Subjects -> MINES AND MINING INDUSTRY (Total: 82 journals)
 Showing 1 - 42 of 42 Journals sorted alphabetically Applied Earth Science : Transactions of the Institutions of Mining and Metallurgy       (Followers: 4) Archives of Mining Sciences       (Followers: 1) BHM Berg- und Hüttenmännische Monatshefte       (Followers: 1) Canadian Mineralogist       (Followers: 5) CIM Journal Clay Minerals       (Followers: 8) Contributions to Mineralogy and Petrology       (Followers: 11) Environmental Geochemistry and Health       (Followers: 2) European Journal of Mineralogy       (Followers: 12) Extractive Industries and Society       (Followers: 2) Gems & Gemology       (Followers: 1) Geology of Ore Deposits       (Followers: 3) Geomaterials       (Followers: 2) Geotechnical and Geological Engineering       (Followers: 8) Ghana Mining Journal       (Followers: 3) Gold Bulletin International Journal of Coal Geology       (Followers: 2) International Journal of Coal Preparation and Utilization       (Followers: 1) International Journal of Coal Science & Technology       (Followers: 1) International Journal of Hospitality & Tourism Administration       (Followers: 14) International Journal of Minerals, Metallurgy, and Materials       (Followers: 8) International Journal of Mining and Geo-Engineering International Journal of Mining and Mineral Engineering       (Followers: 5) International Journal of Mining Engineering and Mineral Processing       (Followers: 5) International Journal of Mining Science and Technology       (Followers: 4) International Journal of Mining, Reclamation and Environment       (Followers: 4) International Journal of Rock Mechanics and Mining Sciences       (Followers: 6) Journal of Analytical and Numerical Methods in Mining Engineering Journal of Applied Geophysics       (Followers: 15) Journal of Central South University       (Followers: 1) Journal of China Coal Society Journal of Convention & Event Tourism       (Followers: 4) Journal of Geology and Mining Research       (Followers: 11) Journal of Human Resources in Hospitality & Tourism       (Followers: 8) Journal of Materials Research and Technology       (Followers: 2) Journal of Metamorphic Geology       (Followers: 15) Journal of Mining Institute Journal of Mining Science       (Followers: 2) Journal of Quality Assurance in Hospitality & Tourism       (Followers: 5) Journal of Sustainable Mining       (Followers: 2) Journal of the Southern African Institute of Mining and Metallurgy       (Followers: 5) Lithology and Mineral Resources       (Followers: 3) Lithos       (Followers: 9) Mine Water and the Environment       (Followers: 4) Mineral Economics Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy       (Followers: 11) Mineral Processing and Extractive Metallurgy Review       (Followers: 4) Mineralium Deposita       (Followers: 4) Mineralogia       (Followers: 2) Mineralogical Magazine       (Followers: 1) Mineralogy and Petrology       (Followers: 2) Minerals Minerals & Energy - Raw Materials Report Minerals Engineering       (Followers: 9) Mining Engineering       (Followers: 5) Mining Journal       (Followers: 3) Mining Report       (Followers: 2) Mining Technology : Transactions of the Institutions of Mining and Metallurgy       (Followers: 2) Mining, Metallurgy & Exploration Natural Resources & Engineering Natural Resources Research       (Followers: 8) Neues Jahrbuch für Mineralogie - Abhandlungen       (Followers: 1) Physics and Chemistry of Minerals       (Followers: 4) Podzemni Radovi Rangeland Journal       (Followers: 1) Réalités industrielles Resources Policy       (Followers: 4) Reviews in Mineralogy and Geochemistry       (Followers: 4) Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica Rock Mechanics and Rock Engineering       (Followers: 6) Rocks & Minerals       (Followers: 2) Rudarsko-geološko-naftni Zbornik Stainless Steel World       (Followers: 17) Transactions of Nonferrous Metals Society of China       (Followers: 9)
Similar Journals
 Mining, Metallurgy & ExplorationNumber of Followers: 0      Hybrid journal (It can contain Open Access articles) ISSN (Print) 2524-3462 - ISSN (Online) 2524-3470 Published by Springer-Verlag  [2469 journals]
• Fire Size and Response Time Predictions in Underground Coal Mines Using
Neural Networks

