Alankrit Walia; Amrit Kumar Roy
Abstract
The complex geography of the Himalayan mountain range, along with the natural circumstances that already exist and the ways in which people have influenced and intervened in the region- makes various regions of the range vulnerable to slope instability. The slope stability of the area that is the subject ...
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The complex geography of the Himalayan mountain range, along with the natural circumstances that already exist and the ways in which people have influenced and intervened in the region- makes various regions of the range vulnerable to slope instability. The slope stability of the area that is the subject of this work is evaluated in Palampur, which is in the Kangra district of Himachal Pradesh. The primary objective of this work is to ensure that the slope remains stable so that the nearby three-sided residential structures and the highway remain protected. After the site visit, the geo-technical studies, which include testing in the form of bore holes and in the laboratory, are carried out. After evaluating the geo-technical technical report, the next step in the process is to begin the analysis of the slope's stability. In order to do an analytical analysis of the slope stability, the area has been subdivided into three portions, and labelled A-A, B-B, and C-C, respectively. Using the numerical modelling approaches, the mitigation design parameters for the area and the circular slip failure are computed. These calculations are based on the geo-technical characteristics of the studied area that have been specified. The factor of safety is calculated for both the natural and stable scenarios by the program. Because of this, some preventative steps and a few improvements are suggested.
Yeluri Sesha Choudary; Karan Singh; T S Ramesh Babu; Garikapati Deepthi
Abstract
The efficiency of geo-polymer mortar is analyzed by replacing fine aggregates with different ratios of copper slag and crumb rubber. Properties such as flow value, setting time, strengthening properties, density, and water absorption are studied for different factors, i.e. molarities of sodium hydroxide ...
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The efficiency of geo-polymer mortar is analyzed by replacing fine aggregates with different ratios of copper slag and crumb rubber. Properties such as flow value, setting time, strengthening properties, density, and water absorption are studied for different factors, i.e. molarities of sodium hydroxide (8, 10, and 12 M), various ratios of alkali-activator solution (1, 2, and 3), and the effect of pre-treating rubber. The results indicate that the increase in molarity increases the compressive strength, setting time, and flow value of mortar. It is observed that NaOH of 12 M and an alkali activator ratio of 2 show high compressive strength, which is 71.79 N/mm2. The rubber treated with alkali improves the bonding between the binder and the rubber, which leads to an increase in the material's strength by 7% for 1 hour and 10% for 24 hours, and density by about 1.5%. It is suggested that the optimum mix with 50% copper slag, 10% rubber with pre-treatment for a period of 1 hour, 12 M NaOH, and alkali activator ratio 2 provide excellent results among all mixes. In conclusion, the findings indicate that the produced mortar contributes to economic and ecological improvement.
A. Abdollahipour; M. Fatehi Marji; H. Soltanian; E. A. Kazemzadeh
Abstract
The permeability and coupled behavior of pore pressure and deformations play an important role in hydraulic fracturing (HF) modeling. In this work, a poroelastic displacement discontinuity method is used to study the permeability effect on the HF development in various formation permeabilities. The numerical ...
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The permeability and coupled behavior of pore pressure and deformations play an important role in hydraulic fracturing (HF) modeling. In this work, a poroelastic displacement discontinuity method is used to study the permeability effect on the HF development in various formation permeabilities. The numerical method is verified by the existing analytical and experimental data. Then the propagation of a hydraulic fracture in a formation with a range of permeabilities is studied. The time required for propagation of an HF to 10 times its initial length is used to compare the propagation velocity in the formations with different permeabilities. The results obtained show that the HF propagation can be significantly delayed by a permeability less than almost 10-9 D. Also the effect of HF spacing on the propagation path is studied. It was shown that the stress shadowing effect of HFs remained for a longer spacing than in the elastic model due to the required time for fluid leak-off in the formation. Also the propagation angles are higher in the poroelastic model predictions than the elastic model. Therefore, it is proposed to use the poroelastic model when studying multi-HF propagation in order to avoid errors caused by neglecting the pore fluid effects on the HF propagation paths.
