Rahim Mortezaie; Seyed Davoud Mohammadi; Vahab Sarfarazi
Abstract
One of the most important tasks in conducting a laboratory research work is how to make the samples. The purpose of this research work is to create heterogeneous rock-like samples containing non-persistent notches. Regarding that, the molds with dimensions of 250 mm x 200 mm x 50 mm are made. A mixture ...
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One of the most important tasks in conducting a laboratory research work is how to make the samples. The purpose of this research work is to create heterogeneous rock-like samples containing non-persistent notches. Regarding that, the molds with dimensions of 250 mm x 200 mm x 50 mm are made. A mixture of plaster and water with different mixing percentages is used to make the heterogeneous samples. Various techniques are also employed to create non-persistent notches on the samples. One of the methods to create a notch is to insert an aluminum blade into the groove of the mold, and finally, remove it after the plaster slurry has hardened. Due to the displacement of the blade and its tilting during slurring, the notches are out of the vertical position. In addition to the mentioned method, other methods such as water jet, cutting by thread, cutting by diamond wire cutting, cutting by rotary saw, and using hand saw are applied. Finally, using a hand saw to create a notch on the samples is chosen as the best method.
Alireza Dolatshahi; Hamed Molladavoodi
Abstract
The structure's response to the region's prevailing loading conditions guides the engineers in estimating the resilience of the structural materials and their reinforcement. One of the main concerns in designing rock structures is paying attention to the size effect phenomenon. The size effect influences ...
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The structure's response to the region's prevailing loading conditions guides the engineers in estimating the resilience of the structural materials and their reinforcement. One of the main concerns in designing rock structures is paying attention to the size effect phenomenon. The size effect influences the nominal strength, brittleness, load capacity, stress intensity factor, the characteristics of the fracture process zone at the crack tip, and the way and path of crack propagation. Therefore, studying the size effect law will make a guideline for correct decision-making, design, and implementation of efficient support systems. As a comprehensive review, this work investigates specimen size effect on the rock's mechanical and fracture properties. With a comprehensive look at this issue, it explains the essential points that help the engineers design rock structures. During the investigations carried out in this work, it is shown that the specimen size affects the fracture and mechanical properties of the rock. The severity of this phenomenon depends on various factors such as the brittleness index, the shape of the notch or crack length, and the size of the particles that create the rock. In concrete, it depends on the additive boosting materials in the concrete.
Exploration
Bardiya Sadraeifar; Maysam Abedi; Seyed Hossein Hosseini
Abstract
The Shavaz iron deposit, located in the southwest Yazd province in Central Iranian Block, near The Bafq metallogenic belt, is a significant and economically valuable iron oxide-apatite resource. It features hematite and a minor content of magnetite, detectable through potential field geophysical ...
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The Shavaz iron deposit, located in the southwest Yazd province in Central Iranian Block, near The Bafq metallogenic belt, is a significant and economically valuable iron oxide-apatite resource. It features hematite and a minor content of magnetite, detectable through potential field geophysical surveys. This study aimed to target magnetite mineralization within the deposit using constrained susceptibility inversion. We began by simulating a multi-source synthetic model with three identical cubes at different depths to evaluate the sparse norm inversion approach. The method was then applied to the case study after the essential magnetic data corrections. To refine the interpretation of residual magnetic anomalies and gain insights into their source and depth, the analytic signal and upward continuation methods were employed. Inversion results across different cross-sections revealed two distinct, shallow, lens-shaped magnetite mineralizations with an average vertical extent of 60 meters. Notably, one magnetite body lies approximately 30 meters deeper due to the Dehshir-Baft fault influence. Low normalized mis-fit values confirmed the successful minimization of the objective function during inversion. Additionally, the reconstructed susceptibility models align well with the previous geological studies and borehole data, demonstrating the efficiency of the sparse norm inversion algorithm.
Exploration
shirin Jahanmiri; Ali Aalianvari; Malihehe Abbaszadeh
Abstract
Groundwater inflow is a critical subject within the domains of hydrology, hydraulic engineering, hydrogeology, rock engineering, and related disciplines. Tunnels excavated below the groundwater table, in particular, face the inherent risk of groundwater seepage during both the excavation process and ...
