Journal of Mining and EnvironmentJournal of Mining and Environment
http://jme.shahroodut.ac.ir/
Tue, 22 Oct 2019 05:38:36 +0100FeedCreatorJournal of Mining and Environment
http://jme.shahroodut.ac.ir/
Feed provided by Journal of Mining and Environment. Click to visit.Combining fuzzy RES with GA for predicting wear performance of circular diamond saw in hard ...
http://jme.shahroodut.ac.ir/article_986_165.html
Predicting the wear performance of circular diamond saw in the process of sawing hard dimensional stone is an important step in reducing production costs in the stone sawing industry. In the present research work, the effective parameters on circular diamond saw wear are defined, and then the weight of each parameter is determined through adopting a fuzzy rock engineering system (Fuzzy RES) based on defining an accurate Gaussian pattern in fuzzy logic with analogous weighting. After this step, genetic algorithm (GA) is used to determine the levels of the four major variables and the amounts of the saw wear (output parameter) in the classification operation based on the fixed, dissimilar, and logarithmic spanning methods. Finally, a mathematical relationship is suggested for evaluation of the accuracy of the proposed models. The main contribution of our method is the novelty of combination of these methods in fuzzy RES. Before this work, all Fuzzy RESs only use simple membership functions and uniform spanning. Using GA for spanning and normal distribution as membership function based upon our latest work is the first work in fuzzy RES. To verify the selected proposed model, rock mechanics tests are conducted on nine hard stone samples, and the diamond saw wear is measured and compared with the proposed model. According to the results obtained, the proposed model exhibits acceptable capabilities in predicting the circular diamond saw wear.Sun, 30 Jun 2019 19:30:00 +0100Determining optimal distance from outlet of auxiliary forcing ventilation system to development ...
http://jme.shahroodut.ac.ir/article_1523_0.html
Auxiliary ventilation of the blind development heading in underground mines is one of the most challenging work activities amongst mining underground operations. The auxiliary forcing ventilation system provides positive pressure, cooling, controlling gas layering, and removing diesel fumes and dust levels from development headings, stopes, and services facilities. The effectiveness of the auxiliary forcing ventilation system depends upon many system variables. Currently, no scientific models and calculations are available that can be used to estimate the optimal distance from the outlet of the auxiliary forcing ventilation system to the development heading in underground mines that can provide the most efficient ventilation close to the face of the heading. In this work, scenarios are developed and simulated with a validated CFD model inside the ANSYS Fluent software. In each scenario, the system parameters such as dead zone, mean age of air, and face velocity are calculated, which are later used in the optimization process. By examining these parameters at the development heading zone, we can quantify the effectiveness of the ventilation system and confirm that the system design meets the government regulations. This work is carried out using the k-epsilon realizable turbulent model inside the ANSYS Fluent software.Fri, 09 Aug 2019 19:30:00 +0100Delineation of alteration zones based on kriging, artificial neural networks, and ...
http://jme.shahroodut.ac.ir/article_1275_165.html
This paper presents a quantitative modeling for delineating alteration zones in the hypogene zone of the Miduk porphyry copper deposit (SE Iran) based on the core drilling data. The main goal of this work was to apply the Ordinary Kriging (OK), Artificial Neural Networks (ANNs), and Concentration-Volume (C-V) fractal modelings on Cu grades to separate different alteration zones. Anisotropy was investigated and modeled based on calculating the experimental semi-variograms of Cu value, and then the main variography directions were identified and evaluated. The block model of Cu grade was generated using the kriging and ANN modelings followed by log-log plots of the C-V fractal modeling to determine the Cu threshold values used in delineating the alteration zones. Based on the correlation between the geological models and the results derived via C-V fractal modeling, Cu values less than 0.479% resulting from kriging modeling had more overlapped voxels with the phyllic alteration zone by an overall accuracy (OA) of 0.83. The spatial correlation between the potassic alteration zone in a 3D geological model and the high concentration zones in the C-V fractal model showed that Cu values between 0.479% and 1.023%, resulting from kriging modeling, had the best overall accuracy (0.78). Finally, based on the correlation between classes in the binary geological and fractal models of the hypogene zone, this research work showed that kriging modeling could delineate the phyllic (with lower grades) and potassic (with higher grades) alteration zones more effectively compared with ANNs.Sun, 30 Jun 2019 19:30:00 +0100Evaluation of stream sediments contamination by potentially toxic elements around mining and ...
http://jme.shahroodut.ac.ir/article_1568_0.html
This study assessed potentially toxic elements concentrations in stream sediments for pollution monitoring in mining, quarrying and farming areas southeastern Nigeria. Levels of Iron (Fe), Molybdenum (Mo), Vanadium (V), Copper (Cu), Lead (Pb), Zinc (Zn), Nickel (Ni), Cobalt (Co), Manganese (Mn), Chromium (Cr), Barium (Ba) and Beryllium (Be) were determined. Concentrations of the elements are in the order Fe>Ba>Mn>Cr>Zn>Pb>Cu>Co>Ni>As>Mo. Positive significant correlation at PEiR(Pb)>EiR(Cu)>EiR(Co)>EiR(Cr)>EiR(V)>EiR(Ni)>EiR(Zn). Ba, Pb and As need to be monitored further to determine their source and recommend possible remedial measures. The result of this study will improve water management efficiency and serve as a benchmark of vulnerability assessment of the study area. This can also be useful for future impact assessment and adequate planning of mine and farming areas. In addition, the result will assist scientist for making appropriate environmental management strategies to reduce the influence of metal contamination triggered from mine sites and farming areas both in Nigeria and globally.Mon, 07 Oct 2019 20:30:00 +0100Risk management in urban tunnels using methods of game theory and multi-criteria decision-making
http://jme.shahroodut.ac.ir/article_1391_165.html
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.Sun, 30 Jun 2019 19:30:00 +0100Calculating inter-sectoral carbon flows of Mining sector via hypothetical extraction method
http://jme.shahroodut.ac.ir/article_1492_0.html
Mining is among the oldest industries. It is the primary source of raw material for most of the sectors. Little is known about complex inter-sectoral carbon linkages of the mining industry. This study estimates inter and intra sectoral carbon linkages impact of the mining sector across ten major economies by applying an input-output model, hypothetical extraction method and its modified version. Hypothetical extraction method removes an industrial block from an economic system afterwards it makes a comparison between before and after removal values. China with 195.47 Mt had the highest mining emissions, followed by USA, India, and Canada with 110.99 Mt, 108.79 Mt, and 76.92 Mt respectively. India’s mining sector with 26.33 t/104 $ was 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 were affected the most from the extraction of mining sector total and forward carbon linkages. While for backward carbon linkage Canada with -1.33% was affected the most. Canada had the highest mixed and internal emissions of 0.42 Mt and 47.88 Mt. However, China had the highest net-backwards 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 numerical findings, the study also discusses mitigation measures for both direct and indirect mining emissions.Sat, 29 Jun 2019 19:30:00 +0100Determination of optimal bandwidth in upscaling process of reservoir data using kernel function ...
