Pub Date : 2017-12-01DOI: 10.22059/IJMGE.2017.213629.594622
A. Bahrami, M. Hosseini, M. Rahimi
In the present research work, a low-ash coal, from Ghouzlou deposit in Iran, with an average ash content of 12% was subjected to some beneficiation experiments such as heavy media separation and flotation. Sieve analysis showed that 62.3% of the coal sample with the size of +2 mm had around 7.3% ash contents. Also, heavy media tests carried out on five size fractions revealed that by setting the separation density at 1.4 g/cm3 for the coarse fraction (+1 mm), a 5% ash product with more than 70% coal recovery was obtainable. Samples with lower ash content ( 5%) based on the Mayer curves to produce a 5% coal product. Moreover, flotation tests on -1 mm fraction could reduce the ash content from more 13.2% to 10.4%.
{"title":"Preliminary Beneficiation and Washability Studies on Ghouzlou's Low-Ash Coal Sample","authors":"A. Bahrami, M. Hosseini, M. Rahimi","doi":"10.22059/IJMGE.2017.213629.594622","DOIUrl":"https://doi.org/10.22059/IJMGE.2017.213629.594622","url":null,"abstract":"In the present research work, a low-ash coal, from Ghouzlou deposit in Iran, with an average ash content of 12% was subjected to some beneficiation experiments such as heavy media separation and flotation. Sieve analysis showed that 62.3% of the coal sample with the size of +2 mm had around 7.3% ash contents. Also, heavy media tests carried out on five size fractions revealed that by setting the separation density at 1.4 g/cm3 for the coarse fraction (+1 mm), a 5% ash product with more than 70% coal recovery was obtainable. Samples with lower ash content ( 5%) based on the Mayer curves to produce a 5% coal product. Moreover, flotation tests on -1 mm fraction could reduce the ash content from more 13.2% to 10.4%.","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"53 1","pages":"119-123"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89561766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-01DOI: 10.22059/IJMGE.2017.232091.594669
E. Bakhtavar, R. Lotfian
The accurate selection of a processing plant site can result in decreasing total mining cost. This problem can be solved by multi-criteria decision-making (MCDM) methods. This research introduces a new approach by integrating fuzzy AHP and gray MCDM methods to solve all decision-making problems. The approach is applied in the case of a copper mine area. The critical criteria are considered adjacency to the crusher, adjacency to tailing dam, adjacency to a power source, distance from blasting sources, the availability of sufficient land, and safety against floods. After studying the mine map, six feasible alternatives are prioritized using the integrated approach. Results indicated that sites A, B, and E take the first three ranks. The separate results of fuzzy AHP and gray MCDM confirm that alternatives A and B have the first two ranks. Moreover, the field investigations approved the results obtained by the approach.
{"title":"Applying an integrated fuzzy gray MCDM approach: A case study on mineral processing plant site selection","authors":"E. Bakhtavar, R. Lotfian","doi":"10.22059/IJMGE.2017.232091.594669","DOIUrl":"https://doi.org/10.22059/IJMGE.2017.232091.594669","url":null,"abstract":"The accurate selection of a processing plant site can result in decreasing total mining cost. This problem can be solved by multi-criteria decision-making (MCDM) methods. This research introduces a new approach by integrating fuzzy AHP and gray MCDM methods to solve all decision-making problems. The approach is applied in the case of a copper mine area. The critical criteria are considered adjacency to the crusher, adjacency to tailing dam, adjacency to a power source, distance from blasting sources, the availability of sufficient land, and safety against floods. After studying the mine map, six feasible alternatives are prioritized using the integrated approach. Results indicated that sites A, B, and E take the first three ranks. The separate results of fuzzy AHP and gray MCDM confirm that alternatives A and B have the first two ranks. Moreover, the field investigations approved the results obtained by the approach.","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"35 1","pages":"177-183"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88301489","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-01DOI: 10.22059/IJMGE.2017.64323
M. Ostad, O. Asghari, A. Rafiee, M. Azizzadeh, F. Khoshbakht
Fracture orientation is a prominent factor in determining the reservoir fluid flow direction in a formation because fractures are the major paths through which fluid flow occurs. Hence, a true modeling of orientation leads to a reliable prediction of fluid flow. Traditionally, various distributions are used for orientation modeling in fracture networks. Although they offer a fairly suitable estimation of fracture orientation, they would not consider any spatial structure for simulated fracture orientations, and would not able to properly reproduce the histograms, and the stereogram of dip and azimuth. To respect this geostatistical and statistical parameters, in this paper a new approach has been presented in which the observed fractures on the image log are firstly clustered, and the major facture families are categorically simulated over the area of study. Afterwards, azimuths are simulated using the probability field obtained from categorical simulation, and dips are conditionally simulated to azimuths. The method is illustrated through a case and the results show that the histograms and stereograms are completely reproduced. In addition, the connectivity of modeled fracture network using the presented method is surveyed in comparison with modeled fracture network using Kent distribution.