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Groundwater inflow is a critical subject within the domains of hydrology, hydraulic engineering, hydrogeology, rock engineering, and related disciplines. Tunnels excavated below the groundwater table, in particular, face the inherent risk of groundwater seepage during both the excavation process and subsequent operational phases. Groundwater inflows, often perceived as rare geological hazards, can induce instability in the surrounding rock formations, leading to severe consequences such as injuries, fatalities, and substantial financial expenditures. The primary objective of this research is to explore the application of machine learning techniques to identify the most accurate method of forecasting tunnel water seepage. The prediction of water loss into the tunnel during the forecasting phase employed a tree equation based on gene expression programming (GEP). These results were compared with those obtained from a hybrid model comprising particle swarm optimization (PSO) and artificial neural networks (ANN). The Whale Optimization Algorithm (WOA) was selected and developed during the optimization phase. Upon contrasting the aforementioned methods, the Whale Optimization Algorithm demonstrated superior performance, precisely forecasting the volume of water lost into the tunnel with a correlation coefficient of 0.99. This underscores the effectiveness of advanced optimization techniques in enhancing the accuracy of groundwater inflow predictions and mitigating potential risks associated with tunneling activities.
Exploration
Hamid Reza Baghzendani; Hamid Aghajani; Gholam Hossein Karami
Abstract
Karsts are important sources of groundwater, and it is crucial to determine their water volume and quality. The Ravansar Karst spring in the Kermanshah province is a significant water resource with a substantial water volume in the area. The source of this spring is the carbonate rock unit from the Cretaceous ...
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Karsts are important sources of groundwater, and it is crucial to determine their water volume and quality. The Ravansar Karst spring in the Kermanshah province is a significant water resource with a substantial water volume in the area. The source of this spring is the carbonate rock unit from the Cretaceous period and is affected by tectonic changes and faulting caused by movements related to the Zagros folding. In this work, geophysical methods of microgravity, electrical resistivity, and induced polarization have been utilized to identify the extent of karst development in the limestone units. The minimum residual gravity values are associated with karstification. The field dataset comprised two electrical profiles with the dipole- dipole and pole-dipole arrays. The resistivity and gravity data were inverted using a 2D algorithm based on the least square’s technique with a smoothing constraint. According to the processing and 3D modelling of gravity data; not only cavity-shaped voids and spacious cavity chambers were identified but also sub-structures and micro-karstification in carbonate rocks were detected. The most significant finding from the field survey is the detection of low gravimetric values, indicating relatively large holes and chambers that were previously unknown and inaccessible from ground level. These findings are consistent with known collapse and sediment infill features, as seen in surface sinkholes, cavities, and karstification systems. Geophysical surveys and field surveys show that the holes and karsts in the area are related to tectonic phenomena and faulting and are conduits for transporting water to the Ravansar spring.
Ali Nejati Kalateh; Amin Roshandel kahoo
Abstract
We inverse the surface gravity data to recover subsurface 3D density distribution with two strategy. In the first strategy, we assumed wide density model bound for inverting gravity data and In the second strategy, the inversion procedure have been carried out by limited bound density. Wediscretize the ...
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We inverse the surface gravity data to recover subsurface 3D density distribution with two strategy. In the first strategy, we assumed wide density model bound for inverting gravity data and In the second strategy, the inversion procedure have been carried out by limited bound density. Wediscretize the earth model into rectangular cells of constant andunidentified density. The number of cells is often greater than the number of observation points thus we have an underdetermined inverse problem. The densities are estimated by minimizing a cost function subject to fitting the observed data. The synthetic results show that the recovered model from the first strategy is characterized by broad density distribution around the true model, butthat of the second strategy is closer to true models.We carry out inversion of gravity data taken over chromite deposit located at Hormozgan providence of Iran for estimating of subsurface density distribution. The recovered model obtained from second strategy has appropriate agreement with previous 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.
Exploitation
R. Ghasemi; B. Tokhmechi; G. Borg
Abstract
The known ore deposits and mineralization trends are important key exploration criteria in mineral exploration within a specific region. Fry analysis has conventionally been considered as a suitable method to determine the mineralization trends related to linear structures. Based upon literature sources, ...
