摘要：This study introduces the"mineral-pore integration"paradigm to address unresolved challenges in understanding flow characteristics within heterogeneous tight oil reservoirs.By analyzing the complementary relationship between minerals and pore-fractures,we highlight the critical role of mineralogical composition in regulating fluid flow dynamics.Existing research has focused on the qualitative pore morphology and size characterization,neglecting the quantitative dependency between minerals and pore structures.To bridge this gap,we propose the development of quantitative discrimination models using machine learning algorithms to decode mineral-pore coupling mechanisms.Additionally,we advocate for multiscale experimental and numerical approaches,including multi-physics field coupling simulations and microscale visualization experiments,to quantify flow disparities in pores formed by different minerals(e.g.,feldspar,clay,carbonate).The integration of these methods aims to reveal novel flow behaviors,optimize displacement strategies,and enhance residual oil recovery.This framework provides a foundational basis for precise reservoir management by linking mineralogy to pore-scale flow mechanisms,offering actionable insights for tight oil exploitation.

摘要：Ultrasonic excitation permeability enhancement technology has attracted great attention in the field of coal seam perme-ability enhancement.This technology has the characteristics of no pollution and low energy consumption.According to the thermal effect,cavitation effect and mechanical vibration effect of ultrasonic wave when ultrasonic wave propagates in two-phase or even multi-phase medium,the triple effect can achieve the purpose of fracturing coal body.It can effectively change the pore and fracture structure of coal and improve the permeability of coal seam.It has become an effective permeability enhancement technology.In this paper,the research work of ultrasonic excitation of coal is summarized from the aspects of theoretical analysis and laboratory test.From the perspectives of pore structure,macro fracture structure and mechani-cal damage behavior response of coal under ultrasonic excitation,the influence of key parameters of ultrasonic excitation on the desorption and seepage of coal gas is analyzed.Combined with the research work of the author's research team and the latest research progress at home and abroad,the bottleneck problems and directions that need to be solved urgently in the application of ultrasonic excitation current increasing technology in low permeability coal seams are pointed out,and a new idea for the application of ultrasonic excitation current increasing technology in coal seam gas extraction is proposed.It is of great scientific significance in the development of deep coal seam gas resources and disaster prevention and control.

摘要：Deep hole pre-cracking blasting(DHPB)technology is the preferred means of preventing and controlling rockburst induced by hard-thick rock layers in coal mines.When DHPB is applied to hard-thick rock layers,the insufficient knowledge about the crack extension scale under different rock properties and blasting parameters may result in undesirable pressure relief.Therefore,LS-DYNA was adopted to analyse the crack extension characteristics under the combined effect of rock tensile strength,explosive density,blasthole spacing,and decoupled coefficient.The Holmquist-Johnson-Cook model(HJC),veri-fied by the results of blasting experiment and numerical simulation in literature,was used to characterise coal-bearing rocks.Numerical analysis was conducted to study the blasting crack extension and fractal damage for rock tensile strength,explosive densities,blasthole spacing,and decoupled coefficients.The results show that the tensile strength of rock is the key factor for blasting design.The fractal damage caused by blasting increases when the tensile strength of rock decreases.For rocks with lower tensile strength,more blasting energy is consumed by the increasing damage area in the crushed zone.Higher explosive density can promote the development of blasting cracks and increase fractal damage,but the increasing range of the crushed zone also wastes a large amount of energy.As the blasthole spacing increases,the fractal damage decreases,and the crack extension scale in the fractured zone first increases and then decreases,and eventually remains almost unchanged.An optimum interval exists for the decoupled coefficient,and the full utilization of explosive energy within the interval leads to penetrating blast cracks and smaller crushed zones.Based on the simulation results,the optimal blasting parameters for coarse sandstone were validated in the field practice.Monitoring data show that the optimized blasting significantly reduces the risk of rockburst.

