Subjects -> MINES AND MINING INDUSTRY (Total: 82 journals)
Showing 1 - 42 of 42 Journals sorted by number of followers
Stainless Steel World     Full-text available via subscription   (Followers: 18)
Journal of Applied Geophysics     Hybrid Journal   (Followers: 16)
Journal of Metamorphic Geology     Hybrid Journal   (Followers: 15)
International Journal of Hospitality & Tourism Administration     Hybrid Journal   (Followers: 14)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 12)
Journal of Geology and Mining Research     Open Access   (Followers: 11)
European Journal of Mineralogy     Hybrid Journal   (Followers: 11)
Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 11)
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 10)
Journal of Human Resources in Hospitality & Tourism     Hybrid Journal   (Followers: 9)
Clay Minerals     Hybrid Journal   (Followers: 9)
Minerals Engineering     Hybrid Journal   (Followers: 9)
Lithos     Hybrid Journal   (Followers: 9)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 9)
Natural Resources Research     Hybrid Journal   (Followers: 8)
Geotechnical and Geological Engineering     Hybrid Journal   (Followers: 8)
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 7)
International Journal of Mining Engineering and Mineral Processing     Open Access   (Followers: 6)
International Journal of Rock Mechanics and Mining Sciences     Hybrid Journal   (Followers: 6)
Journal of Quality Assurance in Hospitality & Tourism     Hybrid Journal   (Followers: 5)
Mine Water and the Environment     Hybrid Journal   (Followers: 5)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
International Journal of Mining and Mineral Engineering     Hybrid Journal   (Followers: 5)
Journal of the Southern African Institute of Mining and Metallurgy     Open Access   (Followers: 5)
Mining Engineering     Full-text available via subscription   (Followers: 5)
Applied Earth Science : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 5)
Resources Policy     Hybrid Journal   (Followers: 4)
International Journal of Mining Science and Technology     Open Access   (Followers: 4)
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 4)
Mineral Processing and Extractive Metallurgy Review     Hybrid Journal   (Followers: 4)
International Journal of Mining, Reclamation and Environment     Hybrid Journal   (Followers: 4)
Physics and Chemistry of Minerals     Hybrid Journal   (Followers: 4)
Mineralium Deposita     Hybrid Journal   (Followers: 4)
International Journal of Coal Geology     Hybrid Journal   (Followers: 4)
Journal of Convention & Event Tourism     Hybrid Journal   (Followers: 4)
Geology of Ore Deposits     Hybrid Journal   (Followers: 4)
Mineralogy and Petrology     Hybrid Journal   (Followers: 3)
Rocks & Minerals     Hybrid Journal   (Followers: 3)
Journal of Sustainable Mining     Open Access   (Followers: 3)
International Journal of Coal Science & Technology     Open Access   (Followers: 3)
Lithology and Mineral Resources     Hybrid Journal   (Followers: 3)
Ghana Mining Journal     Full-text available via subscription   (Followers: 3)
Mining Journal     Full-text available via subscription   (Followers: 3)
Journal of Materials Research and Technology     Open Access   (Followers: 2)
Archives of Mining Sciences     Open Access   (Followers: 2)
Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (Followers: 2)
Mining Report     Hybrid Journal   (Followers: 2)
Mining Technology : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 2)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 2)
International Journal of Coal Preparation and Utilization     Hybrid Journal   (Followers: 2)
Mineralogia     Open Access   (Followers: 2)
Geomaterials     Open Access   (Followers: 2)
Journal of Mining Science     Hybrid Journal   (Followers: 2)
Extractive Industries and Society     Hybrid Journal   (Followers: 2)
Journal of Analytical and Numerical Methods in Mining Engineering     Open Access   (Followers: 2)
BHM Berg- und Hüttenmännische Monatshefte     Hybrid Journal   (Followers: 2)
CIM Journal     Hybrid Journal   (Followers: 1)
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access   (Followers: 1)
Gems & Gemology     Full-text available via subscription   (Followers: 1)
Mineralogical Magazine     Hybrid Journal   (Followers: 1)
Rangeland Journal     Hybrid Journal   (Followers: 1)
Journal of Central South University     Hybrid Journal   (Followers: 1)
Natural Resources & Engineering     Hybrid Journal  
Mining, Metallurgy & Exploration     Hybrid Journal  
Podzemni Radovi     Open Access  
Rudarsko-geološko-naftni Zbornik     Open Access  
Journal of Mining Institute     Open Access  
International Journal of Mining and Geo-Engineering     Open Access  
Journal of China Coal Society     Open Access  
Réalités industrielles     Full-text available via subscription  
Mineral Economics     Hybrid Journal  
Minerals     Open Access  
Gold Bulletin     Hybrid Journal  
Minerals & Energy - Raw Materials Report     Hybrid Journal  
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Mining, Metallurgy & Exploration
Number of Followers: 0  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 2524-3462 - ISSN (Online) 2524-3470
Published by Springer-Verlag Homepage  [2469 journals]
  • Dewatering of Mine Waste Using Geotextile Tubes

