Abstract:Since the 14th Five-Year Plan period,domestic energy and electricity demand has surged,leading to a tightening coal supply-demand situation and an accelerated westward shift in production and development arrangement.Leveraging its low development intensity and abundant resources,Xinjiang has emerged as a critical successor region for China's coal supply.Focusing on the Xinjiang coal industry,this study systematically reviews its resource endowment characteristics,production and development status,and the pattern of coal transport out of Xinjiang,and forecasts the industry development trends.The results indicate that Xinjiang possesses concentrated coal resources,with predicted resources within 2000 m depth accounting for 40％of the national total,featuring advantages such as shallow burial and easy extraction.The four major coal bases exhibit a distribution pattern of"abundance in the north and scarcity in the south".During the 14th Five-Year Plan period,Xinjiang's advanced coal production capacity was rapidly released,with output reaching 540 million tonnes in 2024,increasing its share of national production to 11.3％.Outbound transport volume grew to 140 million tonnes,forming a transport corridor pattern primarily reliant on railway networks with coordinated"North-Central-South"routes.In the future,Xinjiang's coal production capacity and output will continue to grow.By the end of the 15th Five-Year Plan period,railway outbound transport capacity is expected to exceed 250 million tonnes per year.Coupled with increasing demand in its primary target markets,Xinjiang's pivotal role in securing national coal supply will become more pronounced,with a clear trend toward deeper integration into Chinas unified national market.

Abstract:Portable near-infrared(NIR)spectroscopy often suffers from spectral peak overlap,high inter-variable correlation,and sensitivity to sampling conditions in coal quality analysis,which lead to insufficient modeling accuracy and stability.To address these issues,we proposed a collaborative prediction method for coal volatile matter and calorific value based on a multi-task feature decoupling U-shaped network(MTFD-Unet).Firstly,the method improves data quality through iterative outlier removal and standard normal variate transformation,then it employs a Unet architecture to extract shared features,and further introduces a feature decoupling module to separate task-specific information,thereby balancing indicator correlation and specificity.Experimental results on 600 coal samples show that the proposed model achieves correlation coefficients of 0.8086 and 0.8584 for volatile matter and calorific value prediction,respectively.The prediction accuracy and stability significantly outperform multiple baseline models,and the method maintains strong robustness under noise interference.This research provides an efficient,accurate,and highly adaptable technical pathway for portable,rapid,and multi-index online detection of coal quality.

Abstract:To ensure the stable operation of the scraper chain transmission system and improve production efficiency,we investigated the tension control technology for scraper chain drive systems in bolter-miners.First,the working principle and mechanical characteristics of the scraper chain transmission system were analyzed to identify key parameters and influencing factors for tension control.Based on this,combining with the actual working conditions of bolter-miners,an adaptive control-based tension control strategy was proposed,thus to achieve precise control of the tension in the scraper chain transmission system by real-time monitoring of tension changes,integrating hydraulic transmission systems and system identification algorithms.Simulation and experimental studies were conducted.The simulation results show that this control strategy enables precise tension control of the scraper chain transmission system,avoiding issues such as chain slack or over-tensioning.Experimental results further verified the reliability and practicality of the control strategy,providing a new solution for tension control in the scraper chain transmission system of bolter-miners.

