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     Hybrid Journal   (Followers: 4)
Archives of Mining Sciences     Open Access   (Followers: 1)
BHM Berg- und Hüttenmännische Monatshefte     Hybrid Journal   (Followers: 1)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
CIM Journal     Hybrid Journal  
Clay Minerals     Hybrid Journal   (Followers: 8)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 11)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 2)
European Journal of Mineralogy     Hybrid Journal   (Followers: 12)
Extractive Industries and Society     Hybrid Journal   (Followers: 2)
Gems & Gemology     Full-text available via subscription   (Followers: 1)
Geology of Ore Deposits     Hybrid Journal   (Followers: 3)
Geomaterials     Open Access   (Followers: 2)
Geotechnical and Geological Engineering     Hybrid Journal   (Followers: 8)
Ghana Mining Journal     Full-text available via subscription   (Followers: 3)
Gold Bulletin     Hybrid Journal  
International Journal of Coal Geology     Hybrid Journal   (Followers: 2)
International Journal of Coal Preparation and Utilization     Hybrid Journal   (Followers: 1)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Hospitality & Tourism Administration     Hybrid Journal   (Followers: 14)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 8)
International Journal of Mining and Geo-Engineering     Open Access  
International Journal of Mining and Mineral Engineering     Hybrid Journal   (Followers: 5)
International Journal of Mining Engineering and Mineral Processing     Open Access   (Followers: 5)
International Journal of Mining Science and Technology     Open Access   (Followers: 4)
International Journal of Mining, Reclamation and Environment     Hybrid Journal   (Followers: 4)
International Journal of Rock Mechanics and Mining Sciences     Hybrid Journal   (Followers: 6)
Journal of Analytical and Numerical Methods in Mining Engineering     Open Access  
Journal of Applied Geophysics     Hybrid Journal   (Followers: 15)
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of China Coal Society     Open Access  
Journal of Convention & Event Tourism     Hybrid Journal   (Followers: 4)
Journal of Geology and Mining Research     Open Access   (Followers: 11)
Journal of Human Resources in Hospitality & Tourism     Hybrid Journal   (Followers: 8)
Journal of Materials Research and Technology     Open Access   (Followers: 2)
Journal of Metamorphic Geology     Hybrid Journal   (Followers: 15)
Journal of Mining Institute     Open Access  
Journal of Mining Science     Hybrid Journal   (Followers: 2)
Journal of Quality Assurance in Hospitality & Tourism     Hybrid Journal   (Followers: 5)
Journal of Sustainable Mining     Open Access   (Followers: 2)
Journal of the Southern African Institute of Mining and Metallurgy     Open Access   (Followers: 5)
Lithology and Mineral Resources     Hybrid Journal   (Followers: 3)
Lithos     Hybrid Journal   (Followers: 9)
Mine Water and the Environment     Hybrid Journal   (Followers: 4)
Mineral Economics     Hybrid Journal  
Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 11)
Mineral Processing and Extractive Metallurgy Review     Hybrid Journal   (Followers: 4)
Mineralium Deposita     Hybrid Journal   (Followers: 4)
Mineralogia     Open Access   (Followers: 2)
Mineralogical Magazine     Hybrid Journal   (Followers: 1)
Mineralogy and Petrology     Hybrid Journal   (Followers: 2)
Minerals     Open Access  
Minerals & Energy - Raw Materials Report     Hybrid Journal  
Minerals Engineering     Hybrid Journal   (Followers: 9)
Mining Engineering     Full-text available via subscription   (Followers: 5)
Mining Journal     Full-text available via subscription   (Followers: 3)
Mining Report     Hybrid Journal   (Followers: 2)
Mining Technology : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 2)
Mining, Metallurgy & Exploration     Hybrid Journal  
Natural Resources & Engineering     Hybrid Journal  
Natural Resources Research     Hybrid Journal   (Followers: 8)
Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Minerals     Hybrid Journal   (Followers: 4)
Podzemni Radovi     Open Access  
Rangeland Journal     Hybrid Journal   (Followers: 1)
Réalités industrielles     Full-text available via subscription  
Resources Policy     Hybrid Journal   (Followers: 4)
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 4)
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 6)
Rocks & Minerals     Hybrid Journal   (Followers: 2)
Rudarsko-geološko-naftni Zbornik     Open Access  
Stainless Steel World     Full-text available via subscription   (Followers: 17)
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 9)
Similar Journals
Journal Cover
International Journal of Coal Science & Technology
Journal Prestige (SJR): 2.063
Citation Impact (citeScore): 3
Number of Followers: 1  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2095-8293 - ISSN (Online) 2198-7823
Published by SpringerOpen Homepage  [228 journals]
  • Petrographic composition of coal within the Benue Trough, Nigeria and a
           consideration of the paleodepositional setting

