Jinwei Fu; Mohammad Reza Safaei; Hadi Haeri; Vahab Sarfarazi; Mohammad Fatehi Marji; Leige Xu; Ali Arefnia
Abstract
In this work, the mechanical behavior of strata deformation due to drilling and surface loading is investigated using a 3D physical model. For this purpose, a scaled-down physical model is first designed. Then the tunnel drilling and support system are built. The subsidence experiments performed due ...
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In this work, the mechanical behavior of strata deformation due to drilling and surface loading is investigated using a 3D physical model. For this purpose, a scaled-down physical model is first designed. Then the tunnel drilling and support system are built. The subsidence experiments performed due to tunnel excavation and loading in a very dense and loose soil are performed. Soil is clayey sand (SC), and the percentages of its components are as sand (S = 1. 41%), gravel (G = 25%), and clay (C = 9.33%). Unstable tunnel support experiments are also carried out using physical simulation. Finally, deformations of soil surface and subsidence of strata are observed and recorded. In the tunnel with segmental support, 18.75% more load is applied than in the unsupported tunnel, and the total subsidence of the strata is reduced by 36.2%. The area of the deformed inner layers is decreased by 74.2%, and the length of the affected area in the largest layer is decreased by 48%. The depth of the cavity created at the surface is 46.66% less.
Gh.H. Ranjbar; K. Shahriar; K. Ahangari
Abstract
Although segmental tunnel linings are often used for seismic areas, the influence of segment joints on the segmental lining behavior under seismic loading has not been thoroughly considered in the literature. This paper presents the results of a numerical study investigating the effects of the rotational, ...
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Although segmental tunnel linings are often used for seismic areas, the influence of segment joints on the segmental lining behavior under seismic loading has not been thoroughly considered in the literature. This paper presents the results of a numerical study investigating the effects of the rotational, axial, and radial joint stiffness of the longitudinal joints on the structural forces in segmental tunnel lining under seismic loading. A 3D finite element method is adapted to establish elaborate numerical models of the segments. The validity of the numerical model was tested by comparing the results obtained with the well-known analytical methods presented by Wang and Penzien. The results demonstrate that by increasing the rotational stiffness of the segmental joint, the bending moment increases. When the rotational stiffness ratio is less than 0.5, the positive and negative bending moment variations are more. The numerical modeling results show the variations in the bending moment and the difference between the positive and negative bending moment values increased by increasing the acceleration of seismic loading. Moreover, it is significant for the values. By increasing the rotational stiffness ratio of the segmental joint, the axial force ratio decreases. By increasing the axial and shear stiffness ratio of segmental joint, the variations in the bending moment and axial force in segmental lining is not significant and is ignorable in designing segmental lining.
Ankit Verma; Akhilesh Nautiyal
Abstract
Roads are said to be the backbone of the development of any nation. In the developing nations like India, it is the primary mode of transportation, which makes its significance much higher. Highway geometric alignment is an important aspect for maintaining road safety and the effective movement of traffic ...
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Roads are said to be the backbone of the development of any nation. In the developing nations like India, it is the primary mode of transportation, which makes its significance much higher. Highway geometric alignment is an important aspect for maintaining road safety and the effective movement of traffic on any road. Highway geometry features are meant to be picked, sized, and placed in order to achieve various design goals including sight distance, car stability, driver convenience, drainage, economic growth, and aesthetic qualities. Due to the rapid increase in the growth of traffic in the past few years, it has become important to ensure safe design alignment to serve the future needs efficiently and economically. A case study of NH-05 is used in the present work to design the existing highway to improve its geometric features by considering future forecasted traffic and covering all safety measures given by the Indian Road Congress (IRC) recommendations. The OpenRoads software was used as a designing tool, and all designs were made keeping the design speed at 50 kmph. The roadway width has been decided to be 13.0 m, with the carriageway width set at 7.5 m and the width of the shoulder at 2.4 m. The cross-slope or camber has been determined to be 2.4% for bituminous surfaces and 3.6% for earthen surfaces, with a maximum super-elevation of 7%. Thus the results obtained can be used to solve the traffic congestion problems, particularly due to the high traffic volume, and enhance road safety.
Exploitation
K. Mostafaei; H. R. Ramazi
Abstract
Madan Bozorg is an active copper mine located in NE Iran, which is a part of the very wide copper mineralization zone named Miami-Sabzevar copper belt. The main goal of this research work is the 3D model construction of the induced polarization (IP) and resistivity (Rs) data with quantifying the uncertainties ...