{"title":"Categorical fracture orientation modeling: applied to an Iranian oil field","authors":"M. Ostad, O. Asghari, A. Rafiee, M. Azizzadeh, F. Khoshbakht","doi":"10.22059/IJMGE.2017.64323","DOIUrl":"https://doi.org/10.22059/IJMGE.2017.64323","url":null,"abstract":"Fracture orientation is a prominent factor in determining the reservoir fluid flow direction in a formation because fractures are the major paths through which fluid flow occurs. Hence, a true modeling of orientation leads to a reliable prediction of fluid flow. Traditionally, various distributions are used for orientation modeling in fracture networks. Although they offer a fairly suitable estimation of fracture orientation, they would not consider any spatial structure for simulated fracture orientations, and would not able to properly reproduce the histograms, and the stereogram of dip and azimuth. To respect this geostatistical and statistical parameters, in this paper a new approach has been presented in which the observed fractures on the image log are firstly clustered, and the major facture families are categorically simulated over the area of study. Afterwards, azimuths are simulated using the probability field obtained from categorical simulation, and dips are conditionally simulated to azimuths. The method is illustrated through a case and the results show that the histograms and stereograms are completely reproduced. In addition, the connectivity of modeled fracture network using the presented method is surveyed in comparison with modeled fracture network using Kent distribution.","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"51 1","pages":"139-146"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81675728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-12-01DOI: 10.22059/IJMGE.2017.233613.594675
M. Khosravi, Farzaneh Hamedi Azad, M. Bahaaddini, T. Pipatpongsa
In this paper, the problem of a retaining wall under active translation mode is investigated numerically. To this end, a series of numerical models is conducted using the discrete element code, PFC2D. The backfill soil is simulated by an assembly of separate cohesionless circular particles. Backfill soil was prepared by pouring soil particles from a specific height under gravity force and giving them enough time for appropriate settlement. Different heights of retaining walls are simulated and the lateral earth pressure on the wall is observed under both at-rest and active conditions. Numerical results compared with predictions from some analytical methods and measurements from physical models. The active state of earth pressure is defined as the earth pressure distribution corresponding to the values of wall displacement where the failure zone in the backfill is fully developed. The numerical results showed that the fully active state of earth pressure occurred at a wall displacement corresponding to the strains required for reaching the critical state in biaxial compressive tests.
{"title":"DEM Analysis of Backfilled Walls Subjected to Active Translation Mode","authors":"M. Khosravi, Farzaneh Hamedi Azad, M. Bahaaddini, T. Pipatpongsa","doi":"10.22059/IJMGE.2017.233613.594675","DOIUrl":"https://doi.org/10.22059/IJMGE.2017.233613.594675","url":null,"abstract":"In this paper, the problem of a retaining wall under active translation mode is investigated numerically. To this end, a series of numerical models is conducted using the discrete element code, PFC2D. The backfill soil is simulated by an assembly of separate cohesionless circular particles. Backfill soil was prepared by pouring soil particles from a specific height under gravity force and giving them enough time for appropriate settlement. Different heights of retaining walls are simulated and the lateral earth pressure on the wall is observed under both at-rest and active conditions. Numerical results compared with predictions from some analytical methods and measurements from physical models. The active state of earth pressure is defined as the earth pressure distribution corresponding to the values of wall displacement where the failure zone in the backfill is fully developed. The numerical results showed that the fully active state of earth pressure occurred at a wall displacement corresponding to the strains required for reaching the critical state in biaxial compressive tests.","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"62 1","pages":"191-197"},"PeriodicalIF":0.0,"publicationDate":"2017-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88848334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.22059/IJMGE.2016.202595.594600
naeim ghaeini hesarouieh, M. Mousakhani, H. B. Amnieh, A. Jafari
One of the key outcomes of blasting in mines is found to be rock fragmentation which profoundly affects downstream expenses. In fact, size prediction of rock fragmentation is the first leap towards the optimization of blasting design parameters. This paper makes an attempt to present a model to predict rock fragmentation using Mutual Information (MI) in Meydook copper mine. Ten parameters are considered to influence fragmentation. On the other hand, Rock Engineering System (RES) is employed for sake of comparison between different methods. To validate the results, six blasting scenarios are selected out and compared with results of both models. The coefficients R2, RMSE and MAE were used in an attempt to assess the performance of presented models. The values of the coefficients R2, RMSE and MAE considering two methods of MI and RES for 30 blasting cycles are calculated as (0.81, 10.7, and 9.02) and (0.75, 11.87, and 9.61), respectively, implying the better capability of MI model to predict fragmentation.