    • Abstract: Abstract The petrographic composition of Cretaceous-age coals hosted in the Benue Trough, Nigeria is presented and discussed in terms of the paleodepositional settings that influenced the coal-bearing formations. The Benue Trough is a failed arm of the triple junction of an inland sedimentary basin that extends in a NE-SW direction from the Gulf of Guinea in the south, to the Chad Basin in the north. A total of twenty-nine (29) coal samples were obtained from nineteen coal localities in the Upper (UBT), Middle (MBT), and Lower Benue Trough (LBT). The high average volatile matter yield, low average ash yield, high calorific value (24.82 MJ/kg, on average), and low sulphur values indicate good quality coal deposits. The organic matter is dominated by vitrinite, reported at an average of 59.3% by volume (mineral-matter free). Variation was noted in the inertinite content across three sub-regions. Liptinite macerals were not commonly observed in the studied samples and were absent in the MBT samples. Coal facies studies decipher the paleoenvironmental conditions under which the vegetation accumulated. Indices commonly used are the gelification index (GI), tissue preservation index (TPI), ground water index (GWI and variations), vegetation index (VI), and wood index (WI). Comparing the array of coal facies models applied, the MBT samples differ from the UBT and LBT samples, concurring with the coal quality data. The UBT and LBT coals formed in an upper deltaic to drier piedmont plane depositional environment, while the MBT coal formed in a lower deltaic marsh to wet forest swamp depositional environment. All samples indicate an ombrotrophic paleomire. In view of the modified equations and the plots used, interpreting depositional environments from just a single model is not reliable.
      PubDate: 2022-05-18
       
  • Mobile power generation system based on biomass gasification

    • Abstract: Abstract Disaster-hit and/or un-electrified remote areas usually have electricity accessibility issues and an abundance of plant-derived debris and wood from destroyed wooden structures; this can be potentially addressed by employing a decentralized ultra-small biomass-fed gasification power generating system. This paper presents an assessment of the technical viability of an ultra-small gasification system that utilizes densified carbonized wood pellets/briquettes. The setup was run continuously for 100 h. A variety of biomass was densified and carbonized by harnessing fugitive heat sources before charging into the reactor. Carbonized briquettes and furnished blends exhibited inferior gasification performance compared to the carbonized pellets. In the absence of tar blockage problems, steady-state conditions were achieved when pre-treated feedstock was used. Under steady-state conditions for carbonized pellets gasification operated at an equivalence ratio of 0.32, cold gas efficiency and carbon conversion achieved 49.2% and 70.5%, respectively. Overall efficiency and maximum power output of 20.3% and 21 kW were realised, respectively. It was found that the system could keep stable while the low heating valve of syngas was over 4 MJ/m3 on condition that avoiding tar blocking issues. The results indicate that the proposed compact ultra-small power generation system is a technically feasible approach to remedy power shortage challenge. In addition, process simulation considering carbonized wood gasification combined power generation was formulated to produce syngas and electricity. Woody pellets with the flow rate of 20 kg/h could generate a 15.18 kW power at the air flow rate of 40 Nm3/h, which is in a good agreement with 15 kW in the 100 h operation. It is indicated that the gasification combined power generation cycle simulated by Aspen simulator could achieve reliable data to assist the complicated experiment operation.
      PubDate: 2022-05-13
       
  • Amelioration of acidic soil using fly Ash for Mine Revegetation in
           Post-Mining Land

