Case Study
A. Mirzaghorbanali; N. Aziz
Abstract
The load transfer mechanisms of cable bolts differ from those for normal rebar bolts. The cable bolts used in mines are basically steel strands with different constructions depending on the number of wires or elements and the way they are laid. Tendon bolts (rebar and cable) are normally evaluated for ...
Read More
The load transfer mechanisms of cable bolts differ from those for normal rebar bolts. The cable bolts used in mines are basically steel strands with different constructions depending on the number of wires or elements and the way they are laid. Tendon bolts (rebar and cable) are normally evaluated for their strength and load transfer properties. The tendon strength can be evaluated by the tensile failure tests, while the load transfer strength is evaluated by the pull and shear strength tests. Short Encapsulation Pull Testing (SEPT) is normally used to study the load transfer capacities of tendons, and it can be undertaken in both the laboratory and in situ. A new apparatus known as Minova Axially Split Embedment Apparatus (MASEA) was used to study load-displacement characteristics of smooth versus spiral profile cable bolts. Minova Stratabinder grout was used for encapsulating 400-mm long 19 wire 22-mm diameter superstrand cable in embedment units. The anchorage of the cable on the two sides of the embedment apparatus were intentionally installed at different lengths to allow the cable to be pulled out from one side of the anchorage. The spiral wire strand cable bolts achieved a higher peak pull-out load at a minimum displacement in comparison with the smooth surface wire strand. The peak pull out force increased with the age of encapsulation grout. The use of MASEA was easier to assemble and test at a short period of time, thus allowing the quick and repeated tests undertaken.
Case Study
A. Entezari Harsini; S. A. Mazaheri; S. Saadat; J. F. Santos
Abstract
This paper presents the new geochemical isotopes Sr and Nd, and the mineralization data for the south Neyshabour volcanic rocks located in NE Iran. Based on the chemical classifications, the studied rocks are basaltic trachy andesite, trachy andesite, trachyte, and trachy dacite in composition. All the ...
Read More
This paper presents the new geochemical isotopes Sr and Nd, and the mineralization data for the south Neyshabour volcanic rocks located in NE Iran. Based on the chemical classifications, the studied rocks are basaltic trachy andesite, trachy andesite, trachyte, and trachy dacite in composition. All the analyzed volcanic rocks display enrichment in light rare earth elements (LREE) relative to the heavy rare earth elements (HREE), have significant negative Ti and Nb anomalies, and have a positive U anomaly. The tectonic discrimination diagrams for the volcanic rocks in the studied area show a post-collisional arc environment. These characteristics are the specifications of the subduction-related volcanic rocks generated in a post-collisional setting. The initial 87Sr/86Sr ratios ranging from 0.70408 to 0.70593and the εNdi values between +3.34 and +5 for the four samples analyzed indicate that the studied rocks are derived from a lithospheric mantle source. Finally, it is concluded that these volcanic rocks should have formed in a post-collisional environment that followed the Neo-Tethys subduction. There are strong evidence for copper mineralization in these volcanic rocks. The main copper oxide minerals are malachite and atacamite. The copper sulfide minerals such as chalcocite, minor bornite, and covellit are also present. Chalcocite is the most abundant sulfide ore mineral present in this area. This mineralization is observed as open space filling and thin veinlets, and it is partially controlled by linear structures and fault zones. Based on the identified characteristics, this ore deposit is hydrothermal. Carbonate alteration is frequently seen in the area but argillic alteration is very low, and this issue displays a hydrothermal solution with an alkaline pH.
Research Note
H. Bejari; A. A. Daya; A. Roudini
Abstract
Based on existence of the chromite deposits in the Sistan and Baluchestan province in Iran, and also various applications of chromite in different industries, it is expected that the establishment of chromite processing plant is required in the erelong. The geographical location of a processing plant ...