Abstract:The Huainan Coalfield is overlain by an ultra-thick unconsolidated layer,with its basal Quaternary aquifer characterized by significant thickness and high water abundance.The direct water-filling source for the No.5 coal seam roof at Banji Mine primarily originates from vertical and lateral recharge by this aquifer.This subjects the mine not only to severe threats from unconsolidated aquifer roof water hazards but also to risks of strata subsidence and subsequent shaft deformation/failure due to aquifer dewatering.Therefore,ensuring"zero water inflow"from the unconsolidated layer during mining is imperative.To address these challenges,an advance regional control strategy for roof water hazards was proposed,based on directional drilling and long-distance grouting technologies,shifting the control philosophy from passive treatment to active prevention.Before panel extraction,grouting modification was implemented in the vertical water-conducting stratum above the roof water-conducting fracture zone,while a grout curtain was constructed to cut off lateral recharge channels.Numerical simulation verified the reliability of the treated stratum.A flexible quantification index for grouting materials was established,and an optimal flexible cement-clay slurry mix was determined through proportioning tests,effectively reducing the risk of post-mining grout layer failure.Given the absence of a basal aquitard near the unconsolidated layer,a high-pressure grout diffusion control process was developed.Field application demonstrated that this technology successfully severed the vertical and lateral water recharge pathways to the roof before mining.The treated roof stratum remained intact during extraction,achieving the goal of"zero water inflow"from the unconsolidated layer.

Abstract:Burnt rock exhibits fractured structure,well-developed fissures,and strong water-bearing capacity,making it a critical factor in controlling the surrounding rock of roadways in shallow coal seams in western China.Based on the actual engineering conditions of the burnt rock zone in the lower 11 coal seam exposed by the+1710 return air cross-cut in Yushuling Coal Mine,we employed methods such as field measurement and numerical simulation to establish a fissure density zoning system for roadway surrounding rock to identify its disaster evolution mechanism,and proposed targeted zonal control countermeasures and support optimization schemes.The results indicate that the fissure density of burnt rock exposed by roadways can be categorized into three zones:intact zone,fissured zone,and fractured zone.The corresponding support systems focus on cable bolt densification,grouting reinforcement,and combined shed support,respectively,achieving an integrated zonal control mode of support-reinforcement-protection.

Abstract:Aiming at the influence of mudstone bedding inclination on its mechanical behavior and rupture response characteristics,taking mudstone specimens from Caojiatan Coal Mine of Shaanxi Coal mine as the research object,laboratory tests and discrete element numerical simulation were used to explore the influence of bedding dip angle on mudstone mechanical behavior and its relationship with macroscopic crack evolution characteristics.Firstly,uniaxial compression tests were carried out on mudstone specimens with different bedding dip angles(0°,15°and 30°).It was found that with the increase of bedding dip angle,the compressive strength of specimens under uniaxial compression decreased,the large penetrating cracks that dominated the macro-failure of specimens tilted to the horizontal direction,and the failure mode of rock mass gradually changed from brittle failure to ductile failure.In order to deeply explore the effects of weak bedding structure on the mechanical properties of mudstone specimens and the evolution law of microcracks,numerical models of different bedding angles(0°～90°)were established by using discrete element PFC numerical simulation software,and the weak bedding structure plane was realized by layering modeling and weakening the bonding contact parameters of interlayer particles.The results show that the uniaxial compressive peak stress,peak strain and elastic modulus of stratified mudstone first decrease and then increase with the increase of dip angle.In the process of loading failure,micro-cracks occur first on the weak structural plane of bedding,the pre-cutting effect of bedding is obvious,and the generation and propagation attitude of large penetrating cracks are also controlled by the angle of bedding plane.It shows that the existence of bedding structural plane has a significant deterioration effect on the bearing capacity of mudstone,and the influence of bedding dip angle on the stability of surrounding rock and the early warning of the failure of rock bedding structure should be fully considered in the control of underground roadway surrounding rock.