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The known ore deposits and mineralization trends are important key exploration criteria in mineral exploration within a specific region. Fry analysis has conventionally been considered as a suitable method to determine the mineralization trends related to linear structures. Based upon literature sources, to date, no investigation has been carried out that includes the Sensitivity Analysis of Feature's Number (SAFN), Sensitivity Analysis of Window Size (SAWS), and Sensitivity Analysis of Spatial Distribution (SASD) of Fry analysis related to mineral locations. In this work, SAFN, SAWS, and SASD are performed by moving several different sub-windows among the main window in order to identify the main trends of mineralization by Fry analysis in the Bavanat region of Iran, which is qualified by its regional and local faults pattern. Based upon our investigation, the effectiveness of the window size and the number of features on Fry analysis are 15-30%. The determined main trends of sub-windows increase, whereas its distribution function of Fry outputs is more similar to the distribution function of Fry outputs of the main window. Moreover, the directions of rose diagrams could be changed due to the edge effects of marginal features around the selected window. However, by selecting an appropriate window, this problem can be solved. Additionally, by an appropriate window selection, the most suitable regional situation is an area that contains the largest number of deposits with a similar metallogenetic origin. Based upon our investigation, the distribution function of the Fry outputs is the main factor that directly controls the identified mineralization pattern of the selected windows.
H. Mahdiyanfar
Abstract
Over the past two decades, the frequency domain (FD) of the geochemical data has been studied by some researchers. Metal zoning is one of the challenging subjects in the mining exploration, where a new scenario has been proposed for solving this problem in FD. Three mineralization areas including the ...
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Over the past two decades, the frequency domain (FD) of the geochemical data has been studied by some researchers. Metal zoning is one of the challenging subjects in the mining exploration, where a new scenario has been proposed for solving this problem in FD. Three mineralization areas including the Dalli (Cu-Au), Zafarghand (Cu-Mo), and Tanurcheh (Au-Cu) mineralization areas are selected for this investigation. After transferring the surface geochemical data to FD, the geochemical signals obtained are filtered using the wavenumber-based filters. The high and moderate frequency signals are removed, and the residual signals are interpreted by the statistical method of principal component analysis (PCA). In order to discriminate the deep metal ore deposits, the principal factors of elemental power spectrum extracted by PCA are depicted in a novel diagram (PC1 vs. PC2). This approach indicates that the geochemical data in the Dalli and Zafarghand deep ore deposits have similar frequency behaviors. The Au, Mo, and Cu elements in these two areas are discriminated from the Au, Mo, and Cu mineralization elements of the Tanurcheh area as a deep non-mineralization zone in this diagram. This new criterion used for distinguishing the buried ore deposits and deep non-mineralization zones is properly confirmed by the exploratory deep drilled boreholes. The geochemical anomaly filtering demonstrates that the strong signatures of deep mineralization are associated with the low frequency geochemical signals at the surface, and the buried mineralization areas with weak surface anomaly can be identified using the geochemical FD data.
Mineral Processing
A.R. Ghasemi; A.R. Hasankhoei; E. Razi; Gh.A. Parsapour; S. Banisi
Abstract
Pelletizing plant of the Gol-E-Gohar mining and industrial company consists of a burner, a dry ball mill (6.2 m × 13 m), and an air separator. The ball mill consists of a 2 m-long drying and an 11 m-long grinding chambers. The iron ore concentrate is fed to the drying chamber by a feed chute. It ...
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Pelletizing plant of the Gol-E-Gohar mining and industrial company consists of a burner, a dry ball mill (6.2 m × 13 m), and an air separator. The ball mill consists of a 2 m-long drying and an 11 m-long grinding chambers. The iron ore concentrate is fed to the drying chamber by a feed chute. It was found that when the feed moisture content increased from 1.3% to 3.5%, the throughput decreased by 12% (35 t/h) indicating a low performance of the dryer. Monitoring the wear rate of flights for a period of 12 months showed that the first 0.8 m (59%) length of the dryer length did not experience any wear. To overcome this problem, various feed chute designs with different geometries were simulated by the KMPCDEM© software. With the aim of arriving at a proper material trajectory, where the total length of the dryer is used, a new feed chute was selected. The simulation results indicated that if the height of the feed chute is increased from 1.60 to 2.26 m and the slope is increased from 45 to 48 degrees the material arrives at the first 0.48 m of the drying chamber. In this manner, the unused part of the drying chamber decreases from 59% to 36% of the length. After installation of the new feed chute during a period of three months, the throughput increased by 36 t/h.