Read More
Based on existence of the chromite deposits in the Sistan and Baluchestan province in Iran, and also various applications of chromite in different industries, it is expected that the establishment of chromite processing plant is required in the erelong. The geographical location of a processing plant can have a strong influence on the success of an industrial venture. The processing plant site selection is a multi-criteria decision problem. The conventional methods used for a plant location selection are inadequate for dealing with the imprecise or vague nature of a linguistic assessment. To overcome this difficulty, the fuzzy multi-criteria decision-making methods are proposed. This paper presents an application of the analytic hierarchy process (AHP) method based on the fuzzy sets (Fuzzy AHP) used to select an appropriate site for a chromite processing plant in the Sistan and Baluchestan province. For this purpose, based on the concentration of chromite deposits in different regions of the province, four feasible alternatives including the Zahedan, Khash, Iranshahr, and Nikshahr cities are selected for a chromite processing plant. The quantitative and qualitative criteria such as availability of raw materials, availability of labors, education, climatic conditions, environmental impacts, infra-structural facilities and security, and local community considerations are used to compare the feasible alternatives. Finally, the alternatives are ranked, and a convenient location is recommended for the construction of the chromite processing plant. The results obtained show that the city of Zahedan is the best alternative.
Case Study
H. Fattahi
Abstract
Slope stability analysis is an enduring research topic in the engineering and academic sectors. Accurate prediction of the factor of safety (FOS) of slopes, their stability, and their performance is not an easy task. In this work, the adaptive neuro-fuzzy inference system (ANFIS) was utilized to build ...
Read More
Slope stability analysis is an enduring research topic in the engineering and academic sectors. Accurate prediction of the factor of safety (FOS) of slopes, their stability, and their performance is not an easy task. In this work, the adaptive neuro-fuzzy inference system (ANFIS) was utilized to build an estimation model for the prediction of FOS. Three ANFIS models were implemented including grid partitioning (GP), subtractive clustering method (SCM), and fuzzy c-means clustering method (FCM). Several important parameters such as cohesion coefficient, internal angle of friction, slope height, slope angle, and unit weight of slope material were utilized as the input parameters, while FOS was used as the output parameter. A comparison was made between these three models, and the results obtained showed the superiority of the ANFIS-SCM model. Also performance of the ANFIS-SCM model was compared with multiple linear regression (MLR). The results obtained demonstrated the effectiveness of the ANFIS-SCM model.
Case Study
H. Moeini; A. Aryafar
Abstract
Anomaly recognition has always been a prominent subject in preliminary geochemical explorations. Among the regional geochemical data processing, there are a range of statistical and data mining techniques as well as different mapping methods, which serve as presentations of the outputs. The outlier’s ...
Read More
Anomaly recognition has always been a prominent subject in preliminary geochemical explorations. Among the regional geochemical data processing, there are a range of statistical and data mining techniques as well as different mapping methods, which serve as presentations of the outputs. The outlier’s values are of interest in the investigations where data are gathered under controlled conditions. These values in exploration geochemistry indicate the mineralization occurrences, and therefore, their identification is vital. Both the robust parametric (based on Mahalanobis distance) and non-parametric (based on depth functions) techniques have been developed for a multivariate outlier identification in geochemistry data. In this research work, we applied the local multivariate outlier identification approach to delineate the geochemical anomaly halos in the Hamich region, which is located in the SE of Birjand, South Khorasn province, East of Iran. For this purpose, 396 litho-geochemical samples that had been analyzed for 44 elements were used. The obtained results show a good agreement with the geological and mineral indices of Pb, Zn, and Cu in the southern part of the area. Such studies can be used by a project director to optimize the core drilling places in detailed exploration steps.
Research Note
M. Hosseinzadeh; M. Alizadeh; S. M. Raouf Hosseini
Abstract
In this work, a bench-scale process was developed using mineral-processing methods to recover iron from a placer deposit located in Bardaskan, Khorasan-e-Razavi, Iran. The mineralogical studies were performed by X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Electron Probe Micro-Analyzer (EPMA), ...
Read More
In this work, a bench-scale process was developed using mineral-processing methods to recover iron from a placer deposit located in Bardaskan, Khorasan-e-Razavi, Iran. The mineralogical studies were performed by X-ray Diffraction (XRD), X-ray Fluorescence (XRF), Electron Probe Micro-Analyzer (EPMA), and an optical microscope. These studies indicated that titanomagnetite, magnetite, and hematite were presented in the sample as valuable minerals. In contrast, the gangue minerals were silicates such as pyroxene, plagioclase, quartz, feldspar, calcite, and some secondary minerals. The optimum liberation degree of the iron-containing minerals was obtained to be 75 µm with average Fe and TiO2 contents of 5% and 1%, respectively. The analysis showed that magnetite was the main iron mineral, and most of the hematite was formed due to martitization. Also minor ilmenite contents were found in hematite and magnetite in a blade form. The maximum TiO2 content in the magnetite lattice was 19%, only 8% of which was recovered to the magnetic product. Eventually, an iron concentration flow sheet was developed, which included the removal of a major part of silicates and then iron minerals by a low intensity wet magnetic separator. The final product contained 55, 7.8, and 0.77% of Fe, TiO2, and V2O5, respectively, which can be used for iron production, and V2O5 extraction (as the by-product).
