Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery a...Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery and the high-value utilization of residual carbon(RC)in FS are the keys to realizing the win-win situation of the coal chemical industry in terms of economic and environmental benefits.The structural properties,such as pore,surface functional group,and microcrystalline structures,of RC in FS(FS-RC)not only affect the flotation recovery efficiency of FS-RC but also form the basis for the high-value utilization of FS-RC.In this paper,the characteristics of FS-RC in terms of pore structure,surface functional groups,and microcrystalline structure are sorted out in accordance with gasification type and FS particle size.The reasons for the formation of the special structural properties of FS-RC are analyzed,and their influence on the flotation separation and high-value utilization of FS-RC is summarized.Separation methods based on the pore structural characterist-ics of FS-RC,such as ultrasonic pretreatment-pore-blocking flotation and pore breaking-flocculation flotation,are proposed to be the key development technologies for improving FS-RC recovery in the future.The design of low-cost,low-dose collectors containing polar bonds based on the surface and microcrystalline structures of FS-RC is proposed to be an important breakthrough point for strengthening the flotation efficiency of FS-RC in the future.The high-value utilization of FS should be based on the physicochemical structural proper-ties of FS-RC and should focus on the environmental impact of hazardous elements and the recyclability of chemical waste liquid to es-tablish an environmentally friendly utilization method.This review is of great theoretical importance for the comprehensive understand-ing of the unique structural properties of FS-RC,the breakthrough of the technological bottleneck in the efficient flotation separation of FS,and the expansion of the field of the high value-added utilization of FS-RC.展开更多
In-situ stress is a critical factor influencing the permeability of coal reservoirs and the production capacity of coalbed methane(CBM)wells.Accurate prediction of in-situ stress and investigation of its influence on ...In-situ stress is a critical factor influencing the permeability of coal reservoirs and the production capacity of coalbed methane(CBM)wells.Accurate prediction of in-situ stress and investigation of its influence on coal reservoir permeability and production capacity are significant for CBM development.This study investigated the CBM development zone in the Zhengzhuang area of the Qinshui Basin.According to the low mechanical strength of coal reservoirs,this study derived a calculation model of the in-situ stress of coal reservoirs based on the multi-loop hydraulic fracturing method and analyzed the impacts of initial fractures on the calculated results.Moreover,by combining the data such as the in-situ stress,permeability,and drainage and recovery data of CBM wells,this study revealed the spatial distribution patterns of the current in-situ stress of the coal reservoirs and discussed the impacts of the insitu stress on the permeability and production capacity.The results are as follows.(1)Under given fracturing pressure,longer initial fractures are associated with higher calculated maximum horizontal principal stress values.Therefore,ignoring the effects of the initial fractures will cause the calculated values of the in-situ stress to be less than the actual values.(2)As the burial depth increases,the fracturing pressure,closure pressure,and the maximum and minimum horizontal principal stress of the coal reservoirs in the Zhengzhuang area constantly increase.The average gradients of the maximum and minimum horizontal principal stress are 3.17 MPa/100 m and 2.05 MPa/100 m,respectively.(3)Coal reservoir permeability is significantly controlled by the magnitude and state of the current in-situ stress.The coal reservoir permeability decreases exponentially with an increase in the effective principal stress.Moreover,a low lateral pressure coefficient(less than 1)is associated with minor horizontal compressive effects and high coal reservoir permeability.(4)Under similar conditions,such as resource endowments,CBM well capacity is higher in primary structural coal regions with moderate paleotectonic stress modification,low current in-situ stress,and lateral pressure coefficient of less than 1.展开更多
The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct ...The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working conditions.Based on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were researched.Firstly,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution characteristics.The influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure area.Thirdly,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal.展开更多
A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition...A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.展开更多
Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status.However,this sorption swelling switch mechanism has not been...Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status.However,this sorption swelling switch mechanism has not been considered in current analytical permeability models.This study introduces a normalized sorption non-equilibrium index(SNEI)to characterize the sorption status,quantify the dynamical variations of matrix swelling accumulation and internal swelling partition,and formulate the sorption swelling switch model.The incorporation of this index into the extended total effective stress concept leads to an analytical transient coal permeability model.Model results show that the sorption swelling switch itself results in the permeability switch under stress-constrained conditions,while the confined bulk swelling suppresses the permeability recovery to the continuous reduction under displacement-constrained conditions.Model verifications show that current experimental observations correspond to the early stages of the transient process,and they could be extended to the whole process with these models.This study demonstrates the importance of the sorption swelling switch in determining permeability evolution using simple boundary conditions.It provides new insights into experimentally revealing the sorption swelling switch in the future,and underscores the requirement of a rigorous model for complex coupled processes in large-scale coal seams.展开更多
The quality upgrading and deashing of inferior coal by chemical method still faces great challenges.The dangers of strong acid,strong alkali,waste water and exhaust gas as well as high cost limit its industrial produc...The quality upgrading and deashing of inferior coal by chemical method still faces great challenges.The dangers of strong acid,strong alkali,waste water and exhaust gas as well as high cost limit its industrial production.This paper systematically investigates the ash reduction and desilicification of two typical inferior coal utilizing ammonium fluoride roasting method.Under the optimal conditions,for fat coal and gas coal,the deashing rates are 69.02%and 54.13%,and the desilicification rates are 92.64%and 90.27%,respectively.The molar dosage of ammonium fluoride remains consistent for both coals;however,the gas coal,characterized by a lower ash and silica content(less than half that of the fat coal),achieves optimum deashing effect at a reduced time and temperature.The majority of silicon in coal transforms into gaseous ammonium fluorosilicate,subsequently preparing nanoscale amorphous silica with a purity of 99.90%through ammonia precipitation.Most of the fluorine in deashed coal are assigned in inorganic minerals,suggesting the possibility of further fluorine and ash removal via flotation.This research provides a green and facile route to deash inferior coal and produce nano-scale white carbon black simultaneously.展开更多