Z. Rezaei; M. Ataee-pour; H. Madani
Abstract
Providing a fresh and cool airflow in underground mines is one of the main concerns during mining. Destruction of support systems, the presence of undesirable objects in the airway and distortion of airflow are the parameters involved that would result in pressure loss, which would affect the ventilation ...
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Providing a fresh and cool airflow in underground mines is one of the main concerns during mining. Destruction of support systems, the presence of undesirable objects in the airway and distortion of airflow are the parameters involved that would result in pressure loss, which would affect the ventilation network. There are a lot of research works about the ventilation network planning that consider the confidence in the planning but how reliable are these designs? These questions can be answered using the quantitative reliability evaluation. For the reliability evaluation of mine ventilation network, tunnel resistance and flow rate changes for all branches are considered as the reliability indices and criteria. This paper describes a stepwise method for evaluation of the underground coal mine network reliability associated with major losses using the cut set method. The reliability of the entire network is achieved by the reliability of every single component. The proposed model is implemented by the Takht coal mine. The Takht mine ventilation network probability of failure is in the range of 19-100% so reliability is in the range of 0-81% for the entire ventilation network.
R. Aram; M. Abdollahi; P. Pourghahramani; M. Mohseni; A. Khodadadi Darban
Abstract
In this research work, the solubility of sphalerite concentrate due to mechanical activation in planetary ball mill in both the wet and dry modes is investigated, and the parameters of mean particle size, BET specific surface area, SEM, and XRD are analyzed. The results of the particle size analysis ...
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In this research work, the solubility of sphalerite concentrate due to mechanical activation in planetary ball mill in both the wet and dry modes is investigated, and the parameters of mean particle size, BET specific surface area, SEM, and XRD are analyzed. The results of the particle size analysis and BET specific surface area show that the size of particles for the non-activated sample decrease from 51 to 30 microns but the BET specific surface area increase from 0.17 m2/g to 1.03 m2/g for the residue and feed samples. In the wet and dry mode mechanical activation, the mean particle size and BET specific surface area in the residue samples are reduced relative to the leaching feed. The results of the micro-structure characterization also show that the amorphization of the residue compared to the leaching feed increases in both modes of mechanical activation. The crystallite size and lattice strain of the activated samples in the residue increase and decrease compared to the leaching feed, respectively.
V. Heydarnoori; M. H. Khosravi; M. Bahaaddini
Abstract
The cavability assessment of rock mass cavability and indicating the damage profile ahead of a cave-back is of great importance in the evaluation of a caving mine operation, which can influence all aspects of the mine operation. Due to the lack of access to the caved zones, our current knowledge about ...
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The cavability assessment of rock mass cavability and indicating the damage profile ahead of a cave-back is of great importance in the evaluation of a caving mine operation, which can influence all aspects of the mine operation. Due to the lack of access to the caved zones, our current knowledge about the damage profile in caved zones is very limited. Among the different approaches available, physical modelling can provide a useful tool for assessment of the cave propagation and understanding the cave-back mechanism. Despite the general belief of the continuous damage profile ahead of a cave, the recent studies have shown a different mechanism of banding fracture. In order to investigate the caving mechanism ahead of a cave, a base friction apparatus is designed in this work. The base friction powder is used as the modelling material for physical testing, where its strength properties is significantly dependent on its unit weight. The effects of the material’s unit weight and the undercutting process on the cavability and cave-back height are studied. The experimental results undertaken in this research work clearly confirm the banding fracture mechanism in the caved zone, rather than continuous yielding. The effect of the undercutting sequence on the cave-back height is investigated through three different scenarios of symmetric undercutting with a gradual increase in span, symmetric undercutting with a sudden increase in span, and asymmetric undercutting. The results obtained show that the ground deformation is significantly dependent on the undercutting sequence, where choosing a greater undercutting span results in a faster cave propagation and smaller accessible undercut spans.
Gaurav Juneja; Ravi Kumar Sharma
Abstract
This paper presents the numerical analysis of square and circular skirted footings placed on different sands using the PLAXIS 3D software. The numerical analysis is done using the Mohr-coulomb (M-C) yield criteria. The size of the footings is considered as 100 mm for both the square and circular footings. ...
