M. Ziaei; A. Kamkar Rouhani; A. Zendahdel
Abstract
One of the major strengths of a Geographic Information System (GIS) in geosciences is the ability to integrate and combine multiple layers into mineral potential maps showing areas which are favorable for mineral exploration. These capabilities make GIS an extremely useful tool for mineral exploration. ...
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One of the major strengths of a Geographic Information System (GIS) in geosciences is the ability to integrate and combine multiple layers into mineral potential maps showing areas which are favorable for mineral exploration. These capabilities make GIS an extremely useful tool for mineral exploration. Several spatial modeling techniques can be employed to produce potential maps. However, these methods can be divided into knowledge -and data-driven techniques. The goal of this study is to use GIS in mapping gold deposit potentials in Torud-Chah Shiran area. After collecting relevant exploration data and defining appropriate exploration model for the mineralization zone, several layers including proved mineralization map, geological map, remote sensing derived, alteration map, geochemical and aeromagnetic maps were imported in to GIS environment. For integrated exploration modeling, two methods were used: fuzzy logic and weight of evidence methods. Finally, the results of the two methods were compared. The result of each method had statistical problems but these problems were alleviated using the map of differences that was in a good agreement with reality.
V. F. Navarro-Torres; R. N. Singh
Abstract
Water has an important role in creating pollution problems in the mining regimes influencing the surrounding surface
environment. The purpose of this study is to make an assessment of groundwater quality in an underground mine site in
Portugal with a view of determining the pollution potential ...
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Water has an important role in creating pollution problems in the mining regimes influencing the surrounding surface
environment. The purpose of this study is to make an assessment of groundwater quality in an underground mine site in
Portugal with a view of determining the pollution potential of groundwater. In the corresponding surface area of this
underground mine, intersections of four faults form rock blocks which delimit the surface subsidence influencing the
flow pattern of the surface streams and the groundwater table resulting in inflow of groundwater and rainwater into
mining excavations. When this water comes into contact with the virgin rock mass containing pyrites in presence of
atmospheric air, acid mine water is formed. This acidic water reacts with the broken rock material dissolving metallic
sulphides into solution and also carrying suspended solids. When discharged in the “Boldehão” River, these waters
produce diverse environmental impact levels such as pH low and Zn high levels risk cause for irrigation, pH, Cu, Fe and
Mn high level risk for consumption human, and pH, Cu and Zn cause high level for fishes.
M. Jahani; M. Noaparast; A. Farzanegan; G. Langarizadeh
Abstract
In this research, the efficiency of the comminution circuit as well as the efficiency of size classification equipment of the concentrator plant 2 of Sarcheshmeh copper complex was studied. The comminution circuit of this plant includes one SAG mill in a closed circuit with a vibrating screen and one ...
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In this research, the efficiency of the comminution circuit as well as the efficiency of size classification equipment of the concentrator plant 2 of Sarcheshmeh copper complex was studied. The comminution circuit of this plant includes one SAG mill in a closed circuit with a vibrating screen and one ball mill with a size classification system of hydrocyclone. The goal of this work was to calculate the proportion of each of these mills at energy consumption and generating suitable product for flotation as a further process. Three stages of sampling were performed and consumed energy was also modeled. The average efficiency of the initial ball mill was obtained which was equal to 72.96%. The average of the proportion of (consumed) energy by SAG and ball mills from total consumed energy at mills, was 44.65% and 55.35% respectively. The proportion of SAG and ball mills in producing the final product (particles finer than 74 µm) was 55.38% and 44.62% respectively. That is, the SAG mill produces about 10.76% more than the ball mill in the final product. The average consumed energy at SAG and ball mills to produce one ton of final product was 23.16 kWh/t and 36.05 kWh/t respectively. Thus, the ball mill consumes 12.89 kWh/t, more energy than the SAG mill in producing the final product. The average cyclones’ imperfection was 0.361 and therefore the average efficiency of cyclones’ separation was equal to 63.9% and the average efficiency of the vibrating screen was equal to 99.89%. As overflow of the initial cyclones (final product of comminution circuit) forms feed of rougher cells, cyclones’ inappropriate performance could severely influence the whole flotation process.
