Case Study
H. Mansouri; M. A. Ebrahimi Farsangi
Abstract
A linear superposition method was used for modeling the time history of the production blast vibrations and optimizing the blast sequence to reduce vibration levels in Sar-Cheshmeh copper mine, Kerman, Iran. A single-hole blast for modeling and two double-hole blasts with time delays of 25 and 65 ms ...
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A linear superposition method was used for modeling the time history of the production blast vibrations and optimizing the blast sequence to reduce vibration levels in Sar-Cheshmeh copper mine, Kerman, Iran. A single-hole blast for modeling and two double-hole blasts with time delays of 25 and 65 ms between two holes for modeling validation were carried out. The generated vibrations were measured at seven points with different distances and directions around the blasts. These records contain information about the complex mechanism of seismic energy radiation from an explosive source as well as the filtering effect of the signal travel path. Totally, 40 seismograms were synthesized (3 components for each point) for two blasts using the linear superposition method. The results obtained presented a good correlation between the synthetic and measured seismograms. Also, a comparison was made between the measured peak particle velocities (PPVs) and those obtained from the scaled-distance method and linear superposition modeling. This shows the merits of linear superposition modeling to predict PPVs. Moreover, the recorded seismograms of the single-hole blast were used to simulate the vibrations produced by a production blast at seven points. Furthermore, by using a systematic variation of firing delay in the modeling procedure, the effect of delay on the production blast vibrations was studied. The production blast simulations showed that for Sar-Cheshmeh copper mine, the blasts carried out with the inter-row delays more than 40 ms can significantly reduce vibration levels.
Research Note
S. Safari Sinegani; A. Abedi; H. Asghari; A. A. Safari Sinegani
Abstract
Phytoremediation is a technology that uses plants for the remediation of the contaminated soils, sediments, tailings, and groundwaters. In this work, the ability of TrifoliumAlexanderium for the phytoremediation of the tailings soil in the Anjir-Tange coal washing plant was investigated. For this purpose, ...
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Phytoremediation is a technology that uses plants for the remediation of the contaminated soils, sediments, tailings, and groundwaters. In this work, the ability of TrifoliumAlexanderium for the phytoremediation of the tailings soil in the Anjir-Tange coal washing plant was investigated. For this purpose, Trifolium sp. was cultivated in three soils consisting of the tailings dam, an agricultural soil, and a mixed soil. The concentrations of Fe, Cr, Cd, and P, and the factorsTF (translocation factor), BCF (bio-concentration factor), and BAF (bio-accumulation factor) were measured in the soils and plants after the harvest of Trifolium sp. The results obtained showed that BCFs in the agricultural soil, tailings dam, and mixed soil were 10.4, 12.24, and 7.23, respectively. These results also showed that TrifoliumAlexanderiumwas able to accumulate Cd in the root tissues and stabilize it, and thus it can be regarded as an appropriate species for the stabilization of the Cd ions in the contaminants and soils.The results obtained suggest that this plant can be a good candidate for use in the revegetation and phytostabilization of the Cd-contaminated lands in the region.
Case Study
R. Rahmannejad; A. Kargar; V. Maazallahi; E. Ghotbi-Ravandi
Abstract
The ground reaction curve (GRC) is a vital component of the convergence-confinement method, which possesses many applications in the underground space designs. It defines a relation between the tunnel wall deformations and the ground pressure acting on the tunnel walls. Generally, GRC includes descending ...
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The ground reaction curve (GRC) is a vital component of the convergence-confinement method, which possesses many applications in the underground space designs. It defines a relation between the tunnel wall deformations and the ground pressure acting on the tunnel walls. Generally, GRC includes descending and ascending branches. According to many researchers, the descending branch trend for the ground pressure stops after the critical deformation, and thus the ground pressure on the support system increases due to the formation of a loosening zone and an ascending branch, and finally, the creation of an ultimate pressure on the support system. In this work, two relations are proposed to determine the ultimate ground pressure acting on a circular tunnel in a continuous medium. It is assumed that the rock mass obeys the elastic perfectly plastic model with a cohesionless behavior in the broken zone. This is accomplished by incorporating the Duncan-Fama solution and the two models of Yanssen-Kötter and Caquot rigid plastic. The ground pressure obtained by the Caquot model shows a better correlation with the Goel-Jethwa equation compared with the Yanssen-Kötter solution.