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Madan Bozorg is an active copper mine located in NE Iran, which is a part of the very wide copper mineralization zone named Miami-Sabzevar copper belt. The main goal of this research work is the 3D model construction of the induced polarization (IP) and resistivity (Rs) data with quantifying the uncertainties using geostatistical methods and drilling. Four profiles were designed and surveyed using the CRSP array based on the boreholes. The data obtained was processed, 2D sections of IP and Rs were prepared for each profile by inverting the data, and these sections were evaluated by some exploratory boreholes in the studied area. Based on the geostatistical methods, 3D block models were constructed for the 2D IP and Rs data, and the uncertainties in the prepared models were obtained. The mineralization location was determined according to the geophysical detected anomalies. In order to check the models, some locations were proposed for drilling in the cases that the borehole data was unavailable. The drilling results indicated a high correlation between the identified anomalies from the models and mineralization in the boreholes. The results obtained show that it is possible to construct 3D models from surveyed 2D IP & Rs data with an acceptable error level. In this way, the suggested omitted drilling locations were optimized so that more potentials could be obtained for copper exploration by the least number of boreholes.
Environment
Zaenal Zaenal; Noor Fauzi Isniarno; Delina Mutiara; Sofie Nur’aini; Hasyim Fadhilah; Elfida Moralista; Andrieanto Nurrochman
Abstract
Blasting is a fundamental open-pit mining operation necessary for rock breakage, but it also generates significant environmental noise pollution. Excessive noise from blasting not only endangers health but also poses problems to compliance with regulations, particularly in regions where acoustic standards ...
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Blasting is a fundamental open-pit mining operation necessary for rock breakage, but it also generates significant environmental noise pollution. Excessive noise from blasting not only endangers health but also poses problems to compliance with regulations, particularly in regions where acoustic standards differ, such as Indonesia's use of both dBL and dBA standards. This research addresses the need for reliable and context-dependent predictive models for blasting noise, aiming to compare analytical and empirical formulas with machine learning techniques in dBA prediction. Measurements were conducted at 30 blasts at an open-pit coal mine in Indonesia, South Sumatra, using homogeneous acoustic sensors. The measured data points for frequency, dBL, and dBA were matched to calculated data using equations. Random Forest (RF) and Artificial Neural Network (ANN) predictive models using measured frequency and dBL as predictive variables were also derived. Results show that used Finn-derived equation has poor predictive accuracy, with errors exceeding 80%. Among the analytical and empirical models, Equation 3 performed the best, with an average error of 9%, while a site-spesific regression model based on measurements had an improved error rate of 5%. Machine learning models outperformed all models, with the RF model exhibiting an average error of 2% and demonstrating higher stability and consistency. The ANN model also did well, but with more variation and some overestimations.
Rock Mechanics
Festus Kunkyin-Saadaari; Jude Baah Offei; Sadique Ibn Sadique; Victor Kwaku Agadzie; Ishamel Abeiku Forson
Abstract
The underground mining operations at the Obuasi Gold Mine rely heavily on the stability of hard rock pillars for safety and productivity. The traditional empirical and numerical methods for predicting pillar stability have limitations, prompting the exploration of advanced machine learning techniques. ...
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The underground mining operations at the Obuasi Gold Mine rely heavily on the stability of hard rock pillars for safety and productivity. The traditional empirical and numerical methods for predicting pillar stability have limitations, prompting the exploration of advanced machine learning techniques. Hence, this work investigates the applicability of stacked generalisation techniques for predicting the stability status of hard rock pillars in underground mines. Four stacked models were developed, using Gradient Boosting Decision Trees (GBDTs), Random Forest (RF), Extra Trees (ET), and Light Gradient Boosting Machines (LightGBMs), with each model taking turns as the meta-learner, while the remaining three models acted as the base learners in each case. The models were trained and tested on a dataset of 201 pillar cases from the AngloGold Ashanti Obuasi Mine in Ghana. Model performance was evaluated using classification metrics, including accuracy, precision, recall, F1-score and Matthews Correlation Coefficient (MCC). The RF-stacked model demonstrated the best overall performance, achieving an accuracy of 93.44%, precision of 94.27%, recall of 93.44%, F1-score of 93.59%, and MCC of 88.90%. Feature importance analysis revealed pillar depth and pillar stress as the most influential factors affecting pillar stability prediction. The results indicate that stacked generalisation techniques, particularly the RF-stacked model, offer promising capabilities for predicting hard rock pillar stability in underground mining operations.