Bijan Afrasiabian; Kaveh Ahangari; Ali Noorzad
Abstract
High-level vibrations caused by blasting operations in open-pit mining can exert adverse effects such as destruction of surrounding surface structures. Therefore, it is essential to identify the factors effective in mitigating the damaging effects of ground vibration in open-pit mines, and monitor them. ...
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High-level vibrations caused by blasting operations in open-pit mining can exert adverse effects such as destruction of surrounding surface structures. Therefore, it is essential to identify the factors effective in mitigating the damaging effects of ground vibration in open-pit mines, and monitor them. This study investigates the effects of some of the most important blast design parameters in a row of blast holes. According to the advantages of numerical methods, the 3D discrete element method is employed for this purpose. The Peak Particle Velocity (PPV) values are measured along the central hole at the distances of one meter. The results obtained demonstrate that an increase in the blast damage factor and inter-hole delay time results in higher PPV values. However, the increased delay time has no remarkable effect on reducing the development of the blast damage zone. On the other hand, as the decoupling increases, the PPV values diminish, leading to substantial reductions in the ground vibration and rock mass damage. It is also observed that the elimination of sub-drilling does not significantly reduce ground vibrations. The analysis of the results obtained from the numerical modeling show that the discontinuities of the rock mass act as a filter, which could decrease the wave energy by more than 90%. Moreover, it is found that the direction of the discontinuities also affects the emission of waves caused by the blast. The PPV values are reduced, and the damaged zone is less developed if the discontinuities are opposite of the slope surface.
H.R Baghzendani; H. Aghajani; M. Solimani
Abstract
Detection of subsurface structures by means of gravity method can be used to determine mass distribution and density contrast of rock units. This distribution could be detected by different geophysical methods, especially gravity method. However, gravity techniques have some drawbacks and can't be always ...
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Detection of subsurface structures by means of gravity method can be used to determine mass distribution and density contrast of rock units. This distribution could be detected by different geophysical methods, especially gravity method. However, gravity techniques have some drawbacks and can't be always successful in distinguishing subsurface structures. Performance of the gravity technique could be further improved by simultaneous combination and introducing additional information from other geophysical data. This study used existing relation between seismic and gravity methods to better clarify subsurface structures. This relationship relates mass distribution of the medium to velocity of wave propagation in that media. This method was applied on an area that consists of three mud volcanoes. After completion of the primary model by forward modeling, mass distribution and analysis of seismic velocity were provided on a 2-D profile. Bouguer anomaly map of gravity data of the area was obtained and negative anomalies were identified. These negative anomalies could be related to the existence of mud volcanoes. A 2-D seismic line was also acquired over the greatest mud volcano, as additional information for direct modeling. The Gardner equation was used for further velocity estimation by density values. This velocity model also compared with seismic velocity analysis for evaluation. The final results indicated that density modeling and the use of seismic velocity model increases the resolution of subsurface structures imaging. Separation of subsurface layers was implemented correctly in the velocity model resulting from gravity data and subsurface discontinuities of the area that become more obvious by this technique.
Akbar farzanegan; Bahareh Arabzadeh; Vahid Hasanzadeh
Abstract
Discrete Element Method (DEM) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. Prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is ...
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Discrete Element Method (DEM) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. Prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is possible by DEM simulation. In this article, a new approach was used to assess the main parameters of a transparent ball mill constructed in mineral processing laboratory of the University of Tehran. The mill shell and crushing balls are made of Plexiglas® and compressed glass respectively. The true values of mechanical parameters for these materials, required for DEM modeling, were unknown. The authors back-calculated the best values of mechanical properties of Plexiglas and compressed glass materials based on a large number of DEM simulations. Back-calculation procedure was mainly based on the comparison between electrical power draw measured in real mill and mechanical power draw calculated by DEM model while trying to simulate particle flow regime inside the real mill accurately. The results showed that the optimal number and design of lifters can be adequately determined by improving torque and kinetic energy in crushing elements through DEM simulation trials based on the back-calculated mechanical parameters.