Case Study
M. R. Tavakoli Mohammadi; Seyed M. J. Koleini; M. Abdollahy
Abstract
Efforts to increase the mass transfer coefficient, enhance the contact area, and decrease the power input of contractors have given risen to the development of the pre-dispersed solvent extraction (PDSE) contactor and the devise of the new dissolved nitrogen PDSE (DNPDSE) contactors. The studies conducted ...
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Efforts to increase the mass transfer coefficient, enhance the contact area, and decrease the power input of contractors have given risen to the development of the pre-dispersed solvent extraction (PDSE) contactor and the devise of the new dissolved nitrogen PDSE (DNPDSE) contactors. The studies conducted after the design of the new contactor to determine the working conditions for its suitable performance (2.5-3.5 bar pressure, 0.1 L/min sparger flow rate, and 1.5 L of the aqueous phase) showed that for all the evaluated conditions (i.e. the pressure, polyaphron type, and dilution percentage), the recovery in the DNPDSE contactor was higher than that in the PDSE one. In addition, pictures of the performance modes of the two contactor indicated the presence of the organic phase in the form of colloidal gas aphrons (CGAs) in the DNPDSE contactor and of polyaphron aggregations in the PDSE one. This is a good reason for the increased copper recovery in the DNPDSE contactor. The best recovery for the extraction process in the DNPDSE contactor was achieved using the anionic polyaphron of sodium dodecylbenzene sulphonate (NaDBS) with five-fold dilution at 3.5 bar.
Case Study
M. Noroozi; R. Kakaie; Seyed M. E Jalali
Abstract
Fault zones and fault-related fracture systems control the mechanical behaviors and fluid-flow properties of the Earth’s crust. Furthermore, nowadays, modeling is being increasingly used in order to understand the behavior of rock masses, and to determine their characteristics. In this work, fault ...
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Fault zones and fault-related fracture systems control the mechanical behaviors and fluid-flow properties of the Earth’s crust. Furthermore, nowadays, modeling is being increasingly used in order to understand the behavior of rock masses, and to determine their characteristics. In this work, fault zones and fracture patterns are reviewed, and also comprehensive studies are carried out on the fracture geometry and density variations. A model to describe damage zones around the strike-slip faults is developed, in which the range of damage zone styles commonly found around strike-slip fault zones are shown. A computer code, named DFN-FRAC3D, is developed for the two- and three-dimensional stochastic modeling of rock fracture systems in fault zones. In this code, the pre-existing and fault-related fractures are modeled by their respective probability distributions, and the joint density may be varied by the distance from the fault core. This work describes the theoretical basis and the implementation of the code, and provides a case study in the rock fracture modeling to demonstrate the application of the prepared code.
Case Study
M. J. Babaei; M. A. Molaei; A. Dehghani
Abstract
This study aims to estimate the function of copper consumption using the Johansen approach in time series data, between 1991-2011 in Iran. The literature review of specialized consumption and demand functions shows factors influencing the consumption of copper including copper price variables, aluminum ...
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This study aims to estimate the function of copper consumption using the Johansen approach in time series data, between 1991-2011 in Iran. The literature review of specialized consumption and demand functions shows factors influencing the consumption of copper including copper price variables, aluminum price as a substitute commodity, oil price as a complementary commodity, and industrialization intensity. For this purpose, raw data from the World Bank and International Copper Study Group, were used to extract the initial data needed for the current study, and then research variables were calculated and applied in a seasonal manner. In the next stage, using vector autoregressive, Johansen cointegration test, and vector error correction model, the existence of long-run cointegrated equilibrium relationship was surveyed by vector error correction model. Model estimation results show that there is a positive correlation between between industrialization intensity variable and the price of substitute product (Aluminum) and copper consumption ratio Moreover, there was a significant negative correlation between copper prices and complementary commodity price (Oil), during the review period in Iran. It should be noted that aluminum and copper prices can impact the copper consumption, and an awareness of this can influence making copper sales contracts domestically and abroad.
