Abstract:China's coal resource development has rapidly shifted toward the western mining areas with superior resources,during which large-scale and high-intensity mining has induced frequent seismicity of magnitude 2.0 and above.In 2024,Inner Mongolia's raw coal pro-duction ranked first nationwide,but mining-induced seismicity(MIS)were particularly severe.To effectively curb the surge of MIS in In-ner Mongolian Mining Areas,the geological and sedimentary characteristics of mines affected by MIS were analyzed.Twenty-six cases of mining-induced seismic events of magnitude 2.0 and above since 2020 were reviewed to summarize their occurrence characteristics and development trends.Based on surface displacement monitoring and overlying rock separation observations,the study preliminarily re-vealed the specific influence of complex sedimentary strata fracturing on frequent MIS.The causes of MIS were clarified,and control strategies including active pressure relief,reduction of subsidence load,and optimization of production layout were proposed.Industrial-scale experiments were conducted in mines severely affected by MIS to validate the effectiveness of the proposed strategies.The results in-dicate that the Cretaceous strata in the mining areas affected by MIS in Inner Mongolia experienced fluvial and weathering deposition and underwent extensive carbonate cementation,forming significant unconformities with the underlying Jurassic strata.Their overall occur-rence patterns and mechanical properties exhibit abrupt spatial variations,resulting in the unique regularity and mechanisms of MIS in In-ner Mongolian coal mines.MIS predominantly occur during adjacent goaf mining,with sources located in goaf areas and negligible im-pact on underground workings and the surface.Even when previously affected working faces resume production at reduced speed or are temporarily suspended,MIS may recur,highlighting the complexity of MIS induced by overlying rock fractures.The strata that control MIS are not fixed but dynamically change.After MIS occurrence,the surface subsides rapidly in a step-like manner,and fractures within the causative strata and overlying rocks propagate quickly.Destabilization of any strata within the extended fracture zone may trigger fur-ther MIS,which is the main reason why MIS in Inner Mongolian coal mines is difficult to control effectively.Following the implementa-tion of control engineering,accumulated energy in the Cretaceous strata was steadily released,surface subsidence was effectively mitig-ated,and the frequency of MIS was significantly reduced.Optimizing the mining layout reduces adverse effects from high-intensity min-ing and controls MIS at its source,thereby facilitating coordinated active regulation of MIS and rock bursts,which is essential for the stable release of mine production capacity.These findings advance a rational understanding of MIS in Inner Mongolian mining areas and can offer valuable approaches for the effective control of MIS.

Abstract:In the raw coal sorting process,large gangue blocks,steel wires,woven bags,and other foreign objects are first identified and removed to avoid adverse impacts on subsequent processing stages or the occurrence of safety accidents.Current coal foreign-object detec-tion algorithms are primarily designed for closed-set scenarios and focus on detecting known object categories,exhibiting limited capabil-ity in detecting and recognizing unknown-category targets-particularly anchor rods,novel support materials,and other objects with com-plex appearances and semantic uncertainty.Consequently,there is an urgent need to investigate object detection models that can simultan-eously handle both known and unknown foreign objects.Firstly,a text-image bimodal feature extraction architecture is constructed based on the DINO network,and the Path Aggregation Feature Pyramid Network(PAFPN)is introduced.A multi-layer feature extraction strategy is adopted to enhance the perception of small-scale foreign objects.Secondly,a multimodal feature fusion module based on the self-attention mechanism and cross-attention mechanism is built,and a language-guided query selection mechanism is incorporated to achieve deep interaction between text and visual features,thereby improving the semantic consistency of features and cross-category gen-eralization ability.Finally,a vision-text multimodal decoding module is designed,which inserts a text guidance mechanism at the query update stage of each layer to improve the accuracy and robustness of multimodal feature alignment.An open and dynamic environment with multi-category combinations was constructed based on a self-built coal foreign object dataset,and systematic experiments are conduc-ted.The results demonstrate that the proposed method outperforms all baselines in mAP@0.5 on known-category detection across open-ness levels,and attains unknown-category recall rates of 41.24％,52.26％,and 57.13％on unknown-category detection,confirming its zero-shot effectiveness.The method proposed in this paper demonstrates effectiveness in detecting foreign objects in unknown types of coal,providing effective technical support for the open-set detection of foreign objects in coal.