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Abstract: Abstract The prediction of the coal mine fire response time, defined as the remaining time before conditions at attack positions grow untenable for firefighters, plays a vital role in the decision-making process during a mine fire scenario. The knowledge of the response time along with the fire size, fire location, and arrival time could allow for the most suitable decision regarding direct or remote approach to the fire in the mine, mine evacuation planning, and remote attack from the surface. For this reason, this paper presents a data-driven approach to predict the response time and fire size based on available and measurable parameters during underground coal mine fires using two interconnected artificial neural networks (ANNs). A total of 300 fire dynamic simulator (FDS) and fire and smoke simulator (FSSIM) simulations of a straight and flat mine entry (replicating a belt entry) with different fire sizes, air velocities, and dimensions were used in training and testing the ANNs. The results showed that 95% of fire size and response time predictions should be within ± 29 kW and ± 4 s of true values obtained in the fire models, respectively. The approach presented in this work can provide instantaneous predictions of response time and fire size during ongoing mine fires. Additionally, this approach can be utilized in other mine fire locations as well as in different types of tunnels.
PubDate: 2022-06-01

• Scaling and Flow Similarity Considerations to Develop a 1/40th Scale
Aerodynamic Model of a Longwall Coal Mine for Methane Hazards
Investigation

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Abstract: Abstract The present work discusses the nuances of scaling and flow similarity to develop a 1/40th scale version of a longwall coal mine. Details on the geometric, kinematic, and dynamic scaling of the physical model are presented and discussed. This works also discusses using a 30% C $${\text{O}}_{2}$$ – 70% He gas mixture as a surrogate for methane. It also presents the implications of various Reynolds numbers (ranging from 7,000 to 140,000) and rotation of the shearer drums in the dynamic representation of the airflow and gas mixtures in the physical scaled model.
PubDate: 2022-06-01

• Numerical Analysis of the Effect of Bedding Plane Strength on
Laminated Roof Failure in Underground Entries Using Coupled FDM-DEM

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Abstract: Abstract Numerical simulations have been used to investigate roof fall in the past decades. When compared to the continuum-based methods, the discrete element method has been well recognized for its excellent performance in simulating large strain problems and the fracturing processes in the rock mass. However, the discrete element method has its limitations. When simulating a large-scale problem, a large number of particles are required, which consumes significant computational resources. In the present study, a 3D numerical model coupled with the finite difference method (FDM) and the discrete element method (DEM) was created to simulate the laminated roof failure in an eastern coal mine in the USA. In the FDM-DEM coupled model, the laminated roof of the entry is represented by an assembly of bonded particles using PFC3D. The laminated roof is simulated by adding parallel discontinuities. The discontinuities are given certain stiffness and strength parameters in the model. The rest of the surrounding rock, including ribs and floor, is represented by continuum zones using FLAC3D. The strength of the discontinuities is varied sequentially and the fracturing of the laminated roof was analyzed with respect to entry advance. The results showed that the laminated roof fractures along the discontinuities, while an intact roof fractures in a dome shape. Increasing the strength of the discontinuity could enlarge the tensile zone inside the laminated roof and hence change the crack distribution. In addition, the number of cracks in the laminated roof behind the advancing face decreases with the increment of discontinuity strength while this trend is not occurring ahead of the advancing face. The simulation demonstrated that the coupled method using PFC3D/FLAC3D can reproduce the laminated roof failure in underground coal mines.
PubDate: 2022-06-01

• Diesel Aerosols in an Underground Coal Mine

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Abstract: Abstract The case study was conducted in an underground coal mine to characterize submicron aerosols at a continuous miner (CM) section, assess the concentrations of diesel aerosols at the longwall (LW) section, and assess the exposures of selected occupations to elemental carbon (EC) and total carbon (TC). The results show that aerosols at the CM sections were a mixture of aerosols freshly generated at the outby portion of the CM section and those generated in the main drifts that supply “fresh air” to the section. The relatively low ambient concentrations and personal exposures of selected occupations suggest that currently applied control strategies and technologies are relatively effective in curtailing exposures to diesel aerosols. Further reductions in EC and TC concentrations and personal exposures to those would be possible by more effective curtailment of emissions from high-emitting light duty (LD) vehicles.
PubDate: 2022-06-01