摘要：Global pressure to achieve net-zero emissions is driving major shifts in how fossil fuels are used and perceived.With the global push toward renewable energy,demand for coal as a fuel source is expected to decline,enhancing its appeal as a feedstock for advanced carbon materials.This study investigated nitrogen(N)functionalised nanoporous carbon material derived from run-of-mine coal as an electrode material for supercapacitors.Experimental findings and density functional theory(DFT)calculations revealed that N-doping causes a rearrangement of the carbon skeleton structure and improves the surface properties.Scanning electron microscopy(SEM)reveals that the structure is porous.X-ray diffraction analy-sis(XRD)confirms the material's amorphous nature.Raman spectroscopy reveals defects in the material's structure.Brunauer-Emmett-Teller(BET)analysis reveals that doping with nitrogen results in a higher surface area.The N-doped material showed a higher specific capacitance of 169 F/g,energy density of 23.5 Wh/kg,and power density of 600 W/kg.Notably,after 5000 cycles at 1 Ag-1,the capacitance retention remained at 78.2％,and coulombic efficiency was 99.9％.These improvements are attributed to enhanced conductivity and increased surface area for the electrolyte ions.This study highlights the potential of using run-of-mine coal as a viable feedstock for high-performance carbon materials in sustainable energy applications.

摘要：Pre-drill estimation of coal bed permeability is a major challenge for Coal-bed Methane(CBM)extraction and CO2 sequestration in coal beds.Unlike conventional reservoirs,the permeability of coal is solely dependent on fractures,as matrix permeability is negligible.The distribution of primary(face and butt cleats)and secondary fractures(tectonic fractures)imparts significant heterogeneity in coal beds.This remains a challenge for CBM Operators to quantify and map permeability sweet-spots.In this paper,an innovative solution to these is proposed by building permeability models within a sector of the Raniganj coal field,India.Initially,structural realizations are constructed by interpreting thirteen 2D seismic lines over the study area.Thereafter,permeability distribution in these structural models is populated by permeability-depth trends.Separate trends of primary and secondary fractures are derived from literature,field observa-tions,and discrete fracture network(DFN)models of coal samples.The curvature attribute of the interpreted coal beds from seismic reflection surfaces is used as a substitute for the intensity of tectonically controlled fractures.Finally,a workflow of integrating tectonically controlled fracture permeability with cleat-controlled permeability is demonstrated to locate possible permeability sweet-spots.Although the workflow is demonstrated in the Raniganj coalfield,it can be used globally for pre-drill permeability estimation and well-planning during appraisal/development.

摘要：To elucidate the dynamic characteristics of in-situ methane deflagration in coalbed methane wellbores and its mechanisms for fracturing coal rock,this study first developed a simulation experimental system specifically designed for methane in-situ deflagration fracturing.This experimental system,which is capable of withstanding pressures up to 150 MPa and meanwhile applying axial and confining pressures of up to 50 MPa to rock cores,enables the coupled simulation on methane deflagra-tion and rock core fracturing processes.With the aid of this experimental system,physical simulation experiments on in-situ methane deflagration fracturing were conducted,and the following findings were obtained.Methane deflagration loads in enclosed wellbores exhibit characteristics of multi-level pulsed oscillation.With the rise of initial gas pressure,the peak deflagration load increases approximately linearly,with the pressure amplification factor spanning from 23.14 to 31.10,and its peak loading rate grows exponentially.Accordingly,the fracture volume and fracture porosity augment.To be specific,when the initial gas pressure rises from 0.6 to 2.4 MPa,the fracture volume and fracture porosity augment by factors of 14.0 and 8.73,respectively.The fractal dimension of spatial distribution of fractures also increases with the rise of deflagration load,indicating that a higher deflagration load conduces to the development of a larger and more complex fracture network.Methane deflagration fracturing is characterized as a composite fracture mode that involves the impact of strong stress waves and the driving force of high-pressure fluids.The primary factors influencing damage to coal-rock include the high-stress impact in the initial stage of deflagration,the fluid pressure driving effect in the middle stage,and the thermal shock result-ing from high temperatures in the later stage.

摘要：This article investigates the mechanical responses and acoustic emission(AE)characteristics of sandstone under the triaxial differential cyclic loading(DCL)at different unloading rates of confining stress.The test results indicate that strength of rock specimens under different stress paths of triaxial unloading confining stress-differential cyclic loading(TUCS-DCL)can be fitted by the Mohr-Coulomb,Hoek-Brown,and Bieniawski criteria.The confining stress unloading rate can dominate the radial strain rate,while the axial DCL pattern has an unpronounced effect.The confining stress unloading rate affects the energy evolution in radial and axial directions of specimens,with the ratio of radially released energy to axially consumed energy fluctuating more significantly during the fast unloading of confining stress,the valley value of the ratio can serve as a precursor for failure.The confining stress unloading rate has no significant effect on stress-strain phase shift,while axial rapid-loading-slow-unloading can correspond to a larger magnitude of phase shift.AE signals begin to significantly increase after the confining stress is unloaded to zero,and a notable Kaiser effect is observed during cyclic loading preceding the failure.