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      Abstract: Abstract This study proposes a methodology for dewatering of mine waste using a multistage process, combining geotextile tubes and anionic polyacrylamide (PAM), which accelerates the recycling process of water for aggregate mine waste facilities. For this purpose, waste from a rock quarry located in Istanbul was investigated. Flocculation tests revealed that the use of anionic PAM at an optimum dosage reduced sedimentation time and decreased turbidity. The compatibility of geotextiles and mine waste conditioned with different dosages of the effective PAM was evaluated by rapid dewatering tests, considering the water content of the filter cake, amount of infiltrated solid content, and rate of filtration. Geotextile dewatering tests were also performed on PAM-free and conditioned suspensions. The dewatering process was optimized by the use of a geotextile tube in two stages: (i) on the unconditioned suspension and (ii) on recovered PAM-conditioned leachate. Directing PAM-free non-hazardous soil-based material obtained in stage i to alternative beneficial uses is suggested, to minimize the volume of waste. Furthermore, recycling of the effluent obtained at the second stage of the proposed method will ensure more efficient water reuse
      PubDate: 2022-09-29
       
  • Evaluation of Parameters Influencing Potential Gas Flow to the Mine in the
           Event of a Nearby Unconventional Shale Gas Well Casing Breach

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      Abstract: Abstract The integrity of unconventional shale gas well casings positioned in the abutment pillar of a longwall mine could be jeopardized by longwall-induced deformations. Under such scenarios, the surrounding fracture networks could provide pathways for gas flow into the mine creating safety concerns. To provide recommendations for developing guidelines that ensure a safe co-existence of longwall mining and unconventional shale gas production, this study evaluates the impact of parameters that could affect potential shale gas flow into the mine in the event of a casing breach using a discrete fracture network (DFN) model. These parameters are evaluated using a conceptualized DFN realization that is representative of the fractured zone in the overburden, and the range of parameter variations is within values validated with field measurements. The results show that a decrease in fracture aperture (potentially due to longwall-induced stress in the likely vicinity of the breach location) reduces the potential gas flow to the mine by a significantly higher proportion. A 50% decrease in the aperture of the fracture that directly transports the gas from the casing breach location reduces the gas flow to the mine by over 70%. Similarly, changes in the fracture water saturation level significantly affect the gas flow. In all cases, the potential gas flow to the mine is higher if the casing breach occurs at an increased gas well pressure. These findings provide critical information regarding the impact of each of the parameters associated with gas flow in the event of a shale gas casing breach near a longwall mine and could help towards the development of guidelines to ensure a safe coexistence of both industries.
      PubDate: 2022-09-28
       
  • Selective Process Route to Recover Magnetite from Chalcopyrite Dam Copper
           Flotation Tailings

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      Abstract: Copper mine operations consistently generate a large quantity of tailings after their concentration processing. These tailings are either piled up or stored in a dam, where both alternatives of disposal lead to environmental impacts. The dam copper tailings have a huge potential for by-product production thus improving sustainability and profitability in industrial operations. This paper describes a study aiming at producing a magnetite pellet feed as a by-product from a dam chalcopyrite flotation tailings and generating free magnetite non-magnetic rougher tailings. The chemical assay and mineralogy analysis of dam copper flotation tailings indicate low Fe grade (6.34 wt%), high SiO2 grade (63.14 wt%), low magnetite (3.6 wt%), and high iron silicates content (22.72 wt%). The complex mineralogy of these tailings leads to the need of grinding the rougher magnetite pellet feed as fine as 80% of particles smaller than 20 µm (P80) aiming at improving magnetite liberation. The proposed process route comprises a scalping screen, low field rougher, and cleaner magnetic separations using a drum magnetic separator (80 kA/m or 1000 Gauss), followed by silicates reverse cationic flotation as a recleaner step. With this process route, it was possible to produce a high-quality magnetite pellet feed reaching 68.00 wt% of Fe, 2.13 wt% of SiO2, 0.51 wt% of Al2O3, and 95.1 wt% of magnetite. The Blaine specific surface area was 2300 cm2/g, being in the range recommended for pelletizing (1900 up to 3000 cm2/g). The total mass, Fe, SiO2, Al2O3, and magnetite recoveries were 2.77%, 29.71%, 0.09%, 0.12%, and 73.17%, respectively. Most of the magnetite losses, around 20% of total magnetite fed, occurred in the oversize of the scalping screen. Additionally, it generated non-magnetic rougher tailings with less than 1.0 wt% of magnetite that could be used as by-products and reduced the amount of tailings disposal in a dam. This study contributes toward the sustainability of operation, minimizing tailings disposal. Graphical Block diagram of process route to generate magnetite pellet feed from dam copper flotation tailings.
      PubDate: 2022-09-28
       