Rock Mechanics
M. H. Kadkhodaei; E. Ghasemi
Abstract
The CERCHAR abrasivity test is very popular for determination of rock abrasivity. An accurate estimation of the CERCHAR abrasivity index (CAI) is useful for excavation operation costs. This paper presents a model to calculate CAI based on the gene expression programming (GEP) approach. This model is ...
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The CERCHAR abrasivity test is very popular for determination of rock abrasivity. An accurate estimation of the CERCHAR abrasivity index (CAI) is useful for excavation operation costs. This paper presents a model to calculate CAI based on the gene expression programming (GEP) approach. This model is trained and tested based on a database collected from the experimental results available in the literature. The proposed GEP model predicts CAI based on two basic geomechanical properties of rocks, i.e. rock abrasivity index (RAI) and Brazilian tensile strength (BTS). Root mean square error (RMSE), mean absolute error (MAE), Nash-Sutcliffe efficiency (NSE), and coefficient of determination (R2) are used to measure the model performance. Furthermore, the developed GEP model is compared with linear and non-linear multiple regression and other existing models in the literature. The results obtained show that GEP is a strong technique for the prediction of CAI.
Environment
Jitendra Pramanik; Singam Jayanthu; Dr Abhaya Kumar Samal
Abstract
The environmental conditions present in underground (UG) mines working site significantly impacts the productivity, efficiency, effectiveness as well as threatened security levels. Consequently, maintaining safety in mineral excavation process requires continuous monitoring of the intricate and perilous ...
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The environmental conditions present in underground (UG) mines working site significantly impacts the productivity, efficiency, effectiveness as well as threatened security levels. Consequently, maintaining safety in mineral excavation process requires continuous monitoring of the intricate and perilous operating conditions within the mining work site. At this juncture of time, in this information age, when all walks of life is undergoing continuous modernization, with today's workplace being no exception, Internet of Things (IoT) technology is playing a key role in acquiring relevant information to support monitoring vital operational man and machine safety parameters such as temperature, pressure, humidity, luminance and noise levels, and miner's location in subterranean mining operations. This study has attempted to exhaustively explore state of current research on the use of IoT in underground mining applications. This paper examines the utilization of IoT applications for monitoring several environmental parameters, including obnoxious mine gases and dust concentrations, temperature, humidity, groundwater levels, and strata behaviour to facilitate ground support activities. This paper attempts exploitation of possible scopes of IoT integration from the implementation perspective to monitor and control the various aspects that contribute towards various types and incidents of mine accidents. This research elucidates the primary obstacles that impede the widespread implementation of IoT-enabled systems in underground mining applications.
M. Davood Yavari; H. Haeri; V. Sarfarazi; M. Fatehi Marji; H. A. Lazemi
Abstract
The propagation mechanism of cracks emanating from two holes within the concrete specimens is studied by considering the effects of different lateral compressive stresses. The experimental part of this research work is carried out on some specially prepared pre-cracked specimens with two neighbouring ...
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The propagation mechanism of cracks emanating from two holes within the concrete specimens is studied by considering the effects of different lateral compressive stresses. The experimental part of this research work is carried out on some specially prepared pre-cracked specimens with two neighbouring holes under only a uniaxial compression in the laboratory. The numerical modeling part is performed under both the uniaxial compresion and the lateral confinment by the 2D particle flow code (PFC2D). It is shown that the lateral confinement may change the path of crack propagation in a specimen compared to that of the uniaxially-loaded one. Various senarios of the mixed mode radial crack propagation around the holes are obtained, and both the wing (induced tensile) cracks and secondary (shear) cracks are produced and propagated in various paths due to a change in the confining pressure. The fracturing pattern changes from a single tensile crack to that of the several shear bands by increasing the confining pressure. Also the number of shear cracks is increased by increasing the lateral confinement.On the other hand, as the confining pressure increases, the wing cracks start their growth from the walls and reach the center of the cracks under high confinements.
Surya PRATAP Singh; Amrit Kumar Roy
Abstract
This research work provides a bearing capacity equation for a circular footing placed on dense sand overlying loose sand and subjected to vertical and inclined loading, utilizing the limit equilibrium followed by the projected area approach. For the parametric study, the variables include upper dense ...