摘要：In modern room and pillar coal mines,the coal is produced by continuous miner(CM)machines.The CM is used to mine the coal seam by continuously cutting at a vertical face.Depending on the seam thickness,quality,and geotechnical properties,some roof,floor,or interburden rock is often cut along with coal.While CMs can be highly efficient in terms of production rates,they can also generate high concentrations of dust.Dust poses both safety(i.e.,explosibility)and respiratory health hazards.Previous research has generally indicated that CM cutting in rock yields much more respirable dust than cutting in coal.Although in-mine studies that directly evaluate this trend have not been reported,understanding relative dust generation from different geologic strata could have important implications.In many mines,for instance,the rock is the primary source of respirable silica and silicates,which can be especially hazardous.To mitigate dust generated by the CM,mines use a variety of controls including ventilation,on-board scrubber systems,and water sprays.However,the relative effects of controls on dust generated from different strata have also not been widely investigated.In this field study,respirable dust sampling was conducted in the intake and return airways of an active CM during periods when the cutting was targeted either primarily at the coal seam(bottom cut)or primarily at the roof rock(top cut)in a standard entry.Results indicated that CM cutting in rock strata generated somewhat finer particles and respirable dust concentra-tions that were 2.1-26 times higher than cutting in coal strata,although the coal height being cut was about 2.2-2.9 times greater than the rock height.Additionally,the analysis of dust mineralogy generally showed a mix of both carbonaceous(coal)and mineral particles regardless of the target strata.Furthermore,the study was designed to evaluate the effects of two typical combinations of CM scrubber and ventilation conditions,and increased pressure and volume through the CM water sprays.In general,operation of the scrubber tended to yield lower and somewhat finer respirable dust concentra-tions,irrespective of the strata the CM was targeting.Increased water spray pressure and volume sometimes appeared to reduce the respirable dust concentration when the CM was targeting the roof rock,but no effect could be discerned when the CM was targeting the coal seam.

摘要：Coal bursts pose significant safety and operational challenges in deep mining environments,necessitating effective mitiga-tion strategies to address high-stress concentrations and dynamic failure risks.This study evaluated the efficacy of hydraulic fracturing as a preconditioning tool at a longwall face of the Mengcun coal mine with strong coal bursts,Shaanxi Province.The program involved the systematic creation of a fracture network through high-pressure fluid injection,monitored via microseismic arrays,stress measurements,and hydrological sensors.Results demonstrated that hydraulic fracturing effec-tively redistributed in-situ stresses,reducing high-stress concentrations by up to 30％,lowering the frequency of high-energy microseismic events,and enhancing the stability of fractured zones.However,the presence of unfractured blind spots and interactions with pre-existing faults highlighted the need for optimized well placement and adaptive fracturing designs.These findings underscore the potential of hydraulic fracturing as a critical preconditioning tool in high-stress mining operations,which could provide a framework for improving safety and efficiency in similar geological and operational settings.

摘要：Joints play a crucial role in the stability of surrounding rock in deep underground engineering.Studying the mechanical properties and evolution laws of rocks with different joint characteristics under true triaxial stress is highly significant.This paper presents the results of a series of true triaxial cyclic loading and unloading experiments conducted on natural stiff-jointed and artificially jointed granite,where the correlation between fracture characteristics and joint inclination was investigated.It was observed that the peak strength,plastic volumetric strain,and failure mode of the jointed granite varied considerably with joint inclination.This underscores the significant influence of joint inclination on the mechanical behavior of deep granite.Building upon a comprehensive understanding of the strength characteristics and deformation evolution in jointed granite with varying inclinations,a new dilation angle model was developed,incorporating the coupling effects of plastic volumetric strain and joint inclination.A strong agreement was found between our theoretical predictions and test data,suggesting that the proposed dilation angle model can effectively describe the dilatancy characteristics of granite with joints.This study is anticipated to offer a theoretical basis for excavation and support design,as well as stability analysis of deep jointed rock masses.