• Development of Low-cost Smelting Reduction Process Using Cupola Furnace
for Efficient Use of Inferior Grade Manganese Ores and Rejects

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Abstract: Abstract Consumption of manganese ores is increasing day by day mainly due to increased demand of steel products. Low-grade manganese ores and rejects are generated during mining of high-grade resources for production of manganese alloys. These low-grade resources hold significant portion of manganese values as well as creating problems of storage and mining space for mine owners. This study has been carried out to develop a low-cost process to recover values from these kinds of ores using a conventional cupola furnace. Different types of ore blends of 0.5-ton quantity composed of low-grade Mn ore, dolomite, quartz, cast iron and coke were smelted in pilot scale cupola furnace to produce high MnO slag and pig iron. Attempts were made to improve Fe-reduction and separation from MnO-bearing slag by controlling the air flow rate, burden composition, ore agglomeration, pre-reduction, use of different reductants, etc. It was found that developed process is capable to produce slag with MnO: > 35% and Fe (t) < 5% using low-grade Mn ores (Mn: 27.36%; Fe (t): 22.36%; SiO2: 6.75%; Al2O3: 12.36%). The process can achieve Fe reduction between 50 and 70% of total input Fe. Low reduction efficiency is mainly due to low retention time (1–2 h) of liquid slag in the furnace and additional gangue materials contributed by low-grade coke and furnace lining dilutes MnO level in slag. Cupola furnace uses coke (0.3–0.5 ton/ton of ore) as a source of energy and reducing agent which is relatively cheaper than electricity. It is easy to operate and need less capex than the competing technologies to process low-grade ores and rejects to produce synthetic MnO–enriched product which can be used as a cheaper raw material for ferroalloy, battery, and chemical industry. So, the process has shown potential to be further explored using suitably designed cupola (hot blast, etc.) and specifically designed agglomerates to achieve further MnO-enriched products.
PubDate: 2022-06-01

• Stochastic modeling of iron in coal seams using two-point and
multiple-point geostatistics: A case study

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Abstract: Abstract This work addresses the problem of quantifying iron content in a coal deposit in the Republic of Kazakhstan. The process of resource estimation in the mining industry usually involves building geological domains and then estimating the grade of interest within them. In coal deposits, the seam layers usually define the estimation domains. However, the main issue with the coal deposit in this study is that the iron dataset is solely based on data from three newly drilled drill holes located a significant distance apart and additional rock samples from stopes. A massive amount of geological information comes from legacy drill hole data sampled a long time ago, but there is no evidence of proper QA/QC being performed on those samples. For this reason, a workflow was introduced to construct a representative training image from legacy data and stochastically model geological domains within these three drill holes using a multiple-point geostatistics technique. Once the geological model was obtained, a two-point geostatistics algorithm was applied to model the iron inside each geological domain. The results showed that direct sampling (DeeSse) is a suitable multiple-point geostatistics algorithm that can reproduce the long-range connectivity and curvilinear features of seam layers. Furthermore, a sequential Gaussian simulation was used to model the iron in the corresponding domains. Both methods were extensively evaluated using different statistical tools and analyses.
PubDate: 2022-06-01

• Experimental Study of Improving a Mine Ventilation Network Model Using
Continuously Monitored Airflow

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Abstract: Abstract A calibrated and well-tuned ventilation network model plays a critical role in mine ventilation planning, optimization, and ventilation control. Moreover, it is critical to the mine fire simulation program as well since the fire simulation is built upon the mine ventilation model. The contaminants generated from a fire are transported by airflows throughout the mine ventilation system. The accuracy of the fire simulation results not only depends on the fire source model itself but also on the ventilation network model. With the increasing use of atmospheric monitoring systems in underground mines, airflow is continuously monitored using airflow sensors in the key areas of mines to ensure a steady and reliable ventilation. Experimental studies have been conducted at an experimental mine, the Safety Research Coal Mine (SRCM), to gain a better understanding on how to use the continuously monitored airflow data to improve the calibration of the mine ventilation network model. This paper introduces an improved method to calibrate a ventilation network using continuous airflow monitoring and addresses the practical problems encountered while calibrating and tuning the ventilation network of the SRCM using continuously monitored airflow data. In this study, the fluctuation of the air velocity sensor readings is analyzed, and the sensor location correction factors are applied to obtain a more accurate average air velocity for the ventilation network calibration.
PubDate: 2022-06-01