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This research work provides a bearing capacity equation for a circular footing placed on dense sand overlying loose sand and subjected to vertical and inclined loading, utilizing the limit equilibrium followed by the projected area approach. For the parametric study, the variables include upper dense sand layer thickness ratio (0.5 to 2.00), friction angle of upper dense sand (41° to 45°) and lower loose sand layer (31° to 35°), and applied load inclination (0° to 30°). The highest and lowest increases in bearing capacity are reported for friction angle combinations of 45°–35° and 41°–31° for various thickness ratios, respectively. For load inclinations of 0°, 10°, 20°, and 30°, bearing capacity is reduced by 43.51%, 72.17%, 85.64%, and 22.62%, 48.56%, 62.17% for friction angles of upper dense and lower loose sand layer combinations of 45° and 35° and at a thickness ratio of 0.5 and 2.0. Considering finite element results, the average deviation of the bearing capacity derived from the suggested equation at surface footing is 7%, 5%, 22%, and 23% for 0°, 10°, 20°, and 30° load inclinations, respectively. The proposed bearing capacity equation yield results that are compared with the available literature, with average deviations of 62%, 50%, 36%, and 36% for load inclination values of 0°, 10°, 20°, and 30°, respectively.
N. Habibkhah; H. Hassani; A. Maghsoudi; M. Honarmand
Abstract
The Dehaj area, located in the southern part of the Urumieh-Dokhtar magmatic belt, is a well-endowed terrain hosting a number of world-class porphyry copper deposits. These deposits are all hosted in an acidic to intermediate volcano-plutonic sequence greatly affected by various types of the hydrothermal ...
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The Dehaj area, located in the southern part of the Urumieh-Dokhtar magmatic belt, is a well-endowed terrain hosting a number of world-class porphyry copper deposits. These deposits are all hosted in an acidic to intermediate volcano-plutonic sequence greatly affected by various types of the hydrothermal alterations, whether argillic, phyllic or propylitic. Although there are a handful of hitherto-discovered porphyry copper deposits in the area, the geological setting of the area suggests the possibility of finding further deposits. The recognition and delineation of the hydrothermal alterations can pave the way for the discovery of further potential zones that possibly host the porphyry copper deposits. The current work proposes a hybrid methodology applied to the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery by combining the application of dimension reduction and fractal techniques to delineate the hydrothermally-altered zones In order to reduce the dimensionality of multi-band ASTER data, Robust Principal Component Analysis (RPCA) was employed to elicit the traces of hydrothermally-related mineral assemblages including illite, sericite, quartz, kaolinite, epidote, and chlorite. Highlighting the existence of the aforementioned minerals, the extracted components require interpretation, i.e. a boundary is required to constraint the hydrothermally affected zones from the rest of the geological units. In order to tackle such a challenge, the authors introduce the concept of value-pixel fractal technique for the extracted principal components. The Prediction-Area (P-A) plot is used for the validation, which shows that the identified alterations correlate with the mineralization. The results obtained are verified by a geological survey, where a number of samples are collected from the delineated zones. The samples are analyzed by the XRD techniques, finding that this work is successful in classifying the hydrothermally-altered zones.
Rock Mechanics
Tanveer Wagay; Manju Suthar
Abstract
An experiment was conducted to evaluate the load-bearing capacity of a soil nailing system that consisted of four 10mm nails and four 12mm nails, reinforced in a slope with three different flexible facing materials: geo-composite facing, aluminium facing, and galvanized iron facing. The nails were spaced ...
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An experiment was conducted to evaluate the load-bearing capacity of a soil nailing system that consisted of four 10mm nails and four 12mm nails, reinforced in a slope with three different flexible facing materials: geo-composite facing, aluminium facing, and galvanized iron facing. The nails were spaced 200mm apart horizontally and vertically from centre to centre. The results of the stress-strain test showed that the geo-composite and galvanized iron facings with 12mm diameter nails exhibited high strength of 0.25N/mm2 with less displacement. The relationship between stress, displacement, and the type of nails used with identical facing was examined. The stability of the slope was also analysed to investigate the impact of nail parameters and type of facing on displacement under varying loading conditions.
Exploitation
Gebremariam Mesele; Miruts Hagos; Bheemalingeswara Konka; Tsegabrhan Gebreset; Misgan Molla; N Rao Cheepurupalli; Girmay Hailu; Negassi Debeb; Assefa Hailesilasie
Abstract
The Dallol Depression, located in the northern Danakil Depression, has a complex geological history shaped by Afar rifting, containing approximately 1.7 km of evaporite deposits. These deposits, heavily influenced by volcanic activity and extensional tectonic faulting, exhibit significant structural ...