摘要：The substantial emissions of greenhouse gases,particularly CO2,constitute a primary driver of global warming.CCUS is proposed as an effective mitigation strategy which is often estimated to account for about 15％of cumulative carbon emission reduction.In-situ CO2 mineralization sequestration,compared to conventional geological storage methods such as depleted oil and gas reservoirs,unmineable coal seams,and deep saline aquifers,offers the advantage of permanent immobilization of injected carbon.However,uncertainties persist regarding the characteristics of geochemical interactions under reservoir pore conditions,as well as the kinetic mechanisms of mineralization reactions.Additionally,geochemical reactions may lead to solid particle transport and deposition,potentially causing pore throat occlusion.Pilot projects in Iceland and the United States have demonstrated the feasibility of this technology,but the field remains in the early deployment stage.In this review,the mechanisms of in-situ mineralization have been elucidated,the primary factors influencing the reaction kinetics have been discussed,and the current research status in this field has been summarized.It is emphasized that establishing a reliable system for evaluating storage capacity and understanding the kinetic mechanisms governing CO2 conversion into minerals at multi-phase interfaces are key priorities for future work.

摘要：The fracture volume is gradually changed with the depletion of fracture pressure during the production process.However,there are few flowback models available so far that can estimate the fracture volume loss using pressure transient and rate transient data.The initial flowback involves producing back the fracturing fluid after hydraulic fracturing,while the second flowback involves producing back the preloading fluid injected into the parent wells before fracturing of child wells.The main objective of this research is to compare the initial and second flowback data to capture the changes in fracture volume after production and preload processes.Such a comparison is useful for evaluating well performance and optimizing frac-turing operations. We construct rate-normalized pressure(RNP)versus material balance time(MBT)diagnostic plots using both initial and second flowback data(FBi and FBs,respectively)of six multi-fractured horizontal wells completed in Niobrara and Codell formations in DJ Basin.In general,the slope of RNP plot during the FBs period is higher than that during the FBi period,indicating a potential loss of fracture volume from the FBi to the FBs period.We estimate the changes in effective fracture volume(Vef)by analyzing the changes in the RNP slope and total compressibility between these two flowback periods.Vef during FBs is in general 3％-45％lower than that during FBi.We also compare the drive mechanisms for the two flowback periods by calculating the compaction-drive index(CDI),hydrocarbon-drive index(HDI),and water-drive index(WDI).The dominant drive mechanism during both flowback periods is CDI,but its contribution is reduced by 16％in the FBs period.This drop is generally compensated by a relatively higher HDI during this period.The loss of effective fracture volume might be attributed to the pressure depletion in fractures,which occurs during the production period and can extend 800 days.

摘要：Aiming at reducing the dust pollution during the tunneling process and improving the application efficiency of air curtain dust prevention technology,according to the changes of radial jet velocity(vr),axial extraction velocity(ve)and extrac-tion distance(L)in the formation process of air curtain,the numerical simulation method was used to analyze the rules of airflow structure evolution and the diffusion characteristics of dust particles in fully mechanized excavation tunnel.The results indicate that as vr and ve increase,the migration path of the wall jet of the air curtain changes into an axial direction;as L decreases,the migration distance increases accordingly.These phenomena make the airflow distribution in the working face tends to be uniform.The dust diffusion distance reduces as well,wherein,the range of the discrete area of dust particles decreases sharply,until all dust particles are concentrated in the accumulation area.On this basis,the vr,ve and L were optimized and applied in the 63up08 fully mechanized working face.By the application of the optimal parameters,the average dust removal efficiency at the driver's position increased by 71％.The dust concentration was reduced and the working environment had been improved effectively.

摘要：Lignite provides energy security and contributes economically.However,it also causes dirty outcomes in terms of climate aspect.In addition to the energy and climate dimensions of the Sustainable Development Goals,there is also a water issue:lignite is usually found submerged below the local groundwater tables.Mining lignite could be exploited to achieve drinkable and agriculturally usable water.In today's literature,while the impact of lignite production on global warming and emis-sions are already highly discussed,the water management side of the issue is regularly omitted.However,considering the complex interlink between these three areas(the Water-Energy-Climate(WEC)nexus)is necessary within policy coherence,which is mostly ignored even though it is one of the development targets.Here in this framework,Türkiye,which aims to reduce its heavy dependency on energy imports,is worth studying because almost all of its coal,the country's largest fossil resource,is lignite.Therefore,this study examines the WEC nexus related to lignite production and combustion and seeks policy coherence between their outputs in the context of Türkiye's historical steps to climate change mitigation,specifically oriented with the Paris Agreement.This story expands from the absence of specific development policy objectives to the practicalities of politics and economics.