http://jme.shahroodut.ac.ir/article_1455_165.html
Upscaling based on the bandwidth of the kernel function is a flexible approach to upscale the data because the cells will be coarse-based on variability. The intensity of the coarsening of cells in this method can be controlled with bandwidth. In a smooth variability region, a large number of cells will be merged, and vice versa, they will remain fine with severe variability. Bandwidth variation can be effective in upscaling results. Therefore, determining the optimal bandwidth in this method is essential. For each bandwidth, the upscaled model has a number of upscaled blocks and an upscaling error. Obviously, higher thresholds or bandwidths cause a lower number of upscaled blocks and a higher sum of squares error (SSE). On the other hand, using the smallest bandwidth, the upscaled model will remain in a fine scale, and there will be practically no upscaling. In this work, different approaches are used to determine the optimal bandwidth or threshold for upscaling. Investigation of SSE changes, the intersection of two charts, namely SSE and the number of upscaled block charts, and the changes of SSE values versus bandwidths, are among these approaches. In this particular case, if the goal of upscaling is to minimize the upscaling error, the intersection method will obtain a better result. Conversely, if the purpose of upscaling is computational cost reduction, the SSE variation approach will be more appropriate for the threshold setting.Sun, 30 Jun 2019 19:30:00 +0100Evaluation of background geochemical speciation of heavy metals in overburden topsoil of ...
http://jme.shahroodut.ac.ir/article_1524_0.html
Metals are ubiquitous within the earth crust. However, the exceptional high-level concentration of heavy metals in the soil due to natural or anthropogenic activities and the chemical forms in which they exist determine the level of risk they portend to the environment. This work was aimed at determining the background level of the presence of seven priority toxic metals (Cr, Ni, Pb, As, Cd, Cu, Zn) in the chemical phases of the overburden topsoil of a bituminous deposit prior to mining activities through the speciation analysis. The grab samples of overburden topsoil were initially obtained and homogenized to composites based on locations for the subsequent sequential extraction procedure (SEP). The specific physico-chemical properties of the sampled soils were simultaneously determined to complement the SEP inferential analysis. The results obtained showed that most metals were spatially bounded to the Fe-Mn oxides (reducible phase) followed by the organic (oxidizable) and the carbonates phases, respectively. Fractionally, the dominant soil texture in the studied area was sand (55.45%); however, the colloidal organic matter and Fe-Mn oxide phases played the dominant roles in the sorption activities of the selected metals. The soil chemical phase with the least metal pool was the exchangeable (water/salt) soluble fraction. The overall assessment revealed that the geogenic heavy metals in the topsoil posed no threats since a marginal fraction of the metals existed in the bio-available form in non-toxic concentrations in the order of Pb > Zn > Cu, while the potential mobility of metals showed that Zn was preferentially higher than Pb and Cu, respectively.Fri, 09 Aug 2019 19:30:00 +0100Airflow inside tunnel boring machine: A numerical study and an experimental verification
http://jme.shahroodut.ac.ir/article_1456_165.html
Knowledge of the airflow distribution inside a Tunnel Boring Machine (TBM) can create a safe working environment for workers and machinery. The airflow quality and the related mass flow rate in the ventilation system should be sufficient to dilute gases and remove dust inside the tunnel. In this work, airflow distribution in the single shield TBM tunnel was studied using computational fluid dynamics. The finite volume-based finite element method was used in the simulation based on the 3D complex geometry of TBM. In order to validate the numerical results, the air velocity inside the Chamshir tunnel was measured experimentally at different sections. With a length of 7050 m and a final diameter of 4.6 m, the Chamshir water transport tunnel is located in the south of Iran. The results obtained show that there is not enough airflow in 59.6% of the TBM space in the current working conditions. In other words, there are many dead zones from the control cabin to the end of gantry 6 in the backup system. Several applicable scenarios were studied to remove the dead zone area and optimize the airflow velocity by employing high capacity jet fan in the ventilation system. The results show that the dead zone volume can be decreased by about 5.21% by increasing the airflow rate of the jet fan.Sun, 30 Jun 2019 19:30:00 +0100Delineation of alteration zones based on artificial neural network and concentration-volume ...
http://jme.shahroodut.ac.ir/article_1494_0.html
In this paper, two specific goals are followed. First, the capability of Artificial Neural Network technique has been investigated for ore grade estimation. The different training algorithms and number of hidden neurons were used to estimate copper grade with borehole dataset in the hypogene zone of porphyry copper-gold deposit, Masjed-Daghi, Iran. The performance of ANN was compared in function learning and estimation with ordinary kriging. The kriging algorithms smooth the data, and thus its use for pre-processing of data for fractal analysis is not suitable. One alternative to such a problem is the use of ANN. Second, the results obtained from the ANN estimation, along with the C-V fractal model, were used to delineate the potassic and phyllic alteration areas in the hypogene zone of Cu-Au porphyry deposit. To achieve this purpose, the log-log plot was generated based on the results obtained from ANN, and then breakpoints of this plot were used to determine the threshold values in order to delineate the alteration zones. In order to investigate the correlation between geological model and C-V fractal results, the log ratio matrix was used. The results has been shown that Cu values less than 0.38% has more overlapped voxels with phyllic alteration zone by overall accuracy (OA) of 0.72. Based on spatial correlation between the potassic alteration zones resulted from 3D geological modeling and high concentration zones in C-V model has concluded that Cu values greater than 0.38% has more overlapped voxels with potassic alteration zone by overall accuracy of 0.76.Tue, 02 Jul 2019 19:30:00 +0100A programming method to estimate proximate parameters of coal beds from well-logging data using ...
http://jme.shahroodut.ac.ir/article_1433_165.html
This paper presents an innovative solution for estimating the proximate parameters of coal beds from the well-logs. To implement the solution, the C# programming language was used. The data from four exploratory boreholes was used in a case study to express the method and determine its accuracy. Then two boreholes were selected as the reference, namely the boreholes with available well-logging results and the proximate analysis data. The values of three well-logs were selected to be implemented in a system of equations that was solved, and the effect of each well-log on the estimated values of the proximate parameter was expressed as a coefficient called the effect factor. The coefficients were incorporated in an empirical relationship between the parameter and the three well-logs. To calculate the coefficients used for the most accurate estimation, a total of 22960 systems of equations were defined and solved for every three logs. As there was the possibility of 560 combinations for selecting three logs from all the available 16 logs, the three equation-three variable systems were solved more than 12 million times. The programming methods were utilized to achieve the final results. The results of each system were tested for deviation of the estimated values of volatile matter, ash, and moisture, and the coefficients of the lowest deviation were accepted to be applied in the relation. Implementing this method for estimating the volatile matter resulted in an average deviation of 10.5%. The corresponding estimated values of the ash and moisture contents were 22% and 14%, respectively.Sun, 30 Jun 2019 19:30:00 +0100Application of simulated annealing for optimization of blasting costs due to air overpressure ...
http://jme.shahroodut.ac.ir/article_1514_0.html
Estimating the costs of blasting operations is an important parameter in open-pit mining. Blasting and rock fragmentation depend on two groups of variables. The first group consists of mass properties, which are uncontrollable, and the second one is the drill-and-blast design parameters, which can be controlled and optimized. The design parameters include burden, spacing, hole length, hole diameter, sub-drilling, charge weight, charge length, stemming length, and charge density. Blasting costs vary depending on the size of these parameters. Moreover, blasting brings about some undesirable results such as air overpressure, fly rock, back-break, and ground vibration. This paper proposes a mathematical model for estimating the costs of blasting operations in the Baghak gypsum mine. The cost of blasting operations in the objective function is divided into three parts: drilling costs, costs of blasting system, and costs of blasting labours. The decision variables used to minimize the costs include burden, spacing, hole diameter, stemming length, charge density, and charge weight. Constraints of the model include the boundary and operational limitations. Air overpressure in the mine is also anticipated as one of the model constraints. The non-linear model obtained with consideration of constraints is optimized by simulated annealing (SA). After optimizing the model by SA, the best values for the decision variables are determined. The value obtained for the cost was obtained to be equal to 2259 $ per 7700 tons for the desired block, which is less than the blasting costs in the Baghak gypsum mine.Mon, 29 Jul 2019 19:30:00 +0100Pre-treatment of toxic element and cationic dye onto natural biomass: characterization and ...