B. Alipenhani; A. Majdi; H. Bakhshandeh Amnieh
Abstract
Determining the hydraulic radius of the undercut in the block caving method is one of the key issues in this method. The hydraulic radius is directly related to the minimum caving span. In this research work, the rock mass cavability is investigated using the UDEC and 3DEC software. Since the factors ...
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Determining the hydraulic radius of the undercut in the block caving method is one of the key issues in this method. The hydraulic radius is directly related to the minimum caving span. In this research work, the rock mass cavability is investigated using the UDEC and 3DEC software. Since the factors affecting the cavability are very diverse and numerous, firstly, by 2D modeling in the UDEC software and examining the trend of changes in the minimum caving span, the most important factors including the depth, dip of the joint, number of joints, angle of friction of the joint surface, and joints spacing are selected for the final study. The variation trend of each variable is investigated by keeping the other variables constant (single-factor study) among various factors. In the second step, the minimum caving span for the five main factors and values is determined in the single-factor study using the SPSS software and the multivariate regression method. Then the power function of the minimum caving span is chosen based on the selected variables with a coefficient of determination of 0.76. In continuation, a simple 3D model is built from the undercut. A linear equation is achieved between the results of the 3D and 2D modeling results in similar conditions. In a model with certain conditions, using the equation obtained from the numerical method, the calculated hydraulic radius of caving is 22.5 m, which is close to the result obtained from the Laubscher's empirical method with the same condition (24 m).
Rock Mechanics
M. Rezaei; M. Asadizadeh
Abstract
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 ...
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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).
Amir Mohammad Nasrollahzadeh Bafti; Mohammad Jahani Chegeni; Ahmad Moghooeinejad; Zahra Manafi
Abstract
Flotation is the most important method for processing sulfide copper ores. Due to the high cost and environmental hazards caused by the chemical reagents used in this process (collectors, frothers, pH regulators, depressants, etc.), the possibility of replacing all these reagents or at least some of ...
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Flotation is the most important method for processing sulfide copper ores. Due to the high cost and environmental hazards caused by the chemical reagents used in this process (collectors, frothers, pH regulators, depressants, etc.), the possibility of replacing all these reagents or at least some of them are of special importance through environmentally friendly methods such as bio-flotation using halophilic bacteria. These bacteria have the ability of growth and proliferation in salty media and relatively neutral pHs such as sea salty water. In this research work, the four types of halophilic bacteria Halobacillus sp., Alkalibacillus almallahensis, Marinobacter sp., and Alkalibacillus sp. are studied to replace frothers (MIBC and F7240), depressant (sodium metabisulfite), and pH regulator (lime) in sulfide copper flotation using a Denver laboratory flotation cell. The results obtained indicate that each of the four types of bacteria mentioned above along with collectors (gasoil, Z11, and C7240) as the only chemical reagents (bio-flotation + collector) can depress pyrite better than the bacteria-free mode (flotation + all chemical reagents). Iron recovery in tailings in the standard flotation test is 46.8%, which is, respectively, increased to 91.9%, 74.5%, 70.3%, and 76.9% using the halophilic bacteria of Halobacillus sp., Alkalibacillus almallahensis, Marinobacter sp., and Alkalibacillus sp. On the other hand, the recovery of chalcopyrite using the bio-flotation method is lower than its recovery using the flotation method. Copper recovery in the concentrate in the standard flotation test is 89.1%, which is reached to 58.8%, 71.4%, 62.5%, and 69.4%, respectively, using the above bacteria in the bio-flotation method.
Environment
Asghar Azadehranjbar; Shahrzad khoramnejadian; Saeidreza Asemi Zavareh; Alireza Pendashteh
Abstract
Mining and minerals extraction and purification are critical in today’s world. However, these processes may have negative consequences on the environment. Xanthates which are essential in the floatation process are found to be significant polluting chemicals. In this manuscript, the effect of different ...