    • Abstract: Abstract This paper described the use of fly ash for soil amelioration of acidic soils to promote plant growth. In mining sites, acid sulfate soils/rocks, which contain sulfide minerals (e.g. pyrite FeS2), have appeared as a result of overburden excavation. The excessively acidic condition inhibits plant growth due to the dissolution of harmful elements, such as Al, Fe, and Mn. Fly ash, an alkaline byproduct of coal combustion generated in thermal power plants is expected to be adopted to ameliorate acidic soils. However, the mixing ratio of fly ash must be considered because excessive addition of fly ash can have a negative impact on plant growth due to its physical/chemical properties. The pot trials using Acacia mangium demonstrate the evolution of plant growth with a 5%–10% addition of fly ash into acidic soil. When the acidic soil has a high potential for metal dissolution, the metal ions leached from the acidic soil are large, making it difficult to improve plant growth due to osmotic and ionic stress. This work suggests that the effects of fly ash on metal ions leached from the soil have to be considered for the amelioration of acidic soil.
      PubDate: 2022-05-13
       
  • Sustainable reclamation practices for a large surface coal mine in
           shortgrass prairie, semiarid environment (Wyoming, USA): case study

    • Abstract: Abstract Sustainable reclamation practices for large surface coal mines in USA semiarid environment contribute to the quality of the environmental on a long term basis where environmental resources are protected for future generation. Land, after reclamation, must be suitable for the previous use of greatest economic or social values to the community area. In the semiarid climate of USA, non-developed land is mainly utilized for crops, grazing, and wildlife. Completion of various stages of the reclamation processes includes verification and approval of reclamation criteria and performance standards created by state agencies. The sustainable reclamation practices were investigated at the USA’s largest surface coal mine of the semiarid environment in Wyoming. These practices include building post-mining topography to the approximate original contour and reestablish a stable hydrologic system to drain surface water. All available spoil material is backfilled and graded to achieve the post-mining topography which closely resembles the pre-mining topography. No overburden material or other coal waste material is left in stockpiles at the mine. Detailed planning until the end of mining, the knowledge of available volumes of suitable backfill material and soil is necessary for sustainable management practices. Diverse and permanent vegetation capable of stabilizing soil surfaces and capable of self-regeneration is established. Sustainable management of the reclamation effort is achieved by enforcement processes developed by the state and federal agencies. Monthly inspections of mining and reclamation operations and reviews of annual reports submitted by the operator help determine if the reclamation processes are occurring according to the permit plan.
      PubDate: 2022-05-09
       
  • Numerical and theoretical investigations of the effect of the gangue-coal
           density ratio on the drawing mechanism in longwall top-coal caving

    • Abstract: Abstract Discrete element calculations of the top-coal drawing process for different gangue-coal density ratios were conducted to investigate the effect of the gangue-coal density ratio on the drawing mechanism in longwall top-coal caving. The effects were analyzed for the drawing body, the top-coal boundary, and the recovery of top coal. The results show that for increasing density ratio, the initial drawing body on the goaf side is farther away from the drawing support and its width and volume gradually increase. The upper part of the sickle-shaped drawing body extends near the initial drawing body with increasing density ratio in the normal cycling stage, and the distance from the drawing body to the initial drawing body is its maximum width. The larger the density ratio, the smaller the height of the top coal above the goaf at the end of the initial drawing process. The height of the top-coal boundary decreases with increasing density ratio, until it reaches a limit. In a normal cycle, due to hysteretic development, the top-coal boundary moves toward the goaf until the density ratio is approximately 2.0, which is consistent with the physical experiment results. Finally, increasing the advance length of the working face is beneficial for increasing the overall recovery of top coal.
      PubDate: 2022-05-03
       
  • Correction to: Petrology, physicochemical and thermal analyses of selected
           cretaceous coals from the Benue Trough Basin in Nigeria

    • PubDate: 2022-05-02
       
  • Geochemical signatures of potassium metasomatism in anthracite from the
           Himalayan fold-thrust belts of Sikkim, India