http://jme.shahroodut.ac.ir/article_1498_165.html
This researchdescribe wastewater pre-treatment that contaminated with Methylene Blue dye (MB) and Ni(II) ion by Athelia Bombacina fungus dead biomass (ABFDB). Researches finding on ABFDB characterization by SEM, XRD, CHNS and FT-IR analysis show that ABFDB can be used as efficient sorbent, because ABFDB cellular wall consist of Chitin, β-Glucan and Cellulose biopolymers, generally. Results show that removal of MB and Ni(II) ion by ABFDB sorbent is more than 86.41 and 66.2%, respectively. So, after parameters investigation of MB and Ni(II) ion sorption process by ABFDB, the response surface method was employed for optimization and study the interaction of operational parameters on the sorption of pollutants. This low-cost and natural environmental friendly biosorbent can be utilized for pretreatment process in the first step of wastewater treatment project.Sun, 30 Jun 2019 19:30:00 +0100Development of a GEP model to assess CERCHAR abrasivity index of rocks based on geomechanical ...
http://jme.shahroodut.ac.ir/article_1516_0.html
The CERCHAR abrasivity test is very popular for determination of rock abrasivity. An accurate estimation of the CERCHAR abrasivity index (CAI) is useful for excavation operation costs. This paper presents a model to calculate CAI based on the gene expression programming (GEP) approach. This model is trained and tested based on a database collected from the experimental results available in the literature. The proposed GEP model predicts CAI based on two basic geomechanical properties of rocks, i.e. rock abrasivity index (RAI) and Brazilian tensile strength (BTS). Root mean square error (RMSE), mean absolute error (MAE), Nash-Sutcliffe efficiency (NSE), and coefficient of determination (R2) are used to measure the model performance. Furthermore, the developed GEP model is compared with linear and non-linear multiple regression and other existing models in the literature. The results obtained show that GEP is a strong technique for the prediction of CAI.Fri, 02 Aug 2019 19:30:00 +0100Fuzzy tonnage-average grade model based on extension principle
http://jme.shahroodut.ac.ir/article_1459_165.html
Due to the nature of the geological and mining activities, different input parameters in the grade estimation and mineral resource evaluation are always tainted with uncertainties. It is possible to investigate the uncertainties related to the measurements and parameters of the variogram model using the fuzzy kriging method instead of the kriging method. The fuzzy kriging theory has already been the subject of relatively various research studies but the main weak point in such studies is that the results of the fuzzy estimations are not used in decision-making and planning. A very common, but key, tool of decision-making for mining engineers is the tonnage-average grade models. Under conditions where measurements or/and variogram model parameters are tainted with uncertainties, the tonnage-average grade model will be uncertain as well. Therefore, it is necessary to use the fuzzy tonnage-grade model instead of the crisp ones, and the next analysis steps and decision-makings are done accordingly. In this paper, the computational principles of the fuzzy tonnage-average grade curve and a case study regarding its usage are presented.Sun, 30 Jun 2019 19:30:00 +0100Characterizing Rare Earth Elements by coupling multivariate analysis, factor analysis and ...
http://jme.shahroodut.ac.ir/article_1542_0.html
The traditional approaches of modeling and estimation of highly skewed deposits have led to incorrect evaluations and create challenges and risks in resource management. The low concentration of the rare earth elements deposits, on the one hand, and their strategic importance on the other, enhances the necessity of multivariate modeling of these deposits. The wide variations of the grades and its relation with different rock units increase the complexities of the modeling of rare earth elements. In this study, the Gazestan Magnetite-Apatite deposit, was investigated and modeled using statistical and geostatistical methods. Light and heavy rare earth elements in apatite minerals are concentrated in the form of fine monazite inclusions. Using 908 assayed samples, 64 elements including light and heavy rare earth elements from drill cores were analyzed. By performing the necessary pre-processing and stepwise factor analysis, and taking into account the threshold of 0.6 in six stages, a mineralization factor including phosphorus with the highest correlation has been obtained. Then, by using a concentration-number fractal analysis on the mineralization factor, the rare earth elements were investigated in various rock units such as magnetite-apatite units. Next, using sequential Gaussian simulation, the distribution of light, heavy, and total rare earth elements and the mineralization factor in various realizations was obtained. Finally, based on the realizations, the analysis of uncertainty in the deposit was performed. All multivariate studies confirm the spatial structure analysis, simulation and analysis of rock units, and the relationship of phosphorus with mineralization.Tue, 10 Sep 2019 19:30:00 +0100Ant colony algorithm as a high-performance method in resource estimation using LVA field; A ...
http://jme.shahroodut.ac.ir/article_1445_165.html
Kriging is an advanced geostatistical procedure that generates an estimated surface or 3D model from a scattered set of points. This method can be used for estimating resources using a grid of sampled boreholes. However, conventional ordinary kriging (OK) is unable to take locally varying anisotropy (LVA) into account. A numerical approach has been presented that generates an LVA field by calculating the anisotropy parameters (direction and magnitude) in each cell of the estimation grid. After converting the shortest anisotropic distances to Euclidean distances in the grid, they can be used in variography and kriging equations (LVAOK). The ant colony optimization (ACO) algorithm is a nature-inspired metaheuristic method that is applied to extract image features. A program has been developed based on the application of ACO algorithm, in which the ants choose their paths based on the LVA parameters and act as a moving average window on a primary interpolated grid. If the initial parameters of the ACO algorithm are properly set, the ants would be able to simulate the mineralization paths along continuities. In this research work, Choghart iron ore deposit with 2,447 composite borehole samples was studied with LVA-kriging and ACO algorithm. The outputs were cross-validated with the 111,131 blast hole samples and the Jenson-Shannon (JS) criterion. The obtained results show that the ACO algorithm outperforms both LVAOK and OK (with a correlation coefficient value of 0.65 and a JS value of 0.025). Setting the parameters by trial-and-error is the main problem of the ACO algorithm.Sun, 30 Jun 2019 19:30:00 +0100Application of cut set method to reliability evaluation of mine ventilation networks
http://jme.shahroodut.ac.ir/article_1539_0.html
Providing 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 air flow are the parameters which would result in pressure loss which affect ventilation network. There is a lot of research about the ventilation networks planning that considered the confidence in the planning, but how reliable are these designs? These questions can be answered by using quantitative reliability evaluation. For reliability evaluation of mine ventilation network, tunnels resistance and flow rate changes for all branches were considered as the reliability indices and criteria. This paper describes a stepwise method for evaluation of 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 was validated by Takht coal mine. Takht mine ventilation network probability of failure is in the range of 0.19 to 1, so reliability is in the range of zero to 0.81 for the entire ventilation network.Fri, 16 Aug 2019 19:30:00 +0100Geostatistical estimation to delineate oxide and sulfide zones using geophysical data; a case ...