Hydroconversion of coal tar to produce aromatic hydrocarbons(BTX)represents a crucial strategy for the highvalue hierarchical utilization of coal.This study focused on the hydrocracking of hydrorefined products derive...Hydroconversion of coal tar to produce aromatic hydrocarbons(BTX)represents a crucial strategy for the highvalue hierarchical utilization of coal.This study focused on the hydrocracking of hydrorefined products derived from coal tar to enhance the production of benzene,toluene,and xylene(BTX).Various reaction conditions,including reaction temperature,hydrogen pressure,space velocity,and hydrogen-to-oil volume ratio,were systematically explored to optimize BTX yields while also considering the process’s economic feasibility.The results indicate that increasing the reaction temperature from 360℃ to 390℃ significantly favors the production of BTX,with yields increasing from 21.42%to 41.14%.Similarly,an increase in hydrogen pressure from 4 MPa to 6 MPa boosts BTX production,with yields rising from 36.31%to 41.14%.Reducing the space velocity from 2 h^(-1) to 0.5 h^(-1) also favors the BTX production process,with yields increasing from 37.96%to 45.13%.Furthermore,raising the hydrogen-to-oil volume ratio from 750 to 1500 improves BTX yields from 41.61%to 45.44%.Through economic analysis,the optimal conditions for BTX production were identified as a reaction temperature of 390℃,hydrogen pressure of 5-6 MPa,space velocity of 1 h^(-1),and hydrogen-to-oil volume ratio of 1000,achieving a BTX yield of 43.73%.This investigation highlights the importance of a holistic evaluation of hydrocracking conditions to optimize BTX production.Furthermore,the findings offer valuable insights for the design and operation of industrial hydrocracking processes aimed at efficiently converting coal tar-derived hydrorefined feedstock into BTX.展开更多
Understanding the variations in microscopic pore-fracture structures(MPFS) during coal creep under pore pressure and stress coupling is crucial for coal mining and effective gas treatment. In this manuscript, a triaxi...Understanding the variations in microscopic pore-fracture structures(MPFS) during coal creep under pore pressure and stress coupling is crucial for coal mining and effective gas treatment. In this manuscript, a triaxial creep test on deep coal at various pore pressures using a test system that combines in-situ mechanical loading with real-time nuclear magnetic resonance(NMR) detection was conducted.Full-scale quantitative characterization, online real-time detection, and visualization of MPFS during coal creep influenced by pore pressure and stress coupling were performed using NMR and NMR imaging(NMRI) techniques. The results revealed that seepage pores and microfractures(SPM) undergo the most significant changes during coal creep, with creep failure gradually expanding from dense primary pore fractures. Pore pressure presence promotes MPFS development primarily by inhibiting SPM compression and encouraging adsorption pores(AP) to evolve into SPM. Coal enters the accelerated creep stage earlier at lower stress levels, resulting in more pronounced creep deformation. The connection between the micro and macro values was established, demonstrating that increased porosity at different pore pressures leads to a negative exponential decay of the viscosity coefficient. The Newton dashpot in the ideal viscoplastic body and the Burgers model was improved using NMR experimental results, and a creep model that considers pore pressure and stress coupling using variable-order fractional operators was developed. The model’s reasonableness was confirmed using creep experimental data. The damagestate adjustment factors ω and β were identified through a parameter sensitivity analysis to characterize the effect of pore pressure and stress coupling on the creep damage characteristics(size and degree of difficulty) of coal.展开更多
Coal pyrolysis is a fundamental reaction in the thermal processing and utilization of coal.Investigating the behavior and kinetics of coal pyrolysis is crucial for optimizing,designing,and developing a composite riser...Coal pyrolysis is a fundamental reaction in the thermal processing and utilization of coal.Investigating the behavior and kinetics of coal pyrolysis is crucial for optimizing,designing,and developing a composite riser for the staged pyrolysis gasification process of pulverized coal.In this study,the non-isothermal pyrolysis behavior and kinetics of coal were examined at different heating rates(30,50,100,300,500,700,and 900℃/min)using thermogravimetry(TG)coupled with Fourier-transform infrared spectroscopy.Analysis of the TG/derivative TG(TG/DTG)curves indicated that coal pyrolysis mainly occurred between 300℃ and 700℃.Higher heating rates led to more volatiles being released from the coal,and a higher temperature was required to achieve rapid pyrolysis.Kinetic analysis showed that both the model-free methods(Friedman,Flynn-Wall-Ozawa,and Kissinger-Akahira-Sunose)and the model-based method(Coats-Redfern)effectively describe the coal pyrolysis process.The change in the Ea values between the two kinetic models was consistent throughout the pyrolysis process,and the most probable mechanism was the F2 model(secondary chemical reaction).In addition,the heating rate did not change the overall reaction order of the pyrolysis process;however,a higher heating rate resulted in a decrease in the Ea value during the initial pyrolysis stage.展开更多
Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential...Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite preparation.We prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an additive.The combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading capacity.Results showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface area.The loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% EG.These data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed composite.The obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical compatibility.The SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.展开更多
Coal gasification fly ash(CGFA)is an industrial solid waste from the coal circulating fluidized bed(CFB)gasification process,and it needs to be effectively disposed to achieve sustainable development of the environmen...Coal gasification fly ash(CGFA)is an industrial solid waste from the coal circulating fluidized bed(CFB)gasification process,and it needs to be effectively disposed to achieve sustainable development of the environment.To realize the application of CGFA as a precursor of porous carbon materials,the physicochemical properties of three kinds of CGFA from industrial CFB gasifiers are analyzed.Then,the activation potential of CGFA is acquired via steam activation experiments in a tube furnace reactor.Finally,the fluidization activation technology of CGFA is practiced in a bench-scale CFB test rig,and its advantages are highlighted.The results show that CGFA is characterized by a high carbon content in the range of 54.06%–74.09%,an ultrafine particle size(d50:16.3–26.1 μm),and a relatively developed pore structure(specific surface area SSA:139.29–551.97 m^(2)·g^(-1)).The proportion of micropores in CGFA increases gradually with the coal rank.Steam activation experiments show that the pore development of CGFA mainly includes three stages:initial pore development,dynamic equilibrium between micropores and mesopores and pore collapse.The SSA of lignite fly ash(LFA),subbituminous fly ash(SBFA)and anthracite fly ash(AFA)is maximally increased by 105%,13%and 72%after steam activation;the order of the largest carbon reaction rate and decomposition ratio of steam among the three kinds of CGFA is SBFA>LFA>AFA.As the ratio of oxygen to carbon during the fluidization activation of LFA is from 0.09 to 0.19,the carbon conversion ratio increases from 14.4%to 26.8%and the cold gas efficiency increases from 6.8%to 10.2%.The SSA of LFA increases by up to 53.9%during the fluidization activation process,which is mainly due to the mesoporous development.Relative to steam activation in a tube furnace reactor,fluidization activation takes an extremely short time(seconds)to achieve the same activation effect.It is expected to further improve the activation effect of LFA by regulating the carbon conversion ratio range of 27%–35%to create pores in the initial development stage.展开更多
Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration potential.Since the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this...Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration potential.Since the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this further,desorption of the adsorbed gas due to pressure drop is investigated in this paper,to achieve an improved understanding of the long-term fate of injected CO_(2) during post-injection period.This paper presents a dual porosity model coupling gas flow,adsorption and geomechanics for studying coupled processes and effectiveness of CO_(2) sequestration in coals.A new adsorption?desorption model derived based on thermodynamics is incorporated,particularly,the desorption hysteresis is considered.The reliability of the proposed adsorption-desorption isotherm is examined via validation tests.It is indicated that occurrence of desorption hysteresis is attributed to the adsorption-induced pore deformation.After injection ceases,the injected gas continues to propagate further from the injection well,while the pressure in the vicinity of the injection well experiences a significant drop.Although the adsorbed gas near the well also decreases,this decrease is less compared to that in pressure because of desorption hysteresis.The unceasing spread of CO_(2) and drops of pressure and adsorbed gas depend on the degree of desorption hysteresis and heterogeneity of coals,which should be considered when designing CO_(2) sequestration into coal seams.展开更多
The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous...The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control results.This article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its effectiveness.The overview encompassed several key elements,delving into anchoring theory and grouting reinforcement theory.The new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also highlighted.The discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole pressure.An examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was conducted.Additionally,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting reinforcement.Furthermore,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable bolts.The application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was introduced.Finally,the existing problems in grouted bolting control technology for deep soft rock roadways are analyzed,and the future development trend of grouted bolting control technology is anticipated.展开更多
In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue t...In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue that affects the safe mining of deep,steeply inclined coal seams.In this work,we adopt a perspective centered on localized deformation in coal-rock mining and systematically combine theoretical analyses and extensive data mining of voluminous microseismic data.We describe a mechanical model for the urgently inclined mining of both the sandwiched rock pillar and the roof,explaining the mechanical response behavior of key disaster-prone zones within the deep working face,affected by the dynamics of deep mining.By exploring the spatial correlation inherent in extensive microseismic data,we delineate the“time-space”response relationship that governs the dynamic failure of coal-rock during the progression of the sharply inclined working face.The results disclose that(1)the distinctive coal-rock occurrence structure characterized by a“sandwiched rock pillar-B6 roof”constitutes the origin of rockburst in the southern mining area of the Wudong Coal Mine,with both elements presenting different degrees of deformation localization with increasing mining depth.(2)As mining depth increases,the bending deformation and energy accumulation within the rock pillar and roof show nonlinear acceleration.The localized deformation of deep,steeply inclined coal-rock engenders the spatial superposition of squeezing and prying effects in both the strike and dip directions,increasing the energy distribution disparity and stress asymmetry of the“sandwiched rock pillar-B3+6 coal seam-B6 roof”configuration.This makes worse the propensity for frequent dynamic disasters in the working face.(3)The developed high-energy distortion zone“inner-outer”control technology effectively reduces high stress concentration and energy distortion in the surrounding rock.After implementation,the average apparent resistivity in the rock pillar and B6 roof substantially increased by 430%and 300%,respectively,thus guaranteeing the safe and efficient development of steeply inclined coal seams.展开更多
We collected high-quality teleseismic events recorded by 12 broadband seismographs deployed in the Anyuan Coal Mine and its adjacent areas in Pingxiang City,Jiangxi Province for nearly two years.The H-κ-c stacking me...We collected high-quality teleseismic events recorded by 12 broadband seismographs deployed in the Anyuan Coal Mine and its adjacent areas in Pingxiang City,Jiangxi Province for nearly two years.The H-κ-c stacking method was employed to obtain the crustal thickness and Poisson's ratio distribution,then the characteristics of crustal structure below the stations were obtained by using the time-domain linear inversion method.The crustal thickness in the Anyuan Coal Mine and its adjacent areas ranges from approximately 32~35 km,with an average thickness of 33 km,which is consistent with the crustal thickness results in South China from previous studies using the receiver function method.The average Poisson's ratio of the crustal bulk composition in the study area varies between 0.22 and 0.25,which is lower than the global value with a 0.27 average,indicating a predominantly intermediate-acidic or felsic crustal composition.There is a weak negative correlation between Poisson's ratio and crustal thickness estimates in the Anyuan Coal Mine and its adjacent areas,suggesting that the absence of mafic-ultramafic materials in the lower crust is associated with the process of crustal delamination.The velocity inversion results indicate that the crustal structure including three velocity discontinuity interfaces,with the first at a depth of approximately 1.5 km,the second at about 10~15 km,and the third being the Moho.The study also indicates that the results obtained by the H-κ-c stacking method are significantly better than those obtained by the H-κmethod,effectively reducing the standard deviation and dispersion of crustal thickness and vP/vSratio.展开更多
Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. B...Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. Bed to bed gypsum samplings (and their chemical analyses) of huge gypsum deposits from Sulaiman foldbelt is a base for industrialist and also planers to develop cement and gypsum industries to increase export and foreign exchange for the development of area and Pakistan. Low and high grade sedimentary iron deposits, silica sand and uranium host rocks and their extensions in Sulaiman and Kirthar foldbelts are presented. Anomalies of a few base metals arise as a result of geochemical exploration carried at part of Loralai District of Balochistan. Theropod dinosaurs were frequent in India, while Poripuchian titanosaurs (Sauropoda, Dinosauria) were frequent in Pakistan. Besides some ichnotaxa, many bone taxa such as 1 titanosauriform, 14 titanosaurian sauropod (including one new titanosaur), and 3 theropod dinosaurs are established from Pakistan. Among these 12 titanosaur species and 3 theropod species are named in about 10 km<sup>2</sup> area of Vitakri dome and 2 titanosaur species are named in about a few hundred square meter area of Mari Bohri (Kachi Bohri) which is about 10 km westward from Vitakri dome. Pakistan is a unique country which discoverd 14 diversified titanosaurs in a short area and also in a short period (67 - 66 million years ago/Ma). About 400 bones found from a few meter thick upper part of upper shale horizon of latest Maastrichtian Vitakri Formation which is base for titanosaur taxa. Cranial material is in low fraction (but include significant diverse snouts), caudal vertebrae are prominent, the cervicals, dorsals and sacrals have significant numbers, forelimb and hind limb bones have balanced fraction. Humeri, femora and tibiae are most common. To know the position of Pakistani titanosaurs among titanosaurs and sauropods, there is a need to extend list of characters for phylogenetic analyses. This broad feature list should include main characters of titanosaurs from Pakistan and also from global world.展开更多