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This paper presents the numerical analysis of square and circular skirted footings placed on different sands using the PLAXIS 3D software. The numerical analysis is done using the Mohr-coulomb (M-C) yield criteria. The size of the footings is considered as 100 mm for both the square and circular footings. The three different friction angles (Ø) of sand 36˚, 40˚, and 42˚ are used to study the effect of sand compactness. The depth of the skirt (h) varies from 0B to 2B (B is the width of the footing). The surface roughness between skirt-sand and footing-sand is considered partially rough and completely rough. The interface friction factor (δ) for a partially rough and fully rough interface is taken as 2/3Ø and Ø. All the tests are conducted by applying a prescribed displacement (s/B) of 20% of the footing size. The results obtained from the present work reveal that the inclusion of structural skirts with the footings appreciably increases the bearing capacity and reduces the settlement of the footing by increasing the skirt depth. The results obtained show that the skirted footing is found to be more effective in loose sand compared to dense sand in increasing the bearing capacity. The numerical analysis results are also verified with the experimental results available in the literature and multiple regression model. This work shows that the prediction of the accuracy of the results is quite good with the experimental results and the generated regression model.
Mineral Processing
Zehra Khan; Abhishek Sharma
Abstract
Due to rapid growth in infrastructure sector, the construction of high-rise buildings is becoming very popular among all the countries. Engineers face significant issues with high rise buildings, particularly in terms of structural and foundation aspects. Many old design approaches can't be used with ...
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Due to rapid growth in infrastructure sector, the construction of high-rise buildings is becoming very popular among all the countries. Engineers face significant issues with high rise buildings, particularly in terms of structural and foundation aspects. Many old design approaches can't be used with certainty since they involve extrapolation far beyond the domains of existing experience, hence structural and geotechnical engineers are being compelled to use more advanced analysis and design methodologies. The current study is an attempt to predict the bearing capacity and settlement behavior of piled-raft footing when embedded into cohesionless deposit. The numerical analysis has been carried out to examine the effect of numerous key parameters of pile and raft such as pile length (10, 15, 20 m), pile diameter (0.3, 0.4, 0.5 m), pile number (16, 20, 24), pile spacing (2D, 3D, 4D) (where “D” is diameter of the pile), raft thickness (0.4, 0.5, 0.6 m), and angle of internal friction of soil (25°, 30°, 35°) on load-settlement behavior of the piled- raft foundation using ABAQUS software. A constant spacing between the piles, i.e. 3D was used throughout the analysis. The results of numerical investigation revealed an improvement in bearing capacity and a reduction in settlement value on increasing length, diameter and number of piles and also with increasing angle of internal friction. The current study not only increases the bearing capacity of the foundation but provides a cost-effective foundation technique to engineers.
Environment
Podicheti Ravi Kiran; Ramchandar Karra
Abstract
Opencast coal mines play a crucial role in meeting the energy demands of a country. However, the operations will result in deterioration of ambient air quality, particularly due to particulate emissions. The dispersion of particulate matter will vary based on the mining parameters and local meteorological ...
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Opencast coal mines play a crucial role in meeting the energy demands of a country. However, the operations will result in deterioration of ambient air quality, particularly due to particulate emissions. The dispersion of particulate matter will vary based on the mining parameters and local meteorological conditions. There is a need to establish a suitable model for predicting the concentration of particulate matter on a regional basis. Though a number of dispersion models exist for prediction of dust concentration due to opencast mining, machine learning offers several advantages over traditional modeling techniques in terms of data driven insights, non-linearity, flexibility, handling complex interactions, anomaly detection, etc. An attempt has been made to assess the dispersion of particulate matter using machine learning techniques by considering the mining and meteorological parameters. Historical data comprising of mine working parameters, meteorological conditions, and particulate matter pertaining to one of the operating opencast coal mines in southern India has been utilized for the study. The data has been analyzed using different machine learning techniques like bagging, random forest, and decision tree. The performance metrics of test data are compared for different models in order to find the best fit model among the three techniques. It is found that for PM10, many of the times bagging technique gave a better accuracy, and for PM2.5, decision tree technique gave a better accuracy. Integration of mine working parameters with meteorological conditions and historical data of particulate matter in developing the model using machine learning techniques has helped in making more accurate predictions.