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Mining and minerals extraction and purification are critical in today’s world. However, these processes may have negative consequences on the environment. Xanthates which are essential in the floatation process are found to be significant polluting chemicals. In this manuscript, the effect of different parameters on the recovery of lead from Nakhlak lead mine was investigated considering the impact of used chemicals on the surrounding environment including air, soil and native plant species. The reason for this investigation was to achieve the optimal conditions for the minimum consumption of xanthates and other chemicals. The optimal recovery was obtained in the presence of xanthate (1 kg/t) and sodium silicate (0.4 kg/t). In addition, MIBC showed to be more efficient in the floatation process. Furthermore, it was observed that higher xanthate contents are required for the floatation of large particles. Therefore, smaller particles of feed can decrease xanthate consumption. A particle size of 100 µm showed the best floatation recovery with the least xanthate requirement.
Environment
Mehdi Soleymani Gharegol; Kazem Badv; Behzad Nemati akhgar
Abstract
This paper carried out the study on removing cyanide from aqueous solutions by modified zeolite with hexadecyltrimethylammonium bromide. After determining the properties of the prepared adsorbent by the XRD, SEM, FTIR, and BET techniques, the effect of parameters such as the initial concentration of ...
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This paper carried out the study on removing cyanide from aqueous solutions by modified zeolite with hexadecyltrimethylammonium bromide. After determining the properties of the prepared adsorbent by the XRD, SEM, FTIR, and BET techniques, the effect of parameters such as the initial concentration of cyanide, pH, contact time, temperature, and the ionic strength of cyanide was examined by batch tests, and the effects of bed depth and flow rate on the performance of cyanide adsorption was investigated by column process. The XRD analysis showed the presence of clinoptilolite mineral in the structure of the raw zeolite, and the surface coating of raw zeolite by surfactant was detected by the SEM method. The FT-IR results confirmed the adsorption of cationic surfactant on the surface of the modified zeolite. The Langmuir, Freundlich and Tamkin adsorption models showed an excellent ability to describe the cyanide adsorption isotherm using the studied adsorbent. The adsorption capacity of cyanide by modified zeolite was 3.97 mg/g, significantly increased compared to the maximum adsorption capacity of raw zeolite cyanide (0.54 mg/g). The pseudo-second-order model has an excellent ability to describe the adsorption kinetics of cyanide contaminants using natural and modified zeolites. Maximum cyanide uptake capacity was achieved at pH value 8. Cyanide removal decreased with increasing pH and ionic strength of the stock solution and increased with an increase in solution temperature. Column study results confirmed that the adsorption capacity increased with the increasing bed depth, and decreased with increasing flow rate. Yoon-Nelson curves are closer to the experimental curves with high R2 values.
Rock Mechanics
E. Farrokh
Abstract
The study of downtime and subsequently machine utilization in a given project is one of the major requirements of an accurate estimation of TBM performance and daily advance rate. Interestingly, while it is very common to report the components of downtime when discussing a tunneling project in the literature; ...
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The study of downtime and subsequently machine utilization in a given project is one of the major requirements of an accurate estimation of TBM performance and daily advance rate. Interestingly, while it is very common to report the components of downtime when discussing a tunneling project in the literature; there has not been a great amount of in-depth studies on this topic in the recent years. This work presents an in-depth analysis of the different components of hard rock TBM tunneling downtime on the basis of the information about several TBM tunneling projects from around the world including some that are underway or completed in the recent years. This includes the comparison of the recorded downtimes with those predicted by the existing models for these tunnels. The results of this comparison show that with the existing models, there is a poor correlation between the predicted and the actual downtime component values. This indicates that the existing models might be outdated or, in some cases, incompatible with the newly developed technologies. In order to provide a more accurate downtime model, an in-depth statistical analysis of the information about the same tunnels, used for the comparative studies, is conducted to develop the new “hard rock TBM downtime model”. This model includes a set of formulas and tables as well as some charts to predict different activities’ downtimes for three major hard TBM types including open TBM, single-shield TBM, and double-shield TBM. The comparison between the new model predictions and the actual values show a good agreement. The results of this work can be very helpful for the evaluation of time and cost to complete a TBM tunneling project, especially when the downtime is expected to be high.
Rock Mechanics
K. Bour; K. Goshtasbi
Abstract
The design of underground spaces is mainly carried out using empirical, analytical, and numerical methods. The convergence confinement method (CCM) is an analytical technique that is widely utilized in analyzing the stability of underground spaces. However, the main challenge in the stability analysis ...