• Stress Redistribution in a Longwall Yield Pillar — a Comparison between
Active Seismic Tomography and Theory

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Abstract: Abstract Gate road yield pillars are subject to increases in stress as the longwall face advances through a panel. Safe, efficient underground mining is dependent upon proper pillar sizing. Theoretical models of pillar loading are well accepted, and geotechnical measurements, including convergence monitoring, have provided important information about stress levels and distributions within pillars. Numerical modeling has developed as a method which complements empirical and theoretical pillar behavior concepts, and allows prediction of the behavior of various pillar sizes under changing conditions. Seismic tomography has seen fairly limited application in the mining industry, but has potential to be a valuable method to further improve understanding of coal pillar performance under changing loading conditions. This research presents a case study from a longwall mine in the western USA. A two-entry gate road yield pillar in the headgate of the mine was instrumented with seismometers and convergence monitoring stations, and was monitored over a period of about 6 months as the longwall face approached the pillar. In this paper, the stress distribution imaged using seismic tomography is compared to the stress distribution expected from theoretical models, geotechnical measurements, and numerical models. The tomography results generally agree with those proposed by theory, convergence measurements, and numerical modeling results. The agreement of the methods provides validation for the theorized stress redistribution, and this study provides further evidence that tomography can indicate the redistribution of induced stress within a mined rockmass and is another tool available to ensure that mining is conducted safely and efficiently.
PubDate: 2022-06-01

• Study on Optimization of Stope Structure Parameters for Steeply Inclined
Medium-thick Broken Ore Bodies

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Abstract: Abstract Broken rock mass and unreasonable stope structure parameters can cause excessive ore loss and dilution in sublevel caving; this is the main problem faced by caving mining in recent years. This paper proposes a stope structure parameter optimization method suitable for steeply inclined medium-thick broken ore bodies and evaluates the reliability and effectiveness through case studies. To solve the problem of large ore loss and dilution in the high-end wall sublevel caving method of Xilinhot fluorite mine, it is necessary to select proper stope structure parameters. Based on the theory of random media, an end-wall ore drawing experiment was carried out, and the bulk flow parameters needed to optimization of stope structure parameters were determined. In the experiment, it was found the draw-out body of high-end wall ore drawing showed a fine top and a thick bottom; the granular media had good fluidity. The reasonable caving step is determined to be 1.2 m instead of the 1.6 m originally used. Through the optimization experiment of the mining route position along the vein, the study found that the best route position is different with the ore body inclination. When the inclination angle of the ore body was 90°, the reasonable route was located in the center of the ore body. When the inclination angle of the ore body was between 85° and 90°, the route moved from the center of the ore body to the footwall at a rate of 22.5%. When the inclination angle of the ore body was between 80° and 85°, the route moved to the footwall at a rate of 54.8%. When the inclination angle of the ore body is not greater than 80°, the route should be arranged on the boundary of the footwall. Field application results showed the dilution rate reduced by 7.66% and the recovery rate increased by 7.31%. Field test results verify the effectiveness and applicability of the optimized stope structure, which corroborates the effectiveness and applicability of the optimized stope structure.
PubDate: 2022-06-01

• A Process Mineralogy Approach to the Flotation of Complex Lead–Zinc Ores
from Görgü (Malatya) Region

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Abstract: Abstract Complex and non-sulfide lead–zinc ores are difficult to concentrate, but the growing demand for lead and zinc metals necessitated their beneficiation. Froth flotation is practically the most effective method in their beneficiation when optimum flotation conditions are attained. The aim of the current study is to use process mineralogy as a tool to understand the flotation behavior of these complex lead–zinc ores. The ore samples were characterized by element, XRD, MLA, thin section, and polished section mineralogical analysis, which clearly demonstrated oxidation and carbonation of the primary minerals. In the rougher flotation stage, a lead concentrate with 17.29% Pb and a zinc concentrate with 9.89% Zn could be obtained by 76.71% lead and 15.49% zinc recoveries from the ore samples containing 7.84% Zn and 4.54% Pb. The flotation results were delineated by process mineralogy data and poor results were explained in terms of (i) complex nature of the ore and similarity in the surfaces of different mineral particles, (ii) poly-metallic occurrence and spatial distribution of elements, (iii) poor liberation of particles, and (iv) lack of hydrophobicity on particle surfaces.
PubDate: 2022-06-01