Coal mining-induced surface subsidence poses significant ecological and infrastructural challenges, necessitating a comprehensive study to ensure safe mining practices, particularly in underwater conditions. This proj...Coal mining-induced surface subsidence poses significant ecological and infrastructural challenges, necessitating a comprehensive study to ensure safe mining practices, particularly in underwater conditions. This project aims to address the extensive impact of coal mining on the environment, infrastructure, and overall safety, focusing on the Shigong River area above the working face. The study employs qualitative and quantitative analyses, along with on-site engineering measurements, to gather data on crucial parameters such as coal seam characteristics, roof rock lithology, thickness, water resistance, and structural damage degree. The research encompasses a multidisciplinary approach, involving mining, geology, hydrogeology, geophysical exploration, rock mechanics, mine surveying, and computational mathematics. The importance of effective safety measures and prevention techniques is emphasized, laying the foundation for research focused on the Xingyun coal mine. The brief concludes by highlighting the potential economic and social benefits of this project and its contribution to valuable experience for future subsea coal mining.展开更多
In China,the oversupply of coal occurred in 2009,and from that year onwards,China’s coal economy began a low-carbon and clean transformation.Evaluating transformation performance is the research goal of this paper.Th...In China,the oversupply of coal occurred in 2009,and from that year onwards,China’s coal economy began a low-carbon and clean transformation.Evaluating transformation performance is the research goal of this paper.The data collection for this paper includes data on deep processing of Chinese coal products from 2009 to 2020,as well as data on asset structure evolution and financial performance of 34 listed companies in the Chinese coal mining.Entropy value method is used to calculate the entropy value of low-carbon transformation,and the regression analysis is used to study the performance of cleaner transformation,the conclusion is as follows:(1)From 2009 to 2020,in China’s total energy consumption,coal consumption accounted for 71.6%in 2009 and 56.8%in 2020,the goals set by the state have been achieved.(2)The national goal of reducing the proportion of coal consumption and reducing carbon emissions has forced the transformation of deep processing of coal products.The transformation of coal enterprises towards low-carbon and clean production has achieved remarkable results.(3)From 2009 to 2020,the non coal industry income of 34 listed companies in China’s coal mining industry increased by 8.21%annually.At the same time,the asset structure was adjusted,and nearly 80%of the asset structure evolution showed an orderly development trend.(4)The regression analysis results show that the entropy value of coal deep processing products and the entropy value of asset structure adjustment are significantly related to transformation performance.The paper proposes to summarize the successful experience of China’s coal energy economic transformation,lay a foundation for achieving the carbon peak and carbon neutral goals in the future,further increase the intensity of coal deep processing,increase the proportion of clean energy in total energy consumption,and strive to control asset operation towards the goal of increasing the proportion of non coal industry income.展开更多
This study underscores the significance of online monitoring of standard substances for bituminous coal and anthracite,two commonly used fossil fuels.Terahertz technology emerges as a powerful non-destructive detectio...This study underscores the significance of online monitoring of standard substances for bituminous coal and anthracite,two commonly used fossil fuels.Terahertz technology emerges as a powerful non-destructive detection method capable of revealing the physical and chemical properties of measured objects.In this research,terahertz time-domain spectroscopy technology was employed to investigate the spectral characteristics of four distinct types of bituminous coal and anthracite samples.The refractive index and absorption coefficient spectra of these samples were calculated across a frequency range of 0.5 THz to 2.5 THz.Furthermore,principal component analysis was conducted using all refractive index and absorption coefficient data within this frequency band.Through the analysis and comparison with known parameters of coal standard materials,it was established that carbon content primarily influences the refractive index of bituminous coal and anthracite,while ash content predominantly affects the absorption effect.These findings underscore the potential of terahertz spectroscopy in conjunction with principal component analysis to qualitatively assess the similarities and differences between coal samples,thus offering novel insights for the online monitoring of diverse coal types and qualities.展开更多
In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site moni...In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site monitoring means combining borehole peeping and microseismic monitoring, combined with the theoretical analysis to analyze the danger of water breakout in the bottom plate. The results show that: 1) the theoretically calculated maximum damage depth of the bottom plate is 27.5 m, and its layer is located above the Austrian ash aquifer, which has the danger of water breakout;2) the drill hole peeping at the bottom plate of the working face shows that the depth of the bottom plate fissure development reaches 26 m, and the integrity of the water barrier layer has been damaged, so there is the risk of water breakout;3) for the microseismic monitoring of the anomalous area, the bottom plate of the return air downstream channel occurs in the field with a one-week lag, which shows that microseismic monitoring events may reflect the water breakout of the underground. This shows that the microseismic monitoring events can reflect the changes of the underground flow field, which can provide a reference basis for the early warning of water breakout. The research results can provide reference for the prediction of sudden water hazard.展开更多
基金the National Natural Science Foundation of China(No.52374279)the Natural Science Foundation of Shaanxi Province(No.2023-YBGY-055).
文摘Coal gasification fine slag(FS)is a typical solid waste generated in coal gasification.Its current disposal methods of stockpil-ing and landfilling have caused serious soil and ecological hazards.Separation recovery and the high-value utilization of residual carbon(RC)in FS are the keys to realizing the win-win situation of the coal chemical industry in terms of economic and environmental benefits.The structural properties,such as pore,surface functional group,and microcrystalline structures,of RC in FS(FS-RC)not only affect the flotation recovery efficiency of FS-RC but also form the basis for the high-value utilization of FS-RC.In this paper,the characteristics of FS-RC in terms of pore structure,surface functional groups,and microcrystalline structure are sorted out in accordance with gasification type and FS particle size.The reasons for the formation of the special structural properties of FS-RC are analyzed,and their influence on the flotation separation and high-value utilization of FS-RC is summarized.Separation methods based on the pore structural characterist-ics of FS-RC,such as ultrasonic pretreatment-pore-blocking flotation and pore breaking-flocculation flotation,are proposed to be the key development technologies for improving FS-RC recovery in the future.The design of low-cost,low-dose collectors containing polar bonds based on the surface and microcrystalline structures of FS-RC is proposed to be an important breakthrough point for strengthening the flotation efficiency of FS-RC in the future.The high-value utilization of FS should be based on the physicochemical structural proper-ties of FS-RC and should focus on the environmental impact of hazardous elements and the recyclability of chemical waste liquid to es-tablish an environmentally friendly utilization method.This review is of great theoretical importance for the comprehensive understand-ing of the unique structural properties of FS-RC,the breakthrough of the technological bottleneck in the efficient flotation separation of FS,and the expansion of the field of the high value-added utilization of FS-RC.