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The design of underground spaces is mainly carried out using empirical, analytical, and numerical methods. The convergence confinement method (CCM) is an analytical technique that is widely utilized in analyzing the stability of underground spaces. However, the main challenge in the stability analysis is the selection of an accurate constitutive model for rock mass, and particularly, its post-failure behavior. The existence of water plays a significant role in the stability analysis, whereas this effect is not usually considered in the CCM method. In this research work, a circular tunnel in a saturated medium is modelled and compared with its dry condition. Two types of constitutive models namely elastic perfectly plastic (EPP) and strain softening (SS) are used and compared in order to investigate the effect of water and post-failure behavior on the stability of tunnels. With this respect, the codes are written and incorporated in the constitutive models and various analyses are carried out. The results achieved from the analyses show that the elastic reaction of ground in the presence of water in both constitutive models are the same and that the ground reaction curves (GRCs) and longitudinal deformation profiles (LDPs) are similar. However, the trend of GRC is different in the case where the rock failure occurs and the face of the tunnel goes beyond 0.5D. According to the results obtained, the maximum displacement in a saturated medium with different K values for the SS model is more than that for the EPP model.
H.R. Pasand Masoumi; A. Abdollahipour; Kh. Baghernia
Abstract
Determination of the optimum soil conditioning parameters in the earth pressure balance-tunnel boring machines (EPB-TBMs) plays an important role in reaching an optimum thrust force and advance speed. Silty-clay (CL-ML) in line 1 of the Ahwaz metro project is used in order to find the conditioning parameters ...
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Determination of the optimum soil conditioning parameters in the earth pressure balance-tunnel boring machines (EPB-TBMs) plays an important role in reaching an optimum thrust force and advance speed. Silty-clay (CL-ML) in line 1 of the Ahwaz metro project is used in order to find the conditioning parameters of slumps with different water contents and foam agents. The results obtained are a quantitative comparison between the parameters with different soil conditioning and water contents. Hence, the test results can be used to determine the most economical and technical conditioning parameters for a special condition of soil. The optimum quantity of foam expansion ratio (FER), foam injection ratio (FIR), percent ratio between the surfactant agent and the water volume (Cf), and cost for foam in this soil (based on the soil conditioning production cost) are 10, 157%, 2.07, 248 units, respectively. Soil conditioning with the optimum parameters obtained are tested in a TBM in two stages during excavation of 140 rings. This results in a lower soil conditioning cost and almost 40% higher advance speed.
A. Nouri Qarahasanlou; M. Ataei; R. Khaolukakaie; B. Ghodrati; M. Mokhberdoran
Abstract
The life cycle cost of a system is influenced by its maintainability. Maintainability is a design parameter, whose operational conditions can affect it significantly. Hence, the effects of these operational conditions should be quantified early in the design phase. The proportional repair model (PRM), ...
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The life cycle cost of a system is influenced by its maintainability. Maintainability is a design parameter, whose operational conditions can affect it significantly. Hence, the effects of these operational conditions should be quantified early in the design phase. The proportional repair model (PRM), which is developed based on the proportional hazard model (PHM), can be used to analyze maintainability considering the effects of the operational conditions. In PRM, the effects of the operational conditions are considered to be time-independent. However, this assumption may not be valid for some cases. The aim of this paper is to present an approach for prediction of the maintainability performance of the mining facilities considering the time-dependent influencing factors. The stratified Cox regression method (SCRM) is used to determine maintainability in the presence of time-dependent covariates for fleet vehicles operating in Sungun Copper Mine, Iran.
Exploration
H. Sabeti; F. Moradpouri
Abstract
The geo-statistical simulation algorithms for continuous spatial variables have been used widely in order to generate the statistically-honored models. There are two main algorithms doing the continuous variable simulation, Sequential Gaussian Simulation (SGS) and Direct Sequential Simulation (DSS). ...
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The geo-statistical simulation algorithms for continuous spatial variables have been used widely in order to generate the statistically-honored models. There are two main algorithms doing the continuous variable simulation, Sequential Gaussian Simulation (SGS) and Direct Sequential Simulation (DSS). The main advantage of the DSS algorithm against the SGS algorithm is that in the DSS algorithm no Gaussian transformation of the original data is made. In this work, these two simulation algorithms are explained, and their applications to a 3D spatial dataset are deeply investigated. The dataset consists of the porosity values of 16 vertical wells extracted from an actual cube obtained by a seismic inversion process. One well data is excluded from the simulation process for the blind well test. Comparison between the histograms show that the histogram reproduction is slightly better for the SGS algorithm, although the population reproductions are the same for both SGS and DSS results. The DSS algorithm reproduce the mean of input data closer to the mean of well data compared to that of the SGS algorithm. Considering one realization from each simulation algorithm, the RMS error corresponding to all simulated cells against the real values is approximately equal for both algorithms. On the other hand, the error show a slightly less value when the mean of 100 realizations of the DSS result is considered.
