Case Study
M. M Tahernejad; M. Ataei; R Khalokakaie
Abstract
Iran has high potential and unique stone reserves in terms of variety of color, texture, quality, and economic value; nevertheless, in spite of growing mine production during the past decade, in many instances this potential has been overlooked. Therefore it is necessary to investigate strategic factors ...
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Iran has high potential and unique stone reserves in terms of variety of color, texture, quality, and economic value; nevertheless, in spite of growing mine production during the past decade, in many instances this potential has been overlooked. Therefore it is necessary to investigate strategic factors of these mines. The purpose of this study is to evaluate and determine the best strategies for Iran’s quarries. To this end, the mines were analyzed using the Strengths, Weaknesses, Opportunities and Threats (SWOT) approach in combination with Fuzzy Analytic Hierarchy Process (FAHP). Firstly, an environmental analysis was performed and then the SWOT factors were identified. In this way, the sub-factors which have very significant effects on the mines were determined. Using the SWOT matrix, alternative strategies were developed. Subsequently, the strategies were prioritized and the best strategies for these mines were determined. The results show that conservative strategies are the best strategy group for Iran’s quarries.
Case Study
V.F Navarro Torres; G Zamora Echenique; R.N Singh
Abstract
Hydrographically Bolivian Poopó Lake is located in the basin of Desaguadero River and it has over a dozen main tributary rivers and other smaller rivers with lower flow. The mine water discharge from the abandoned and current mining activities polluted these rivers by carrying heavy metals, dissolved ...
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Hydrographically Bolivian Poopó Lake is located in the basin of Desaguadero River and it has over a dozen main tributary rivers and other smaller rivers with lower flow. The mine water discharge from the abandoned and current mining activities polluted these rivers by carrying heavy metals, dissolved and suspended solids which in turn polluted the Poopó Lake which is considered as an important Lake in this area. The present paper deals with the environmental hazards associated with the mining activities with an objective of determining the environmental quality of the Poopó Lake and its tributary rivers, based on physical-chemical analysis of superficial water and sediment samples. The results of the research show that the Poopó Lake water quality can be classified as highly saline, containing high concentration of dissolved or suspended solid, as well arsenic, lead, cadmium, zinc and other heavy metals exceeding the permissible limits of pollutants. Desaguadero River contributed to the Poopó Lake pollution by 70% arsenic, 64% lead, 4.27% zinc and 2.18% cadmium. Other important pollution contributors are Antequera River by 57 % zinc, 32.9 % cadmium and 0.66% lead, and Huanuni River by 61.2% cadmium, 2.23% lead and 34.3% zinc. Vinto foundry, Kori kollo mine and mainly San José mine polluted the Poopó Lake by arsenic and lead through Desaguadero River. Bolivar and Huanuni mines polluted the Poopó Lake by cadmium and zinc through Antequera and Huanuni Rivers. Additionally the mining activities continue to pollute the Poopó Lake by dissolved and suspended solids transporting through Desaguadero, Antequera and Huanuni rivers.
Case Study
S.M.A Hosseini; F Sereshki; M Shariati; S.M.E Jalali; F Crotogino
Abstract
Creep phenomenon in rock engineering plays a key role in development of underground spaces as they must be stable enough for a long period of time. Current research involved designing and manufacturing of a new creep testing machine. The equipment is capable to perform simultaneous light-duty creep tests ...
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Creep phenomenon in rock engineering plays a key role in development of underground spaces as they must be stable enough for a long period of time. Current research involved designing and manufacturing of a new creep testing machine. The equipment is capable to perform simultaneous light-duty creep tests on more than one cylindrical rock samples at a very low cost.To evaluate the equipment’s performance, a series of creep test was performed on salt rock samples and their axial and lateral deformations were measured by dial gauges. Measurements were taken under constant temperature, humidity and sustained loads. The results revealed that the creep rate in lateral direction was far greater than in the axial direction. Another important conclusion was that both axial and lateral creep curves follow the same pattern with an idealized salt rock creep curve. Also, experiments indicated that the steady state creep rate increases with increasing initial stress state. Also, initial stress state showed a great influence on salt primary creep response.
Case Study
Akbar farzanegan; Bahareh Arabzadeh; Vahid Hasanzadeh
Abstract
Discrete Element Method (DEM) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. Prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is ...