Javad Gholamnejad; HamidReza Bahaaddini; Morteza Rastegar
Abstract
Static deformation modulus is recognized as one of the most important parameters governing the behavior of rock masses. Predictive models for the mechanical properties of rock masses have been used in rock engineering because direct measurement of the properties is difficult due to time and cost constraints. ...
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Static deformation modulus is recognized as one of the most important parameters governing the behavior of rock masses. Predictive models for the mechanical properties of rock masses have been used in rock engineering because direct measurement of the properties is difficult due to time and cost constraints. In this method the deformation modulus is estimated indirectly from classification systems. This paper presents the results of a study into the application of Artificial Neural Networks (ANN) technique and Regression models for estimation of the deformation modulus of rock masses. A database, including 225 actual measured deformation modulus, Uniaxial Compressive Strengths of the rock (UCS), and Rock Mass Rating (RMR) was established. Data collected from different projects. For predicting Em by regression, a nonlinear regression method was chosen. This model showed the coefficient correlation of 0.751 and mean absolute percentage error (MAPE) of 9.911%. Also a three-layer ANN was found to be optimum, with an architecture of two neurons in the input layer, four neurons in the hidden layer and one neuron in the output layer. The correlation coefficient determined for deformation modulus predicted by the ANN was 0.786 and the quantity of MAPE was 6.324%. With respect to the results obtained from two models, the ANN technique was shown to be better than the regression model because of its higher accuracy.
SUJIT KUMAR MANDAL; N.K Bhagat; M.M Singh
Abstract
Transmission of blast waves is a complex phenomenon and the characteristics vary with blast design parameters and geo-technical properties of medium. Frequency of vibration and triggering component for structural excitation generally quantifies safe vibration magnitude. At closer distance or higher elevations ...
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Transmission of blast waves is a complex phenomenon and the characteristics vary with blast design parameters and geo-technical properties of medium. Frequency of vibration and triggering component for structural excitation generally quantifies safe vibration magnitude. At closer distance or higher elevations than the blast locations, vertical or transverse component will be the first arrival to trigger the sensor for monitoring and at far off distances longitudinal component triggers the sensor to monitor. Similarly, for shorter depth of blastholes and wider blast geometries, vertical or transverse component triggers the sensor to monitor even for longer distances of measurement. Analyzing the cause of such occurrence, the paper firstly puts forward a mathematical model to illustrate the same. Thereafter, considering single-degree of freedom for dynamic analysis of structures, the paper communicates that incident particle velocity exiting a structure to vibrate should be considered to limit vibration magnitude for safety of structures.
E. Bozorgi; D. Javani; M. Rastegarnia
Abstract
Wellbore instability is a quite common event during drilling, and causes many problems such as stuck pipe and lost circulation. It is primarily due to the inadequate understanding of the rock properties, pore pressure, and earth stress environment prior to well construction. This study aims to use the ...
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Wellbore instability is a quite common event during drilling, and causes many problems such as stuck pipe and lost circulation. It is primarily due to the inadequate understanding of the rock properties, pore pressure, and earth stress environment prior to well construction. This study aims to use the existing relevant logs, drilling, and other data from offset wells to construct a precise mechanical earth model (MEM) describing the pore pressure, stress magnitudes and orientations, and formation mechanical properties of South Pars Gas field. Since the core test data, MDT/XPT data, and LOT/XLOT data were not available to calibrate the developed model, each component of the model was determined using a range of existing methods and relations, and then the wellbore instability was analyzed based on the developed MEM and the Mogi-Coulomb failure criterion. The predicted incidents such as the lost circulation and tight hole were then compared with the caliper log and reported drilling events to determine the consistency of the model. Since the stability analysis based on the developed MEM had the most agreement with the caliper log and reported drilling events, the equations presented by Eaton and Zoback had good estimations of the pore pressure and rock strengths. Also the estimated horizontal stresses were precise enough to enable the constructed MEM to predict the wellbore instabilities. The stress regime in the field of study was strike-slip, which is frequently specified in the industrial technical reports of the studied field. Finally, it was concluded that the Mogi-Coulomb failure criterion minimized the conservative nature of the mud pressure prediction due to the consideration the strengthening effect of the intermediate stress.