摘要：Minor errors in the spoil deposition process,such as placing stronger materials with higher shear strength over weaker ones,can lead to potential dump failure.Irregular deposition and inadequate compaction complicate coal spoil behaviour,neces-sitating a robust methodology for temporal monitoring.This study explores using unmanned aerial vehicles(UAV)equipped with red-green-blue(RGB)sensors for efficient data acquisition.Despite their prevalence,raw UAV data exhibit temporal inconsistency,hindering accurate assessments of changes over time which could be attributed to radiometric errors.To this end,the study introduces an empirical line calibration with invariant targets(ELC-IT),for precise calibration across diverse scenes,particularly in the context of UAV imagery used to monitor the evolving nature of spoil dumps.To evaluate the effec-tiveness of this calibration approach,accuracy assessment of an object-based classification is conducted on both calibrated and uncalibrated data.This classification involves several steps:performing segmentation,carrying out feature extraction,and integrating the extracted features and ground truth labels collected over the time period of UAV image capture into machine learning pipelines.Calibrated RGB data exhibit a substantial performance advantage,achieving a 90.7％overall accuracy for spoil pile classification using ensemble(subspace discriminant),representing a noteworthy 7％improvement compared to classifying uncalibrated data.The study highlights the critical role of data calibration in optimising UAV effectiveness for spatio-temporal mine dump monitoring.These findings play a crucial role in informing and refining sustainable management practices within the domain of mine waste management.

摘要：The fractured rock mass inherently exhibits uncertainty due to the presence of pre-existing discontinuities.In this study,a particle-based model incorporating the discrete fracture network(DFN)to elucidate the dynamic tensile responses and asso-ciated uncertainty of rock mass.At first,the particle-based model was used synthesize the intact rock and split Hopkinson pressure bar(SHPB)system,while the fractures were represented using the smooth fracture model(SJM).Subsequently,the samples of the fractured rock mass with varying joint geometrical configurations were conducted the dynamic tensile test using the numerical SHPB system.The simulated results demonstrate a gradual decrease in dynamic tensile strength(TS)with increasing fracture intensity and fracture length,which can be effectively described by nonlinear exponential func-tions.Additionally,the fracture orientation significantly influences the dynamic TS,however,the anisotropic characteristics gradually diminish as the deviation angle approaches 90°.Furthermore,as fracture intensity and fracture length increase,the dynamic TS variability also rises steadily.However,no noticeable pattern is seen when considering cases with varying fracture orientations.When subjected to SHPB loading,the fractured rock mass primarily exhibits a combined tensile-shear failure mode,contrasting with the pure tensile failure mode exhibited by the intact rock.These findings contribute signifi-cantly to comprehending the dynamic tensile responses of the fractured rock mass and can further enhance the stability analysis of in-situ rock engineering.

摘要：The formation of a pressure relief zone is crucial for rockbust prevention during drilling pressure relief.This study investi-gates the mechanical behavior of high-stress rock under real-time drilling conditions and elucidates the mechanism behind the creation of the pressure relief zone.Utilizing the independently developed SG4500 drilling rig,we conducted a theoreti-cal analysis of the forces acting on the drill bit.The analysis showed that cutting depth is directly proportional to real-time drilling speed,while tangential and normal forces are influenced by drilling diameter.Uniaxial compression tests on red sandstone specimens under high-stress real-time drilling conditions examined the impacts of different drilling speeds(800,400,100 r/min)and diameters(6,8,10,12 mm)on rock mechanical behavior,rockburst characteristics,crack evolution,and peak elastic strain energy.The results indicate that decreasing drilling speed and increasing drilling diameter weaken rock mechanical behavior,including peak strength,Young's modulus,rockburst characteristics,and peak elastic strain energy.Crack evolution analysis reveals that smaller drilling diameters and higher drilling speeds promote the development of far-field cracks,while larger drilling diameters and lower drilling speeds lead to crack formation around the borehole,and significantly affecting rock failure mechanisms.Theoretical analysis further confirms the correlation between crack evolution and stress distribution surrounding the drilling.Under vertical stress,the cracks near the borehole formed during real-time drilling are mainly influenced by tangential compressive and tensile stresses.Overall,this study provides a new perspective on understanding the mechanisms of drilling pressure relief for rockburst prevention.