  • Long-Distance Advanced Pre-grouting Layer Flexible Reinforcement Mechanism
           and Its Application in Large Mining Height Coal Face

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      Abstract: Abstract In terms of the technical problems of rib spalling in large mining height coal face, a long-distance advanced pre-grouting layer flexible reinforcement technology is proposed in this paper. Based on the mechanism and failure mode of rib spalling in the coal face, the mechanical properties of the aluminum plastic composite pipe were analyzed by using the tensile and compression experiment. The deformation and strength characteristics of “flexible pipe + grouting” specimens were studied by uniaxial compression test, splitting test, and shear test. The UDEC numerical simulation software was used to simulate the reinforcement effect of “flexible pipe + grouting” at different positions. Combined with the field application, the feasibility of long-distance advanced pre-grouting layer flexible reinforcement technology was verified. The test results show the following: The coal face has the characteristics of brittle and large deformation. The aluminum plastic composite pipe has the characteristics of good elongation and tensile strength, which can endure the large deformation of the coal face. The “flexible pipe + grouting” can improve the tensile and shear strength of coal. The UDEC numerical simulation analysis indicated that the grouting hole layout of “flexible pipe + grouting” has a significant difference in the reinforcement effect of the coal face. Compared with single row grouting reinforcement, the reinforcement effect of double row grouting holes 1.5 m and 3.0 m away from the roof is better. According to the field application, it is feasible to use aluminum plastic composite pipe as a flexible grouting pipe to reinforce coal seam with 80–100 m long-distance pre-grouting. Long-distance advanced pre-grouting layer flexible reinforcement technology can improve the daily production of coal and reduce the support cost of the coal face. As a new method of reinforcement, long-distance layered flexible reinforcement has a significant effect on the prevention and treatment of rib spalling in large mining height coal face.
      PubDate: 2022-09-27
       
  • Evaluation on Underground Refuge Alternatives and Explosion Survivability:
           a Review

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      Abstract: Abstract Underground mining environments bring occupational health and safety issues with some severe dangers such as mine disasters like explosions. During such events, miners might escape using main access openings, or find a safe haven like refuge alternatives (RAs) to wait and be rescued and evacuated to the surface. In this paper, RAs are explained with their early and current applications. A classification as permanent and portable is explained depending on the conditions and their abilities. This classification is followed by the utilization and survivability of RAs with the requirements and recommendations of the main mining countries. Based on the utilization and survivability constraints, basic human requirements, waiting for a rescue team, and the required physical specifications of RAs during the events are analyzed in detail for various countries with their regulations. Among these, the specification, resistance to the explosion, is discussed in particular, and the studies in the literature are examined in terms of structural deformation. The highest deformed zones, the beneficiation of reinforcing steel components such as stiffeners, and the simulation approaches are investigated through this review.
      PubDate: 2022-09-24
       
  • Stochastic Continuous Modeling for Pillar Stress Estimation and Comparison
           with 2D Numerical, and Analytical Solutions in an Underground Stone Mine