N. Sadrmohammadi; R. Mehrnia; Kh. Rezaei; S. Kadioğlu; M. Honarvar
Abstract
In this paper, a power-law relation modeling called the vario-fractal model is introduced in order to understand the discrepancies between the linear and non-linear distribution of the elements and its application for mineral exploration in the calamine Zn-Pb ore-deposit. From a hypothetical viewpoint, ...
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In this paper, a power-law relation modeling called the vario-fractal model is introduced in order to understand the discrepancies between the linear and non-linear distribution of the elements and its application for mineral exploration in the calamine Zn-Pb ore-deposit. From a hypothetical viewpoint, since geochemical zonation of the supra- and sub-ore elements is a crucial evaluation criterion for concealed/underlying mineralization potentials, this hypothesis can be tested by delineating the fractal surfaces of elements as the geometric evidence of primary geochemical zonation of elements in the calamine mine. A comparison of the linear regression results with the Poisson distribution coefficients indicate the relative tendency of the elements towards a non-linear distribution. Therefore, a logarithmic equation derived from the variance-distance relationship (power-law) is used here for the delineation of fractal surfaces of elements as the geometric features related to proper self-organized distributions. In this research work, the vario-fractal expression of geochemical zonation has trace-element tendencies to the non-linear distribution. The results obtained show that the calamine’s fractional surfaces are mostly of self-organized types, situated at 2 < FD < 3 as "real fractal surfaces", although 3 of the elements appear in the quasi-fractal populations called "near Brownies” here. Moreover, the calamine’s fractal surfaces can be extended throughout the anomalous regions or may be distributed as limited types of the finalized model, which is a fractal-based pattern of geochemical zonation of the elements for evaluation of the hypogenic mineralization potential and has been prioritized to 6 target-areas containing 10 elements with real fractal surfaces and 3 more at near Brownies and then validated by the mineralogical evidence.
Pankaj Rathore; Suresh Kumar Tiwari
Abstract
The main aim of this experimental analysis is to understand the effectiveness of ceramic waste (CW) in stabilizing the clayey soil. The effect of adding various CW percentages (5%, 10%, 15%, 20%, 25%, and 30%) on the geotechnical properties of clayey soil is evaluated by performing a series of laboratory ...
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The main aim of this experimental analysis is to understand the effectiveness of ceramic waste (CW) in stabilizing the clayey soil. The effect of adding various CW percentages (5%, 10%, 15%, 20%, 25%, and 30%) on the geotechnical properties of clayey soil is evaluated by performing a series of laboratory tests like the Atterberg’s limit test, compaction test, unconfined compressive strength (UCS) test, California bearing ratio (CBR) test, and swelling pressure test. Micro-structural analysis including scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) spectroscopy are carried out on untreated and treated clay-ceramic composites. The results obtained indicate that the incorporation of 30% ceramic waste in clay soil increase the maximum dry unit weight (γmax) from 17.20 kN/m3 (CL + 0% CW) to 18.25 kN/m3 (CL + 30% CW). The unconfined compressive strength of clayey soil increases with the addition of ceramic waste. A maximum UCS of 217 kPa is obtained with 25% ceramic content, beyond which it starts decreasing. Similarly, increasing trend in CBR results is observed with an increase in the ceramic waste content. The increment in CBR is approximately 152% (unsoaked condition) and 142% (soaked condition). At the same time, the addition of ceramic waste in clay soil reduces the Atterberg limits, optimum water content (ωopt), and swelling pressure. “It can be concluded from the experimental study that CW can be used as a sustainable alternative soil stabilizer.
H. Dehghani; A. Siami; P. Haghi
Abstract
One of the most important steps involved in mining operations is to select an appropriate extraction method for mine resources. After choosing the extraction method, it is usually impossible to replace it with another one because it may be so expensive that implementation of the entire project could ...