Abstract:Current intelligent photoelectric dry separators mostly perform two-product separation,lacking flexibility when processing raw coal with high middlings content,which can lead to loss of coal resource.The three-product intelligent dry separator,through multi-stage recognition and separation mechanism design,can simultaneously separate three products:clean coal,middlings,and gangue.To clarify the influence of coal quality characteristics(such as particle size composition and density composition)on the separation performance of the three-product dry separator,we conducted tests on a TDS32-300 three-product intelligent photoelectric dry separator to analyze the differences in separation performance with feed materials of different coal quality characteristics.The results show that the probable deviation of the intelligent photoelectric dry separator is much higher than that of heavy medium separation equipment,and the E value used for performance evaluation of heavy medium separation equipment is not suitable for intelligent photoelectric dry separators.The feed characteristics significantly affect the separation performance of the three-product dry separator.Higher content of large particle size fraction leads to better separation performance,and higher content of>70 mm particle sizes is more conducive to the separation.When the feed has a high content of intermediate density fractions,it adversely affects the separation precision of middlings and clean coal in the three-product dry separator.The research results provide insights for the refined separation and system upgrade of three-product intelligent photoelectric dry separators.

Abstract:Selective flocculation flotation,selective oil agglomeration flotation,selective flocculation-gravity separation-flotation are new ideas for solving refractory coal slime.The key lies in expanding the particle size difference between fine clay minerals and coal particles.We selected polyaluminum chloride(PAC),which has certain selectivity for kaolin and coal particles,as the research object,explored the morphological characteristics of the Fe3O4-PAC composite agent prepared by the sol-gel method and the solvothermal method,as well as its selective flocculation effects on kaolin and coal particles.Furthermore,we studied the influence law of the mass ratio of Fe3O4 and PAC in the composite agent on the difference in sedimentation characteristics between coal and kaolinite.The results show that PAC has selectivity for the flocculation of kaolin,and the best effect is achieved at the concentration of 3％.In the preparation of Fe3O4 particles,the solvothermal method is superior to the coprecipitation method.The Fe3O4 particles prepared by the solvothermal method are uniformly spherical with a small particle size.Both the precipitation method and the solvothermal method can prepare the Fe3O4-PAC composite agent,and the one prepared by the solvothermal method performs better in terms of floc sedimentation rate and the transmittance of the supernatant of the solution.With the increase of the proportion of Fe3O4 in the composite agent,the sedimentation rate of kaolin flocs rises,but the amount of the agent required to form an obvious interface also increases.

Abstract:To enhance the anti-impact yielding performance of rockburst-resistant hydraulic supports and mitigate dynamic hazards caused by rockburst in deep coal mining,the original pre-folded energy-absorbing component is reinforced into a novel structural configuration.Numerical simulations are conducted to compare the resistance variations and strain evolution of both original and reinforced components under vertical compression.The influence patterns of rib plate thickness,embedded tube thickness,and hoop thickness on energy absorption performance are systematically investigated.The NSGA-II genetic algorithm is employed for multi-objective optimization of these thickness parameters,yielding optimal dimensional configurations:rib plate thickness of 3.00 mm,embedded tube thickness of 2.45 mm,and hoop thickness of 4.31 mm.Compared to the original design,the optimized component demonstrates enhanced energy absorption performance with more stable resistance fluctuations,thereby achieving superior anti-impact yielding functionality when implemented in hydraulic supports.This study provides valuable insights for the design of anti-impact energy absorption components in rockburst prevention systems.

Abstract:To address the significant mine pressure behavior in rockburst-prone isolated working faces,we took the isolated No.3203 working face as an engineering case.An integrated approach combining theoretical analysis,numerical simulation,and on-site monitoring was employed to systematically investigate the stress evolution characteristics before and after the working face reached a square configuration.Special focus was placed on the influence law of hydraulic support strength and its adaptability.The results show that the load from the overlying strata of adjacent goafs transferred to the isolated working face,forming a significant stress concentration zone.The calculated rockburst risk coefficient for the working face was 0.75,indicating a moderate risk of rockburst instability.When the working face advanced to the square configuration,the peak advance abutment pressure reached 27.0 MPa,with a maximum influence range of approximately 50 m.The hydraulic support strength was negatively correlated with the roof-to-floor convergence.When the support strength reached 1.1 MPa,the roof-to-floor convergence significantly decreased and stabilized.According to the on-site monitoring data,the selected ZF9000/18/34D hydraulic supports performed well.During weighting periods,the average and maximum working resistance of the supports were 7260 and 8527 kN,respectively.The supports ensured the safe and efficient mining,and this study can serve as a reference for hydraulic support adaptability research under similar engineering conditions.