N. R. Ahmadi; M. R. Jafari; M. R. Espahbod; N. Kohansal Ghadimvand
Abstract
Identification of the vertical and horizontal distributions for elemental grades is of an important sign in different mineral exploration stages. The main aim of this work is to determine the vertical distribution directional properties of Cu values in the Milloieh Cu porphyry deposit, Kerman (SE Iran) ...
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Identification of the vertical and horizontal distributions for elemental grades is of an important sign in different mineral exploration stages. The main aim of this work is to determine the vertical distribution directional properties of Cu values in the Milloieh Cu porphyry deposit, Kerman (SE Iran) using the power-law frequency fractal model. This work is carried out based on four mineralized boreholes. The Cu grade vertical distribution in mineralized boreholes indicates a positively skewed distribution in the former and multi-modal distribution in the latter types. The power-law frequency analysis in nature represents that the Cu values in four mineralized boreholes are bifractal. The two sections of these graphs outline a break point of about 0.5-1% for Cu values and fractal dimension range of 1.70-4.97 in the mineralized boreholes.
Mohammad Omidi manesh; Vahab Sarfarazi; Nima Babanouri; Amir Rezaei
Abstract
This work presents the hollow center cracked disc (HCCD) test and the cracked straight through Brazilian disc (CSTBD) test of oil well cement sheath using the experimental test and Particle Flow Code in two-dimensions (PFC2D) in order to determine mode I fracture toughness of cement sheath. The tensile ...
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This work presents the hollow center cracked disc (HCCD) test and the cracked straight through Brazilian disc (CSTBD) test of oil well cement sheath using the experimental test and Particle Flow Code in two-dimensions (PFC2D) in order to determine mode I fracture toughness of cement sheath. The tensile strength of cement sheath is 1.2 MPa. The cement sheath model is calibrated by outputs of the experimental test. Secondly, the numerical HCCD model and CSTBD model with diameter of 100 mm are prepared. The notch lengths are 10 mm, 20 mm, 30 mm, and 40 mm. The tests are performed by the loading rate of 0.018 mm/s. When the notch length in CSTBD is 40 mm, the external work is decreased 48%, related to the maximum external work of model with notch length of 10 mm (0.225 KN*mm decreased to 0.116 KN*mm). When the notch length in HCCD is 30 mm, the external work is decreased 33%, related to the maximum external work of model with notch length of 10 mm (0.06 KN*mm decreased to 0.04 KN*mm). The fracture energy is largely related to the joint length. The fracture energy is decreased by increasing the notch length. In constant to the notch length, the fracture energy of the CSTBD model is more than the HCCD model. Mode I fracture toughness is constant by increasing the notch length. The HCCD test and the CSTBD test yield a similar fracture toughness due to a similar tensile stress distribution on failure surface. The experimental outputs are in accordance to the numerical results.
Exploration
Jabar Habashi; Majid Mohammady Oskouei; Hadi Jamshid Moghadam
Abstract
The studied area located in eastern Iran shows a high potential for various mineralizations, especially copper due to its tectonic activity. Remote sensing data can effectively distinguish these areas because of the sparse vegetation. Therefore, in this study, the ASTER (Advanced Spaceborne Thermal Emission ...
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The studied area located in eastern Iran shows a high potential for various mineralizations, especially copper due to its tectonic activity. Remote sensing data can effectively distinguish these areas because of the sparse vegetation. Therefore, in this study, the ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) multi-spectral data was used to recognize argillic, sericite, propylitic, and iron oxide alterations associated with copper mineralization. For this purpose, two categories (porphyry copper-iron and advanced argillic-iron) related alterations were considered to perform the classification of a 2617 square kilometer area using a neural network classification algorithm. To evaluate the accuracy of the classifier, the confusion matrix was computed, which provides overall accuracy and the kappa coefficient factors for assessing classification accuracy. As a result, 64.17% and 83.5% of overall accuracy, and 0.602 and 0.807 of the kappa coefficient were achieved for the advanced argillic alterations and porphyry copper categories, respectively. Ultimately, the validation of the classifications was carried out using the normalized score (NS) equation, employing quantitative criteria. Notably, the advanced argillic class emerged with the top normalized score of 2.25 out of 4, signifying a 56% alignment with the geological characteristics of the region. Consequently, this outcome has led to the identification of favorable areas in the central and northeastern parts of the studied area.