    • Abstract: Abstract The present study focuses on the inorganic geochemical features of the bituminous coal samples from the Raniganj and the Jharia Basins, as well as the anthracite samples from the Himalayan fold-thrust belts of Sikkim, India. The SiO2 content (48.05 wt% to 65.09 wt% and 35.92 wt% to 50.11 wt% in the bituminous and anthracite samples, respectively) and the ratio of Al2O3/TiO2 (6.97 to 17.03 in the bituminous coal samples and 10.34 to 20.07 in the anthracite samples) reveal the intermediate igneous source rock composition of the minerals. The ratio of the K2O/Al2O3 in the ash yield of the bituminous coal samples (0.03 to 0.09) may suggest the presence of kaolinite mixed with montmorillonite, while its range in the ash yield of the anthracite samples (0.16 to 0.27) may imply the presence of illite mixed with kaolinite. The chemical index of alteration values may suggest the moderate to strong chemical weathering of the source rock under sub-humid to humid climatic conditions. The plot of the bituminous coal samples in the A–CN–K diagram depicts the traditional weathering trend of parent rocks, but the anthracite samples plot near the illite field and are a bit offset from the weathering trend. This may imply the plausible influences of the potassium-metasomatism at post coalification stages, which is further supported by high K2O/Na2O ratio (29.88–80.13). The Fourier transform infrared spectra further reveal the hydroxyl stretching intensity of illite in the anthracite samples substantiating the effect of the epigenetic potassium-metasomatism. The decrease in total kaolinite intensity/compound intensity of quartz and feldspar may provide additional evidence towards this epigenetic event.
      PubDate: 2022-04-30
       
  • Habitat quality assessment of mining cities based on InVEST model—a case
           study of Yanshan County, Jiangxi Province

    • Abstract: Abstract The assessment of the spatiotemporal evolution of habitat quality caused by land use changes can provide a scientific basis for the ecological protection and green development of mining cities. Taking Yanshan County as an example of a typical mining city, this article discussed the spatial pattern and evolution characteristics of habitat quality in 2000 and 2018 based on the ArcGIS platform and the InVEST model. The conclusions are as below: from 2000 to 2018, the area of farmland and construction land changed the most in the study area. Among them, the area of farmland decreased by 3.48%, and the area of industrial and mining land and construction land increased by 53.25%. Areas of low, relatively low and high habitat quality expanded, and areas of medium and relatively high habitat quality shrank, which is closely related to the distribution of land use. The areas with high habitat degradation degrees appear around cities, mining areas and watersheds, while the areas with low habitat degradation degrees are mainly distributed in the southern woodland. The distribution of cold and hot spots in the habitat quality distribution of Yanshan County presents a pattern of “hot in the south and cold in the north”. The results are of great significance to the precise implementation of ecosystem management decisions in mining cities and the creation of a landscape pattern of “beautiful countrysides, green cities, and green mines”.
      PubDate: 2022-04-26
       
  • Optically powered gas monitoring system using single-mode fibre for
           underground coal mines

    • Abstract: Abstract We present an optically powered, intrinsically safe gas monitoring system to measure four essential environmental gases (CH4, CO2, CO and O2), together with ambient temperature and pressure, for underground mines. The system is based on three key technologies developed at UNSW: (1) power-over-fibre (PoF) at 1550 nm using a single industry-standard, low-cost single-mode fibre (SMF) for both power delivery and information transmission, (2) liquid–crystal-based optical transducers for optical telemetry, and (3) ultra-low power consumption design of all electronics. Together, this approach allows each gas monitoring station to operate with less than 150 mW of optical power, meeting the intrinsic safety requirements specified by the IEC60079-28 standard. A 2-month field trial at BMA’s Broadmeadow underground mine proved the cabling compatibility to the mine’s existing optical network and the stability of the system performance. Compared with conventional electrically powered gas sensors, this technology bypasses the usual roadblocks of underground gas monitoring where electrical power is either unsafe or unavailable. Furthermore, using one fibre for both power delivery and communication enables longer distance coverage, reduces optical cabling and increases multiplexing possibilities and data throughput for better awareness of underground environment.
      PubDate: 2022-04-26
       
  • Advances of nanotechnologies for hydraulic fracturing of coal seam gas
           reservoirs: potential applications and some limitations in Australia