摘要：In the process of oil and gas production,reservoir pressure depletion leads to changes in pore pressure and in-situ stress in caprock,which may reactivate closed faults in caprock,break the sealing of caprock,and make depleted oil and gas reservoirs unsuitable for gas storage.In order to effectively evaluate the sealing of faults in caprock above depleted reservoir and provide a basis for a reasonable selection of injection time and location for gas storage,this paper comprehensively considers fault slip potential(FSP)and fault tensile potential(FTP),and establishes a fault sealing evaluation model in caprock above depleted reservoir.The influences of distance of fault from reservoir top,reservoir pressure depletion degree,cap mechanical property,fault occurrence,fault frictional property and in-situ stress anisotropy in caprock on different types of FSP and FTP are analyzed.The results show that for normal faults,reverse faults,and strike-slip faults,FTP increases with reservoir depletion and does not cause tensile failure,among which FTP is the smallest for normal faults.FSP is the key to controlling fault sealing in caprock above depleted reservoir.For reverse faults and strike-slip faults,in the early stage of reservoir depletion,the FSP is larger when the fault is farther away from the top of the reservoir,while normal faults are the opposite.When the normal fault is closer to the top of the reservoir,the cap poisson ratio is smaller,the Biot's coefficient is larger,the internal friction coefficient of the fault is smaller,the inherent shear strength of the fault is smaller,σH/σv is smaller,σh/σv is smaller,45°＜β＜75°,α=0°or α=180°,the FSP is larger with the reservoir depletion,and the shear failure of the fault is the most likely.At this time,the reservoir pressure should be strictly controlled not to be too small,so that it can be suitable for the construction of gas storage.Under other conditions,the possibility of shear failure of the caprock is less.For reverse faults and strike-slip faults,when σH/σv is smaller,the FSP decreases first and then increases with reservoir depletion.Although the possibility of shear failure decreases in the initial stage of reservoir depletion,it increases in the later stage.The research results can provide a theoretical basis for the reconstruction of underground gas storage.

摘要：Discrete fracture network(DFN)commonly existing in natural rock masses plays an important role in geological complexity which can influence rock fracturing behaviour during fluid injection.This paper simulated the hydraulic fracturing process in lab-scale coal samples with DFNs and the induced seismic activities by the discrete element method(DEM).The effects of DFNs on hydraulic fracturing,induced seismicity and elastic property changes have been concluded.Denser DFNs can comprehensively decrease the peak injection pressure and injection duration.The proportion of strong seismic events increases first and then decreases with increasing DFN density.In addition,the relative modulus of the rock mass is derived innovatively from breakdown pressure,breakdown fracture length and the related initiation time.Increasing DFN densities among large(35-60 degrees)and small(0-30 degrees)fracture dip angles show opposite evolution trends in relative modu-lus.The transitional point(dip angle)for the opposite trends is also proportionally affected by the friction angle of the rock mass.The modelling results have much practical meaning to infer the density and geometry of pre-existing fractures and the elastic property of rock mass in the field,simply based on the hydraulic fracturing and induced seismicity monitoring data.

摘要：The presence of inorganic constituents in coal is controlled by different geological factors,which,in turn,affect the technological,environmental,and health impacts of the coal.The main aim of this study is to objectively assess the mineralogical and geochemical characteristics of a thickest low-rank coal seam in the Lower Indus Basin southeastern Pakistan,and further investigate different controlling factors.The analytical results of major oxides,trace elements,and rare earth elements revealed that the weathering conditions were progressively variable and moderate.The sediment source,mainly of felsic and intermediate composition,was dominated by granitic rocks.The geochemical assessment reveals different depositional factors like marine environment influenced,while transitional and freshwater sediments influenced the center of the coal peat mire.Strontium,Zinc,and several hazardous trace elements,including Cu,Ni,Cr,and Co,have higher concentrations in these coals compared to world low-rank,U.S.,and Chinese coals.The relatively higher concentration of Sr in the thick coal seam in the Lower Indus Basin,compared to other coals seams in Pakistan and the enrichment of Sr was primarily controlled by the denudation of crystalline rocks and marine influx in the coal-basin.The REY distribution pattern showed that enrichment of medium and heavy rare earth elements is higher than light rare earth elements in the coal seam.The Gd distribution pattern in the coal seam demonstrated that strong positive anomalies had a good affinity with paleo-acidic water concentration in the study area.The higher concentration of Sr and other elements enables a better assessment understanding of the coal geochemical history.