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One of the most important steps involved in mining operations is to select an appropriate extraction method for mine resources. After choosing the extraction method, it is usually impossible to replace it with another one because it may be so expensive that implementation of the entire project could be economically impossible. Choosing a mining method depends on the geological and geometrical characteristics of the mine. Due to the complexity of the process of choosing an appropriate mining method and the effect of the parameters involved on the results of this process, it is necessary to utilize the new decision-making methods that have the ability to consider the relationship between the existing parameters and the mining methods. Grey and TODIM (an acronym in Portuguese, i.e. Tomada de Decisão Interativa Multicritério) decision-making methods are among the existing ones, which in addition to the convenience, show high accuracy. The proposed models are presented to determine the best mining method in the Gol-e-gohar iron ore mine in Iran. The results obtained are compared with the methods used in the previous research works. Among the decision-making methods introduced, the open pit mining method is the most appropriate option and the square-set mining is the worst one.
Environment
B. Shokouh Saljoughi; A. Hezarkhani
Abstract
The Shahr-e-Babak district, as the studied area, is known for its large Cu resources. It is located in the southern side of the Central Iranian volcano–sedimentary complex in SE Iran. Shahr-e-Babak is currently facing a shortage of resources, and therefore, mineral exploration in the deeper and ...
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The Shahr-e-Babak district, as the studied area, is known for its large Cu resources. It is located in the southern side of the Central Iranian volcano–sedimentary complex in SE Iran. Shahr-e-Babak is currently facing a shortage of resources, and therefore, mineral exploration in the deeper and peripheral spaces has become a high priority in this area. This work aims to identify the geochemical anomalies associated with the Cu mineralization using the Spectrum–Area (S–A) multi-fractal and Wavelet Neural Network (WNN) methods. At first, the Factor Analysis (FA) is applied to integrate the multi-geochemical variables of a regional stream sediment dataset related to major mineralization elements in the studied area. Then the S–A model is applied to decompose the mixed geochemical patterns obtained from FA and compare with the results obtained from the WNN method. The S–A model, based on the distinct anisotropic scaling properties, reveals the local anomalies due to the consideration of the spatial characteristics of the geochemical variables. Most of the research works show that the capability (i.e. classification, pattern matching, optimization, and prediction) of an ANN considering its successful application is suitable for inheriting uncertainties and imperfections that are found in mining engineering problems. In this paper, an alternative method is presented for mineral prospecting based on the integration of wavelet theory and ANN or wavelet network. The results obtained for the WNN method are in a good agreement with the known deposits, indicating that the WNN method with Morlet transfer function consists of a highly complex ability to learn and track unknown/undefined complicated systems. The hybrid method of FA, S–A, and WNN employed in this work is useful to identify anomalies associated with the Cu mineralization for further exploration of mineral resources.
Exploration
N. Mahvash Mohammadi; A. Hezarkhani
Abstract
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, ...
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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.
Exploitation
S. Moosazadeh; H. Aghababaie; Seyed H. Hoseinie; B. Ghodrati
Abstract
Utilization is one of the main managerial factors that is applied for construction process analysis well. It directly affects the project duration and construction costs. Therefore, a utilization study in tunneling projects is essential. In this work, the utilization of an earth pressure balance Tunnel ...
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Utilization is one of the main managerial factors that is applied for construction process analysis well. It directly affects the project duration and construction costs. Therefore, a utilization study in tunneling projects is essential. In this work, the utilization of an earth pressure balance Tunnel Boring Machine (TBM) in Tabriz urban railway project was studied using the Monte Carlo simulation approach. For this purpose, the unit operation during one working shift such as boring time, ring building time, and locomotive travel time was recorded and saved in data base. In addition, the general down times such as TBM and back-up system maintenance, surface and tunnel logistic maintenance, cutting tools’ replacement, and locomotive delay times were recorded and considered in simulation. The results of this work show that the mean simulated project duration time of case study TBM is approximately 859 shifts and close to the real data with a difference of 0.92%. Finally, the average estimated utilization factor was found to be approximately 14%.