http://jme.shahroodut.ac.ir/article_1432_165.html
Delineation of oxide and sulfide zones in mineral deposits, especially in gold deposits, is one of the most essential steps in an exploration project that has been traditionally carried out using the drilling results. Since in most mineral exploration projects there is a limited drilling dataset, application of geophysical data can reduce the error in delineation of the sulfide and oxide zones. For this purpose, we produced a 3D model of Induced Polarization (IP) data using the ordinary kriging technique. Then the modelling results were compared with the drilling data. The results obtained showed that the 3D geophysical models would properly delineate the sulfide and oxides zones. This work presents a new application of the IP results for separation of these zones. In addition, the conducted variography in this work suggests reducing the profile spacing of dipole-dipole IP arrays down to 25 m. This would properly enrich the integration of geophysical and geological results in the modelling of gold deposits.Sun, 30 Jun 2019 19:30:00 +0100Effect of number of freeze–thaw cycles and freezing temperature on mode I and mode II ...
http://jme.shahroodut.ac.ir/article_1515_0.html
The freeze–thaw process, as a weathering factor, considerably affects the properties of rocks and concrete. Therefore, the effect of freeze–thaw on the physical and mechanical properties of materials should be taken into account in areas with the risk of this process. Given that few studies have been conducted on the effect of freeze–thaw process on the fracture toughness, this study aimed at investigating the effect of freeze–thaw cycles and freezing temperature on the mode I and mode II fracture toughness of cement mortar. To this end, specimens were exposed to 0, 5, 10, 20 and 30 freeze–thaw cycles and the mode I and mode II fracture toughness was determined in different cycles. The effect of freezing temperature in a freeze–thaw cycle on the mode I and mode II fracture toughness was also investigated. The damage factor was also defined based on the effective porosity of cement mortar, and its changes with the number of freeze–thaw cycles and mode I and mode II fracture toughness were studied. Finally, the decay function model provided by Mutluturk was investigated. According to the results, the mode I and mode II fracture toughness of cement mortar decreased linearly with increasing the number of freeze–thaw cycles. The mode I and mode II fracture toughness decreased linearly with increasing the freezing temperature in a freeze–thaw cycle. The damage factor increased with increasing the number of freeze–thaw cycles and, additionally, its relationship with mode I and mode II fracture toughness exhibited a linear behavior.Mon, 29 Jul 2019 19:30:00 +0100Detection of Mo geochemical anomaly in depth using a new scenario based on spectrum–area ...
http://jme.shahroodut.ac.ir/article_1499_165.html
Detection of deep and hidden mineralization using the surface geochemical data is a challenging subject in the mineral exploration. In this work, a novel scenario based on the spectrum–area fractal analysis (SAFA) and the principal component analysis (PCA) has been applied to distinguish and delineate the blind and deep Mo anomaly in the Dalli Cu–Au porphyry mineralization area. The Dalli mineral deposit is located on the volcanic–plutonic belt of Sahand–Bazman in the central part of Iran. The geochemical data was transformed to the frequency domain using the Fourier transformation, and SAFA was applied for classification of geochemical frequencies and detection of geochemical populations. The very low-frequency signals in the fractal method were separated using the low-pass filter function and were interpreted using PCA. This scenario demonstrates that the Mo element has an important role in the mineralization phase in the very low-frequency signals that are related to the deep mineralization; it is an important innovation in this work. Then the Mo geochemical anomaly has been mapped using the inverse Fourier transformation. This research work shows that the high-power spectrum values in SAFA are related to the background elements and the deep mineralization. Two exploratory boreholes drilled inside and outside the deep Mo anomaly area properly confirm the results of the proposed approach.Sun, 30 Jun 2019 19:30:00 +0100A numerical analysis of effect of segmental lining joints on tunnel support internal forces ...
http://jme.shahroodut.ac.ir/article_1517_0.html
During an earthquake, performance of segmental tunnel lining, compared to continuous in-cast concrete lining is generally related to the joints between segments. To better understand the influence of segment joints, their effect on internal forces induced in tunnel lining simultaneously with the effects of other influential parameters should be considered. In this study the segmental joints were simulated by representative stiffnesses and effects of these characteristics in relation with other parameters such as soil-liner interface behavior, number of segments in each ring and thickness of segments on internal forces induced in structure have been investigated. For this purpose, two-dimensional numerical analyses were performed and results were discussed. Numerical results showed that under seismic condition, the components which have the most signiﬁcant role on internal axial forces induced in the segmental lining are rotational stiffness and axial stiffness of joints. Also bending moments are more affected by the rotational stiffness. Generally, the radial joint stiffness has less effect on the induced internal forces. With the increase in number of segments and their thickness, effect of joint stiffness on internal forces increases and design of joints should be given more attention; but effects of joint stiffness and frictional behavior at soil-liner interface on maximum induced forces are almost independent of each other. Also in a specified joint behavior, by variation in each of other parameters including soil-liner interface condition, number of segments and their thickness, the absolute magnitude of maximum induced internal forces sometimes change significantly.Fri, 02 Aug 2019 19:30:00 +0100Delineation of podiform-type chromite mineralization using geochemical mineralization ...
http://jme.shahroodut.ac.ir/article_1470_165.html
The aim of this work was to delineate the prospects of podiform-type chromite by staged factor analysis and geochemical mineralization prospectivity index in Balvard area, SE Iran. The stream sediment data and fault density were used as the exploration features for prospectivity modeling in the studied area. In this regard, two continuous fuzzified evidence layers were generated and integrated using fuzzy operator. Then fractal modeling was used for defuzzification of the prospectivity model obtained. Furthermore, the prediction-area plot was used for evaluation of the predictive ability of the generated target areas. The results obtained showed that using the prospectivity model, 82% of mineral occurrences was predicted in 18% of the studied area. In addition, the target areas were correlated with the geological particulars including ultrabasic and serpentinization rocks, the host rocks of the podiform-type chromite deposit type.Sun, 30 Jun 2019 19:30:00 +0100Numerical analysis of slide-head-toppling failure
http://jme.shahroodut.ac.ir/article_1518_0.html
In layered and blocky rock slopes, toppling failure is a common mode of instability that may occur in mining engineering. If this type of slope failure occurs as a consequence of another type of failure, it is referred to as the secondary toppling failure. “Slide-head-toppling” is a type of secondary toppling failures, where the upper part of the slope is toppled as a consequence of a semi-circular sliding failure at the toe of the slope. In this research work, the slide-head-toppling failure is examined through a series of numerical modeling. Phase 2, as a software written based on the finite element method, is used in this work. Different types of slide-head-toppling failures including blocky, block-flexural, and flexural are simulated. A good agreement can be observed when the results of the numerical modeling are compared with those for the pre-existing physical modeling and analytical method.Fri, 02 Aug 2019 19:30:00 +0100A finite element model to simulate magnetic field distribution and laboratory studies in wet ...