    • Abstract: Some of the most promising potential applications of nanotechnology to hydraulic fracturing of coal seam gas (CSG) are reviewed with a focus on Australian CSG wells. Three propitious applications were identified: (1) Nanoparticle enhanced viscoelastic surfactants (VES) fracturing fluids to prevent fluid loss by up to 30%, made possible by the formation of pseudo-filter cakes and reducing the viscosity of the VES fluids. Besides, there is no requirement of clay control additives or biocides. (2) Nano-proppants to extend fracture networks and reduce proppant embedment by introducing them prior to the emplacement of larger proppants. Fly Ash nanoparticles can be particularly effective because of their high sphericity and mechanical strength. (3) Nanoparticle-coated proppants, to mitigate the migration of particle fines by restricting them close to their source by adsorption, with MgO being the most effective. The use of nanotechnology in hydraulic fracturing applications is currently hindered due to a discordant regulatory environment compounded by the cost of the nanoparticles themselves, as well as, a lack of field data to validate the technology under real downhole conditions. Although the necessary field tests are unlikely to be conducted for as long as abundant natural gas is available, exploratory studies could pave the way for future applications. Graphical abstract
      PubDate: 2022-04-26
       
  • Stability of inner dump slope under coal pillar support: case study in an
           open-pit coal mine

    • Abstract: Abstract The stability of an inner dump slope was investigated under the effect of coal pillar support considering the development position of dumping. Based on the instability mechanism and load distribution characteristics of the supporting coal pillar, the three-dimensional mechanical effects of the supporting coal pillar are characterized. Using the two-dimensional equivalent principle and the residual thrust method, the stability of the inner dump slope was analyzed under the effect of pillar support at different dump development positions. The quantitative effects of various factors on the inner dump slope stability were revealed, and the coal pillar shape parameters were optimized through numerical simulations. The results indicate that the slope stability coefficient is linearly related to the top width and height of the coal pillar, slope angle, and base inclination angle, and has an exponential relation with the coal pillar strike length and slope height increment. There are quadratic and absolute value relations with the coal pillar outer and the inner bottom angle, respectively. The top width of the coal pillar in the inner dump of Shengli East No.2 open-pit coal mine should be at a level of + 824 m, and the optimal top width and height are 15 and 36.7 m, respectively. The instability mechanism of the supporting and retaining coal pillar obtained by numerical simulations and the stability of the inner dump are in good agreement with the theoretical analysis. Our results provide a theoretical basis for the design, treatment, and safe implementation of similar open-pit mine slope engineering.
      PubDate: 2022-04-26
       
  • Research and practice of intelligent coal mine technology systems in China

    • Abstract: Abstract This study considered the role of coal as China’s basic energy source and examines the development of the coal industry. We focused on the intelligent development of coal mines, and introduced the “Chinese mode” of intelligent mining in underground coal mines, which uses complete sets of technical equipment to propose classification and grading standards. In view of the basic characteristics and technical requirements of intelligent coal mine systems, we established a digital logic model and propose an information entity and knowledge map construction method. This involves an active information push strategy based on a knowledge demand model and an intelligent portfolio modeling and distribution method for collaborative control of coal mines. The top-level architecture of 5G+ intelligent coal mine systems combines intelligent applications such as autonomous intelligent mining, human–machine collaborative rapid tunneling, unmanned auxiliary transportation, closed-loop safety control, lean collaborative operation, and intelligent ecology. Progress in intelligent mining technology was described in terms of a dynamic modified geological model, underground 5G network and positioning technology, intelligent control of the mining height and straightness of the longwall working face, and intelligent mining equipment. The development of intelligent coal mines was analyzed in terms of its imbalances, bottlenecks, and the compatibility of large-scale systems. Implementation ideas for promoting the development of intelligent coal mines were proposed, such as establishing construction standards and technical specifications, implementing classification and grading standards according to mining policy, accelerating key technology research, and building a new management and control model.
      PubDate: 2022-04-15
       