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The Dallol Depression, located in the northern Danakil Depression, has a complex geological history shaped by Afar rifting, containing approximately 1.7 km of evaporite deposits. These deposits, heavily influenced by volcanic activity and extensional tectonic faulting, exhibit significant structural variability. This research focuses on the potash-bearing section of the salt sequence, which consists of several distinct layers including the marker bed, sylvinite member, upper carnallitite member, bischofitite member, lower carnallitite member, and kainitite member. Employing satellite imagery (Landsat Thematic Mapper), geological and structural mapping, borehole data, and seismic analysis, this study characterizes the sub-surface features of the evaporites and estimates their reserves. The RockWorks software facilitated the development of a subsurface stratigraphic map and a three-dimensional fence diagram for enhanced interpretation. Seismic data indicate that while the upper layers of the evaporite deposits are largely horizontal and undeformed, deeper layers exhibit considerable tectonic disturbance. Thickness variations were observed, with evaporite and alluvial deposits being thinner at the southeastern rim and thicker in the eastern concession center. The total potash reserve is estimated at approximately 2.96 billion tons, of which 877.76 million tons (29.60%) remain unexploited. Current borehole designs restrict the company's extraction capacity to 24.64%. This study recommends revising mining strategies, incorporating updated borehole designs and advanced geophysical methods to improve potash recovery and promote sustainable practices in the Dallol region.
Exploitation
Avula Rajashekar Yadav; Sreenivasa Rao Islavath; Srikanth Katkuri
Abstract
The installation gallery/set-up room of a longwall panel is driven for installation of the longwall face machineries to start the extraction of coal from the longwall panel. The width of the installation gallery is 8 to 9 m. This gallery needs to be stabilized till the face machineries to be deployed ...
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The installation gallery/set-up room of a longwall panel is driven for installation of the longwall face machineries to start the extraction of coal from the longwall panel. The width of the installation gallery is 8 to 9 m. This gallery needs to be stabilized till the face machineries to be deployed from the driving of the room as it required to stand more than 8 to 10 months and develop the high stress concentration, roof-to-floor convergence and yield zone in the roof and sides. Hence, in this study, a deep longwall mine of India is considered to analyze the behavior of set-up room. For this, a total of twelve 3D numerical models are developed and analyzed considering Mohr’s-Coulomb failure criterion. Three panels located at 417, 462, 528 m having three different widths (8, 10 and 12 m) of set-up rooms are examined. The width of the set-up room is taken based on the length of the shield support. The results in terms of vertical stress distribution, vertical displacement, roof-to-floor convergence, plastic strain and yield zone distribution are presented.
Exploitation
Kamel Menacer; Abderrazak Saadoun; Abdellah Hafsaoui; Mohamed Fredj; Abdelhak Tabet; Djamel Eddine Boudjellal; Riadh Boukarm; Radouane Nakache
Abstract
Mining blasting efficiency is essential for mining operations for economic and technical reasons. Rock blasting operations should be conducted optimally to obtain a particle size distribution that optimises downstream operations, such as loading, transport, crushing, and grinding. The nature of the stemming ...
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Mining blasting efficiency is essential for mining operations for economic and technical reasons. Rock blasting operations should be conducted optimally to obtain a particle size distribution that optimises downstream operations, such as loading, transport, crushing, and grinding. The nature of the stemming material significantly impacts the degree of rock fragmentation during mining operations. Stemming refers to the material used to fill the space above explosives in a borehole, which helps confine the explosive energy and optimise rock fragmentation during detonation.This study aims to evaluate the stemming materials and their effect on the particle size distribution of blasted rocks at the Chouf Amar quarry in M'Sila, Algeria. The analyses performed in this study indicate that the blasting results obtained by the company reflect poor fragmentation quality, with a significant quantity of oversized fragments, making up 20–23% of the total pieces. To address this issue, a new operational blasting plan is proposed to enhance fragmentation quality. This plan employed three stemming materials: drill cuttings, 3/8 crushed aggregates, and sand. The test blasts were performed in a limestone quarry, and the results were evaluated using the highly reliable and widely respected image analysis software WipFrag 3.3. The results reveal that using crushed aggregates as stemming material significantly improves fragmentation quality, reducing the proportion of oversized fragments from an average of 23% (with sand stemming) to 2.6%.
Mineral Processing
Hosein Najmaddaini; Mostafa Maleki Moghaddam; Saeid Zare; Masoud Rezaei; Mohammad Ali Motamedineya; Gholamreza Biniaz
Abstract
AbstractThe structural characteristics of mill liners, such as lifter shape and mill speed, significantly influence the grinding process. At the Sarcheshmeh slag flotation plant, the 6×6 meters SAG mill was initially equipped with 48 rows of liners, designed in a Hi-Lo configuration for the first ...