Abstract:Since its release,Standard for Design of General Layout and Transportation for Coal Enterprises has effectively promoted the standardization work of the general layout and transportation in the coal industry.Its provisions cover a lot of relevant specification contents,which is convenient for designers to query and use.However,with the development of the specifications in the coal and related industries,many of its provisions are in conflict with the actual situations in practical work,affecting the practical application effect of the standards and specifications.Combining some design experiences,review requirements in practical work and the latest specifications,the author conducts a detailed discussion on the relevant provisions in the standard,providing relevant suggestions for the better application and revision of the standard.

Abstract:To clarify the dynamic stability evolution mechanism of remaining coal pillars in underlying room-and-pillar goafs under the disturbance of over-gob mining,we took the over-gob mining of the shallow buried thin coal seam in Sandaogou Mine as an engineering case.A comprehensive approach integrating theoretical analysis and numerical simulation was employed to systematically investigate the deviatoric stress field evolution and plastic zone expansion characteristics of the remaining coal pillars under over-gob mining.The research results show that the safety factor of the coal pillars remained from the room-and-pillar mining in the 5-2 coal seam reaches 1.541,indicating a feature of long-term stability.The spatial distribution of failure characteristics in the remaining coal pillars of the 5-2 coal seam exhibits an"O"shape,with the stability of pillars in the central area of the goaf significantly inferior to those in the boundary areas.The instability of central pillars is likely to induce overall instability of the pillar group.The distribution of the deviatoric stress field and the expansion of the plastic zone in the remaining coal pillars are primarily governed by the mining parameters.Moreover,the larger the room-and-pillar mining dimensions in the 5-2 coal seam,the more significant the disturbance effect from the over-gob mining in the 4-4 coal seam on the stability of the remaining pillars.

Abstract:To intelligently control belt conveyors based on coal flow,thereby save energy and reduce consumption,and mitigate equipment wear,we studied a coal flow monitoring and intelligent speed control system for belt conveyors based on algorithm model.The system integrates algorithm model technology to capture and analyze coal flow images on the belt in real time.By employing the U2-Net algorithm,the system accurately segments and recognizes the images to calculate the coal flow.Based on this data,the system intelligently adjusts the operating speed of the belt conveyor according to a preset optimal speed regulation strategy,ensuring transportation efficiency while minimizing energy consumption.

Abstract:To address the complex fault mechanisms and scarcity of fault samples in coal shearer height adjustment systems,an experimental platform based on virtual-physical interaction was proposed and constructed,to effectively acquire multi-source fault characteristic data.The platform utilizes multi-domain coupling modeling technology to achieve high-fidelity mapping of the physical system and ensures the safe operation of the physical entity through spatially optimized design of mechanical structures and sensor layouts.Relying on the collaborative operation mechanism of hardware and software subsystems,the platform dynamically couples the physical entity and the virtual simulation model.Typical fault simulation experiments and extreme working condition simulations were conducted based on the platform,and the consistency between virtual and physical fault data was evaluated using cosine similarity.The experimental results show that the similarity between real and simulated data is above 0.9,fully verifying the platform's robustness and its ability to generate accurate and effective fault data.Additionally,the platform can generate key fault characterization parameters that are difficult to be directly monitored in the physical entity,providing reliable multi-dimensional experimental data support and theoretical foundation for intelligent fault diagnosis of coal shearer height adjustment systems.