基金sponsored by the National Natural Science Foundation of China(42002181)projecta public bidding project of 2020 Shanxi Provincial Science and Technology Program(20201101002-03).
文摘In-situ stress is a critical factor influencing the permeability of coal reservoirs and the production capacity of coalbed methane(CBM)wells.Accurate prediction of in-situ stress and investigation of its influence on coal reservoir permeability and production capacity are significant for CBM development.This study investigated the CBM development zone in the Zhengzhuang area of the Qinshui Basin.According to the low mechanical strength of coal reservoirs,this study derived a calculation model of the in-situ stress of coal reservoirs based on the multi-loop hydraulic fracturing method and analyzed the impacts of initial fractures on the calculated results.Moreover,by combining the data such as the in-situ stress,permeability,and drainage and recovery data of CBM wells,this study revealed the spatial distribution patterns of the current in-situ stress of the coal reservoirs and discussed the impacts of the insitu stress on the permeability and production capacity.The results are as follows.(1)Under given fracturing pressure,longer initial fractures are associated with higher calculated maximum horizontal principal stress values.Therefore,ignoring the effects of the initial fractures will cause the calculated values of the in-situ stress to be less than the actual values.(2)As the burial depth increases,the fracturing pressure,closure pressure,and the maximum and minimum horizontal principal stress of the coal reservoirs in the Zhengzhuang area constantly increase.The average gradients of the maximum and minimum horizontal principal stress are 3.17 MPa/100 m and 2.05 MPa/100 m,respectively.(3)Coal reservoir permeability is significantly controlled by the magnitude and state of the current in-situ stress.The coal reservoir permeability decreases exponentially with an increase in the effective principal stress.Moreover,a low lateral pressure coefficient(less than 1)is associated with minor horizontal compressive effects and high coal reservoir permeability.(4)Under similar conditions,such as resource endowments,CBM well capacity is higher in primary structural coal regions with moderate paleotectonic stress modification,low current in-situ stress,and lateral pressure coefficient of less than 1.
基金supported by Distinguished Youth Funds of National Natural Science Foundation of China (No.51925402)National Natural Science Foundation of China (Nos.51904203 and 52174125)+4 种基金the China Postdoctoral Science Foundation (No.2021M702049)the Tencent Foundation or XPLORER PRIZEShanxi Science and Technology Major Project Funds (No.20201102004)Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering (No.2021SX-TD001)Open Fund Research Project Supported by State Key Laboratory of Strata Intelligent Control and Green Mining Co-founded by Shandong Province and the Ministry of Science and Technology (No.SICGM202209)。
文摘The relationship between support and surrounding rock is of great significance to the control of surrounding rock in mining process.In view of the fact that most of the existing numerical simulation methods construct virtual elements and stress servo control to approximately replace the hydraulic support problem,this paper establishes a new numerical model of hydraulic support with the same working characteristics as the actual hydraulic support by integrating numerical simulation software Rhino,Griddle and FLAC3D,which can realize the simulation of different working conditions.Based on this model,the influence mechanism of the supporting strength of hydraulic support on surrounding rock stress regulation and coal stability in front of the top coal caving face in extra thick coal seam were researched.Firstly,under different support intensity,the abutment pressure of the bearing coal and the coal in front of it presents the “three-stage”evolution characteristics.The influence range of support intensity is 15%–30%.Secondly,1.5 MPa is the upper limit of impact that the support strength can have on the front coal failure area.Thirdly,within a displacement range of 2.76 m from the coal wall,a support strength of1.5 MPa provides optimal control of the horizontal displacement of the coal.
基金Funded by National Natural Science Foundation of China (No.52074218)。
文摘A hydrotalcite(layered double hydroxide, LDH) inhibitor which is suitable for the whole process of coal spontaneous combustion and a LDH inhibitor containing rare earth lanthanum elements were prepared. The inhibition effect and mechanism were analyzed by scanning electron microscopy(SEM),X-ray diffraction(XRD), thermal performance analysis, in-situ diffuse reflectance infrared spectroscopy and temperature-programmed experiment. The results have shown that the inhibitor containing lanthanum can play a good inhibitory role in every stage of coal oxidation. During the slow oxidation of coal samples, the inhibitor containing lanthanum ions can slow down the oxidation process of coal and increase the initial temperature of coal spontaneous combustion. At the same time, because the hydroxyl groups in LDHs are connected with-COO-groups on the coal surface through hydrogen bonds, the stability of coal is improved. With the increase of temperature, LDHs can remove interlayer water molecules and reduce the surface temperature of coal. CO release rate of coal samples decreases significantly after adding inhibitor containing lanthanum element, and the maximum inhibition rate of the inhibitor is 58.1%.
基金supported by the Australian Research Council(Grant No.DP200101293)the National Natural Science Foundation of China(Grant No.42202286)the Zhejiang Collaborative Innovation Center for Prevention and Control of Mountain Geological Hazards(Grant No.PCMGH-2017-Z-02).
文摘Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status.However,this sorption swelling switch mechanism has not been considered in current analytical permeability models.This study introduces a normalized sorption non-equilibrium index(SNEI)to characterize the sorption status,quantify the dynamical variations of matrix swelling accumulation and internal swelling partition,and formulate the sorption swelling switch model.The incorporation of this index into the extended total effective stress concept leads to an analytical transient coal permeability model.Model results show that the sorption swelling switch itself results in the permeability switch under stress-constrained conditions,while the confined bulk swelling suppresses the permeability recovery to the continuous reduction under displacement-constrained conditions.Model verifications show that current experimental observations correspond to the early stages of the transient process,and they could be extended to the whole process with these models.This study demonstrates the importance of the sorption swelling switch in determining permeability evolution using simple boundary conditions.It provides new insights into experimentally revealing the sorption swelling switch in the future,and underscores the requirement of a rigorous model for complex coupled processes in large-scale coal seams.
文摘The quality upgrading and deashing of inferior coal by chemical method still faces great challenges.The dangers of strong acid,strong alkali,waste water and exhaust gas as well as high cost limit its industrial production.This paper systematically investigates the ash reduction and desilicification of two typical inferior coal utilizing ammonium fluoride roasting method.Under the optimal conditions,for fat coal and gas coal,the deashing rates are 69.02%and 54.13%,and the desilicification rates are 92.64%and 90.27%,respectively.The molar dosage of ammonium fluoride remains consistent for both coals;however,the gas coal,characterized by a lower ash and silica content(less than half that of the fat coal),achieves optimum deashing effect at a reduced time and temperature.The majority of silicon in coal transforms into gaseous ammonium fluorosilicate,subsequently preparing nanoscale amorphous silica with a purity of 99.90%through ammonia precipitation.Most of the fluorine in deashed coal are assigned in inorganic minerals,suggesting the possibility of further fluorine and ash removal via flotation.This research provides a green and facile route to deash inferior coal and produce nano-scale white carbon black simultaneously.