Abstract:With the continuous expansion of coal mining scale in China,longwall faces are developing toward ultra-long lengths exceed-ing 600 m.For a 600 m scraper conveyor alone,the combined mass of the chains and scrapers exceeds 200 t,and the power consumption of the chain drive system accounts for approximately 30％of the rated full-load power.To address issues such as excessive chain mass,high overall energy consumption,and material redundancy,lightweight design has gradually become a key technical approach for improv-ing the operational reliability and economic efficiency of scraper conveyors.This paper focuses on lightweight technologies for scraper conveyors and systematically reviews the current research status and development trends both domestically and internationally.Material lightweighting is currently a major research focus.High-performance non-metallic materials,such as carbon fiber composites,ultra-high-molecular-weight polyethylene,and rock-based composite materials,exhibit low density and excellent wear and corrosion resistance,demonstrating promising potential for application in components such as scrapers and middle troughs.Lightweight metallic materials,in-cluding aluminum-alloyed high-manganese steels,can achieve substantial weight reduction while maintaining adequate strength and ser-vice life.In addition,surface strengthening and modification technologies—such as laser cladding,plasma surfacing,and bionic surface structures—enhance wear resistance and indirectly reduce material redundancy by extending component service life,thereby contributing to lightweight design.Structural lightweighting also plays an important role through advanced design optimization methods.Topology op-timization,parametric optimization,and structural layout optimization have been widely applied to key components such as chain links,scrapers,middle troughs,and gearbox housings,achieving varying degrees of weight reduction.In particular,structural layout optimiza-tion approaches-such as multi-motor series driving and scraper spacing optimization-balance power and load distribution at the system level,further promoting lightweighting without altering individual component structures.In addition,low-friction chain transmission sys-tems reduce sliding friction between scrapers and middle troughs through tribological design,thereby lowering energy consumption and wear and providing an alternative pathway for lightweighting.Despite these achievements,existing lightweight research still exhibits not-able limitations.Some lightweight materials show insufficient mechanical stability under complex operating conditions.Many studies re-main at the simulation stage and lack long-term underground engineering validation;certain optimized structures require high machining precision and incur elevated manufacturing costs,hindering large-scale application.Meanwhile,under coal dust and moisture conditions,the performance of low-friction transmission systems tends to degrade over time,and their manufacturing and maintenance costs remain relatively high,restricting practical implementation.Future research should emphasize multi-objective collaborative optimization,balan-cing weight reduction with strength,service life,and manufacturing cost.At the structural level,further exploration of optimized and dis-ruptive design concepts—such as replacing traditional round-link chains with wire-rope-driven systems—should be pursued.In terms of materials,accelerated development and application of novel high-strength lightweight materials are required.Meanwhile,deeper integra-tion of lightweight design with advanced manufacturing technologies,such as additive manufacturing,should be promoted,together with enhanced integration and comprehensive application of lightweight technologies,to ultimately achieve overall lightweighting of scraper conveyors.In summary,lightweight research on scraper conveyors is not only an important approach to addressing energy security and low-carbon development requirements,but also a necessary pathway for promoting intelligent and green development in coal mining.