soghra salehi; M. Noaparast; S.Z. Shafaei; A. Amini; A. Heidarnia
Abstract
In this work, hydrochloric acid is used to remove iron impurities in the bauxite ore contained in the diasporite mineral located in the Sari region. The bauxite ore was calcined at different temperatures and times, and then dissolved in a hydrochloric acid solution. After determining the optimum calcination ...
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In this work, hydrochloric acid is used to remove iron impurities in the bauxite ore contained in the diasporite mineral located in the Sari region. The bauxite ore was calcined at different temperatures and times, and then dissolved in a hydrochloric acid solution. After determining the optimum calcination conditions in 1 h at 900 °C, the response surface methodology (RSM) with four factors in five levels was employed in order to evaluate the effects of calcination temperature, calcination time, acid concentration, and leaching time on the iron leaching efficiency. A quadratic model is proposed using this methodology to correlate the leaching variables. The test results indicate that the model is consistent with the experimental data, and that the most important varriables involved are the acid concentration, leaching time, and squared term of calcination temperature (A2). The maximum iron recovery was 94.97%, and the Fe grade in the solids remained was 2.35% at the calcination temperature of 900 °C, a calcination time of 1 hour, and a leaching time of 2 h in hydrochloric acid (6 mM).
J. Abdollahisharif; E. Bakhtavar; H. Nourizadeh
Abstract
Nitrogen oxides and carbon monoxide gases together with dust are known as the major pollutants arising during the blasting operations using the ammonium nitrate-fuel oil (ANFO) explosive at the Sungun surface mine, located in the northwest of Iran. The pollutants were monitored during some blasting operations ...
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Nitrogen oxides and carbon monoxide gases together with dust are known as the major pollutants arising during the blasting operations using the ammonium nitrate-fuel oil (ANFO) explosive at the Sungun surface mine, located in the northwest of Iran. The pollutants were monitored during some blasting operations at the mine. It was concluded that the gases and dust clouds initially went up to the peak height, and were then released in the direction of wind flow. A large volume of the pollutants in the form of clouds, which fell at the mine and its surrounding environment, was usually discharged again to the atmosphere due to other mining activities. It was also found that all kinds of pollutants at the mine imposed high risks to the ecosystem of the mine. The maximum concentration of the pollutants belonged to the particles with a size more than 20 microns. The southern part of the mine had a more potential vulnerability than its northwestern part, according to the monthly wind rose diagrams of Sungun. The investigations carried out at the mine and its surrounding environment have indicated that the current traditional blasting operations have discharged a considerable amount of pollutants into the mine and the Arasbaran protected area. The current blasting pattern should be improved, especially through analyzing and changing the stemming materials and length, in order to provide a safe environment for the ecosystem of the mine and the Arasbaran area.
Feridon ghadimi; Mohammad Ghomi; Abdolmotaleb Hajati
Abstract
Altogether 20 groundwater samples were collected around the Lakan Pb and Zn mine in Iran. Samples were analyzed for 8 constituents including Fe, Pb, Hg, Mn, Zn, CN, SO4 and Cl using standard method. The results show that the average concentrations of constituents were 0.01, 0.60, 0.10, 0.01, 0.40, 35, ...
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Altogether 20 groundwater samples were collected around the Lakan Pb and Zn mine in Iran. Samples were analyzed for 8 constituents including Fe, Pb, Hg, Mn, Zn, CN, SO4 and Cl using standard method. The results show that the average concentrations of constituents were 0.01, 0.60, 0.10, 0.01, 0.40, 35, 0.01 and 5.95 mg/kg for Fe, Mn, Pb, Zn, Hg, SO4, CN and Cl, respectively. The computed contamination index ranged between 2.38 and 443. It was concluded that contamination index shows a medium to high contaminated situation for Pb and Hg in groundwater around the tailings dam. Based on a multivariate analysis, four main sources of these hydrochemical data were identified. (1) Zn, Mn, TDS and SO4 have both natural and anthropogenic sources; (2) Hg constituent represents a natural source and Pb shows a anthropogenic source due to Lakan mine; (3) CN and Fe have anthropogenic source and mainly originated from the plant processing; (4) Cl represents a natural source.