http://jme.shahroodut.ac.ir/article_1489_165.html
Low-intensity magnetic separators are widely used in the research works and the industry. Advancement in the magnetic separation techniques has led to an expansion in the application of this method in different fields such as enrichment of magnetic mineral, wastewater treatment, and medicine transfer in the human body. In the mineral processing industry, the main application of wet magnetic separation is via drum separators. The design of this separator is based on drum rotation inside a tank media, where a permanent magnet placed inside the drum as an angle form produces a magnetic field. In the present work, the magnetic variables involved (magnetic flux density, intensity of magnetic field, and gradient of magnetic field intensity) were simulated in the drum wet low-intensity magnetic separator using the finite element method and a COMSOL Multiphysics simulator; these variables were further validated through the measured data. A comparison between the simulation and laboratory measurements (of the magnetic field) showed that the mean value of the simulation error in 94 points in 2 sections was equal to 9.6%. Furthermore, the maximum simulation error in the middle of the magnets, as the most important part of the magnetic field distribution in the process of magnetic separation, was in the 6th direction and equal to 7.8%. Therefore, the performed simulation can be applied as a first step to design and construct more advanced magnetics separators.Sun, 30 Jun 2019 19:30:00 +0100Copper recovery from thickener overflow by electrocoagulation/flotation (ECF): optimization of ...
http://jme.shahroodut.ac.ir/article_1519_0.html
Electrocoagulation/flotation (ECF) process is a novel approach in mining industry that implemented to return Cu metal to production cycle which improves copper recovery and reduces wasting water. In this research, Response surface methodology [RSM] is applied to optimizing effective factors on Cu metal recovery and produced sludge volume in thickener overflow. To this end D-optimal experimental design is utilized. The influences of four independent parameters such as electrolysis time, initial pH, current density and electrodes type were studied to investigate the initial Cu grade percentage (28%) and produced sludge volume from thickener overflow. All these parameters were found to have important effects on the Cu metal recovery and produced sludge volume. Linear and quadratic models were utilized for Cu grade and sludge volume, respectively. The important of independent variables and interaction between them were assessed by ANOVA. Optimum operating conditions with 27.22% Cu grade was taken to be; electrolysis time: 6.5 min, initial pH: 6.7, current density: 50.2 A/m2, electrode type: Fe-Al. Similarly, for produced sludge volume with 861 cm3 was found electrolysis time: 15 min; initial pH: 4.1; current density: 48.7; electrode type: Fe-Al. The outcomes underscored from a practical point of view of electrocoagulation known as an acceptable method for Cu recovery from mine industrials especially in mineral processing plant.Fri, 02 Aug 2019 19:30:00 +0100Reprocessing of Sangan iron ore tailings by flotation
http://jme.shahroodut.ac.ir/article_1450_165.html
The Sangan processing plant consists of four consecutive low-intensity magnetic separation steps with the same magnetic field intensity of 1300 Gauss for upgradation of iron ore. Hence, the iron ore minerals with lower magnetic susceptibility or interlocked with gangue minerals have no opportunity for upgradation, and proceed to the tailing dam. Flotation is a powerful technique for upgradation of these materials, and it is the focus of this research work. A sample of 43.09% Fe and 12.1% FeO was taken from the tailings of second step of magnetic separation. The ore minerals of the sample were determined to be magnetite and hematite. A concentrate of 67% Fe and mass recovery of 50% was produced through the Davis tube test. A reverse flotation route was selected for upgradation of the sample. Fatty acid-based anionic collectors with trade names Alke and Dirol were used in the flotation experiments. The design of experiments was done by resolution IV fractional factorial design with nine factors at two levels per factor. A resolution IV design allows discrimination of all main effects and two-factor interactions. A concentrate of 53.92% Fe at a mass recovery of 60% was obtained at optimum flotation conditions of solid content 20%, pH 12, collector concentration of 1 kg/t, starch as depressant at a concentration of 5 kg/t, Alke/Dirol collector mass ratio of 30/70, conditioning time of 10 min., and concentration of Ca2+ as activator 1 kg/t. In this research work, the concept of natural depression of iron minerals in the reverse flotation was introduced and evaluated.Sun, 30 Jun 2019 19:30:00 +0100Effect of segmental joint stiffness on tunnel lining internal forces under static conditions
http://jme.shahroodut.ac.ir/article_1557_0.html
According to the wide application of segmental lining in mechanized tunneling, recognizing the behavior of segmental lining joints is important in tunnels designing. In structural analysis of the tunnel segmental lining, segmental joints can be considered as elastic joints and their stiffness characteristics are affected by rotational, shear and axial stiffness. The purpose of this study is to investigate the effect of rotational, shear and axial stiffness of segmental lining joints on internal forces (bending moment and axial force), and indicate the bearing capacity of the tunnel segmental lining under static loading by numeral method. For this purpose, three-dimensional numerical analysis was done by ABAQUS software. The results show that by increasing rotational stiffness of the segmental joint, bending moment increases, and for lower values of rotational stiffness, bending moment variations are higher, while axial force variations are very slight in compared to joints rotational stiffness. So by increasing the bending moment, bearing capacity of segmental lining decreases. By increasing axial and shear stiffness of the segmental joint, changes of bending moment and axial force in segmental lining are very negligible. Therefore, increasing axial and shear stiffness of the joint, has no effect on the bearing capacity of the segmental lining.Mon, 23 Sep 2019 20:30:00 +0100Anomaly delineation of porphyry copper deposits of Hanza Region through geochemical data ...
http://jme.shahroodut.ac.ir/article_1460_165.html
Hanza region is located in the southern part of Urumieh–Dokhtar Metallogenic belt in southeastern Iran. This region includes six known porphyry copper deposits and it is considered as an ore- bearing region from geochemical point of view. The aim of this research is to examine effective processing techniques in the analysis of stream sediment geochemical datasets and ASTER satellite images. The processing methods have led to identification of eight new prospective areas. These methods are aimed at providing univariate geochemical maps. The stream sediment geochemical mapping for Cu and Mo was performed by the sample catchment basin approach. The results derived from this approach have been mapped in four classes associated with the first quartile, third quartile and threshold values obtained from Median Absolute Deviation method. False-colour composite and band ratio techniques were adopted as two well-known methods for the processing of an ASTER scene spanning the study area. Eight new targets for possible mineralization have been resulted from geochemical data analyses. Image processing techniques on the ASTER multispectral data have also revealed widespread hydrothermal alterations associated with the known porphyry copper deposits and the new prospects.Sun, 30 Jun 2019 19:30:00 +0100Analysis of Reliability and Maintainability for Multiple Repairable Units (Case Study: Sungun ...