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AbstractThe structural characteristics of mill liners, such as lifter shape and mill speed, significantly influence the grinding process. At the Sarcheshmeh slag flotation plant, the 6×6 meters SAG mill was initially equipped with 48 rows of liners, designed in a Hi-Lo configuration for the first half and a Lo-Lo configuration for the second. Throughout the mill shell liner's 1700-hour operational period, monitoring identified 30 failures. Investigations revealed that defects in the liner design and improper charge motion were the main causes. This study proposes modifications and standardization of the shell liner design, tailored to the specific circuit conditions, to enhance performance and reliability. The redesign included several key changes: 1) Reducing the number of rows: The number of liner rows was decreased from 48 to 32. 2) Adjusting lifter angle: The lifter angle was increased from 23 to 30o to optimize performance. 3) Eliminating Hi-Lo design liners: The Hi-Lo design liners were changed to Hi-Hi, and 4) Reducing liner variety: The variety of liners was streamlined from 5 types to 2. The installation of the proposed liners optimized the charge trajectory for grinding, resulting in higher liner's lifetime. It extended the liner life by 30% and eliminated liner failures, reducing them from 30 to zero. The wear rate for the proposed design was 0.05 mm/hour, while the original design had a wear rate of 0.11 mm/hour. This difference corresponds to a factor of 2.3 times improvement.
M. Koneshloo; Jean-Paul Chiles
Abstract
The kaolinitic clays have been exploited for more than a hundred years, in the western part of the Charentes Basin, France, and belong to a paleo-deltaic network. The recent deposits are relatively richer in alumina in comparison with the older ones. The genesis of the kaolin deposits of the Charentes ...
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The kaolinitic clays have been exploited for more than a hundred years, in the western part of the Charentes Basin, France, and belong to a paleo-deltaic network. The recent deposits are relatively richer in alumina in comparison with the older ones. The genesis of the kaolin deposits of the Charentes Basin follows simple geological rules, but their detailed geometry has a great complexity, reinforced by the fact that one must distinguish very different clay qualities. The exploitation of the complex deposits which are buried in the deeper level needs the more powerful tools. The paper aims at analyzing the adequacy of the traditional method used in the exploitations of the kaolin deposits of the Charentes Basin in comparison with another method based on geostatistics to define criteria of selection and classification of reserves.
M. Ataei; S.R. Torabi; B. Alizadeh Sevary
Abstract
Qomroud water conveyance tunnel (lot 1&2) with the length of 16 kilometers is considered as one of the greatest development and national projects in Iran. Since about 2 kilometers of tunnel pass through alluvium and the rest of the tunnel pass through various types of geological units, and due to the ...
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Qomroud water conveyance tunnel (lot 1&2) with the length of 16 kilometers is considered as one of the greatest development and national projects in Iran. Since about 2 kilometers of tunnel pass through alluvium and the rest of the tunnel pass through various types of geological units, and due to the complexity of geological condition and variety of effective criteria, suitable selection of excavation machine is crucial. In this respect, application of a suitable method which can select the best, according to the consideration of these entire criteria would be so important. One of the best decision making methods is Analytic Hierarchy Process (AHP) which has a strong theoretical basis. Using this method, this paper selects the most suitable excavation machine for Qomroud water conveyance tunnel. The results show that the EPB TBM Single Shield is the best alternative.
Mineral Processing
Ayman M. Ibrahim; Han Wang; Dianwen Liu; Peilun Shen; Hassan A. Osman; Muhannad Alhaj; Mohamed A. Ibrahim; Misbah Khalil
Abstract
In this study, Pb²⁺ and STG were used as effective co-activation reagents before sodium sulfide treatment to assess their effect on smithsonite floatability. The flotation test results showed that sodium sulfide nonahydrate (SSN) and sodium diethyl dithiocarbamate (DDTC) concentrations significantly ...