  • An automated water dispensing system for controlling fires in coal yards

    • Abstract: Abstract In spite of recent moves to wean the world of fossil fuels, coal remains the main source of power in many countries. Coal yards are prone to spontaneous ignition, a problem faced in every country that stores or transports coal. Depending on the environment-temperature, ventilation, and the rank of the coal-heating and self-ignition can be a longer or shorter process, but the possibility can never be entirely dismissed. A plethora of studies have modelled this oxidation behavior and proposed countermeasures. Most often, human intervention is necessary, which is both slow and dangerous for the firefighters involved. In this study, we propose to build a complete firefighting solution which is mounted on a number of towers sufficient to cover the area of an open coal yard, complete with redundancy. Each tower includes an inexpensive infrared detector, a water dispenser and a controller programmed to identify areas of elevated temperature, and actuate the dispenser. The heat direction algorithm calculates the parameters to position the water dispenser so that it covers the area. A prototype has been built from inexpensive components to demonstrate the effectiveness at detecting and extinguishing arising fires, and a solution has been costed for the coal yard in the case study. This work has been conducted in collaboration with the managers of the coal yard of a power plant.
      PubDate: 2022-04-09
       
  • Influence of stress wave-induced disturbance on ultra-low friction in
           broken blocks

    • Abstract: Abstract Deep rock mass tends to be broken into blocks when mining for materials deep below the surface. The rock layer of the roof of the mine can be regarded as a system of blocks of fractured rock mass. When subjected to high ground stress and mining-induced disturbance, the effect of the ultra-low friction of the block system easily becomes apparent, and can induce rock burst and other accidents. By taking the block of rock mass as research object, this study developed a test system for ultra-low friction to experimentally examine its effects on the broken blocks under stress wave-induced disturbance. We used the horizontal displacement of the working block as the characteristic parameter reflecting the effect of ultra-low friction, and examine its characteristic laws of horizontal displacement, acceleration, and energy when subjected to the effects of ultra-low friction by changing the frequency and amplitude of the stress wave-induced disturbance. The results show that the frequency of stress wave-induced disturbance is related to the generation of ultra-low friction in the broken block. The frequency of disturbance of the stress wave is within 1–3 Hz, and significantly increases the maximum acceleration and horizontal displacement of the broken blocks. The greater the intensity of the stress wave-induced disturbance is, the higher is the degree of block fragmentation, and the more likely are effects of ultra-low friction to occur between the blocks. The greater the intensity of the horizontal impact load is, the higher is the degree of fragmentation of the rock mass, and the easier it is for the effects of ultra-low friction to occur. Stress wave-induced disturbance and horizontal impact are the main causes of sliding instability of the broken blocks. When the dominant frequency of the kinetic energy of the broken block is within 20 Hz, the effects of ultra-low friction are more likely.
      PubDate: 2022-04-08
       
  • Effect of layered joints on rockburst in deep tunnels

    • Abstract: Abstract The existence of joints in the surrounding rock mass has a considerable effect on tunnel rockbursts. Herein, we studied the effect of layered joints with different inclination angles and spacings on rockburst in deep tunnels and investigated the failure area, deformation process of the surrounding rock mass, stress change inside the surrounding rock mass, velocity of the failed rock, and the kinetic energy of the failure. The failure type of the surrounding rock mass can thus be determined. The results showed that the intensity of rockburst increases as rock quality designation (RQD) decreases, while the deformation rate of the surrounding rock mass first increases and then decreases. The deformation rate exhibits a turning point between RQD = 50 and 70, below which the deformation rate of the surrounding rock mass gradually decreases, ultimately ceasing to be a rockburst. Rockburst always occurs perpendicular to the direction of the joint. When σx = σy, as the joint inclination angle changes from 45° to 90°, the intensity of a rockburst first decreases (from 45° to 60°), and then increases (from 60° to 90°). When combined with the evolution law of stress and strain energy, the rockburst process can be divided into four stages.
      PubDate: 2022-04-05
       
  • Characterization and mode of occurrence of rare earth elements and yttrium
           in fly and bottom ash from coal-fired power plants in Java, Indonesia