http://jme.shahroodut.ac.ir/article_1543_0.html
The appropriate operating of mining machines is affected by both executive and different environmental factors. Considering the effect and the related risks is led to a better understanding of the failures of such machines. This leads to proper prediction of reliability parameters of machines. In this research, the reliability and maintainability analysis of loading and haulage machines in Sungun Copper Mine with considering repair condition as Multiple Repairable Units has been performed. For this purpose, the data necessary for loading and haulage equipment including 2 loaders and 8 dump truck for 15 month period are collected and categorized in 10 operational units after the system and subsystems of the department are determined. Initially, the time between failures (TBFs) and time to repair (TTRs) for each unit was calculated. Then, 20 sub-systems were developed. Primarily, the Stata software was utilized to do the heterogeneity test for all the sub-systems. In consequence, most of the sub-systems were regarded as the heterogeneous ones, except 7 of them including dump truck units 1, 2, 3, 4, 5, 7 and 8 in TBFs. Hence, "PHM" which is a covariate-based model displayed the heterogeneous group. Its reliability function was also estimated. For the next step, the trend tests were done on the non-heterogeneous sub-systems by means of Minitab software. Homogeneous subsystems with failure trend modeled by the “NHPP”. Afterwards, the non-trended subsystems formed the data group. Later, correlation tests were modeled by the “HPP”. Finally, the reliability and maintainability functions were calculated with 95% confidence level.Fri, 13 Sep 2019 19:30:00 +0100Studying ilmenite dissolution using mechanical activation method
http://jme.shahroodut.ac.ir/article_1462_165.html
In this work, the effects of temperature, acid concentration, and mechanical activation on dissolution of ilmenite were studied using the statistical design of experiment technique. Mechanical activation was carried out using a planetary ball mill in dry mode, and the resulting structural changes were characterized by the particle size analysis, specific surface area measurements, and X-ray diffraction method. The results obtained indicated that intensive milling led to a significant decrease in the ilmenite particle size and that after 20 minutes, particles tended to agglomerate. However, after 90 minutes, the BET specific surface area increased to 9.36 m2/g. In addition to surface changes, mechanical activation led to intense changes and disorders in the crystal structure of ilmenite as amorphization degree increased to 94.30% and the volume weighted crystallite size and lattice strain changed from 346 nm and 0.13% to 14 nm and 1.44%, respectively. The results of the dissolution tests in the form of experimental design indicated that a suitable model could fit the experimental data in 95% confidence level. The coefficient factors for acid concentration, mechanical activation, and temperature were 3.75%, 33.04%, and 9%, respectively. Mechanical activation had the highest effect on titanium extraction in comparison to the other factors involved. Also in addition to its dominant effect on ilmenite dissolution, it also weakened the temperature effect. However, the results of the kinetic tests proved that mechanical activation led to promotion of the temperature effect on increasing the dissolution reaction rate in the initial stages. Finally, a dissolution yield of more than 98% was achieved through 90 minutes of activation at 95° C and 55 wt.% acid concentration.Sun, 30 Jun 2019 19:30:00 +0100Geostatistical and multifractal modeling of geological and geophysical characteristics in ...
http://jme.shahroodut.ac.ir/article_1537_0.html
This study aims to figure out spatial relationships between geophysical and geological models in a case study pertaining to copper-sulfide mineralization through an integrated 3D analysis of favorable target. The Ghalandar Skarn-Porphyry Cu Deposit, which is located in NW Iran, was selected for this research. Three geophysical surveys of direct current electrical resistivity and induced polarization tomography along with magnetometry were performed to construct physical properties of electrical resistivity, chargeability and magnetic susceptibility, respectively. Inverse modeling and geostatistical interpolation were utilized to generate physical models in 3D. A 3D model of Cu grade was generated using ordinary kriging (OK), but indicator kriging (IK) method was run to design a 3D model of rock types through incorporating drilling results. Block models of geophysical and geological characteristics were cast in a similar 3D mesh to investigate their relationships in copper mineralization. A concentration-volume multifractal method was used to divide each model into its subsets, where the most productive portions in association with Cu-bearing mineralization were distinguished. Note that subsets of geophysical models were spatially matched with geological models of Cu grade and rock types. Zones with low electrical resistivity, high chargeability, and low magnetic susceptibility corresponded to the main source of Cu mineralization in a dominated skarn rock types setting.Sun, 11 Aug 2019 19:30:00 +0100Processing a multifold ground penetration radar data using common-diffraction-surface stack method
http://jme.shahroodut.ac.ir/article_1493_165.html
Recently, the non-destructive methods have become of interest to the scientists in various fields. One of these method is Ground Penetration Radar (GPR), which can provide a valuable information from underground structures in a friendly environment and cost-effective way. To increase the signal-to-noise (S/N) ratio of the GPR data, multi-fold acquisition is performed, and the Common-Mid-Points (CMPs) are acquired. Compared to the traditional CMP method, which is applied to a CMP, the Common-Reflection-Surface (CRS) method is introduced for seismic data processing considering the neighboring CMPs. In addition, instead of a point on the reflector, CRS assumes that the reflector is part of a circle. With these two characteristics, CRS produces a stack section with a high S/N ratio. The Common-Diffraction-Surface (CDS) method, which is a simplified version of CRS, enhances the diffractors related to the underground anomalies like pipeline, flume, and caves. We apply the CDS stack method on a multi-fold GPR data and compare it to the CRS results. These results show that the CDS method can provide a high S/N ratio stack section compared to the traditional CMP method.Sun, 30 Jun 2019 19:30:00 +0100Solvent extraction and stripping of zinc from synthetic chloride solution in the presence of ...
http://jme.shahroodut.ac.ir/article_1569_0.html
In this research, solvent extraction and stripping of zinc ions from Zn-Mn-Cd bearing solution was investigated using D2EHPA as extractant in chloride media. So, the efficiency of extraction and stripping stages were evaluated separately and different parameters such as pH, extractant concentration, reaction temperature and contact time were studied. Based on the results, 97% of zinc, 14% of manganese and 3% of cadmium were extracted at pH=2.5, 10% (v/v) of D2EHPA and 40 °C from solution containing 5 g.L-1 of each metal ions. The stripping isotherms of zinc, manganese and cadmium at different pHs showed that manganese and zinc were stripped at two different pHs. So, more than 70% of manganese and more than 90% of zinc were stripped at pH=2.5 and pH=0.5, respectively. Kinetic studies indicated that the extraction and stripping of zinc in the first 0.5-1 minutes is high. The McCabe–Thiele diagrams showed that two stages of extraction and two stages of stripping in continues counter-current ﬂow condition is adequate to separate zinc from other two Mn and Cd elements. The dominant Zn specie extracted by D2EHPA is ZnCl+ and the values of thermodynamic parameters (ΔHo, ΔSo and ΔGo) were 25.65 kJ·mol−1, 79.20 J·K−1·mol−1 and 0.86 kJ·mol−1, respectively which showed the reaction is endothermic and at equilibrium.Mon, 07 Oct 2019 20:30:00 +0100Influence of microwave treatment on surface roughness, hydrophobicity, and chemical composition ...
http://jme.shahroodut.ac.ir/article_1478_165.html
The influence of microwave treatment on the surface roughness, hydrophobicity, and chemical composition of galena was studied. The pure galena specimens and purified galena concentrate were used in this work. A conventional multi-modal oven (with a frequency of 2.45 GHz and a maximum power of 900 W) was used to conduct the experiments. The results obtained from the atomic-force microscopy analysis showed that the surface roughness of galena decreased after the microwave radiation. The results also showed that the surface hydrophobicity of galena increased with increase in the duration of the microwave radiation, which was in good agreement with the micro-flotation mass recovery results. The increased surface hydrophobicity may be attributed to the decreased surface roughness by microwave radiation or formation of sulfur on the surface. The results of the SEM/EDS analyses indicated that after microwave radiation, the amount of S increased, whereas Pb decreased on the surface of galena, indicating that the average atomic number of the galena surface changed due to microwave treatment.Sun, 30 Jun 2019 19:30:00 +0100Use of a mixed integer programming model to achieve an optimum size of blast block in open-pit ...