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      Abstract: Abstract Pillar collapses are events that due to their severe consequences can be classified as high risk. The design of pillars in underground room-and-pillar operations should migrate to risk-based design approaches. The authors of this work proposed a risk-based pillar design methodology that integrates stochastic discrete element modeling for pillar strength estimation, and stochastic finite volume modeling (FVM) for stress estimation. This paper focuses on the stochastic FVM component for stress estimation. The mining and geomechanical aspects of a case study mine (CSM) are described and pillar stresses are estimated by using three approaches: (1) analytical solutions, (2) 2D finite element modeling, and (3) 3D finite volume modeling. This operation extracts a 30° dipping deposit, which makes current underground stone mine design guidelines inapplicable for this CSM. This work compares results from each stress estimation approach and discusses uses the point estimate method as a simplified stochastic approach to evaluate the effect of rock mass elastic properties variability on pillar stress distribution. Results from this work show that the three estimation approaches lead to different estimations, possibly, due to the wide range of assumptions each estimation approach considers. It was also determined that the horizontal to vertical stress ratio has a significant impact on pillar stress magnitude. Therefore, it is recommended to perform in situ stress measurements, or assume worst-case-scenario values to account and reduce uncertainty due to this parameter. The stochastic stress estimation approach used in this paper provides results that can integrate a risk-based pillar design framework.
      PubDate: 2022-09-24
       
  • Aeromagnetic and Radiometric Data Interpretation to Delineate the
           Structural Elements and Probable Precambrian Mineralization Zones: a Case
           Study, Egypt

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      Abstract: Abstract This study focused on joint interpretation of the aeromagnetic and radiometric data to allocate and describe the structural elements and mineralization zones such as uranium, gold, and sulfide in the Gebel Umm Tineidba and its surroundings, Eastern Desert, Egypt. The study region is covered by exposures of Precambrian rocks such as gneisses, migmatites, ophiolitic mélange, metavolcanics, younger granites, and Quaternary sedimentary covers. The application of the total intensity magnetic and reduced-to-pole maps, power spectrum, analytic signal, tilt-angle, and local wavenumber maps helps in recognizing magnetic sources distribution, lineament features, and mineral zones delineation. The obtained results indicate that the depths of the deeper NE–SW, NNE–SSW, and N–S trending structures extend from 400 to 1750 m and shallower ones range from 100 to 400 m. Finally, the main trends of these structures affect the probable mineralization zones.
      PubDate: 2022-09-22
       
  • Perceptive Driving Assistant System for Opencast Mines During Foggy
           Weather

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      Abstract: Abstract During harsh weather conditions, the presence of fog, dust in the environment degrades the image’s quality, which affects the visibility of drivers of heavy earth-moving machinery in opencast mines. Due to low visibility, mining operations cannot be carried out as drivers are easily prone to accidents. This paper proposes a technique that includes developing a vision enhancement system called perceptive driving assistant system for increasing visibility of real-time video of the road in front of the vehicle for operators of heavy earth-moving machinery at opencast mines during harsh weather conditions to overcome the problem. The system consists of high-quality Internet Protocol cameras and thermal cameras for real-time image processing and other well-defined devices, which is quite capable of enhancing the visibility of the image, outlining edges of the road, and detecting obstacles present on the path of operators for smooth driving and reducing threat of accidents. A high-speed graphical processing unit has been used for quality-performance parallel computing, which is well suited for real-time operations to empower fast real-time operations. The calculated frame per second (fps) of image enhancement, object detection, and edge detection is 17.91, 15.91, and 25.09 fps, respectively. The actual frame rate is 26.07 fps, and after applying the algorithm, the final frame rate is 19.65 fps. The calculated accuracy of the object detection model is 81.23%. Field trials indicate that the developed system has performed adequately during foggy weather.
      PubDate: 2022-09-21
       
  • Analysis of Steel Prop Supports Subjected to Vertical and Lateral Loading

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      Abstract: Abstract Standing supports have been used in coal mines for decades to enhance roof support capability. Sometimes standing supports are used as a tool to resist the lateral movement of spalled ribs. Researchers from the National Institute for Occupational Safety and Health (NIOSH) are conducting a testing program for different types of standing supports (steel and timber) to investigate the effect of lateral loading on their vertical loading capacities and the factors affecting their lateral loading capacities. In this paper, the mine roof simulator (MRS), at the NIOSH Pittsburgh research facility, was used to determine the response of steel props to vertical and horizontal loadings. Finite element models (FEMs) were developed and verified using the tested steel props. To justify the testing program for testing standing supports with end-conditions of rock-like materials, the verified prop models were used to study the effect of a wide range of roof and floor materials (gray shale, shale, and claystone) on the critical buckling loads of the steel props. Also, several lateral loading scenarios were evaluated in which the steel props were laterally loaded at different heights. The critical buckling load for steel props setting up against a claystone roof and floor was found to be one-half of that shown by the MRS test where roof and floor platens are made of steel. Minimum prop performance was observed when the lateral load was applied at the mid-height of the steel prop, especially at small lateral displacement (less than 2 in).
      PubDate: 2022-09-10
       