{"title":"Prediction of fragmentation due to blasting using mutual information and rock engineering system; case study: Meydook copper mine","authors":"naeim ghaeini hesarouieh, M. Mousakhani, H. B. Amnieh, A. Jafari","doi":"10.22059/IJMGE.2016.202595.594600","DOIUrl":"https://doi.org/10.22059/IJMGE.2016.202595.594600","url":null,"abstract":"One of the key outcomes of blasting in mines is found to be rock fragmentation which profoundly affects downstream expenses. In fact, size prediction of rock fragmentation is the first leap towards the optimization of blasting design parameters. This paper makes an attempt to present a model to predict rock fragmentation using Mutual Information (MI) in Meydook copper mine. Ten parameters are considered to influence fragmentation. On the other hand, Rock Engineering System (RES) is employed for sake of comparison between different methods. To validate the results, six blasting scenarios are selected out and compared with results of both models. The coefficients R2, RMSE and MAE were used in an attempt to assess the performance of presented models. The values of the coefficients R2, RMSE and MAE considering two methods of MI and RES for 30 blasting cycles are calculated as (0.81, 10.7, and 9.02) and (0.75, 11.87, and 9.61), respectively, implying the better capability of MI model to predict fragmentation.","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"114 1","pages":"23-28"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86455947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.22059/IJMGE.2017.215656.594629
M. Ziaii, A. Pouyan, Rahman Yousefzadeh, J. Ghiasi-Freez
Traditional methods of chromite exploration are mostly based on geophysical techniques and drilling operations. They are expensive and time-consuming. Furthermore, they suffer from several shortcomings such as lack of sufficient geophysical density contrast. In order to overcome these drawbacks, the current research work is carried out to introduce a novel, automatic and opto-geometric image analysis (OGIA) technique for extracting the structural properties of chromite minerals using polished thin sections prepared from outcrops. Several images are taken from polished thick sections through a reflected-light microscope equipped with a digital camera. The images are processed in filtering and segmentation steps to extract the worthwhile information of chromite minerals. The directional density of chromite minerals, as a textural property, is studied in different inclinations, and the main trend of chromite growth is identified. Microscopic inclination of chromite veins can be generalized for exploring the macroscopic layers of chromite buried under either the surface quaternary alluvium or overburden rocks. The performance of the OGIA methodology is tested in a real case study, where several exploratory boreholes are drilled. The results obtained show that the microscopic investigation outlines through image analysis are in good agreement with the results obtained from interpretation of boreholes. The OGIA method represents a reliable map of the absence or existence of chromite ore deposits in different horizontal surfaces. Directing the exploration investigations toward more susceptible zones (potentials) and preventing from wasting time and money are the major contributions of the OGIA methodology. It leads to make an optimal managerial and economical decision.