Case Study
H. Khoshdast; M. Mahmoodabadi
Abstract
A new method is developed for a fast identification of the stability situation of industrial processes. The proposed method includes two factor ratios of the control constants for the upper and lower control limits to process these constants. An indication ratio is then defined as the ratio of the maximum ...
Read More
A new method is developed for a fast identification of the stability situation of industrial processes. The proposed method includes two factor ratios of the control constants for the upper and lower control limits to process these constants. An indication ratio is then defined as the ratio of the maximum data range value to the difference between the maximum and average values for individual data points. It is shown that if the indication ratio comes into values between the corresponding control factor ratios, the process will be under control, and otherwise, if the indication ratio decreases to smaller than the lower control factor ratio or gets more than the upper control factor ratio, the process will be expected to be out-of-control. Validation of the method was successfully resulted using two series of quality control datasets obtained from Zarand Iron Ore Complex (Zarand, Iran) and Miduk Copper Complex (Shahr Babak, Iran). The results obtained show that the process responses predicted by the proposed method are in agreement with those indicated by the conventional chart-based method. The developed method eliminates the need for drawing the process control charts used to assess the process control level. The superiority of the proposed method over the chart-based method becomes apparent especially when a large number of control charts are necessary to be drawn and interpreted for engineering decision-making purposes.
Case Study
M. Nikkhah
Abstract
Nowadays acoustic emission (AE) testing based on the Kaiser Effect (KE) is increasingly used to estimate the in-situ stress in laboratories. In this work, this effect is assessed on cylindrical specimens in numerical simulations of the cyclic loadings including loading, unloading, and re-loading cycles ...
Read More
Nowadays acoustic emission (AE) testing based on the Kaiser Effect (KE) is increasingly used to estimate the in-situ stress in laboratories. In this work, this effect is assessed on cylindrical specimens in numerical simulations of the cyclic loadings including loading, unloading, and re-loading cycles using a 3D code called the particle flow code (PFC) based upon the distinct element method. To achieve this objective, at first, the numerical model is calibrated using a laboratory test performed on the selected sandstone specimens. The results obtained show that PFC and the distinct element code are useful tools used to investigate the damage and KE of a brittle rock. Also the results obtained by the triaxial modeling show that a combination of triaxial loading stresses change the results of uniaxial loading. Further, KE is influenced under confining stresses so that larger confining stresses lead to greater differences between the KE stress during the uniaxial and pre-stress loadings.
Case Study
M. Rezaie; A. Moradzadeh; A. Nejati Kalate
Abstract
One of the most remarkable basis of the gravity data inversion is the recognition of sharp boundaries between an ore body and its host rocks during the interpretation step. Therefore, in this work, it is attempted to develop an inversion approach to determine a 3D density distribution that produces a ...
Read More
One of the most remarkable basis of the gravity data inversion is the recognition of sharp boundaries between an ore body and its host rocks during the interpretation step. Therefore, in this work, it is attempted to develop an inversion approach to determine a 3D density distribution that produces a given gravity anomaly. The subsurface model consists of a 3D rectangular prisms of known sizes and positions and unknown density contrasts that are required to be estimated. The proposed inversion scheme incorporates the Cauchy norm as a model norm that imposes sparseness and the depth weighting of the solution. A physical-bound constraint is enforced using a generic transformation of the model parameters. The inverse problem is posed in the data space, leading to a smaller dimensional linear system of equations to be solvedand a reduction in the computation time. For more efficiency, the low-dimensional linear system of equations is solved using a fast iterative method such as Lanczos Bidiagonalization. The tests carried out on the synthetic data show that the sparse data-space inversion produces blocky and focused solutions. The results obtained for the 3D inversion of the field gravity data (Mobrun gravity data) indicate that the sparse data-space inversion could produce the density models consistent with the true structures.