文摘Hydroconversion of coal tar to produce aromatic hydrocarbons(BTX)represents a crucial strategy for the highvalue hierarchical utilization of coal.This study focused on the hydrocracking of hydrorefined products derived from coal tar to enhance the production of benzene,toluene,and xylene(BTX).Various reaction conditions,including reaction temperature,hydrogen pressure,space velocity,and hydrogen-to-oil volume ratio,were systematically explored to optimize BTX yields while also considering the process’s economic feasibility.The results indicate that increasing the reaction temperature from 360℃ to 390℃ significantly favors the production of BTX,with yields increasing from 21.42%to 41.14%.Similarly,an increase in hydrogen pressure from 4 MPa to 6 MPa boosts BTX production,with yields rising from 36.31%to 41.14%.Reducing the space velocity from 2 h^(-1) to 0.5 h^(-1) also favors the BTX production process,with yields increasing from 37.96%to 45.13%.Furthermore,raising the hydrogen-to-oil volume ratio from 750 to 1500 improves BTX yields from 41.61%to 45.44%.Through economic analysis,the optimal conditions for BTX production were identified as a reaction temperature of 390℃,hydrogen pressure of 5-6 MPa,space velocity of 1 h^(-1),and hydrogen-to-oil volume ratio of 1000,achieving a BTX yield of 43.73%.This investigation highlights the importance of a holistic evaluation of hydrocracking conditions to optimize BTX production.Furthermore,the findings offer valuable insights for the design and operation of industrial hydrocracking processes aimed at efficiently converting coal tar-derived hydrorefined feedstock into BTX.
基金supported by the National Natural Science Foundation of China(Nos.52121003,51827901 and 52204110)China Postdoctoral Science Foundation(No.2022M722346)+1 种基金the 111 Project(No.B14006)the Yueqi Outstanding Scholar Program of CUMTB(No.2017A03).
文摘Understanding the variations in microscopic pore-fracture structures(MPFS) during coal creep under pore pressure and stress coupling is crucial for coal mining and effective gas treatment. In this manuscript, a triaxial creep test on deep coal at various pore pressures using a test system that combines in-situ mechanical loading with real-time nuclear magnetic resonance(NMR) detection was conducted.Full-scale quantitative characterization, online real-time detection, and visualization of MPFS during coal creep influenced by pore pressure and stress coupling were performed using NMR and NMR imaging(NMRI) techniques. The results revealed that seepage pores and microfractures(SPM) undergo the most significant changes during coal creep, with creep failure gradually expanding from dense primary pore fractures. Pore pressure presence promotes MPFS development primarily by inhibiting SPM compression and encouraging adsorption pores(AP) to evolve into SPM. Coal enters the accelerated creep stage earlier at lower stress levels, resulting in more pronounced creep deformation. The connection between the micro and macro values was established, demonstrating that increased porosity at different pore pressures leads to a negative exponential decay of the viscosity coefficient. The Newton dashpot in the ideal viscoplastic body and the Burgers model was improved using NMR experimental results, and a creep model that considers pore pressure and stress coupling using variable-order fractional operators was developed. The model’s reasonableness was confirmed using creep experimental data. The damagestate adjustment factors ω and β were identified through a parameter sensitivity analysis to characterize the effect of pore pressure and stress coupling on the creep damage characteristics(size and degree of difficulty) of coal.
基金the financial support from the National Natural Science Foundation of China(Grant No.21576293 and 21576294)。
文摘Coal pyrolysis is a fundamental reaction in the thermal processing and utilization of coal.Investigating the behavior and kinetics of coal pyrolysis is crucial for optimizing,designing,and developing a composite riser for the staged pyrolysis gasification process of pulverized coal.In this study,the non-isothermal pyrolysis behavior and kinetics of coal were examined at different heating rates(30,50,100,300,500,700,and 900℃/min)using thermogravimetry(TG)coupled with Fourier-transform infrared spectroscopy.Analysis of the TG/derivative TG(TG/DTG)curves indicated that coal pyrolysis mainly occurred between 300℃ and 700℃.Higher heating rates led to more volatiles being released from the coal,and a higher temperature was required to achieve rapid pyrolysis.Kinetic analysis showed that both the model-free methods(Friedman,Flynn-Wall-Ozawa,and Kissinger-Akahira-Sunose)and the model-based method(Coats-Redfern)effectively describe the coal pyrolysis process.The change in the Ea values between the two kinetic models was consistent throughout the pyrolysis process,and the most probable mechanism was the F2 model(secondary chemical reaction).In addition,the heating rate did not change the overall reaction order of the pyrolysis process;however,a higher heating rate resulted in a decrease in the Ea value during the initial pyrolysis stage.
基金financially supported by the National Natural Science Foundation of China, China (Nos. 52274252 and 51874047)the Special Fund for the Construction of Innovative Provinces in Hunan Province, China (No. 2020RC3038)the Changsha City Fund for Distinguished and Innovative Young Scholars, China (No. kq1802007)。
文摘Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building applications.Stone coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite preparation.We prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an additive.The combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading capacity.Results showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface area.The loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% EG.These data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed composite.The obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical compatibility.The SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.
基金financially supported by the Special Research Assistant Fund Project of Chinese Academy of Sciences.