Abstract:Ground L-shaped well gas extraction and pressure relief is an important technical means for gas extraction in coal mining areas.In response to the current problems of low drainage efficiency,difficult well completion and large difficulty in well deviation control during the gas extraction process of ground L-shaped horizontal wells,the technical principle of L-shaped horizontal well gas extraction was analyzed and three key technical points,including well location deployment,key technologies for drilling and well completion,and negative pressure drainage technology,are summarized.According to the gas migration law,the L-shaped well layout range was optimized;the three-casing wellbore structure design was sorted out and proposed,the wellbore trajectory control technology was optimized,the anti-pressing directional drilling technology,well completion and well washing technology,and cementing technology of L-shaped wells were studied,and the L-shaped well drilling technology system was established.According to the characteristics of gas extraction and pressure relief by L-shaped wells,two negative pressure extraction modes and negative pressure extraction control management systems at different stages were proposed,namely the general-specific mode,and specific-general mode.The"flow rate guarantee and negative pressure variation"control method was adopted at each stage.The gas extraction effect of ground L-shaped wells in Huaibei mining area was studied and analyzed.The pure gas extraction volume of Guobei Coal Mine reached 2.7×106 m3,and the pure gas extraction volume of a group of L-shaped horizontal wells implemented in Zhuxianzhuang Coal Mine was up to 5875 m3 per day,achieving safe mining.On this basis,the future development direction of L-shaped well technology was proposed,mainly including the precision of design parameters,precise control of horizontal section trajectory,large displacement horizontal well drilling,refined drainage management,and joint ground-surface L-shaped mining-induced well gas extraction technology.

Abstract:To enhance the flotation efficiency of hard-to-float coking coal,we prepared a novel composite collector(B2)by mixing kerosene(B1)with isomeric alcohol ethoxylates 1305(TO-5).We also compared the performance of B1 and B2 on their flotation effect,flotation kinetic characteristics and frothing performance during multi-stage flotation of hard-to-float coking coal.The results show that:at B1 dosage of 3000 g/t,low level of frother resulted in significant decrease of flotation index.By contrast,at B2 dosage of 1000 g/t,the clean coal with similar ash and higher yield ban be obtained at the same low frother level.The flotation kinetic tests show that the R2 of the flotation fitting employing the classical first-order kinetic model ae both above 0.999.The k value of B1 at 3000 g/t,B2 at 1000 g/t and B2 at 3000 g/t are 1.3439,1.5809 and 1.7203,respectively,indicating that the flotation rate of B2 is higher.The timed-release flotation curves show that B2 can achieve higher clean coal yields than B2 at the same clean ash level.Surface tension tests show that the TO-5 molecule in B2 can significantly reduce the surface tension of the gas/liquid interface.High-speed camera images of bubbles and laser particle sizing tests show that B2 can produce more bubbles with smaller size,and XPS test show that TO-5 can increase the content of hydrophobic functional groups on coal surface.The findings show that B2 is an efficient collector to strengthen the hard-to-float coking coal flotation,which provide a reference for the subsequent research and development of high-efficiency collectors.

Abstract:To investigate the effect of the paste filling body on the roof and the influence laws of different factors on roof subsidence in paste filling working faces,w take the fully mechanized paste filling working face of Weisang Coal Mine as an engineering case.Using a combined research approach of theoretical analysis,numerical simulation,and field measurement,the spatial interaction relationship between the roof and the filling body is studied.The influence of face length(140～200 m),mining height(1.5～3.0 m),filling body strength(2.0～3.5 MPa),and filling rate(80%～95%)on roof subsidence is investigated,the influence laws of different factors on roof subsidence are analyzed,and the key influencing factors are determined.The weights of each factor are determined using the range analysis method and adjusted according to practical conditions.Theoretical analysis indicates when the roof initially contacts the filling body at the start of mining,the roof span is 1.82 m.As the working face continuously advances,the contact area between the roof and the filling body increases,and the roof subsidence value tends to reach its maximum of 0.333 m.Increases in face length and mining height cause an increase in the maximum roof subsidence value,with increments of 11.8%and 101.9%,respectively.Increases in filling body strength and filling rate cause a decrease in the maximum roof subsidence value,with reductions of 29.1%and 22.7%,respectively.The range analysis method yields the influence weight of each factor:mining height is the key influencing factor,accounting for 49.7%of the weight.The secondary influencing factors are filling body strength,filling rate,and face length,accounting for 22.8%,16.2%,and 11.3%of the weight,respectively.