Case Study
S. E. Mirsalari; M. Fatehi Marji; J. Gholamnejad; M. Najafi
Abstract
Analysis of the stresses, displacements, and horizontal strains of the ground subsidence due to underground excavation in rocks can be accomplished by means of a hybridized higher order indirect boundary element/finite difference (BE/FD) formulation. A semi-infinite displacement discontinuity field is ...
Read More
Analysis of the stresses, displacements, and horizontal strains of the ground subsidence due to underground excavation in rocks can be accomplished by means of a hybridized higher order indirect boundary element/finite difference (BE/FD) formulation. A semi-infinite displacement discontinuity field is discretized (numerically) using the cubic displacement discontinuity elements (i.e. each higher order element is divided into four sub-elements bearing a cubic variation in the displacement discontinuities). Then the classical finite difference formulation (i.e. the backward, central, and forward finite difference formulations) is hybridized using the boundary element formulation, enabling us to obtain the nodal tangential stresses and horizontal strains along the elements. Several example problems are solved numerically, and the results obtained are then compared with their corresponding results available in the literature. These comparisons show the effectiveness and validness of the proposed method. A classical practical problem is also used to verify the applicability of the hybridized method.
Case Study
A. Alipour; A. A. Khodaiari; A. Jafari; R. Tavakkoli-Moghaddam
Abstract
Open-Pit Production Scheduling (OPPS) problem focuses on determining a block sequencing and scheduling to maximize Net Present Value (NPV) of the venture under constraints. The scheduling model is critically sensitive to the economic value volatility of block, block weight, and operational capacity. ...
Read More
Open-Pit Production Scheduling (OPPS) problem focuses on determining a block sequencing and scheduling to maximize Net Present Value (NPV) of the venture under constraints. The scheduling model is critically sensitive to the economic value volatility of block, block weight, and operational capacity. In order to deal with the OPPS uncertainties, various approaches can be recommended. Robust optimization is one of the most applicable methods in this area used in this study. Robust optimization based on the box counterpart formulation is applied to deal with the OPPS problem. To have a comparison between the solutions of the box counterpart optimization model and the deterministic model, a Two-Dimensional (2D) numerical study of a hypothetical open-pit mine is conducted followed by additional computations on the actual large-scale instances (Marvin orebody). This investigation shows that the different features of the robust planning under uncertainty can be scheduled. Also the price of robustness is obtained in different levels of conservatism.
Case Study
H. Amani; H. Naderi
Abstract
Gallium extraction from Jajarm Bayer process liquor (Jajarm, Iran) was investigated using microemulsions. Also the behavior of aluminum was studied as an impurity. Kelex100 (4-ethyl, 1-methyl, 7-octyl, 8-hydroxyquinoleine), iso-decanol and n-butanol, and kerosene were used as the surfactant, co-surfactant, ...
Read More
Gallium extraction from Jajarm Bayer process liquor (Jajarm, Iran) was investigated using microemulsions. Also the behavior of aluminum was studied as an impurity. Kelex100 (4-ethyl, 1-methyl, 7-octyl, 8-hydroxyquinoleine), iso-decanol and n-butanol, and kerosene were used as the surfactant, co-surfactant, and oil phase, respectively. Ternary phase diagrams were produced using various co-surfactants at different C/S ratios. The results obtained show that Winsor II is the predominant region, and the least area was obtained using iso-decanol at C/S = 4. Using n-butanol or iso-decanol at C/S = 2, 100% of gallium was extracted. The equations of the statistical models for the gallium and aluminum extractions using different co-surfactants were calculated. While the highest gallium extraction (100%) was obtained using n-butanol, due to the high co-extraction of aluminum, the lowest separation and enrichment factors were obtained for this system. The highest separation and enrichment factors were obtained using iso-decanol at C/S = 2. The point with the compositions of XAF = 30, XOF = 20, and XC/S = 50 was found to be a suitable choice, and led to 74% and 14% extractions for gallium and aluminum, respectively. An enrichment factor of 5.28 was obtained.
Case Study
R. Dabiri; M. Bakhshi Mazdeh; H. Mollai
Abstract
The aim of this study was to determine the extent of metal pollutions and the identification of their major sources in the vicinity of the Sangan iron mine occurring in NE Iran. Soil samples were collected from the vicinity of the mine site and analyzed for heavy metals. In addition, the chemical speciation ...