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In this study, Pb²⁺ and STG were used as effective co-activation reagents before sodium sulfide treatment to assess their effect on smithsonite floatability. The flotation test results showed that sodium sulfide nonahydrate (SSN) and sodium diethyl dithiocarbamate (DDTC) concentrations significantly impacted floatability, achieving maximum recoveries of 89.32% and 93.19%, respectively. XPS analysis confirmed that Na₂S treatment introduced sulfur species onto the smithsonite surface, enhancing collector attachment and facilitating the formation of PbS and ZnS. FTIR analysis further substantiated that co-activation enhances DDTC adsorption via C=S vibrations, thereby increasing the number of active sites available for interaction with the collector relative to direct sulfidation. FESEM-EDS and AFM analysis at pH 9 confirmed that co-activation resulted in the formation of denser, cloud-like layers of PbS and ZnS on the surface. These layers improved flotation efficiency, increased hydrophobicity, and strengthened DDTC interaction, thus promoting flotation. Additionally, ToF-SIMS and EPMA analyses indicated higher Pb⁺ and S⁻ intensities in the co-activation system, confirming enhanced surface reactivity and substantiating the increased activity and diversity of sulfidation products. This study offers an effective approach to enhancing smithsonite flotation recovery by optimizing surface chemistry and collector attachment.
H. Haeri; A. R Khaloo; K. Shahriar; M. Fatehi Marji; P. Moaref vand
Abstract
In this work, the mechanism for fracture of brittle substances such as rocks under a uniform normal tension is considered. The oriented straight micro-cracks are mostly created in all the polycrystalline materials resulting from the stress concentrations. The present work focuses on the interactions ...
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In this work, the mechanism for fracture of brittle substances such as rocks under a uniform normal tension is considered. The oriented straight micro-cracks are mostly created in all the polycrystalline materials resulting from the stress concentrations. The present work focuses on the interactions of the pre-existing micro-cracks, which can grow and propagate within a rock-like specimen. The micro-crack initiation and propagation in rock-like specimens is investigated using the Fortran Code TDDCRACK2D, which is a 2D displacement discontinuity method (DDM) for crack analysis, a boundary element computer code based on the linear elastic fracture mechanics (LEFM) theory. In the present work, a higher order DDM is used to implement special crack tip elements for estimation of the stress intensity factors (SIFs) and crack initiation angles for the wing-crack problems initiated at different angles from the original micro-crack tips in an infinite specimen under a uniform tension.
C. Bempah; H-J. Voigt; A. Ewusi
Abstract
The focus of this research work is on the determination of the impact of mining on the groundwater quality in the historical mining region of SW Ashanti region in Ghana. This work describes the characteristics of the groundwater chemistry and pollution of the aquifer in the gold-ore bearing formation, ...
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The focus of this research work is on the determination of the impact of mining on the groundwater quality in the historical mining region of SW Ashanti region in Ghana. This work describes the characteristics of the groundwater chemistry and pollution of the aquifer in the gold-ore bearing formation, which is highly weathered and fractured. The fractures control the permeability and depth of the groundwater within the studied area. The concentrations of the major ions and trace elements (As, Fe, Cu, Mn, and Zn) present are determined in 63 groundwater wells at dry and wet seasons. The results obtained showed that the concentrations of these ions and elements were below the World Health Organization (WHO) guideline values for drinking water. However, concentrations of the As and Fe ions were very high above the guideline values. The wells with high As and Fe concentration levels might be located at an apparent rock fractured zone that extends to a nearby mine. Such fractured zones allow groundwater to move more rapidly away from a mine, creating more severe mine-drainage pollution in their paths. The results obtained from this study suggested a possible risk to the population of the studied area, given the toxicities of the As and Fe ions, and the fact that for many people living in the studied area, groundwater is a main source of their water supply.
A. Khojamli; F. Doulati Ardejani; A. Moradzadeh; A. Nejati Kalateh; A. Roshandel Kahoo; S. Porkhial
Abstract
The Ardabil geothermal area is located in the northwest of Iran, which hosts several hot springs. It is situated mostly around the Sabalan Mountain. The Sabalan geothermal area is now under investigation for the geothermal electric power generation. It is characterized by its high thermal gradient and ...
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The Ardabil geothermal area is located in the northwest of Iran, which hosts several hot springs. It is situated mostly around the Sabalan Mountain. The Sabalan geothermal area is now under investigation for the geothermal electric power generation. It is characterized by its high thermal gradient and high heat flow. In this study, our aim is to determine the fractal parameter and top and bottom depths of the magnetic sources. A modified spectral analysis technique named “de-fractal spectral depth method” is developed and used to estimate the top and bottom depths of the magnetized layer. A mathematical relationship is used between the observed power spectrum (due to fractal magnetization) and an equivalent random magnetization power spectrum. The de-fractal approach removes the effect of fractal magnetization from the observed power spectrum, and estimates the parameters of the depth to top and depth to bottom of the magnetized layer using the iterative forward modelling of the power spectrum. This approach is applied to the aeromagnetic data of the Ardebil province. The results obtained indicated variable magnetic bottom depths ranging from 10.4 km in the northwest of Sabalan to about 21.1 km in the north of the studied area. In addition, the fractal parameter was found to vary from 3.7 to 4.5 within the studied area.