Case Study
K. Tanguturi; R. Balusu
Abstract
Fundamental understanding of the goaf gas distribution in a gassy coal mine is necessary for developing effective goaf gas drainage strategies in the longwall coal mine. The goaf gas was subjected to the surface and body forces that were classified depending upon whether they acted on the surface area ...
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Fundamental understanding of the goaf gas distribution in a gassy coal mine is necessary for developing effective goaf gas drainage strategies in the longwall coal mine. The goaf gas was subjected to the surface and body forces that were classified depending upon whether they acted on the surface area or the volume of the gas element. Of these forces, the body forces were more predominant in displacing the goaf gas present in the underground mine. The buoyancy forces were classified as the body forces; they are the predominant forces acting on the goaf gas. The buoyancy forces depend mainly upon the density variation in the gas species and the panel orientation or panel geometry. If the temperature variations are neglected, the buoyancy forces that cause the displacement of the goaf gas depend mainly upon the panel orientation. In this work, numerical investigations were carried out using the computational fluid dynamics (CFD) techniques for the fundamental understanding of the goaf gas displacement for various panel orientations. The numerical results obtained for various panel orientations indicated that the goaf gas is displaced towards the tailgate (TG) side when the maingate (MG) was downdip, towards the MG side when MG was updip, towards the start-up of the panel when the face was downdip, and towards the face when the face was updip.
Case Study
A. Ghasemloonia; S. D. Butt
Abstract
Underground caverns in rock salt deposits are the most secure disposal method and a type of gas-storing facility. Gas storage plays a vital role in ensuring that a strategic relationship is secured between an established energy infrastructure provider and a midstream energy company. The Fischells Brook ...
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Underground caverns in rock salt deposits are the most secure disposal method and a type of gas-storing facility. Gas storage plays a vital role in ensuring that a strategic relationship is secured between an established energy infrastructure provider and a midstream energy company. The Fischells Brook area is a pillow-shaped body of salts located in the St. George's Bay area of southwest Newfoundland, which has three layers of salt beds, and is capable of excavating caverns for the storage purposes. The development of cavern facilities requires the stability analysis through numerical models and experimental facilities. This work was motivated to examine the engineering feasibility of the salt cavern characteristics in this area, and to investigate its stability under creep behavior. An experimental test facility was developed to investigate the constitutive parameters governing the creep of rock salt, and the constitutive parameters were implemented into a developed finite element model to investigate the stability of the cavern over a 5-year period. Also a stress-based dilatancy failure envelope was developed to interpret the results of the numerical model, and to conduct sensitivity analyses for different design scenarios. The design recommendations developed in this study will be implemented as a key part of an engineering feasibility study for underground caverns in salt deposits in western Newfoundland.
Case Study
H. Shahi; R. Ghavami Riabi; A. Kamkar Ruhani; H. Asadi Haroni
Abstract
In this research work, the frequency domain (FD) of surface geochemical data was analyzed to decompose the complex geochemical patterns related to different depths of the mineral deposit. In order to predict the variation in mineralization in the depth and identify the deep geochemical anomalies and ...
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In this research work, the frequency domain (FD) of surface geochemical data was analyzed to decompose the complex geochemical patterns related to different depths of the mineral deposit. In order to predict the variation in mineralization in the depth and identify the deep geochemical anomalies and blind mineralization using the surface geochemical data for the Dalli Cu-Au porphyry deposit, a newly developed approach was proposed based on the coupling Fourier transform and principal component analysis. The surface geochemical data was transferred to FD using Fourier transformation and high and low pass filters were performed on FD. Then the principal component analysis method was employed on these frequency bands separately. This new combined approach demonstrated desirably the relationship between the high and low frequencies in the surface geochemical distribution map and the deposit depth. This new combined approach is a valuable data-processing tool and pattern-recognition technique to identify the promising anomalies, and to determine the mineralization trends in the depth without drilling. The information obtained from the exploration drillings such as boreholes confirms the results obtained from this method. The new exploratory information obtained from FD of the surface geochemical distribution map was not achieved in the spatial domain. This approach is quite inexpensive compared to the traditional exploration methods.