  • Optimization of High-grade Fluorspar Recovery from Rare Earth Element
           Carbonatite Deposit Using Column Flotation

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      Abstract: Abstract Fluorite (calcium fluoride—CaF2), also known as fluorspar, is an industrial mineral used in metallurgy, hydrofluoric acid production, and ceramics manufacturing. Based on the results from a previous study, a low-grade fluorspar by-product (20.0% CaF2) originating from the exploitation of a rare earth carbonatite deposit can be improved to 75.4% by combining magnetic separation and acid leaching. The present research aimed to develop and optimize a column flotation process to increase the purity of this fluorspar by-product by removing residual silicate minerals and meeting the requirements for ceramic manufacturing (> 85% CaF2). The optimal flotation conditions required for maximizing the recovery and improving the grade of a fluorspar by-product were identified using a conventional approach combined with a response surface methodology (Box-Behnken design). Optimal fluorspar flotation was achieved under the following conditions: 3.6 g/kg of sodium oleate as the collector, 2 g/kg of sodium silicate as the pH modifier and depressant, a conditioning time of 35 min, a flotation time of 7 min, and a solid-to-liquid ratio (S/L) of the pulp of 5%. Under these conditions, 86.8% fluorspar recovery was achieved, and the grade increased from 76.5% in the feed (metallurgical grade) to 88.6% (ceramic grade) in the final concentrate. The silicon content decreased from 5.66% in the feed to 1.12% in the fluorspar concentrate. Using magnetic separation before the flotation improves the final content of fluorspar in the concentrate with the final grade of 94.4%.
      PubDate: 2022-09-09
       
  • A New Workflow of X-ray CT Image Processing and Data Analysis of
           Structural Features in Rock Using Open-Source Software

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      Abstract: Abstract  X-ray computed tomography (CT) images of rock specimens often contain artifacts which must be corrected before scientific analyses are performed. This paper presents a new workflow of automated image processing to utilize poor-quality X-ray CT scan images. The workflow runs on the open-source image analysis software and efficiently separates desired features from low-contrast scanned images. The new workflow is a two-step technique using contrast enhancement and automated feature segmentation to generate noise-free binary images. The results of binary images using the proposed workflow and using a conventional thresholding technique are analyzed to show the quality of the proposed method. The paper also presents a workflow of estimating the structural geometries of features in two and three dimensions. The results of the structural feature analyses and computational time were compared between the open-source (ImageJ) and commercial image analysis software (Bruker Computed Tomography Analyzer). The commercial software was more computationally efficient, but the task-specific macros in open-source software enabled the user-desired automation in image processing and data extraction of desired structural features of comparable quality.
      PubDate: 2022-09-08
       
  • Machine Learning Prediction of the Load Evolution in Three-Point Bending
           Tests of Marble

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      Abstract: Abstract Three-point bending (TPB) tests were conducted on prismatic Nestos marble (Greece) specimens. The specimens were instrumented with piezoelectric sensors, and comprehensive recordings of acoustic emission (AE) signals were obtained. Machine learning in the form of artificial neural networks (ANNs) was then applied in an effort to investigate whether specimen load evolution can be predicted as a function of AE signals. A number of ANN models were developed, and the optimum model was selected based on the highest coefficient of determination (CoD) value as well as the lowest root mean square error (RMSE) value that was calculated for each model. The best performing ANN model exhibits accuracy above 99% with an RMSE value below 4%. It can be concluded that ANNs can potentially be applied to predict rock behavior under load especially when such loads lead to failure.
      PubDate: 2022-09-07
       