Abstract:The drilling method has been successfully applied in the shaft construction of deep water-bearing weak cemented bedrock in the west,which shows the development direction of less people,safety,green and intelligent well construction technology.In order to solve the engineering problems of shaft construction by this method,the drilling method sinking technology is continuously iteratively de-veloped.The key technical problems are analyzed from many aspects,such as drilling rig,cutter cutterhead,rock breaking drilling,shaft wall structure and construction technology.The recent domestic research and application progress are introduced,and the key research dir-ection in the future is put forward.Key technical problems:China's existing shaft drilling rigs are difficult to meet the characteristics of the strata in western China and the construction requirements of deep and large shafts.It is urgent to develop a new generation of large shaft drilling rigs with large drilling torque,sufficient power and high automation level.When crossing the Jurassic argillaceous sandstone in the west,the effect of slag discharge is poor,the tool wear is serious,the drilling efficiency is low,and it is easy to make slurry.Borehole wall structure and design calculation method suitable for western formation characteristics;stability calculation of floating and sinking process of deep and large shaft wall.Research progress of key technologies:ZMD120/1200 new drilling rig suitable for shaft construction in deep water-bearing bedrock in western China was developed.Taking rock breaking specific energy and rock drillability as characteristic para-meter classification indexes,the classification standard of Jurassic rock drillability is proposed.The distribution law and main influencing factors of slag discharge flow field are clarified,and the evaluation index and method of optimizing the structure form of bit slag suction port are put forward,and the mechanical mechanism of rock breaking by milling cutter is revealed.Developed a new type of low solid mud and control technology;a new type of high-strength drilling wellbore structure adapted to the conditions of the western region is proposed,and the corresponding design and calculation methods are improved.The large specific gravity backfill material was prepared,and the floating sinking and backfill technology of deep and large wellbore was developed.The key research directions in the future are as follows:optimization and upgrading of drilling rigs and intelligent monitoring,global optimization of high-efficiency drilling of cutterhead and cut-ter-ballast discharge parameters,drilling method and shaft sinking technology in western Permo-Carboniferous strata,drilling method and shaft sinking technology system and related standards and specifications in western China.

Abstract:The coal seams in the Huanglong Coalfield are overlain by the thick sandstone aquifer of the Luohe Formation.This aquifer fea-tures abundant groundwater reserves and sufficient recharge,leading to severe water inrush hazards from the roof during coal mining.Con-sequently,the technology for preventing and controlling roof water hazards has become a critical technical challenge restricting safe mine production.To comprehensively analyze the current status of water inrush disasters prevention and control in coal mining under the ex-tremely thick roof sandstone aquifer in the Huanglong Coalfield,and explore the key research directions for roof water inrush disasters prevention and control based on new technologies in the future,the research progress of water inrush disasters prevention and control in the extremely thick composite roof sandstone aquifer in the Huanglong Coalfield in recent years was comprehensively summarized from the perspective of water inrush disasters prevention theory and technology.Based on the characteristics of roof water inrush disasters dur-ing coal seam mining in the Huanglong Coalfield,roof water inflow patterns can be broadly categorized into three major classes and six specific types.Among these,continuous high-flow water hazards,as well as pulsed water inflow and bed-separation-induced water inrush under the non-continuous inflow category,constitute the primary forms of hazards.In theory,by summarizing the water sources,channels,water inrush signs,roof structure,aquifer recharge-runoff-discharge conditions,roof overlying rock breakage,and water conduction chan-nel evolution caused by water inrush disasters in extremely thick roof sandstone aquifers,it has been clarified that under the influence of high-intensity mining,the research status of the development of water fissure zones develops significantly,with a maximum fracture-to-mining height ratio exceeding 30.The direct connection of this zone with the aquifer has been identified as the cause of continuous water inflow.The dual effects of aquifer recharge and mining extrusion are the cause of pulse-type water inrush disasters caused by the forma-tion of detachment space in the intersection area of the curved subsidence zone of the overlying rock and the fissure zone.Overall,the de-formation and inrush disasters characteristics of the overlying rock and the water inrush disasters disaster mechanism under strong mining conditions have been clarified.From a technical perspective,through the analysis of existing water-conducting cracks based on the advant-ages and disadvantages of technologies such as interstitial zone development height exploration,aquifer hydrogeological parameter acquis-ition,and water inrush disasters control for extremely thick roof sandstone aquifers,it is proposed that"groundwater interception"com-bined with long-distance directional drilling and targeted sounding technology to form a"source-cutting,centralized drainage"is a technic-al system that can effectively prevent and control water inrush in extremely thick roof sandstone aquifers.Furthermore,the direction for developing a multi-source intelligent monitoring and early warning technology within this technical framework has been clarified.On the basis of summarizing the current theories and technologies for water inrush disasters prevention and control in extremely thick roof sand-stone aquifers,combined with cutting-edge development directions,it was clarified that the Huanglong Coalfield is still facing problems such as the unclear mechanism of water release from the complex flow path of separated layer water under strong mining conditions and the disaster-causing mechanism.It pointed out the key development directions in the future in terms of deep-seated water inrush mechan-ism,high-precision detection and monitoring,research and development of new grouting materials,water-retaining mining and ecological protection,as well as mine water resource utilization and intelligent hazard prevention and control.