• Numerical Evaluation on Stress and Permeability Evolution of Overlying
Coal Seams for Gas Drainage and Gas Disaster Elimination in Protective
Layer Mining

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Abstract: Abstract Coalbed methane development is an important way to effectively utilize clean energy and reduce carbon dioxide and other gas emissions. However, due to the low permeability of coal seams, the development of coalbed methane in China has encountered great difficulties. Protective layer mining can efficiently minimize in situ stress and increase coal seam permeability, thus improving the gas drainage and eliminating the gas disaster. This study analyzed the characteristics of gas migration and the change in permeability during in situ stress releasing process through experiments and numerical simulation to study the gas drainage effect of a coal mine in an unloaded coal seam under specific geological conditions. First, a stress–strain-seepage coupled test of coal is carried out, and the evolution features of coal permeability during stress loading and unloading processes are investigated. Second, experimental results are used to develop a mathematical model of coal seepage under mining unloading conditions. Finally, a numerical model is developed based on the real geological conditions of the Wulan coal mine to explore the characteristics of in situ stress release and permeability evolution, as well as the gas drainage process in an unloaded coal seam. Combining protective layer mining and gas drainage technology, the risk of gas outburst is significantly eliminated.
PubDate: 2022-06-01

• Respirable dust constituents and particle size: a case study in a
thin-seam coal mine

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Abstract: Abstract This paper presents a case study of respirable dust characterization in a thin-seam coal mine in southern WV. Samples were collected in the intake, near the feeder breaker, and downwind of an active roof bolter, as well as in three downwind locations from the continuous miner during four separate cuts. The dust was analyzed using: scanning electron microscopy with energy-dispersive X-ray (SEM–EDX) to estimate particle size and mineralogy distributions; thermogravimetric analysis (TGA) to estimate coal, non-carbonate, and carbonate mass fractions; and Fourier transform-infrared (FT-IR) spectroscopy to estimate quartz and kaolinite mass content. SEM–EDX results were generally consistent with those obtained in previous studies of other central Appalachian mines, including presence of relatively high non-carbonate minerals content (primarily aluminosilicates and silica) associated with the rock strata encountered in the mine. Downwind of the miner, fine aluminosilicate particles were particularly abundant and apparently influenced the SEM–EDX analysis for some samples, resulting in underestimation of coal content relative to TGA. Comparison of the microscopy results to those from the TGA and FT-IR indicates some interference between aluminosilicates and coal dust is simply due to high sample loading—however, presence of coal-mineral micro-agglomerates is also indicated.
PubDate: 2022-05-05

• Hot Surface Ignition of Liquid Fuels Under Ventilation

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Abstract: Abstract Mine equipment fires remain as one of the most concerning safety issues in the mining industry, and most equipment fires were caused by hot surface ignitions. Detailed experimental investigations were conducted at the NIOSH Pittsburgh Mining Research Division on hot surface ignition of liquid fuels under ventilation in a mining environment. Three types of metal surface materials (stainless steel, cast iron, carbon steel), three types of liquids (diesel fuel, hydraulic fluid, engine oil), four air ventilation speeds (0, 0.5, 1.5, 3 m/s) were used to study the hot surface ignition probability under these conditions. Visual observation and thermocouples attached on the metal surface were used to indicate the hot surface ignition from the measured temperatures. Results show that the type of metal has a noticeable effect on the hot surface ignition, while ventilation speed has a mixed influence on ignition. Different types of liquid fuels also show different ranges of ignition temperatures. Results from this work can be used to help understand equipment mine fires and develop mitigation strategies.
PubDate: 2022-05-04

• Flow Characteristics of Fresh Cemented Paste Backfill Containing
Flocculant under Variable Shear Rate Based on Water Migration