Seyyed M. Hoseini; F. Sereshki; M. Ataei
Abstract
By evaluation of the blasting results, a proper blast pattern can be presented. It is, therefore, essential to employ a reliable method to evaluate blastings for the effective control and optimization of the main cycle operations. This paper aims to propose a criterion for evaluating the blasting results ...
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By evaluation of the blasting results, a proper blast pattern can be presented. It is, therefore, essential to employ a reliable method to evaluate blastings for the effective control and optimization of the main cycle operations. This paper aims to propose a criterion for evaluating the blasting results such as the fragmentation, muckpile condition, back-break, and fly rock, and to make a possible comparison between the blast parameters including the blasting pattern, explosives used, hole depths, and volume of the blasted rocks in the lead and zinc mine in Angouran (Iran). Using the global criterion, making the decision matrix dimensionless, and defining the appropriate conditions for the results obtained, a scalar value is devoted for the blasts, whose larger values denote a larger deviation from the proper blasting conditions and express undesirable blasts regarding the blasting results. By taking into consideration the mining operation conditions and weights of the results obtained, the influence of the results obtained on the mining operation index is also investigated using the genetic algorithm. Furthermore, by composing the weighted decision matrix, the blastings are evaluated and classified. Analyzing the results obtained for blastings in the Angouran mine reveals that the proposed method is an effective approach for evaluation of the blasting results and comparison of the blasts.
Exploitation
M. Bavand Savadkoohi; B. Tokhmechi; E. Gloaguen; A.R. Arab-Amiri
Abstract
Computer graphics offer various gadgets to enhance the reconstruction of high-order statistics that are not correctly addressed by the two-point statistics approaches. Almost all the newly developed multiple-point geostatistics (MPS) algorithms, to some extent, adapt these techniques to increase the ...
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Computer graphics offer various gadgets to enhance the reconstruction of high-order statistics that are not correctly addressed by the two-point statistics approaches. Almost all the newly developed multiple-point geostatistics (MPS) algorithms, to some extent, adapt these techniques to increase the simulation accuracy and efficiency. In this work, a scrutiny comparison between our recently developed MPS algorithm, the cross-correlation-wavelet simulation (CCWSIM), and a well-known MPS algorithm, FILTERSIM, is performed. The main motivation to benchmark these two algorithms is that both exploit some digital image processing filters for feature extraction. Indeed, both algorithms compute the similarity (or dissimilarity) between data events in simulation grid and training image in the feature space. In order to compare the accuracy of the algorithms, some statistics such as facies proportion, variogram, and connectivity function are computed. The results obtained reveal an excellent agreement of the CCWSIM realizations with the training image rather than FILTERSIM. Furthermore, on average, the required simulation runtime for CCWSIM is at least 10 times less than that for FILTERSIM.
A. Soltani Khaboushan; M. Osanloo
Abstract
Due to the gradual deepening of the Mazinu coal seams from the ground surface, both the open-pit (OP) and underground (UG) mining methods can be applied for extracting them. Thus, it is a necessity to determine the interface of these mining methods optimally. The present paper aims to determine this ...
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Due to the gradual deepening of the Mazinu coal seams from the ground surface, both the open-pit (OP) and underground (UG) mining methods can be applied for extracting them. Thus, it is a necessity to determine the interface of these mining methods optimally. The present paper aims to determine this interface by generating different scenarios using the OP phases and their relative underground stopes, and comparing them with each other. In this regard, an economic block model is created based on the calorific value of the coal portions involved by each block along with the required economic and technical parameters. Then using the Lerchs-Grossman algorithm, the OP phases are created. Proportional to each phase, the production scheduling of underground stopes is executed. Finally, in order to opt the best scenario, the net present value of the whole project (OP & UG) achieved from different scenarios are compared with each other. The results obtained indicate that the optimum interface of the OP and UG mining activities correspond to the ultimate OP limit with a maximum depth of 200 m from the ground surface.