  • Characterization and Iron Removal Enhancement of El-Zaafarana White Sand

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      Abstract: Abstract Iron is a key detrimental impurity in silica sands that determines their contribution to high-technology industries. Herein, a simple ecologically sound approach is investigated for iron removal from a silica sand sample obtained from the El-Zaafarana area-Egypt. The sample was subjected to a detailed microscopic mineralogical study supported by XRD and XRF characterization. The sample was beneficiated using distilled water attrition scrubbing and screening over a 25 μm sieve followed by leaching using a mixture of equal amounts of phosphoric and oxalic acids. Leaching experiments were designed and analyzed using the Box-Behnken design (BBD) methodology. A model was developed and evaluated using the analysis of variance technique to map the relationship between the residual iron oxide in the produced concentrate and selected variables such as leaching temperature, oxalic acid, and phosphoric acid concentrations. XRD and mineralogical analysis reveal that quartz is the most dominant constituent of the studied sand and other minerals such as kaolinite, iron oxide, rutile, and zircon exist in trace amounts. The head sample shows a silica and iron oxide content of 95.69% and 2379 ppm, respectively. Attrition and separation over a 25 μm sieve increase the silica content to 97.05% and decreases the residual iron oxide to 455 ppm. The final product after leaching under optimized conditions shows 99.82% silica and 55 ppm iron oxide.
      PubDate: 2022-08-30
       
  • A Precipitation-Adsorption Technique for the Removal of Fluoride and
           Phosphate in Phosphogypsum: an Economical and Green Method

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      Abstract: Abstract Phosphogypsum (PG) is a by-product of solid waste produced by the phosphate chemical industry. Owing to large emissions and massive storage issues, it causes a potential threat to our environment. Hereby, a method based on the precipitation and crystallization properties of calcium phosphate-magnesium ammonium phosphate (CP-MAP) followed by its adsorption on active solid waste powder is used as the main principle to treat PG harmlessly. The treatment process and its influencing factors for orthogonal experiments along with the associated environmental safety have been studied in detail. The results showed that this method could simultaneously remove soluble phosphorus and soluble fluorine from PG. When ACP, FA, HBM, and Ur were added to PG at a dosage of 3%, 13.5%, 0.04%, and 0.04%, respectively, the residual phosphate and fluoride contents was 0.061 mg/L and 0.856 mg/L respectively in the PG leaching solution. Compared to state-of-the-art approaches, this method exhibited higher efficiency in removing phosphate and fluoride. Most importantly, this method does not cause any secondary pollution in the process, thereby showing a novel application in large-scale industrial treatment.
      PubDate: 2022-08-29
       
  • Kinetic Study of Copper and Cobalt Dissolution from Sulfidic Ores in
           Sulfate–chloride Media

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      Abstract: Abstract This study investigated the operating parameters that affect the kinetic dissolution of copper and cobalt from sulfidic ores. The sulfuric acid concentration, temperature, sodium chloride concentration, particle size range, and leaching time were selected to deduce the kinetic mechanism of the leaching reaction. Other parameters, such as a stirring speed of 250 rpm and the percentage solid 10% w/v, remained constant. The results reveal that an increase in acid concentration enhances the leaching rate of copper and cobalt. Copper and cobalt dissolution was positively affected by the addition of sodium chloride. The highest leaching rates of copper and cobalt were 24.71% and 15.65%, respectively. The chemical control and diffusion control by shrinking core models are well fitted as the kinetic models representing the dissolution of the minerals. The respective activation energies for copper and cobalt dissolution of 10.92 and 31.023 kJ mol−1 for the chemical control and 18.83 and 37.28 kJ mol−1 for diffusion reaction control were established from temperature-based experiments.
      PubDate: 2022-08-26
       
  • Development of a Real-Time Respirable Coal Dust and Silica Dust Monitoring
           Instrument Based on Photoacoustic Spectroscopy

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      Abstract: Abstract We report the first spectral photoacoustic measurements of silica, coal, and kaolinite dust absorption coefficients from 11 to 13 μm at 5 nm resolution made with a tunable quantum cascade laser. This is important because airborne silica dust and coal dust within mining environments continue to be a problem for mine workers and staff due to their severe health effects on the respiratory system, while other dust types are potentially interferents to their detection. Our real-time spectra compare favorably with the non-real-time filter-based Fourier transform infrared spectrometer (FTIR) spectra obtained using the sampling system developed by NIOSH for their end-of-shift method to determine silica dust concentrations using a portable FTIR. We discuss our new dust generation system and instrument testing chamber. We also show that our PM4 silica mass concentration measurements by a low-cost air quality sensor (SPS30) are in good agreement with the TSI Aerosol Particle Sizer instrument, the NIOSH end of shift method, gravimetric mass, and correlate well with photoacoustic light absorption measurements at a wavelength where silica absorbs strongly.
      PubDate: 2022-08-20
       
  • A Numerical Modeling Approach for Assessment of Seepage Characteristics
           and Performance of Protective Water Barrier Pillars in Underground Coal
           Mines