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Abstract: Abstract The flocculant used in tailing thickening and shearing action in fresh cemented paste backfill (CPB) pipeline transportation will affect the different water distribution characteristics in fresh CPB. This study explores the influence of water migration on the fluidity of fresh CPB. A series of tests (nuclear magnetic resonance, variable shear rate, rheological, and scanning electron microscope) were conducted on fresh CPB with and without flocculant. The results indicated that: fresh CPB exhibited three relaxation peaks, corresponding to adsorbed water, floc water, and free water. As the shear rate increased from 10 to 50s-1, the water content gradually decreased and migrated to more stable water. The addition of APAM further improved water migration and increased the shear stress and apparent viscosity of fresh CPB. Moreover, as the shear rate increased, the structure coefficient of the microstructure of fresh CPB decreased, and the structure coefficient of fresh CPB with flocculant was higher than that of fresh CPB without flocculant. According to the test results, the sum of the floc water and free water content was defined as quasi-active water, and the shear stress, apparent viscosity, and quasi-active water were exponential and linear functions, respectively. For the pipeline transportation of fresh CPB with flocculant, the shear rate should be >30 s−1, and the shear rate corresponding to the balance of quasi-active water should be selected as a pipeline transportation parameter. This study provides a new method for the determination of flow characteristics of fresh CPB pipeline transportation and the selection of transportation speed.
PubDate: 2022-05-04

• Performance of New Inorganic Retarding Sealing Material for Gas Drainage
Boreholes

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Abstract: Abstract Gas drainage in coal mines plays a fundamental role in preventing coal mine accidents, relieving environmental pollution and utilizing coalbed methane (CBM) resources. Since the quality of borehole sealing technology is the key to efficient gas drainage, it is of great significance to develop a sealing material with excellent performance to ensure the long-term high-efficiency operation of gas drainage boreholes. Based on an analysis and summary of currently available research findings, the idea of sealing boreholes with liquid materials was proposed in this study. Firstly, the new inorganic retarding sealing material was briefly introduced, and its properties were tested. Secondly, the self-designed crack grouting test system was applied to test the diffusion performance of the material. The experimental results showed that the new inorganic retarding sealing material was characterized by great stability, thermal stability, fluidity, and thixotropy. The flow and diffusion of selected grout with different water-cement ratios in cracks under different conditions provided guidance for the selection of grouting pressure and the judgment of grouting diffusion distance for on-site grouting. Through the field test of Chengjiao Coal Mine, the effect of sealing is significantly improved compared with traditional materials.
PubDate: 2022-05-01

• Estimation of Optimum Line of Extraction for Continuous Miner Workings and
Development of Continuous Miner Stability Index (CMSI) using 3D Numerical
Modeling and Statistical Approach

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Abstract: Abstract The continuous miner method is the emerging extraction technology for mining the deep-seated coal seams with low investment. This technology is used for the development and depillaring of the pillars/panels in the form of slices and ribs. During the depillaring of coal pillars, the stress and strain development will be higher on the workings, and the ribs and snooks deteriorate and may fail after just extraction. This condition of the workings depends on the line of extraction, either a diagonal line or a straight line. Field experience also concludes that a straight line along a dip-rise direction will be a favorable method compared to diagonal line extraction since it ensures fast rate of extraction. It is an imperative that the optimum line of extraction technique must be required to create safe workings and extract the coal panels safely. Hence, in this study, three emerging lines of extraction techniques, such as diagonal line, straight line along strike, and dip-rise directions, are taken for detailed stability analysis considering three different stages in each technique. Results of numerical investigation also concluded that the straight line along dip-rise extraction technique may have more stability than other techniques. Therefore, this technique is considered optimal to exploit the coal from a deeper depth. In addition, a sensitivity analysis is undertaken by varying mining depth, working stages, and mining height, and a continuous miner stability index is developed to forecast the stability of the underground workings of similar geo-mining conditions using statistical techniques.
PubDate: 2022-04-28

• The Extraction of Silica from Nickel Laterite Ore by Alkaline Hydrothermal
Process