M. Mahjoore; A. Aryafar; M. Honarmand
Abstract
In the present work, the cadmium oxide (CdO) nanoparticles (NPs) are synthesized using the Ferula extract. Ferula acts as a naturally-sourced reducing agent and stabilizer for the construction of the CdO NPs. The biosynthesized CdO NPs are characterized by different techniques such as X-ray powder diffraction ...
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In the present work, the cadmium oxide (CdO) nanoparticles (NPs) are synthesized using the Ferula extract. Ferula acts as a naturally-sourced reducing agent and stabilizer for the construction of the CdO NPs. The biosynthesized CdO NPs are characterized by different techniques such as X-ray powder diffraction (XRD), Fourier transform-infrared (FT-IR), spectroscopy and field emission-scanning electron microscopy (FE-SEM). After ensuring a successful synthesis of the CdO NPs, their photocatalytic activity is studied for the degradation of ciprofloxacin antibiotic in aqueous media under the sunlight. Approximately 95% degradation of ciprofloxacin using the CdO NPs is achieved after 60 minutes. The recycling experiments confirm the high stability and durability of the CdO NPs. Therefore, this work illustrates an efficient strategy for the photo-degradation of ciprofloxacin, and provides a new insight into the removal of pharmaceutical contaminants in aquatic environments.
Areeba Qazi; Kanwarpreet Singh
Abstract
The rock mass classification system is utilized to categorize rocks, and has been used in engineering projects and stability investigations. It focuses on the parameters of rock mass and engineering applications, which include tunnels, slopes, foundations, etc. Rock mass classification is valuable in ...
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The rock mass classification system is utilized to categorize rocks, and has been used in engineering projects and stability investigations. It focuses on the parameters of rock mass and engineering applications, which include tunnels, slopes, foundations, etc. Rock mass classification is valuable in the areas where the collection of samples and yielding of observation is difficult. With the advancement in technology, various machine-based model algorithms have been used, i.e., ANN and MLR in rock mass classification from prior few years. In the present work, the rock mass classification has been discussed, i.e., rock load, stand up time, RQD, RMR, Q, GSI, SMR, and RMi along with their applications. Considering all the parameters, it is concluded that for slope stability in a poor rock condition, the applicability of GSI is sufficient when compared with RMR. GSI also provides a highly accurate valuation of geo-mechanical properties, making it a valuable tool for the engineers and geologists. Also, the RMR values obtained from the ANN model provide better results for tunnels when compared with MLR and the conventional method. The ARMR classification of Slate, Shale, Quartz Schist, Gneiss, and Calcschist at 5 different locations of the world were 51-54, 66-70, 57-60, 35, 65-70, respectively. The range for slate and shale was found to be moderately anisotropic, while quartz schist, gneiss, and calcschist were found to be slightly anisotropic and highly anisotropic.
Rock Mechanics
A. Alikhani; M. Taheri Moghadder; H. Mohammadi
Abstract
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 ...
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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.
Rock Mechanics
Avinash Bhardwaj; Ajay Bhardwaj; Madhusudan Sarda; Namrata Bichewar
Abstract
Narmada valley development authority proposed a scheme under which 12.6 cumecs of water from the Hathani river (Tributary of Narmada) will be lifted to irrigate the command area. At the pumping station lies near Alirajpur, Madhya Pradesh, India, there was a need to protect the slope on both side as water ...
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Narmada valley development authority proposed a scheme under which 12.6 cumecs of water from the Hathani river (Tributary of Narmada) will be lifted to irrigate the command area. At the pumping station lies near Alirajpur, Madhya Pradesh, India, there was a need to protect the slope on both side as water thrust from the upstream side may lead to failure of the slope. This paper presents the stability analysis of the slope using GEO5 software. It was observed that the terrain at the site was a mixture of soil and rocks. The unit weight of the rock and backfill soil observed was 21 kN/m3 and 18 kN/m3. Using numerous techniques factor of safety was calculated for the particular slope and it was observed that a suitable mitigation measure needs to be provided to prevent the failure of the slope. The inclusion of a gabion retaining wall increased the slope's safety factor significantly. The proposed mitigation measure was executed at the site, and the completed wall has not shown any damage till date. The analysis of the slope's stability results, as well as its construction of the gabion retaining wall recommended as a protective measure, are presented in this work.