http://jme.shahroodut.ac.ir/article_1570_0.html
In this paper, we present an integrated model to find the optimum size of blast block that uses (i) a multi-criteria decision-making method to specify the applicable size of the mineable block; (ii) a linear programming method for the selection of the blasted areas to be excavated and in deciding the quantity of ores and wastes to be mined from each one of the selected blocks. These two methods use improved estimates of the orebody characteristics utilizing the blast hole data in addition to the usual borehole statistics to improve the prediction accuracy of the block level ore body characteristics. This work aims to make a mathematical model to figure out the ideal width and length of the blast block in order to curtail drilling and blasting expenses in open-pit mines. As a consequence, the effective blast block size is heeded so as to decrease the expenses of drilling and blasting. Furthermore, a complete set of actual principles is presented to specify the applicable size of the mineable block by means of the multi-criteria decision-making method of fuzzy logic. The aforementioned model is practiced to forecast the block size necessary for the purpose of production planning. Next, a mixed integer programming model is developed to blast planning in order to select the optimal size of the blast block by considering the mineable block. The proposed model is applied in the Chadormalu iron ore mine and the rationality of the model is demonstrated by the outcomes of dissimilar circumstances.Tue, 08 Oct 2019 20:30:00 +0100Performance evaluation of chain saw machines for dimensional stones using feasibility of neural ...
http://jme.shahroodut.ac.ir/article_1246_0.html
Prediction of the production rate of the cutting dimensional stone process is crucial, especially when chain saw machines are used. The cutting dimensional rock process is generally a complex issue with numerous effective factors including variable and unreliable conditions of the rocks and cutting machines. The Group Method of Data Handling (GMDH) type of neural network and Radial Basis Function (RBF) neural network, as two kinds of the soft computing method, are powerful tools for identifying and assessing the unpredicted and uncertain conditions. Hence, this work aims to develop prediction models for estimating the production rate of chain saw machines using the RBF neural network and GMDH type of neural network, and then to compare the results obtained from the developed models based on the performance indices including value account for, root mean square error, and coefficient of determination. For this purpose, the parameters of 98 laboratory tests on 7 carbonate rocks are accurately investigated, and the production rate of each test is measured. Some operational characteristics of the machines, i.e. arm angle, chain speed, and machine speed, and also the three important physical and mechanical characteristics including uniaxial compressive strength, Los Angeles abrasion test, and Schmidt hammer (Sch) are considered as the input data, and another operational characteristic of the machines, i.e. production rate, is considered as the output dataset. The results obtained prove that the developed GMDH model is able to provide highly promising results in order to predict the production rate of chain saw machines based on the performance indices.Tue, 03 Jul 2018 19:30:00 +0100Modelling and optimization of digestion efficiency of bauxite in Bayer process: Iran Alumina company
http://jme.shahroodut.ac.ir/article_1496_165.html
In the present work, we investigated and optimized the digestion efficiency, A/S (Al2O3/SiO2 in red mud), and N/S (Na2O/SiO2 in red mud) of mixed bauxite in Iran Alumina Company using the Bayer process. Digestion experiments were carried out in an induction rotary autoclave on a mix of Jajarm, Yazd, Tash, and Shirin Cheshmeh bauxites. A 4-factor 3-level response surface methodology was applied for the design and analysis of the experiment with the optimization of Na2O concentration, digestion temperature, residence time, and amount of lime addition. Towquadratics and one linear model were derived for the prediction of digestion efficiency, and A/S and N/S responses. The results obtained showed that the optimum amounts for Na2O concentration, temperature, amount of lime addition and residence time were 180 g/L, 275°C, 7.73%, and 50 minutes, respectively, in which the digestion efficiency, A/S, and N/S reached 72.05%, 1.169, and 0.27, respectively. Validation experiment showed that the digestion efficiency, A/S, and N/S were 72.24%, 1.162, and 0.28% respectively, which meant a 2% increase in digestion efficiency and a 0.09 and 0.02 decrease in A/S and N/S, respectively, compared to the current operating condition.Sun, 30 Jun 2019 19:30:00 +0100Fractal-wavelet-fusion-based re-ranking of joint roughness coefficients
http://jme.shahroodut.ac.ir/article_1463_0.html
Nowadays, Barton’s Joint Roughness Coefficients (JRC) are widely used as the index for roughness and as a challenging fracture property. When JRC ranking is the goal, deriving JRC from different fractal/wavelet procedures can be conflicting. Complexity increases when various rankings outcome from different calculation methods. Therefore, using Barton’s JRC, we cannot make a decision based on the proven mathematical theories because each method has a different rank. Ideally, these rankings must be equal but, in practice, they are different for each method. To solve this problem and to achieve a robust and valid ranking for JRC, Condorcetand Borda count methods have been used. These methods have been proposed as fusion approaches. Re-ranking of JRC using different methods integrated with Condorcet showed confusion in ranking of the JRC4, JRC5, and JRC6 profiles. This ambiguity is equal to equalizing decision conditions about all the three at the examination of the winners, losers, and draws in pairwise matrices. Therefore, Borda Count was applied and resulted in robust rankings. In fact, a new approach for a roughness measurement is presented. A new JRC ranking called JRCN is introduced. This new ranking shows a lower sum of squared errors (0.00390) in comparison with the original JRC ranking method (0.00410) and ranked JRCN1 to JRCN10. Thus it is proposed to consider JRCN as a new and improved version of JRC rankings.Wed, 05 Jun 2019 19:30:00 +0100X-Ray mapping and the mineralogy pattern of nickel laterite ore: Bavanat, Fars, Iran
http://jme.shahroodut.ac.ir/article_1512_165.html
According to the classification of the nickel laterite, this paper describes mineralogy test is to reveal where valuable elements are located in the ore, in which mineralogical form. The purpose of the sieving test was to study if some specific particle size contains most of the valuable metals. Based on its chemical composition nickel laterite is classified as a limonite type and the nickel and cobalt content was 0.7 and 0.04%, respectively. Nickel is predominantly associated with hematite and goethite. Based on the mineralogical analysis of the ore, it is observed that remarkable part of nickel is located in hematite. Therefore, nickel cannot be released from hematite lattice. The nickel content in the laterite was 0.7% and the cobalt content 0.04%. The chemical composition of laterite equals with the occurrence of 38.9% iron oxides, 26.9% carbonates, 26.9% quartz, 4.8% chromite, 2.7% magnetite and 1.9% other minerals. EDS line profile analyses were completed on hematite/goethite ooids and there was a slight correlation in the quantities between iron and nickel in each individual ooid. However, iron and nickel do not always show a positive correlation. Nickel grade could be enriched from 0.7 wt.-percent to 0.91 wt.-percent; however nickel recovery was only 45%.Sun, 30 Jun 2019 19:30:00 +0100Studying relationship between coal intrinsic characteristics in spontaneous combustion of coal ...
http://jme.shahroodut.ac.ir/article_1495_0.html
Spontaneous combustion of coal is one of the most horrifying hazards in coal industries, especially in underground coal mines. Thus having a prior knowledge about the occurrence of this phenomenon in underground coal mines is of crucial importance in preventing this process, loss of life, huge economic loss, and environmental pollution. The aim of this work is to determine the spontaneous combustion of coal potential in the Tabas Parvadeh coal mines in Iran in order to assess the effect of coal intrinsic characteristics on its occurrence. For the purpose of this investigation, the coal samples were collected from Parvadeh I to IV, and the coal intrinsic characteristics of the samples were tested. In order to determine the spontaneous combustion of coal propensity in this case study, the Crossing Point Temperature (CPT) test was used. Then the relation between the coal intrinsic characteristics and the CPT test values was determined. The results obtained showed that the B1 seam in Parvadeh II and C1 seam in Parvadeh III had a high potential of spontaneous combustion of coal potential. These results also show that an increase in the moisture, volatile matter, pyrite, vitrinite, and liptinite contents enhance the spontaneous combustion of coal tendency in these mines. The results obtained have major outcomes for the management of this phenomenon in the Tabas Parvadeh coal mines. Therefore, evaluation of the spontaneous combustion of coal hazards in coal mines should start in the first stage of design and carried on during their whole lifecycle, even after mine closure.Tue, 02 Jul 2019 19:30:00 +0100Application of Sequential Gaussian Conditional Simulation into Underground Mine Design Under ...