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      Abstract: Abstract  Providing a suitable protective water barrier pillar (PWBP) is common to reduce inundation hazards in underground coal mines. The imperative factors influencing its performance include the water head acting on the pillar, cover depth, pillar width, strength properties, and permeability characteristics. The mechanical failure of such pillar is a stress-controlled phenomenon, whereas the hydraulic failure is a strain-based phenomenon. A finite-difference numerical modeling approach was developed to study the hydro-mechanical coupled behavior of protective water barrier pillars. The mechanical stability was evaluated in terms of the percentage of failed (ZoF) and intact zones. The influence of the strain-controlled weakening on the permeability of the flow medium was studied through the coupling of the mechanical and hydraulic effects. The coupled steady-state model was used to estimate the outflow rate and its hydraulic stability. The adequacy of the protective pillar was also investigated by assessing mechanical stability and capability to resist hydraulic pressure against the maximum expected water head. A seepage rate-based classification system has also been proposed to evaluate the seepage potential and assess the hydraulic stability. The model has been validated for two case studies at the cover depth of 136–189.5 m and the existing pillar width of 16–42 m against the water head of 25–141 m.
      PubDate: 2022-08-18
       
  • Response Surface Method Optimization to Improve Copper Extraction from
           Refractory Copper Oxide Ore

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      Abstract: Abstract In this study, response surface methodology (RSM) and Box-Behnken design to improve copper extraction from refractory copper oxide ore were investigated. Based on single factor tests, quadratic polynomial equation to describe the relationship between influencing factors (particle size, leaching temperature, sulfuric acid concentration, leaching time) and copper leaching rate could be obtained by RSM. The optimum parameters determined by the model are as follows: particle size 64.60% − 74 µm, leaching temperature 74.15 °C, sulfuric acid concentration 0.49 mol/L, and leaching time 140.85 min. Under these conditions, experimental copper leaching rate of 85.12% could be achieved, which was very close to the predicted maximum value (85.34%) by the model, indicating the quadratic polynomial model was accurate and reliable. Copper leaching rate increased approximately by five percentage points comparing to the result of single factor tests. This study indicates that response surface methodology is an effective method to optimize experiment conditions and achieve an ideal experiment result.
      PubDate: 2022-08-17
       
  • Analysis of SLAM-Based Lidar Data Quality Metrics for Geotechnical
           Underground Monitoring

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      Abstract: Abstract Adverse ground behavior events, such as convergence and ground falls, pose critical risks to underground mine safety and productivity. Today, monitoring of such failures is primarily conducted using legacy techniques with low spatial and temporal resolution while exposing workers to hazardous environments. This study assesses the potential of novel simultaneous localization and mapping (SLAM)-based light detection and ranging (Lidar) data quality for rapid, digital, and eventually autonomous mine-wide underground geotechnical monitoring. We derive a comprehensive suite of quality metrics based on tests in two underground mines for two state-of-the-art mobile laser scanning (MLS) systems. Our results provide evidence that SLAM-based MLS provides data of the quality required to detect geotechnically relevant changes while being significantly more efficient for large mine layouts when compared to traditional static systems. Additionally, we show that SLAM-specific processing can achieve an order of magnitude better relative accuracy relevant for change detection than quality metrics derived from traditionally deployed tests would suggest while reducing SLAM drift error by up to 90%. In collaboration with an operating block cave mine, we confirm these capabilities in field tests on a mine-wide scale and, for the first time, demonstrate methods of rockfall detection using MLS data. While more work is required to investigate optimal collection, processing, and utilization of MLS data, we demonstrate its potential to become an effective and widely applicable data source for rapid, accurate, and comprehensive geotechnical inspections.
      PubDate: 2022-08-16
       
  • Investigation of Explosion Hazard in Longwall Coal Mines by Combining CFD
           with a 1/40th-Scale Physical Model

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      Abstract: Abstract To evaluate methane explosion hazards in longwall coal mines, a CFD model was developed along with a 1/40th-scale, optically accessible model of an underground longwall coal mining section. In this project, CFD models assisted in the design of the physical model to ensure specifications were met for accurately representing the scaling physics as well as to assist in narrowing the experimental matrix and identifying key locations for sensor placement to measure velocity, pressure, and gas concentrations. This research will help develop strategies for methane monitoring that prevent methane ignitions and explosions in longwall coal operations.
      PubDate: 2022-08-15
       
 
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