Environment
Daniyal Ghadyani; Amirhossein Badraddini; Mohammad Mirzehi Kalateh Kazemi; Vahab Sarfarazi; Hadi Haeri; Jinwei Fu; Sohrab Naser Mostofi; Vahid Khodabandeloo; Mohammad Fatehi Marji
Abstract
Regarding the hazard-prone working conditions in underground mines, synchronous monitoring and alarm system is vital to increase the safety. By analyzing the accidents in underground mines in Iran, it can be deduced that most fatalities are related to gas leakage, objects drop off on the head, and not ...
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Regarding the hazard-prone working conditions in underground mines, synchronous monitoring and alarm system is vital to increase the safety. By analyzing the accidents in underground mines in Iran, it can be deduced that most fatalities are related to gas leakage, objects drop off on the head, and not using helmets by the staff. Therefore, a smart helmet with the capability of measuring harmful gasses (regarding the type of the mine), detection of the existence of the helmet on the head, temperature and humidity measurement, and detection of blow on the head is designed and fabricated to eliminate the present dangers and problems. This system displays the evaluated data on a developed software through wireless data transmission hardware. The data transmission hardware is the primary a link between the intelligent safety helmet and the software. To follow the idea, practical experiments have been performed in Parvadeh four and East Parvadeh of Tabas coal mine to confirm the validity of data transmission that culminated in successful results. The results were altered by the complexity of the design of the underground spaces so that in a straight direction, data transmission was held until 430 meters. However, further progress was not possible due to tunnel limitations. Data transmission was reduced to 190 meters in access horizons with curvatures or tilts. According to present standards, some thresholds are defined for each of the mentioned cases such that alarm protocol is activated by exceeding these thresholds in critical circumstances. Then the helmet user and the software’s operator will be informed of the occurred danger and will settle the problem. The system outlined in this study ensures performance reliability through its alarm package. A key innovation is the in-depth examination of the impact of head injuries, transforming it into other factors by analyzing relevant content and setting boundaries for assessment rather than using specific numbers. Furthermore, the most evident aspect of this design is the enhancement of the managerial approach, which includes an attendance evaluation platform and performance reporting within the system.
M. Anemangely; A. Ramezanzadeh; B. Tokhmechi
Abstract
Achieving minimum cost and time in reservoir drilling requires evaluating the effects of the drilling parameters on the penetration rate and constructing a drilling rate estimator model. Several drilling rate models have been presented using the drilling parameters. Among these, the Bourgoyne and Young ...
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Achieving minimum cost and time in reservoir drilling requires evaluating the effects of the drilling parameters on the penetration rate and constructing a drilling rate estimator model. Several drilling rate models have been presented using the drilling parameters. Among these, the Bourgoyne and Young (BY) model is widely utilized in order to estimate the penetration rate. This model relates several drilling parameters to the penetration rate. It possesses eight unknown constants. Bourgoyne and Young have suggested the multiple regression analysis method in order to define these constants. Using multiple regressions leads to physically meaningless and out of range constants. In this work, the Cuckoo Optimization Algorithm (COA) is utilized to determine the BY model coefficients. To achieve this goal, the corresponding data for two wells are collected from one of the oilfields located in SW of Iran. The BY model constants are determined individually for two formations in one of the wells. Then the determined constants are used to estimate the drilling rate of penetration in the other well having the same formations. To compare the results obtained for COA, first, the two mathematical methods including progressive stochastic and multiple regressions were implemented. Comparison between these methods indicated that COA yields more accurate and reliable results with respect to the others. In the following, Particle Swarm Optimization (PSO) and Genetic Algorithm (GA) as meta-heuristic algorithms were applied on the field data in order to determine BY model’s coefficients. Comparison between these methods showed that the COA has fast convergence rate and estimation error less than others.