Abstract:Studying the response mechanism of mechanical characteristics during catastrophic failure of coal is crucial for maintaining mining stability.Using large-size coal specimens as the research subject,conventional triaxial compression tests were conducted to monitor the mechanical behavior of coal under different confining pressures.The conditions and laws of the coal's sub-instability stage were identified,and the failure mechanism of coal under triaxial compression was revealed.The results indicate that the thresholds of the five stages in the complete stress-strain curve increase with rising confining pressure,with peak strain showing a high correlation with confining pressure.The power-law equation provides a good fit for the axial strain rate during the accelerating phase of coal catastrophe.The sub-instability stage only appears when the test environment closely approximates the actual underground conditions of coal.The quasi-static and quasi-dynamic phases account for approximately 37.5%and 62.5%of the total sub-instability time,respectively,with more intense evolution of stress and radial strain occurring during the quasi-dynamic phase.Residual strength is more sensitive than peak strength,and the strength attenuation coefficient gradually decreases as confining pressure increases.Coal failure is predominantly shear-based,accompanied by tensile failure,with varying crack widths at different locations.

Abstract:To construct an intelligent early warning model for rockburst that integrates"mechanism constraints and data-driven"approaches,enabling integrated prediction of hazard"location-time-intensity",a multi-parameter index system was established based on multi-source heterogeneous data.This system integrates real-time monitoring,mining techniques,coal-rock strength,and geological conditions,with temporal and spatial parameters introduced to build a spatio-temporally coupled warning module.Data normalization,K-means clustering imputation,and principal component analysis were applied for feature processing.Predictive models were developed using L2-regularized multiple linear regression,BP neural network,and RNN-GRU neural network,and their performances were compared.The results indicate that the L2-regularized model can interpret factor weights,supporting mechanistic studies and single-indicator warnings.The RNN-GRU model significantly enhances the ability to capture temporal dynamic features through gated recurrent units.Combining with monitoring point location encoding and improved K-means clustering,it enables spatio-temporal distribution prediction of rockburst hazards.In field applications at the Hujierte mining area,the model's predicted magnitudes were close to actual events,with time errors of less than 2.5 hours,location errors of less than 50 meters,and an overall accuracy of 85%,providing a reliable method for intelligent rockburst early warning.

Abstract:To address the frequent failures and operational disruptions of underground belt conveyors in coal mines,which operate in humid,high-temperature,and dusty environments,leading to increased downtime and costs,this paper proposes an intelligent monitoring and control system based on a cloud-edge collaborative architecture and a continual learning AI framework.By integrating computer vision,equipment control,and big data analytics,algorithm models for coal flow anomaly detection were developed,resulting in a visual intelligent monitoring and management system.This system enables intelligent speed regulation of conveyors based on real-time coal volume,and achieves closed-loop management covering damage tracking,anomaly warning,and incident response.Industrial deployment at mines such as Hetaoyu Coal Mine demonstrates the system's effectiveness:belt speed measurement error is within±2%,coal volume statistical error is less than±5%,conveyor idle rate is reduced by 30%,annual electricity savings reach approximately 150000 kWh/km,and roller replacement cycles are extended by 40%.Furthermore,the system reduces daily inspection manpower by 10 person-times,cuts abnormal downtime by 15 minutes per day,and generates annual direct economic benefits of 2 million yuan and indirect benefits of 10 million yuan.This system significantly enhances the reliability,economy,and intellig and intelligence of belt conveyor operations,providing key technical support for efficient and green transportation in coal mines.