    • Abstract: Abstract Fly and bottom ash (FABA) produced primarily from coal combustion in a coal-fired power plant consists of fine particles of the organic and inorganic mixture and trace elements. Eight FABA samples from coal-fired power plants in Java, Indonesia, had been collected for composition and rare earth element and Yttrium (REY) mode of occurrence identification. The geochemical composition of both major and trace elements was determined by inductively coupled plasma-mass spectrometry/atomic emission spectrometry (ICP-MS/AES). Furthermore, the composition of FABA was identified by petrography with reflected light microscopy and X-ray diffraction (XRD) analysis. Simultaneously, scanning electron microscope determines the mode of occurrence of REY with an energy-dispersive X-ray (SEM–EDX). The study finds that the inorganic component of FABA consists of glass, Fe–Mg spinel, mullite, quartz, Fe-oxide mineral, and K-feldspar. In contrast, the organic component is dominated by unburned coal. Glass is the most abundant component with cenospheres as major and pleiospheres as minor constituents. Trace elements analysis indicates REY concentration with heavy REY (HREY) distribution pattern. Moreover, SEM–EDX analysis results show that Yttrium (Y) occurs in glass and has a low concentration in spinel. From the mode occurrence of REY, in particular Yttrium, it can be predicted that alkaline fusion followed by acid leaching will be the most appropriate extraction method to extract REY from Indonesian FABA.
      PubDate: 2022-04-01
       
  • Failure analysis and control technology of intersections of large-scale
           variable cross-section roadways in deep soft rock

    • Abstract: Abstract In deep underground mining, achieving stable support for roadways along with long service life is critical and the complex geological environment at such depths frequently presents a major challenge. Owing to the coupling action of multiple factors such as deep high stress, adjacent faults, cross-layer design, weak lithology, broken surrounding rock, variable cross-sections, wide sections up to 9.9 m, and clusters of nearby chambers, there was severe deformation and breakdown in the No. 10 intersection of the roadway of large-scale variable cross-section at the − 760 m level in a coal mine. As there are insufficient examples in engineering methods pertaining to the geological environment described above, the numerical calculation model was oversimplified and support theory underdeveloped; therefore, it is imperative to develop an effective support system for the stability and sustenance of deep roadways. In this study, a quantitative analysis of the geological environment of the roadway through field observations, borehole-scoping, and ground stress testing is carried out to establish the FLAC 3D variable cross-section crossing roadway model. This model is combined with the strain softening constitutive (surrounding rock) and Mohr–Coulomb constitutive (other deep rock formations) models to construct a compression arch mechanical model for deep soft rock, based on the quadratic parabolic Mohr criterion. An integrated control technology of bolting and grouting that is mainly composed of a high-strength hollow grouting cable bolt equipped with modified cement grouting materials and a high-elongation cable bolt is developed by analyzing the strengthening properties of the surrounding rock before and after bolting, based on the Heok-Brown criterion. As a result of on-site practice, the following conclusions are drawn: (1) The plastic zone of the roof of the cross roadway is approximately 6 m deep in this environment, the tectonic stress is nearly 30 MPa, and the surrounding rock is severely fractured. (2) The deformation of the roadway progressively increases from small to large cross-sections, almost doubling at the largest cross-section. The plastic zone is concentrated at the top plate and shoulder and decreases progressively from the two sides to the bottom corner. The range of stress concentration at the sides of the intersection roadway close to the passageway is wider and higher. (3) The 7 m-thick reinforced compression arch constructed under the strengthening support scheme has a bearing capacity enhanced by 1.8 to 2.3 times and increase in thickness of the bearing structure by 1.76 times as compared to the original scheme. (4) The increase in the mechanical parameters c and φ of the surrounding rock after anchoring causes a significant increase in σt; the pulling force of the cable bolt beneath the new grouting material is more than twice that of ordinary cement grout, and according to the test, the supporting stress field shows that the 7.24 m surrounding rock is compacted and strengthened in addition to providing a strong foundation for the bolt (cable). On-site monitoring shows that the 60-days convergence is less than 30 mm, indicating that the stability control of the roadway is successful.
      PubDate: 2022-03-30
       
  • Evaluating the mechanical properties of anisotropic shale containing
           bedding and natural fractures with discrete element modeling