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Abstract: Abstract Silica was extracted from nickel laterite ore by hydrothermal process with sodium hydroxide as reaction assistant. The effects of reaction temperature, reaction time, and NaOH-to-ore mole ratio on the extraction rate of silica were investigated by a single-factor experiment. The optimal reaction conditions for the preparation of silica were obtained as follows: reaction temperature 250 °C, reaction time 2 h, NaOH-to-ore mole ratio 1.2:1. Under these conditions, the extraction rate of silica could reach more than 98%. The orthogonal experiment was used to investigate the main and secondary effects of each reaction condition on the extraction rate of silica. The results showed that the mole ratio of NaOH-to-ore was the most important factor affecting the extraction rate of silica, followed by reaction temperature and reaction time. XRD, SEM, and EDS were used to analyze the nickel laterite ore and the residue after reaction. The results show that the mechanism of extracting silica by this process is the Si in lizardite (Mg3Si2O5(OH)4) and uncombined quartz (SiO2) react with sodium hydroxide and enter into the leachate in the form of sodium silicate solution, and Mg, Fe, Ni, and other metal elements are enriched in the residue.
PubDate: 2022-04-21

• A Novel Approach for Separation and Recovery of Titanium, Scandium, Iron
from Acidic Wastewater and Red Gypsum Utilization

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Abstract: Abstract At present, acidic wastewater is directly neutralized with lime or limestone, which wastes resources such as titanium, scandium, and iron and generates a great deal of solid waste. This study proposes a novel approach for the separation and recovery of titanium, scandium, and iron from acidic wastewater and red gypsum utilization. The recovery efficiency of titanium in acidic wastewater was 97.59% under the molar ratio of titanium dioxide to phosphoric acid of 1:2.2, the reaction temperature of 85 °C, and the reaction time of 45 min. The scandium in the filtrate after the recovery of titanium can be finely extracted with P507, and 99.79% scandium can be extracted by single-stage extraction under the P507 concentration of 15%, the phase ratio (O/A) of 1:13, and extraction time of 6 min. In addition, the process of extracting scandium with P507 is an exothermic reaction by thermodynamic analysis. The raffinate after extracting scandium can be used for leaching red gypsum. As a result, calcium sulfate with a purity of 98.34% and whiteness of 94.27% was obtained under the leaching temperature of 60℃, the leaching time of 30 min, and the ratio of raffinate volume to red gypsum mass (L/S) of 3.5:1. Subsequently, the 97.64% iron in the leaching solution was recovered by the ammonium jarosite precipitation process, and ammonium sulfate with a purity of 99.65% can be obtained. The process can competently be applied to recover titanium, scandium, and iron in acidic wastewater and resource treatment of red gypsum.
PubDate: 2022-04-21

• Study on Roadway Fault Diagnosis of the Mine Ventilation System Based on
Improved SVM

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Abstract: Abstract Reliable and stable mine monitoring systems are efficient tools for preventing mine accidents. Roadway faults due to deformation, destruction, or damper situation transformation can cause changes in airflow resistance. The airflow quantities of other branches also change. This phenomenon is called ventilation system failure. It is of great significance to determine the network topology location of ventilation system failure according to the changes in air volume perceived by the wind speed sensor. This paper proposes a method of building a sensitivity 0–1 matrix by improving the sensitivity matrix and then establishing a roadway faulty scope library. Taking the Daming coal mine as the experimental object, the improved SVM method was applied to diagnose the fault location in the roadway fault scope library. The experimental results demonstrate that: the improved method is effective and feasible for fault diagnosis of the mine ventilation system. After the fault roadway scope library is established, the sample training time is shortened by 66.5%, and the fault location diagnosis accuracy rate is increased by 13.95%. The proposed method has the best performance in ACU, F1, and G-mean. The research results can provide the theoretical basis and implementation technology for intelligent mine ventilation.
PubDate: 2022-04-18

• Experimental Assessment of an Analytical Model of the Convective Heat
Transfer Coefficient in a Mine Gallery

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Abstract: Abstract This article evaluates the convective heat transfer coefficient of ventilation air in a potash mine in Catalonia (Spain). Through thermal characterization of ventilation air and rock of a gallery in the selected potash mine, the energy balance is obtained, and the parameters involved in the heat transfer process are calculated. With these parameters as a starting point, different models are analyzed to calculate the convective heat transfer coefficient. The results indicate that the optimal models to apply in this mine include the Pethukov–Kirilov, Gnielinski and modified Dittus–Boelter models. Moreover, the conductivity of the adjacent rock is indirectly studied, and it is deduced that throughout the studied section, the adjacent rock is saturated, and in Sect. 6–5 of the gallery, there occurs upwelling of liquid water.
PubDate: 2022-04-07

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