{"title":"An Image Analysis-Based Methodology for Chromite Exploration through Opto-Geometric Parameters; a Case Study in Faryab Area, SE of Iran","authors":"M. Ziaii, A. Pouyan, Rahman Yousefzadeh, J. Ghiasi-Freez","doi":"10.22059/IJMGE.2017.215656.594629","DOIUrl":"https://doi.org/10.22059/IJMGE.2017.215656.594629","url":null,"abstract":"Traditional methods of chromite exploration are mostly based on geophysical techniques and drilling operations. They are expensive and time-consuming. Furthermore, they suffer from several shortcomings such as lack of sufficient geophysical density contrast. In order to overcome these drawbacks, the current research work is carried out to introduce a novel, automatic and opto-geometric image analysis (OGIA) technique for extracting the structural properties of chromite minerals using polished thin sections prepared from outcrops. Several images are taken from polished thick sections through a reflected-light microscope equipped with a digital camera. The images are processed in filtering and segmentation steps to extract the worthwhile information of chromite minerals. The directional density of chromite minerals, as a textural property, is studied in different inclinations, and the main trend of chromite growth is identified. Microscopic inclination of chromite veins can be generalized for exploring the macroscopic layers of chromite buried under either the surface quaternary alluvium or overburden rocks. The performance of the OGIA methodology is tested in a real case study, where several exploratory boreholes are drilled. The results obtained show that the microscopic investigation outlines through image analysis are in good agreement with the results obtained from interpretation of boreholes. The OGIA method represents a reliable map of the absence or existence of chromite ore deposits in different horizontal surfaces. Directing the exploration investigations toward more susceptible zones (potentials) and preventing from wasting time and money are the major contributions of the OGIA methodology. It leads to make an optimal managerial and economical decision.","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"67 1","pages":"97-104"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86532694","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.22059/IJMGE.2017.62153
H. B. Amnieh, M. Bahadori
Ground vibration is one of the undesirable results of blasting operations. Different methods have been proposed to predict and control ground vibration that is caused by blasting. These methods can be classified as laboratory studies, fieldwork and numerical modeling. Among these methods, numerical modeling is the one which saves time and cuts costs since it takes into account the basic principles of mechanics and provides step by step time-domain solutions. In order to use numerical analysis in predicting the results of blasting operations, the accuracy of the output must be verified through field test. In this study, ground vibration caused by blasting in a field operation in Miduk Copper Mine was recorded using 3-components seismometers of the Vibracord seismograph and analyzed by Vibration-Meter software. Propagation of the waves caused by blasting in the mine slope was modeled using discrete element logic in the UDEC numerical software and compared to the results of the field test. Having tested the accuracy of the results obtained, the effect of primer location and the direction of detonation propagation in the blast hole on the rate of ground vibration caused by blasting was investigated. The results show that by changing primer location from the bottom of the hole to its top, the rate of ground vibration caused by blasting increases.
{"title":"Numerical Analysis of the Primer Location Effect on Ground Vibration Caused by Blasting","authors":"H. B. Amnieh, M. Bahadori","doi":"10.22059/IJMGE.2017.62153","DOIUrl":"https://doi.org/10.22059/IJMGE.2017.62153","url":null,"abstract":"Ground vibration is one of the undesirable results of blasting operations. Different methods have been proposed to predict and control ground vibration that is caused by blasting. These methods can be classified as laboratory studies, fieldwork and numerical modeling. Among these methods, numerical modeling is the one which saves time and cuts costs since it takes into account the basic principles of mechanics and provides step by step time-domain solutions. In order to use numerical analysis in predicting the results of blasting operations, the accuracy of the output must be verified through field test. In this study, ground vibration caused by blasting in a field operation in Miduk Copper Mine was recorded using 3-components seismometers of the Vibracord seismograph and analyzed by Vibration-Meter software. Propagation of the waves caused by blasting in the mine slope was modeled using discrete element logic in the UDEC numerical software and compared to the results of the field test. Having tested the accuracy of the results obtained, the effect of primer location and the direction of detonation propagation in the blast hole on the rate of ground vibration caused by blasting was investigated. The results show that by changing primer location from the bottom of the hole to its top, the rate of ground vibration caused by blasting increases.","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"61 1","pages":"53-62"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73931003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.22059/IJMGE.2017.62151