Read More
The aim of this study was to determine the extent of metal pollutions and the identification of their major sources in the vicinity of the Sangan iron mine occurring in NE Iran. Soil samples were collected from the vicinity of the mine site and analyzed for heavy metals. In addition, the chemical speciation of these metals was investigated by means of the sequential extraction procedure. The statistical and spatial variability of the metal concentrations and other soil parameters were also analyzed by the multivariate statistical methods (principal component analysis and cluster analysis). Contaminant Factor (CF) and Enrichment Factor (EF) were used to evaluate soil pollution in the samples. By this study, one can conclude that a notable enrichment of heavy metals happened in the margin of the mining area. The data obtained reveal that soils in the area are contaminated, showing higher levels of Fe, Sn, Co, Cu, Sb, S, and Cd in comparison with their normal distributions. The results of sequential extraction analysis and multivariate (geo)statistical methods show that the variability of Fe, Sn, Co, Cu, Sb, S, and Cd is predominately controlled by the anthropogenic source (mining activity), whereas Pb, Cr, and Zn are mainly of natural (geogenic) origin.
Case Study
M. Ataei; F. Sereshki
Abstract
Like most limestone mines, which produce the raw materials required for cement companies, the transportation cost of the raw materials used in the Shahrood Cement Company is high. It has been tried to build the crushing and grinding plant close to the mine as much as possible. On the other hand, blasting ...
Read More
Like most limestone mines, which produce the raw materials required for cement companies, the transportation cost of the raw materials used in the Shahrood Cement Company is high. It has been tried to build the crushing and grinding plant close to the mine as much as possible. On the other hand, blasting has harmful effects, and the impacts of blast-induced damages on the sensitive machinery, equipment, and buildings are considerable. In such mines, among the blasting effects, blast-induced vibrations have a great deal of importance. This research work was conducted to analyze the blasting effects, and to propose a valid and reliable formula to predict the blast-induced vibration impacts in such regions, especially for the Shahrood Cement Company. Up to the present time, different indices have been introduced to quantify the blast vibration effects, among which peak particle velocity (PPV) has been widely considered by a majority of researchers. In order to establish a relationship between PPV and the blast site properties, different formulas have been proposed till now, and their frequently-used versions have been employed in the general form of , where W and D are the maximum charge per delay and the distance from the blast site, respectively, and , , and describe the site specifications. In this work, a series of tests and field measurements were carried out, and the required parameters were collected. Then in order to generalize the relationship between different limestone mines, and also to increase the prediction precision, the related data for similar limestone mines was gathered from the literature. In order to find the best equation fitting the real data, a simple regression model with genetic algorithm was used, and the best PPV predictor was achieved. At last, the results obtained for the best predictor model were compared with the real measured data by means of a correlation analysis.
Case Study
H. Molayemat; F. Mohammad Torab
Abstract
Coalbed methane (CBM) plays an important role in coal mining safety and natural gas production. In this work, The CBM potential of B2 seam in Parvadeh IV coal deposit, in central Iran, was evaluated using a combination of local regression and geostatistical methods. As there were 30 sparse methane sampling ...
Read More
Coalbed methane (CBM) plays an important role in coal mining safety and natural gas production. In this work, The CBM potential of B2 seam in Parvadeh IV coal deposit, in central Iran, was evaluated using a combination of local regression and geostatistical methods. As there were 30 sparse methane sampling points in the Parvadeh IV coal deposit, no valid variogram was achieved for the methane content. A multivariate adaptive regression splines (MARS) model was used to reproduce the methane content data based on seam depth, thickness, and ash content. The MARS model results were used in ordinary kriging to estimate the methane content in all mine blocks. A combination of MARS modeling and ordinary kriging in CBM studies is introduced, for the first time, in this paper. The results obtained show that high methane zones are located in the central and south western parts of the deposit. The in situ CBM potential varies from 6.0 to 16.1 m3/t, and it was estimated to be 1.39 billion m3 at the average depth of 267 m in an area of 86.55 km2. Although this volume is remarkable, little is known as how much of this resource is actually producible. Consequently, high methane-bearing zones are highly recommended for further studies as a source of natural gas for extraction and reducing the hazards and explosion risks of underground coal mining.