文摘Coal gasification fly ash(CGFA)is an industrial solid waste from the coal circulating fluidized bed(CFB)gasification process,and it needs to be effectively disposed to achieve sustainable development of the environment.To realize the application of CGFA as a precursor of porous carbon materials,the physicochemical properties of three kinds of CGFA from industrial CFB gasifiers are analyzed.Then,the activation potential of CGFA is acquired via steam activation experiments in a tube furnace reactor.Finally,the fluidization activation technology of CGFA is practiced in a bench-scale CFB test rig,and its advantages are highlighted.The results show that CGFA is characterized by a high carbon content in the range of 54.06%–74.09%,an ultrafine particle size(d50:16.3–26.1 μm),and a relatively developed pore structure(specific surface area SSA:139.29–551.97 m^(2)·g^(-1)).The proportion of micropores in CGFA increases gradually with the coal rank.Steam activation experiments show that the pore development of CGFA mainly includes three stages:initial pore development,dynamic equilibrium between micropores and mesopores and pore collapse.The SSA of lignite fly ash(LFA),subbituminous fly ash(SBFA)and anthracite fly ash(AFA)is maximally increased by 105%,13%and 72%after steam activation;the order of the largest carbon reaction rate and decomposition ratio of steam among the three kinds of CGFA is SBFA>LFA>AFA.As the ratio of oxygen to carbon during the fluidization activation of LFA is from 0.09 to 0.19,the carbon conversion ratio increases from 14.4%to 26.8%and the cold gas efficiency increases from 6.8%to 10.2%.The SSA of LFA increases by up to 53.9%during the fluidization activation process,which is mainly due to the mesoporous development.Relative to steam activation in a tube furnace reactor,fluidization activation takes an extremely short time(seconds)to achieve the same activation effect.It is expected to further improve the activation effect of LFA by regulating the carbon conversion ratio range of 27%–35%to create pores in the initial development stage.
基金The research was conducted as part of the“Establishing a Research Observatory to Unlock European Coal Seams for CO_(2) Storage(ROCCS)”project(Grant No.899336)The work of the second author is also sponsored by Shanghai Pujiang Program(Grant No.23PJ1412600)。
文摘Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration potential.Since the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this further,desorption of the adsorbed gas due to pressure drop is investigated in this paper,to achieve an improved understanding of the long-term fate of injected CO_(2) during post-injection period.This paper presents a dual porosity model coupling gas flow,adsorption and geomechanics for studying coupled processes and effectiveness of CO_(2) sequestration in coals.A new adsorption?desorption model derived based on thermodynamics is incorporated,particularly,the desorption hysteresis is considered.The reliability of the proposed adsorption-desorption isotherm is examined via validation tests.It is indicated that occurrence of desorption hysteresis is attributed to the adsorption-induced pore deformation.After injection ceases,the injected gas continues to propagate further from the injection well,while the pressure in the vicinity of the injection well experiences a significant drop.Although the adsorbed gas near the well also decreases,this decrease is less compared to that in pressure because of desorption hysteresis.The unceasing spread of CO_(2) and drops of pressure and adsorbed gas depend on the degree of desorption hysteresis and heterogeneity of coals,which should be considered when designing CO_(2) sequestration into coal seams.
基金the National Natural Science Foundation of China(Nos.52304141 and 52074154)。
文摘The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control results.This article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its effectiveness.The overview encompassed several key elements,delving into anchoring theory and grouting reinforcement theory.The new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also highlighted.The discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole pressure.An examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was conducted.Additionally,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting reinforcement.Furthermore,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable bolts.The application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was introduced.Finally,the existing problems in grouted bolting control technology for deep soft rock roadways are analyzed,and the future development trend of grouted bolting control technology is anticipated.
基金financially supported by the Major Program of the National Natural Science Foundation of China(No.52394191)the Outstanding Ph.D Dissertation Cultivating Program of Xi’an University of Science and Technology(No.PY22001)the National Foundation for studying abroad(No.[2022]87)。
文摘In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue that affects the safe mining of deep,steeply inclined coal seams.In this work,we adopt a perspective centered on localized deformation in coal-rock mining and systematically combine theoretical analyses and extensive data mining of voluminous microseismic data.We describe a mechanical model for the urgently inclined mining of both the sandwiched rock pillar and the roof,explaining the mechanical response behavior of key disaster-prone zones within the deep working face,affected by the dynamics of deep mining.By exploring the spatial correlation inherent in extensive microseismic data,we delineate the“time-space”response relationship that governs the dynamic failure of coal-rock during the progression of the sharply inclined working face.The results disclose that(1)the distinctive coal-rock occurrence structure characterized by a“sandwiched rock pillar-B6 roof”constitutes the origin of rockburst in the southern mining area of the Wudong Coal Mine,with both elements presenting different degrees of deformation localization with increasing mining depth.(2)As mining depth increases,the bending deformation and energy accumulation within the rock pillar and roof show nonlinear acceleration.The localized deformation of deep,steeply inclined coal-rock engenders the spatial superposition of squeezing and prying effects in both the strike and dip directions,increasing the energy distribution disparity and stress asymmetry of the“sandwiched rock pillar-B3+6 coal seam-B6 roof”configuration.This makes worse the propensity for frequent dynamic disasters in the working face.(3)The developed high-energy distortion zone“inner-outer”control technology effectively reduces high stress concentration and energy distortion in the surrounding rock.After implementation,the average apparent resistivity in the rock pillar and B6 roof substantially increased by 430%and 300%,respectively,thus guaranteeing the safe and efficient development of steeply inclined coal seams.
基金supported by the Spark Program of Earthquake Technology of CEA,China(XH20032)open Research Project from the State Key Laboratory of Nuclear Resources and Environment,East China University of Technology(2022NRE17)+1 种基金open Research Project from the State Key Laboratory of Geological Processes,Mineral Resources,China University of Geosciences(GPMR202114)the Graduate Student Innovation Fund of East China University of Technology(YC2022-s628)。
文摘We collected high-quality teleseismic events recorded by 12 broadband seismographs deployed in the Anyuan Coal Mine and its adjacent areas in Pingxiang City,Jiangxi Province for nearly two years.The H-κ-c stacking method was employed to obtain the crustal thickness and Poisson's ratio distribution,then the characteristics of crustal structure below the stations were obtained by using the time-domain linear inversion method.The crustal thickness in the Anyuan Coal Mine and its adjacent areas ranges from approximately 32~35 km,with an average thickness of 33 km,which is consistent with the crustal thickness results in South China from previous studies using the receiver function method.The average Poisson's ratio of the crustal bulk composition in the study area varies between 0.22 and 0.25,which is lower than the global value with a 0.27 average,indicating a predominantly intermediate-acidic or felsic crustal composition.There is a weak negative correlation between Poisson's ratio and crustal thickness estimates in the Anyuan Coal Mine and its adjacent areas,suggesting that the absence of mafic-ultramafic materials in the lower crust is associated with the process of crustal delamination.The velocity inversion results indicate that the crustal structure including three velocity discontinuity interfaces,with the first at a depth of approximately 1.5 km,the second at about 10~15 km,and the third being the Moho.The study also indicates that the results obtained by the H-κ-c stacking method are significantly better than those obtained by the H-κmethod,effectively reducing the standard deviation and dispersion of crustal thickness and vP/vSratio.