S. E. Mirsalari; M. Fatehi Marji; J. Gholamnejad; M. Najafi
Abstract
Analysis of the stresses, displacements, and horizontal strains of the ground subsidence due to underground excavation in rocks can be accomplished by means of a hybridized higher order indirect boundary element/finite difference (BE/FD) formulation. A semi-infinite displacement discontinuity field is ...
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Analysis of the stresses, displacements, and horizontal strains of the ground subsidence due to underground excavation in rocks can be accomplished by means of a hybridized higher order indirect boundary element/finite difference (BE/FD) formulation. A semi-infinite displacement discontinuity field is discretized (numerically) using the cubic displacement discontinuity elements (i.e. each higher order element is divided into four sub-elements bearing a cubic variation in the displacement discontinuities). Then the classical finite difference formulation (i.e. the backward, central, and forward finite difference formulations) is hybridized using the boundary element formulation, enabling us to obtain the nodal tangential stresses and horizontal strains along the elements. Several example problems are solved numerically, and the results obtained are then compared with their corresponding results available in the literature. These comparisons show the effectiveness and validness of the proposed method. A classical practical problem is also used to verify the applicability of the hybridized method.
Mineral Processing
M. Ghanbari; H. Naderi; M. Torabi
Abstract
Solvent extraction of copper from the copper leach solution obtained from the ammoniacal carbonate leaching of the Sarcheshmeh copper concentrate was carried out, and the performance of CP-150, LIX984N, and Kelex100 as well as the effects of different parameters involved were investigated. According ...
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Solvent extraction of copper from the copper leach solution obtained from the ammoniacal carbonate leaching of the Sarcheshmeh copper concentrate was carried out, and the performance of CP-150, LIX984N, and Kelex100 as well as the effects of different parameters involved were investigated. According to the results obtained, the extraction kinetics of all the three extractants was fast. High concentrations (7.5%, V/V) of CP-150 and Kelex100 were required to completely extract copper, while only 1% of LIX984N was sufficient. Addition of hexane to the diluent decreased the capability of CP-150 to extract copper, while it showed less effects on LIX984N and Kelex100. A desirable stripping of copper from the loaded organic phase could be obtained using H2SO4 solution.
M. Dehvedar; P. Moarefvand; A.R. Kiyani; A. R. Mansouri
Abstract
Inadequate hole cleaning can lead to many problems in horizontal and directional wells. In this work, we tried to investigate the cutting transport phenomenon by an experimental directional drilling simulator, considering the differences between the operational and experimental conditions. The inclination, ...
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Inadequate hole cleaning can lead to many problems in horizontal and directional wells. In this work, we tried to investigate the cutting transport phenomenon by an experimental directional drilling simulator, considering the differences between the operational and experimental conditions. The inclination, fluid type (water, foam, viscous, and dense), rotary speed (0 and 110 rpm), nozzle bit size (4, 6, and 8 mm), and stabilizer location (8 and 95 cm from the bit) were included in the tests as the main parameters. It could be concluded that the nozzle size and the stabilizer position influenced the hole cleaning time. In vertical wells, by decreasing the nozzle size from 8 mm to 4 mm, the hole cleaning time was increased. The presence of stabilizer reduced the cleaning time, and optimizing the stabilizer position reduced the probability of cutting bed formation in all inclinations. Finally, a third polynomial equation was fitted between the dimensionless mass and the dimensionless cleaning time.
M. Taghvaeenejad; M.R. Shayestefar; P. Moarefvand
Abstract
At different stages of mining, we always face a degree of uncertainty. Some of these uncertainties, such as the amount of reserve and grade of the deposit, are due to the inherent changes in the deposit and directly affect the technical and economic indicators of the deposit. On the other hand, the heavy ...