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Discrete Element Method (DEM) is extensively used for mathematical modeling and simulating the behavior of discrete discs and discrete spheres in two and three dimensional space, respectively. Prediction of particles flow regime, power draw and kinetic energy for a laboratory or an industrial mill is possible by DEM simulation. In this article, a new approach was used to assess the main parameters of a transparent ball mill constructed in mineral processing laboratory of the University of Tehran. The mill shell and crushing balls are made of Plexiglas® and compressed glass respectively. The true values of mechanical parameters for these materials, required for DEM modeling, were unknown. The authors back-calculated the best values of mechanical properties of Plexiglas and compressed glass materials based on a large number of DEM simulations. Back-calculation procedure was mainly based on the comparison between electrical power draw measured in real mill and mechanical power draw calculated by DEM model while trying to simulate particle flow regime inside the real mill accurately. The results showed that the optimal number and design of lifters can be adequately determined by improving torque and kinetic energy in crushing elements through DEM simulation trials based on the back-calculated mechanical parameters.
Case Study
Mostafa Javid; Behzad Tokhmechi
Abstract
There are two methods for identifying formation interface in oil wells: core analysis, which is a precise approach but costly and time consuming, and well logs analysis, which petrophysists perform, which is subjective and not completely reliable. In this paper, a novel coupled method was proposed to ...
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There are two methods for identifying formation interface in oil wells: core analysis, which is a precise approach but costly and time consuming, and well logs analysis, which petrophysists perform, which is subjective and not completely reliable. In this paper, a novel coupled method was proposed to detect the formation interfaces using GR logs. Second approximation level (a2) of GR log gained from optimum mother wavelet decomposition was used for formation interface detection. Short time Fourier transform (STFT) of a2 was gained since the window band was fixed in the entire of well depths. Inverse STFT of various windows of transformed data was gained, which creates various signals in depth domain. To this end, a novel formulation was developed to obtain modified signal for formation interface detection. The mean of various resulted signals creates a smooth signal the logarithm well of which highlights formation interfaces. Synthetic data were used to test the applicability of proposed algorithm. Accordingly, GR logs corresponding to five different wells located in an oilfield in south of Iran also were used to investigate the accuracy and applicability of the proposed method. Lastly, the validation process took place by comparing the results of core data analysis and the proposed method. Good agreements were obtained between these approaches, demonstrating the applicability of the proposed methodology.
Original Research Paper
A Igder; Ali Akbar Rahmani; Ali Fazlavi; Mohammad Hossein Ahmadi; Mohammad Hossein Ahmadi Azqhandi; Mohammad Hassan Omidi
Abstract
The main objective of the present study is to investigate the feasibility of using Carboxymethyl chitosan magnetic nanoparticles (CCMN) for the adsorption of Cd2+. The study also reports important parameters, which affect the adsorption process, i.e., pH, adsorbent dose, contact time and concentration ...
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The main objective of the present study is to investigate the feasibility of using Carboxymethyl chitosan magnetic nanoparticles (CCMN) for the adsorption of Cd2+. The study also reports important parameters, which affect the adsorption process, i.e., pH, adsorbent dose, contact time and concentration of Cd2+, using Box-Behnken designs. Firstly, functional carboxymethyl chitosan magnetic nanoparticles (about 33 nm) was prepared by chemical coprecipitating and characterized by means of scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR). Then, CCMN was used as the adsorbent for the treatment of effluent. The ANOVA result of the full model shows that pH, adsorbent dosage and metal concentration had a significant effect on metal removal. In addition, this parameters indicates which contact time variable does not have a significant effect (p>0.05).
Research Note
Ali Asghar khodaiari; A Jafarnejad
Abstract
Maximizing economic earnings is the most common goal in cut-off grade optimization of open-pit mining operations. When this is the case, the price of the product has a critical effect on optimum value of cut-off grade. This paper investigates the relationship between optimum cut-off grade and price to ...
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Maximizing economic earnings is the most common goal in cut-off grade optimization of open-pit mining operations. When this is the case, the price of the product has a critical effect on optimum value of cut-off grade. This paper investigates the relationship between optimum cut-off grade and price to maximize total cash flow and net percent value (NPV) of operation. In order to visualize this relationship, two hypothetical mines were employed. To determine the optimum value of cut-off grade in different cases, two nonlinear programming models were formulated, and then, all models were solved using Solver in Excel. The results show that the optimum cut-off grade would always be a descending function of price when we intend to maximize total cash flow. On the other hand, this function may be descending or ascending when we intend to maximize NPV. This result also reveals that both maximum cash flow and maximum NPV always increase and decrease, respectively when the price of product increases or decreases.