文摘Discoveries of many coal seams at depths by drilling carried by Geological Survey of Pakistan in Sor Range and Harnai Gochina, extended the coal seams at depth which is challenge for mine owners to exploit feasibly. Bed to bed gypsum samplings (and their chemical analyses) of huge gypsum deposits from Sulaiman foldbelt is a base for industrialist and also planers to develop cement and gypsum industries to increase export and foreign exchange for the development of area and Pakistan. Low and high grade sedimentary iron deposits, silica sand and uranium host rocks and their extensions in Sulaiman and Kirthar foldbelts are presented. Anomalies of a few base metals arise as a result of geochemical exploration carried at part of Loralai District of Balochistan. Theropod dinosaurs were frequent in India, while Poripuchian titanosaurs (Sauropoda, Dinosauria) were frequent in Pakistan. Besides some ichnotaxa, many bone taxa such as 1 titanosauriform, 14 titanosaurian sauropod (including one new titanosaur), and 3 theropod dinosaurs are established from Pakistan. Among these 12 titanosaur species and 3 theropod species are named in about 10 km<sup>2</sup> area of Vitakri dome and 2 titanosaur species are named in about a few hundred square meter area of Mari Bohri (Kachi Bohri) which is about 10 km westward from Vitakri dome. Pakistan is a unique country which discoverd 14 diversified titanosaurs in a short area and also in a short period (67 - 66 million years ago/Ma). About 400 bones found from a few meter thick upper part of upper shale horizon of latest Maastrichtian Vitakri Formation which is base for titanosaur taxa. Cranial material is in low fraction (but include significant diverse snouts), caudal vertebrae are prominent, the cervicals, dorsals and sacrals have significant numbers, forelimb and hind limb bones have balanced fraction. Humeri, femora and tibiae are most common. To know the position of Pakistani titanosaurs among titanosaurs and sauropods, there is a need to extend list of characters for phylogenetic analyses. This broad feature list should include main characters of titanosaurs from Pakistan and also from global world.
文摘Coal mining-induced surface subsidence poses significant ecological and infrastructural challenges, necessitating a comprehensive study to ensure safe mining practices, particularly in underwater conditions. This project aims to address the extensive impact of coal mining on the environment, infrastructure, and overall safety, focusing on the Shigong River area above the working face. The study employs qualitative and quantitative analyses, along with on-site engineering measurements, to gather data on crucial parameters such as coal seam characteristics, roof rock lithology, thickness, water resistance, and structural damage degree. The research encompasses a multidisciplinary approach, involving mining, geology, hydrogeology, geophysical exploration, rock mechanics, mine surveying, and computational mathematics. The importance of effective safety measures and prevention techniques is emphasized, laying the foundation for research focused on the Xingyun coal mine. The brief concludes by highlighting the potential economic and social benefits of this project and its contribution to valuable experience for future subsea coal mining.
基金fund major project“Research on China’s Natural Resources Capitalization and Corresponding Market Construction”(No.:15zdb163)Construction project of key disciplines of business administration in Jiangsu Province during the 14th five-year plan(SJYH2022-2/285).
文摘In China,the oversupply of coal occurred in 2009,and from that year onwards,China’s coal economy began a low-carbon and clean transformation.Evaluating transformation performance is the research goal of this paper.The data collection for this paper includes data on deep processing of Chinese coal products from 2009 to 2020,as well as data on asset structure evolution and financial performance of 34 listed companies in the Chinese coal mining.Entropy value method is used to calculate the entropy value of low-carbon transformation,and the regression analysis is used to study the performance of cleaner transformation,the conclusion is as follows:(1)From 2009 to 2020,in China’s total energy consumption,coal consumption accounted for 71.6%in 2009 and 56.8%in 2020,the goals set by the state have been achieved.(2)The national goal of reducing the proportion of coal consumption and reducing carbon emissions has forced the transformation of deep processing of coal products.The transformation of coal enterprises towards low-carbon and clean production has achieved remarkable results.(3)From 2009 to 2020,the non coal industry income of 34 listed companies in China’s coal mining industry increased by 8.21%annually.At the same time,the asset structure was adjusted,and nearly 80%of the asset structure evolution showed an orderly development trend.(4)The regression analysis results show that the entropy value of coal deep processing products and the entropy value of asset structure adjustment are significantly related to transformation performance.The paper proposes to summarize the successful experience of China’s coal energy economic transformation,lay a foundation for achieving the carbon peak and carbon neutral goals in the future,further increase the intensity of coal deep processing,increase the proportion of clean energy in total energy consumption,and strive to control asset operation towards the goal of increasing the proportion of non coal industry income.
基金Anhui Province Natural Science Research Project for Universities(2022AH052272)。
文摘This study underscores the significance of online monitoring of standard substances for bituminous coal and anthracite,two commonly used fossil fuels.Terahertz technology emerges as a powerful non-destructive detection method capable of revealing the physical and chemical properties of measured objects.In this research,terahertz time-domain spectroscopy technology was employed to investigate the spectral characteristics of four distinct types of bituminous coal and anthracite samples.The refractive index and absorption coefficient spectra of these samples were calculated across a frequency range of 0.5 THz to 2.5 THz.Furthermore,principal component analysis was conducted using all refractive index and absorption coefficient data within this frequency band.Through the analysis and comparison with known parameters of coal standard materials,it was established that carbon content primarily influences the refractive index of bituminous coal and anthracite,while ash content predominantly affects the absorption effect.These findings underscore the potential of terahertz spectroscopy in conjunction with principal component analysis to qualitatively assess the similarities and differences between coal samples,thus offering novel insights for the online monitoring of diverse coal types and qualities.
文摘In order to clarify the danger of water breakout in the bottom plate of extra-thick coal seam mining, 2202 working face of a mine in the west is taken as the research object, and it is proposed to use the on-site monitoring means combining borehole peeping and microseismic monitoring, combined with the theoretical analysis to analyze the danger of water breakout in the bottom plate. The results show that: 1) the theoretically calculated maximum damage depth of the bottom plate is 27.5 m, and its layer is located above the Austrian ash aquifer, which has the danger of water breakout;2) the drill hole peeping at the bottom plate of the working face shows that the depth of the bottom plate fissure development reaches 26 m, and the integrity of the water barrier layer has been damaged, so there is the risk of water breakout;3) for the microseismic monitoring of the anomalous area, the bottom plate of the return air downstream channel occurs in the field with a one-week lag, which shows that microseismic monitoring events may reflect the water breakout of the underground. This shows that the microseismic monitoring events can reflect the changes of the underground flow field, which can provide a reference basis for the early warning of water breakout. The research results can provide reference for the prediction of sudden water hazard.