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At different stages of mining, we always face a degree of uncertainty. Some of these uncertainties, such as the amount of reserve and grade of the deposit, are due to the inherent changes in the deposit and directly affect the technical and economic indicators of the deposit. On the other hand, the heavy costs of the exploration sector often limit the amount of exploratory information, which necessitates the use of accurate estimation methods. In this work,we examines the modeling and estimation results using the conventional and simple kriging methods and the effects of the diverse indicators used in the classification of mineral storages or the parameters defining these indices. 127 exploratory boreholes with an average depth of 95 m are used to build the block model of the deposit in the Data Mine software. After the statistical studies, the 3D variographic studies are performed in order to identify the anisotropy of the region. A grade block model is constructed using the optimal variogram parameters.Then, using various methods to estimate the block model uncertainty including the kriging estimation variance, block error estimation, kriging efficiency and slope of regression, the mineral reserves are classified according to the JORC standard code. Based on different cut-off grades, the tonnage and average grade are calculated and plotted. In this work, an innovative quantitative method based on the grade-number and grade-volume fractal model is used to indicate the classification of mineral reserves. The use of fractal patterns due to the amplitude of the variation is greater and more important than the standard and provides us with a better understanding of the deposit changes per block. The existence of a minimal difference between the use of the standard and fractal patterns in the slope of the regression method indicates less error and is a proof of more reliable results.
Rock Mechanics
M. M. Samieinejad; N. Hosseini; K. Ahangari
Abstract
In order to analyze the slope stability in open-pit mines, the structural parameters of rock mass such as persistence and spatial orientation of discontinuities are characterized through field surveys, which involve spending high costs and times as well as posing high risks of rock toppling and rock ...
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In order to analyze the slope stability in open-pit mines, the structural parameters of rock mass such as persistence and spatial orientation of discontinuities are characterized through field surveys, which involve spending high costs and times as well as posing high risks of rock toppling and rock fall. In the present work, a new application of terrestrial digital photogrammetry is introduced for characterizing the rock mass structural parameters through preparing photogrammetry images from open-pit walls and building stereomodels. The data extracted from processing the stereo-model generations using photogrammetry images with different focal distances are highly consistent with the data collected through field surveys. However, it must be noted that the weather conditions, natural lighting angle, and applied observation scale may considerably affect the results obtained from stereomodel processing. Nevertheless, by taking into account the parameters such as time, cost, and full access to the required data, this new method can effectively be used in the estimation of rock mass structural parameters for analysis of steep slopes in open pits.
E. Emami Meybodi; Syed Kh. Hussain; M. Fatehi Marji; V. Rasouli
Abstract
In this work, the machine learning prediction models are used in order to evaluate the influence of rock macro-parameters (uniaxial compressive strength, tensile strength, and deformation modulus) on the rock fracture toughness related to the micro-parameters of rock. Four different types of machine ...
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In this work, the machine learning prediction models are used in order to evaluate the influence of rock macro-parameters (uniaxial compressive strength, tensile strength, and deformation modulus) on the rock fracture toughness related to the micro-parameters of rock. Four different types of machine learning methods, i.e. Multivariate Linear Regression (MLR), Multivariate Non-Linear Regression (MNLR), copula method, and Support Vector Regression (SVR) are used in this work. The fracture toughness of mode I and mode II (KIC and KIIC) is selected as the dependent variable, whereas the tensile strength, compressive strength, and elastic modulus are considered as the independent variables, respectively. The data is collected from the literature. The results obtained show that the SVR model predicts the values of KIC and KIIC with the determination coefficients (R2) of 0.73 and 0.77. The corresponding determination coefficient values of the MLR model and the MNLR model for KI and KII are R2 = 0.63, R2 = 0.72, and R2 = 0.62,0.75, respectively. The copula model predicts that the value of R2 for KI is 0.52, and for KII R2=0.69. K-fold cross-validation testing method performs for all these machine learning models. The cross-validation technique shows that SVR is the best-designed model for predicting the fracture toughness mode-I and mode-II.