http://jme.shahroodut.ac.ir/article_1540_0.html
In mining projects, all uncertainties associated with the project must be considered to determine the feasibility study. Grade uncertainty is one of the major components of technical uncertainty that affects the variability of the project. Geostatistical simulation as a reliable approach is the most widely used method to quantify risk analysis to overcome the drawbacks of estimation methods entire an ore-body. In this paper, all developed algorithms by numerous researchers for optimization of underground stope layout were reviewed. After that, a computer program called Stope Layout Optimizer 3D (SLO3D) was developed based on a new heuristic algorithm in order to incorporate the influence of grade variability in final stope layout. Utilizing Sequential Gaussian Conditional Simulation (SGS), 50 simulations and a kriging model were constructed for an underground copper vein deposit situated in the southwest of Iran and final stope layout was carried out separately. It was observed that geostatistical simulation can effectively cope with the weakness of kriging model. Final results showed that the frequency of economic value for all realizations varies between 6.7M$ and 30.7M$. This range of variation helps designers to make a better and lower risk decision under different conditions.Tue, 03 Sep 2019 19:30:00 +0100A comparative study of the SVM and RF methods for classification of alteration zones by using ...
http://jme.shahroodut.ac.ir/article_1513_0.html
Identification and mapping of the significant alterations are the main objectives of the exploration geochemical surveys. The field study is time-consuming and costly to produce the classified maps. Therefore, the processing of remotely sensed data, which provide timely and multi-band (multi-layer) data, can be substituted for the field study. In this study, the ASTER imagery is used for alteration classification by applying two new methods of machine learning, including Random Forest and Support Vector Machine. The 14 band ASTER and 19 derivative data layers extracted from ASTER including band ratio and PC imagery, are used as training datasets for improving the results. Comparison of analytical results achieved from the two mentioned methods confirmed that the SVM model has sufficient accuracy and more powerful performance than RF model for alteration classification in the study area.Mon, 29 Jul 2019 19:30:00 +0100Bayesian Data Fusion, a Reliable Approach for Descriptive Modeling of Ore Deposits
http://jme.shahroodut.ac.ir/article_1449_0.html
Recognition of ore deposit genesis is still a controversial challenge for economic geologists. Here, this task was addressed by the virtue of Bayesian data fusion (BDF) implementing available proofs: semi-schematic examples with two (Cu and Pb + Zn) and three (Cu, Pb + Zn and Ag) evidences. The data, in current paper are just concentrations of indicated elements, were collected from Angouran’s deposit in Iran at prospecting and general exploration stages. BDF was used for discrimination between three geneses of Massive Sulfide, Mississippi and SEDEX types. Better genesis recognition with clear discrimination between the geneses was achieved by BDF as compared with earlier studies. The results showed that uncertainties were reduced from 50% to less than 30% and deposit recognition was improved greatly. Furthermore, we believe that using more properties can have a beneficial effect on the overall outcome. The comparison made between 2 and 3 properties showed that the amount of probable belonging values to any type of deposit was greater in 3 properties. It was also confirmed that using the completed information from the various stages of exploration progress can be amplified and be used for genesis recognition via BDF.Tue, 30 Apr 2019 19:30:00 +0100A mathematical model to optimize allocation sequence in dispatching problem
http://jme.shahroodut.ac.ir/article_1582_0.html
Truck-Shovel fleet, as the most common transportation system in open-pit mines, has a significant part of mining costs, for which optimal management can lead to substantial cost reductions. Among the available dispatch mathematical models, the multi-stage approach is well suited for allocating trucks to respected shovels in a dynamic dispatching program. However, with this kind of modeling sequencing of the allocated trucks is not possible though it is important to find out the best solution so that getting the minimum accrued cost. To comply with the shortcoming of the traditional model, in this paper, a new hybrid model is developed and applied in Copper Mine of Iran, in which for each truck an allocation matrix is considered as input to the genetic algorithm implemented to determine the best solution. According to the obtained results, the optimal sequencing of the trucks can result in a significant (31%) cost reduction in a shift.Sun, 13 Oct 2019 20:30:00 +0100Improving the performance of column flotation recleaner cells of Sungun copper plant through ...
http://jme.shahroodut.ac.ir/article_1572_0.html
The flotation circuit in Sungun copper plant consists of two column flotation cells as cleaner, having fixed-spargers system. To achieve the expected aims in flotation step, there are serious operational challenges such as: fast choking of the static mixers, boiling problem, burping phenomena and pulp overflow to concentrate lander, maintenance and control problems. An attempt was exerted by implementing new helical static mixer in one of cleaner cells instead of old elliptical type to overcome the challenges. The changes resulted in proper performance of the column whereas burping phenomena due to choking was eliminated, finer bubbles were produced, and the boiling and overflow problems were solved. Also, the static mixers life time increased to 7 months in helical column cells from one month in elliptical column cells. In addition to 40% air consumption reduction and 20% solid percent increase in final product, the grade of Cu and Mo increased by helical static mixer replacement up to about 18.7% from 16.8% (11%) and to 511.1 ppm from 263 ppm (94%) in the cleaner step, respectively. Recovery of Cu and Mo were increased about 1.5% and 0.2%, respectively. Finally, the results proved the effectiveness of finer bubble generation on grade improvement is depend on minerals hydrophobicity as Mo grade increased more than Cu.Fri, 11 Oct 2019 20:30:00 +0100Predicting unconfined compressive strength of intact rock using new hybrid intelligent models
http://jme.shahroodut.ac.ir/article_1573_0.html
Bedrock unconfined compressive strength (UCS) is a key parameter in designing thegeosciences and building related projects comprising both the underground and surface rock structures. Determination of rock UCS using standard laboratory tests is a complicated, expensive, and time-consuming process, which requires fresh core specimens. However, preparing fresh cores is not always possible, especially during the drilling operation in cracked, fractured, and weak rocks. Therefore, some attempts have recently been made to develop the indirect methods, i.e. intelligent predictive models for rock UCS estimation, which require no core preparation and laboratory equipment. This work focuses on the application of new combinations of intelligent techniques including adoptive neuro-fuzzy inference system (ANFIS), genetic algorithm (GA), and particle swarm optimization (PSO) in order to predict rock UCS. These models were constructed based on the collected laboratory datasets upon 93 core specimens ranging from weak to very strong rock types. The proposed hybrid model results were compared with each other, and the real data and multiple regression (MR) results. These comparisons were made using coefficient of correlation, mean of square error, mean of absolute error, and variance account for indices. The comparison results proved that the ANFIS-GA combination had a relatively higher accuracy than the ANFIS-PSO combination, and both had a higher capability than the MR model. Furthermore, the ANFIS-GA and ANFIS-PSO model results were completely in accordance with the UCS laboratory test, and they were more accurate than the previous single/hybrid intelligent models. Lastly, a parametric study of the suggested models showed that the density and Schmidt hammer rebound had the highest influence, and porosity had the lowest influence on the output (UCS).Fri, 11 Oct 2019 20:30:00 +0100