Aliasghar Mirmohammadlou, H. Memarian, S. Mohammadi, M. Jafari
Rapid development of engineering activities expands through a variety of rock engineering processes such as drilling, blasting, mining and mineral processing. These activities require rock dynamic fracture mechanics method to characterize the rock behavior. Dynamic fracture toughness is an important parameter for the analysis of engineering structures under dynamic loading. Several experimental methods are used for determination of dynamic fracture properties of materials. Among them, the Hopkinson pressure bar and the drop weight have been frequently used for rocks. On the other hand, numerical simulations are very useful in dynamic fracture studies. Among vast variety of numerical techniques, the powerful extended finite element method (XFEM) enriches the finite element approximation with appropriate functions extracted from the fracture mechanics solution around a crack-tip. The main advantage of XFEM is its capability in modeling different on a fixed mesh, which can be generated without considering the existence of discontinuities. In this paper, first, the design of a drop weight test setup is presented. Afterwards, the experimental tests on igneous (basalt) and calcareous (limestone) rocks with single-edge-cracked bend specimen are discussed. Then, each experimental test is modeled with the XFEM code. Finally, the obtained experimental and numerical results are compared. The results indicate that the experimentally predicted dynamic fracture toughness has less than 8 percent difference with calculated dynamic fracture toughness from extended finite element method
{"title":"Experimental and Numerical Investigation of Rock Dynamic Fracture","authors":"Aliasghar Mirmohammadlou, H. Memarian, S. Mohammadi, M. Jafari","doi":"10.22059/IJMGE.2017.62151","DOIUrl":"https://doi.org/10.22059/IJMGE.2017.62151","url":null,"abstract":"Rapid development of engineering activities expands through a variety of rock engineering processes such as drilling, blasting, mining and mineral processing. These activities require rock dynamic fracture mechanics method to characterize the rock behavior. Dynamic fracture toughness is an important parameter for the analysis of engineering structures under dynamic loading. Several experimental methods are used for determination of dynamic fracture properties of materials. Among them, the Hopkinson pressure bar and the drop weight have been frequently used for rocks. On the other hand, numerical simulations are very useful in dynamic fracture studies. Among vast variety of numerical techniques, the powerful extended finite element method (XFEM) enriches the finite element approximation with appropriate functions extracted from the fracture mechanics solution around a crack-tip. The main advantage of XFEM is its capability in modeling different on a fixed mesh, which can be generated without considering the existence of discontinuities. In this paper, first, the design of a drop weight test setup is presented. Afterwards, the experimental tests on igneous (basalt) and calcareous (limestone) rocks with single-edge-cracked bend specimen are discussed. Then, each experimental test is modeled with the XFEM code. Finally, the obtained experimental and numerical results are compared. The results indicate that the experimentally predicted dynamic fracture toughness has less than 8 percent difference with calculated dynamic fracture toughness from extended finite element method","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"31 1","pages":"37-46"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88426284","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.22059/IJMGE.2016.218483.594634
H. Khoshdast, V. Shojaei, H. Khoshdast
Combining the computational fluid dynamics (CFD) and the design of experiments (DOE) methods, as a mixed approach in modeling was proposed so that to simultaneously benefit from the advantages of both modeling methods. The presented method was validated using a coal hydraulic classifier in an industrial scale. Effects of operating parameters including feed flow rate, solid content and baffle length, were evaluated on classifier overflow velocity and cut-size as the process responses. The evaluation sequence was as follows: the variation levels of parameters was first evaluated using industrial measurement, and then a suitable experimental design was constructed and the DOE matrix was translated to CFD input. Afterwards, the overflow velocity values were predicted by CFD and cut-size values were determined using industrial and CFD results. Overflow velocity and cut-size were statistically analyzed to develop prediction models for DOE responses; and finally, the main and the interaction effects were interpreted with respect to DOE and CFD results. Statistical effect plots along with CFD fluid flow patterns showed the type and the magnitude of operating parameters effects on the classifier performance and visualized the mechanism by which those effects occurred. The suggested modeling method seems to be a useful approach for better understanding the real operational phenomena within the fluid-base separation devices. Furthermore, individual and interaction effects can also be identified and used for interpretation of nonlinear process responses.