Mineral Processing
A. Eskanlou; M. R. Khalesi; M. Abdollahy; M. Hemmati Chegeni
Abstract
The success of flotation operation depends upon the thriving interactions of chemical and physical variables. In this work, the effects of particle size, bubble size, and collector dosage on the bubble loading in a continuous flotation column were investigated. In other words, this work was mainly concerned ...
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The success of flotation operation depends upon the thriving interactions of chemical and physical variables. In this work, the effects of particle size, bubble size, and collector dosage on the bubble loading in a continuous flotation column were investigated. In other words, this work was mainly concerned with the evaluation of the true flotation response to the changes in the operating variables in column flotation. Two bubble sizes of 0.8 and 1.8 mm, three size fractions of 63-106, 106-150, and 150-300 μm, and three different dosages of dodecylamine, as the collector, were tested. According to the results obtained, the particle size fraction of 106-150 μm had the maximum bubble loading for bubble diameter of 1.8 mm, while the particle size of 63-106 μm had the maximum bubble loading for bubble diameter of 0.8 mm. It was also shown that increasing the bubble diameter from 0.8 to 1.8 mm increased the bubble loading in all the particle size fractions and collector dosages. However, the mass loading of air bubbles was strongly related to the collector dosage (contact angle), especially for coarse particles. The amount of collector dosage had an upper limit due to the clustering event, which significantly affected the bubble loading. The clustering was found to be more important in the presence of small particles due to a higher number of particles attached to the bubble surface. It was shown that such interactions of variables of true flotation could reasonably be monitored by the bubble loading measurement.
Seyedeh M. Ehsani; M. Unesi; R. Tamartash
Abstract
Changes in the tailing properties (increasing clay mineral content and fine particles) and poor operation of the dewatering systems have negative impacts on the Tailing Storage Facilities (TSF) of the Shahrbabak copper complex. The design solid concentration of the thickened tailings is 63 wt.% in the ...
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Changes in the tailing properties (increasing clay mineral content and fine particles) and poor operation of the dewatering systems have negative impacts on the Tailing Storage Facilities (TSF) of the Shahrbabak copper complex. The design solid concentration of the thickened tailings is 63 wt.% in the Shahrbabak paste plant but it is well below the design value right now (approx. 55 wt.%). The aim of this work is to find the effects of the clay mineral and dewatering operations on the water recovery and tailing dam capacity. The understudied samples were taken from the thickener underflow and prepared at the required solid concentrations (55, 60, 65, and 70 wt.%). The results obtained showed that the initial settled density varied from 1.044 to 1.146 t/m3 by increasing the solid concentrations from 55 to 63 wt.%. Furthermore, the shrinkage limit density of the two solid concentrations was recorded at 1.52 and 1.62 t/m3, and the crack volume was estimated at 6.3% and 7.2% of the final sample volume. Also the sub-aerial tailing beach slope in the upper quarter and the remainder of TSF was too low and exhibited 2.0% and 1.0%, respectively. However, it is far from the design values (3.5%, 2.5%, and 1.7% from head of the beach to the end). Thus it is clear that the clay minerals and fine particles hold more water in their inner network and occupy a more TSF volume. Nevertheless, the beach slope can be increased by improving the thickener performance and removing the leakage and other periodic water, although it seems impractical to achieve the design value due to the changes in the tailing properties.
S. Aghababaei; H. Jalalifar; A. Hosseini
Abstract
Providing an approach to calculate a suitable panel width for the longwall mining method is considered considering both the technical and economic factors. Based on the investigations carried out, a technical-economic model is proposed to calculate a suitable panel width. The proposed model is a combination ...
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Providing an approach to calculate a suitable panel width for the longwall mining method is considered considering both the technical and economic factors. Based on the investigations carried out, a technical-economic model is proposed to calculate a suitable panel width. The proposed model is a combination of the rock engineering system-based model and the technical relationships to estimate the expected actual face advance rate of the longwall panel and also the economic relationships to determine the operational costs. Applying the technical conditions to the presented model is conducted by the vulnerability index of the advancing operation, which considers the face advance rate as the main important factor that controls the operational costs of the longwall face. The performance evaluation of the presented model is possible by the recordable field data, which is one of its advantages. This process is carried out by a case study, and the results obtained indicate that the developed approach can provide an applicable tool to calculate a suitable panel width.