Case Study
M. Shamsi; M. Noparast; Seyyed Z. Shafaie; M. Gharabaghi; S. Aslani
Abstract
Copper smelting slags are hard materials. Therefore,to recover their copper by flotation method, grinding should be carried out to obtain optimal particle size. Copper smelting slags in the Bardeskan district, with work index of 16.24 kwh/st, were grinded for 65 minutes to reach an acceptable degree ...
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Copper smelting slags are hard materials. Therefore,to recover their copper by flotation method, grinding should be carried out to obtain optimal particle size. Copper smelting slags in the Bardeskan district, with work index of 16.24 kwh/st, were grinded for 65 minutes to reach an acceptable degree of freedom for the flotation tests, with particle size of 80%, smaller than 70 μm. With this grinding time, degree of freedom for copper-bearing minerals was achieved 85-90%. The floatation method performed and the procedure used for the optimization of the effective parameters were described in this paper. The results obtained for the flotation tests, carried out at the optimal conditions after grinding the slags (with a grinding time of65 minutes), showed 62.23% of copper recovery, while, by flotation of copper slags at optimal conditions after increasing the grinding time to 85 minutes (d80 = 48µ), the Cu recovery was increased to 79.89%.
Case Study
M. Otari; R. Dabiri
Abstract
Heavy metal concentration in the soils and sediments has increased worldwide during the last century due to the mining, smelting, and industrial activities. The Forumad chromite deposit is located in the Sabzevar ophiolitic complex (SOC), with a long history of mining activities, yet very little is known ...
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Heavy metal concentration in the soils and sediments has increased worldwide during the last century due to the mining, smelting, and industrial activities. The Forumad chromite deposit is located in the Sabzevar ophiolitic complex (SOC), with a long history of mining activities, yet very little is known about the heavy metal contamination in its surrounding environment. In this research work, the soil pollution by heavy metals was investigated with respect to the geochemical, statistical, and environmental indicators over the chromite mine in Forumad. The concentrations of heavy metals were analyzed, and the results obtained showed that the mean concentrations of Cr (5837.5 ppm) and Ni (570.7 ppm) in the nearby soils and sediments were significantly high. On the other hand, the mean concentrations of the other heavy metals present such as As, Cd, Co, Cu, Pb, and V were close to the geological background values. The multivariate statistical analyses (Pearson coefficient analysis, Cluster analysis, and principal component analysis) were used to understand the various anthropogenic and geological (lithogenic) sources. Our geochemical and environmental assessments suggested that Cr, Ni, Co, and V had similar properties, and their presence in the soils was mainly from the ultramafic rocks and chromite deposits. However, the calculated enrichment factors for Cr and Ni were more than 10, suggesting their anthropogenic sources due to the mining activities. The significant Cr and Ni contaminations in the Forumad nearby soils indicated that the status of heavy metal contaminations of the area should receive further considerations in the metal mine areas throughout SOC.
Case Study
R. Mikaeil; M. Abdollahi Kamran; G. Sadegheslam; M. Ataei
Abstract
Predicting the sawability of the dimension stone is one of the most important factors involved in production planning. Moreover, this factor can be used as an important criterion in the cost estimation and planning of the stone plants. The main purpose for carrying out this work was to rank the sawability ...
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Predicting the sawability of the dimension stone is one of the most important factors involved in production planning. Moreover, this factor can be used as an important criterion in the cost estimation and planning of the stone plants. The main purpose for carrying out this work was to rank the sawability of the dimension stone using the PROMETHEE method. In this research work, four important physical and mechanical properties of rocks including the uniaxial compressive strength, Schmiazek F-abrasivity, mohs hardness, and Young's modulus were evaluated as the criteria. During the research process, two groups of dimension stones were selected and analyzed. The rock samples were collected from a number of Iranian factories for the laboratory tests. The production rate of each sawn stone was selected to verify the proposed sawability ranking method. The results obtained showed that the new ranking method can be reliably used for evaluating the sawability of the dimension stone at any stone factory with different rocks only by the physical and mechanical properties testing.