{"title":"Combined application of computational fluid dynamics (CFD) and design of experiments (DOE) to hydrodynamic simulation of a coal classifier","authors":"H. Khoshdast, V. Shojaei, H. Khoshdast","doi":"10.22059/IJMGE.2016.218483.594634","DOIUrl":"https://doi.org/10.22059/IJMGE.2016.218483.594634","url":null,"abstract":"Combining the computational fluid dynamics (CFD) and the design of experiments (DOE) methods, as a mixed approach in modeling was proposed so that to simultaneously benefit from the advantages of both modeling methods. The presented method was validated using a coal hydraulic classifier in an industrial scale. Effects of operating parameters including feed flow rate, solid content and baffle length, were evaluated on classifier overflow velocity and cut-size as the process responses. The evaluation sequence was as follows: the variation levels of parameters was first evaluated using industrial measurement, and then a suitable experimental design was constructed and the DOE matrix was translated to CFD input. Afterwards, the overflow velocity values were predicted by CFD and cut-size values were determined using industrial and CFD results. Overflow velocity and cut-size were statistically analyzed to develop prediction models for DOE responses; and finally, the main and the interaction effects were interpreted with respect to DOE and CFD results. Statistical effect plots along with CFD fluid flow patterns showed the type and the magnitude of operating parameters effects on the classifier performance and visualized the mechanism by which those effects occurred. The suggested modeling method seems to be a useful approach for better understanding the real operational phenomena within the fluid-base separation devices. Furthermore, individual and interaction effects can also be identified and used for interpretation of nonlinear process responses.","PeriodicalId":36564,"journal":{"name":"International Journal of Mining and Geo-Engineering","volume":"64 1","pages":"9-24"},"PeriodicalIF":0.0,"publicationDate":"2017-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72821246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-06-01DOI: 10.22059/IJMGE.2017.216705.594630
A. Baghbanan, Sadegh Kefayati, M. Torkan, H. Hashemolhosseini, Roohollah Narimani
Due to existence of uncertainties in input geometrical properties of fractures, there is not any unique solution for assessing the stability of slopes in jointed rock masses. Therefore, the necessity of applying probabilistic analysis in these cases is inevitable. In this study a probabilistic analysis procedure together with relevant algorithms are developed using Discrete Fracture Network-Distinct Element Method (DFN-DEM) approach. In the right abutment of Karun 4 dam and downstream of the dam body, five joint sets and one major joint have been identified. According to the geometrical properties of fractures in Karun river valley, instability situations are probable in this abutment. In order to evaluate the stability of the rock slope, different combinations of joint set geometrical parameters are selected, and a series of numerical DEM simulations are performed on generated and validated DFN models in DFN-DEM approach to measure minimum required support patterns in dry and saturated conditions. Results indicate that the distribution of required bolt length is well fitted with a lognormal distribution in both circumstances. In dry conditions, the calculated mean value is 1125.3 m, and more than 80 percent of models need only 1614.99 m of bolts which is a bolt pattern with 2 m spacing and 12 m length. However, as for the slopes with saturated condition, the calculated mean value is 1821.8 m, and more than 80 percent of models need only 2653.49 m of bolts which is equivalent to a bolt pattern with 15 m length and 1.5 m spacing. Comparison between obtained results with numerical and empirical method show that investigation of a slope stability with different DFN realizations which conducted in different block patterns is more efficient than the empirical methods.
由于裂隙输入几何性质的不确定性，对节理岩体中边坡的稳定性评价没有唯一的解。因此，在这些情况下应用概率分析的必要性是不可避免的。本文采用离散断裂网络-离散元法(ddn - dem)方法，提出了一种概率分析方法及相关算法。在卡伦4号坝右坝肩及坝体下游，确定了5组节理和1个主节理。根据卡伦河流域裂缝的几何特征，该桥台可能出现失稳情况。为了评价岩石边坡的稳定性，选择不同的节理几何参数组合，采用DFN-DEM方法对生成和验证的DFN模型进行了一系列数值模拟，以测量干燥和饱和条件下所需的最小支护模式。结果表明，两种情况下所需锚杆长度的分布都符合对数正态分布。在干燥条件下，计算平均值为1125.3 m, 80%以上的模型只需要1614.99 m的螺栓，为间距2 m，长度12 m的螺栓模式。而饱和边坡的计算平均值为1821.8 m, 80%以上的模型只需要2653.49 m的锚杆，相当于长度为15m，间距为1.5 m的锚杆网。数值方法与经验方法所得结果的比较表明，在不同块体模式下，采用不同DFN实现的边坡稳定性研究比经验方法更有效。
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