    • Abstract: Abstract Natural fracture data from one of the Carboniferous shale masses in the eastern Qaidam Basin were used to establish a stochastic model of a discrete fracture network and to perform discrete element simulation research on the size effect and mechanical parameters of shale. Analytical solutions of fictitious joints in transversely isotropic media were derived, which made it possible for the proposed numerical model to simulate the bedding and natural fractures in shale masses. The results indicate that there are two main factors influencing the representative elementary volume (REV) size of a shale mass. The first and most decisive factor is the presence of natural fractures in the block itself. The second is the anisotropy ratio: the greater the anisotropy is, the larger the REV. The bedding angle has little influence on the REV size, whereas it has a certain influence on the mechanical parameters of the rock mass. When the bedding angle approaches the average orientation of the natural fractures, the mechanical parameters of the shale blocks decrease greatly. The REV representing the mechanical properties of the Carboniferous shale masses in the eastern Qaidam Basin were comprehensively identified by considering the influence of bedding and natural fractures. When the numerical model size is larger than the REV, the fractured rock mass discontinuities can be transformed into equivalent continuities, which provides a method for simulating shale with natural fractures and bedding to analyze the stability of a borehole wall in shale.
      PubDate: 2022-03-25
       
  • Simulation research and application on response characteristics of
           detecting water-filled goaf by transient electromagnetic method

    • Abstract: Abstract Water inrush disasters poses a great threat to the safe exploitation of coal resources. To solve this problem, the transient electromagnetic method (TEM) was proposed to accurately detect the water accumulation in the goaf. The electromagnetic response characteristics of different water-filled goaves were studied by electromagnetic field theory, numerical simulation and field verification. Through the models of 100% water accumulation, 50% water accumulation, 0% water accumulation, 100% water accumulation with collapsed rock, 50% water accumulation with collapsed rock and 0% water accumulation with collapsed rock goaf, the characteristics of induced voltage attenuation curves were studied. Meanwhile, the relationship between the attenuation voltage value and area of the transmitting coil, the depth of the goaf, the background resistivity, and the delay time were also simulated. The results illustrate that the attenuation curve of induced voltage presented a regular exponential decay form in the 0% water accumulation model but existed abnormal exaltation for voltage in water-filled model. Through the linear fitting curve, it can be seen that the abnormal intensity of the induced voltage becomes stronger as the distance between the measuring point and the center of the target decrement. Moreover, the abnormal amplitude of the induced voltage increases with the rise of the water accumulation and collapsed rock will weakly reduce the low-resistivity anomalous effect on the water-accumulated goaf. In addition, the response value of the attenuation voltage increased as the area of the transmitting coil increases, but decreased with increasing delay time and increasing background resistivity and depth of the target body. The field detection results of the Majiliang coal mine also confirmed the theoretical analysis and the numerical simulation.
      PubDate: 2022-03-24
       
  • CFD modeling and laboratory studies of dust cleaning efficacy of an
           efficient four stage non-clogging impingement filter for flooded-bed dust
           scrubbers

    • Abstract: Abstract Fibrous-type filters are used to capture dust particles in mining and other occupations where personnel are exposed for prolonged periods. Dust cleansing devices including flooded-bed dust scrubbers use these mesh-type multi-layered filters. These filters trap dust particles efficiently on their surface and inside their mesh. However, their continued operation leads to dust build-up and clogging. This results in increased resistance of the filter and lowered airflow rate through the scrubber. This could potentially enhance the exposure of the miners. A non-clogging self-cleaning impingement screen type dust filter was designed by the authors for use in mining and industrial dust cleansing applications. The filter guides dirt-laden air through rapidly turning paths which forces it to shed heavier particles. The particles impact one of the impermeable solid metallic filter surfaces and are removed from the airstream. A full cone water spray installed upstream prevents any surface build-up of dust. This paper summaried the computer models generated to show the filter operations and laboratory experiments including optical particle counting to establish the cleaning efficiency.
      PubDate: 2022-03-22
       
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
 


Your IP address: 35.172.111.71
 
Home (Search)
API
About JournalTOCs
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-