Abstract:The permanent magnet self-driven technology applied to rotating mechanical transmission systems can enhance the energy effi-ciency and performance of equipment.To enhance the transmission efficiency of small-power asynchronous motor drive systems in exist-ing mine hoists,a permanent magnet external rotor hoist integrating the drive unit and load has been developed.However,its highly integ-rated nature exposes the external surface of the drum directly to large radial time-varying loads,leading to two key technical challenges:① The edge cutting of permanent magnets exacerbates the cogging torque issue:the inner wall of the large-diameter drum requires axial segmented arrangement of a large number of permanent magnets,which must be matched with multiple stator slots.The topological struc-ture design with high power density is not only closely related to the efficiency and cost of the drive system but also effectively restrain the cogging torque caused by changes in magnetic field energy;② Mechano-electromagnetic coupled vibration induced by air gap variation:dynamic loads cause local deformation of the bearing surface,resulting in non-uniform variations in the air gap between the permanent magnets and the external circle of the stator.This exacerbates magnetic field distortion and triggers severe mechano-electromagnetic coupled vibration.It is therefore necessary to reveal the mechanism by which air gap variation affects vibration from a dynamic perspect-ive,which will facilitate the targeted exploration of suppression methods.First,this study reviews the development history of transmission schemes for mine hoists,introduces the permanent magnet external rotor hoist featuring"no reducer,no high-speed shaft,and no coupling,"and analyzes its main advantages over the three-phase asynchronous motor drive scheme.Subsequently,it focuses on elaborating the tech-nical status quo from three aspects:the topological structure design,dynamic analysis of the permanent magnet external rotor hoist,and the influencing factors of the magnetic properties of permanent magnets.This includes:The permanent magnet with external pole arc eccent-ric pole cutting and bidirectional non-magnetic fixing technology;Design methods for the permanent magnet edge structure and asymmet-ric stator slot structure;Analytical methods for air gap variation laws and mechano-electromagnetic coupled vibration characteristics.A 40-pole,168-slot single-rope winding permanent magnet external rotor hoist is taken as an example for verification through a combination of finite element analysis and on-site tests.The results show that:① The"chamfered-edge permanent magnet with external pole arc eccent-ric pole cutting+asymmetric rectangular slot"model can reduce torque ripple by 9％;② The causes of air gap variation include rotor de-formation and stator deformation.The former increases the amplitude of electromagnetic wave,while the latter generates high-order har-monics with orders of±2 and±4 near the main harmonic of the electromagnetic wave.Regarding the influencing aspects of the magnetic properties of permanent magnets,the discussion mainly focuses on two dimensions:the demagnetization characteristics and anti-demag-netization methods of permanent magnets,as well as the eddy current loss and temperature rise control of permanent magnets.Addition-ally,it looks ahead to the research content of permanent magnet external rotor hoists in terms of the magnetic properties of permanent magnets.Finally,the study discusses the layout scheme of the double-rope winding permanent magnet external rotor hoist and its applica-tion prospects in ultra-deep well hoisting systems.Numerical simulation results indicate that when the hoisting height is 2 000 m,the max-imum effective load can reach 70 tons.

Abstract:The development and utilization of lunar mineral resources is an important way to solve the earth's energy crisis.Drilling and coring,an effective method for lunar section sample collection,is a key prerequisite for accurately identifying the characteristics of lunar resource endowments.Restricted by the extreme lunar environment,energy power constraints,and complex lunar subsurface profiles,cur-rent lunar drilling remains hampered by the core bottleneck of insufficient drilling depth.To address the challenge of deep lunar sample collection under low-power conditions,the team proposed a rope-tethered self-excavating drilling coring scheme.A rope-tethered self-ex-cavating drilling coring robot was used to conduct 5-meter-deep drilling and coring tests in lunar regolith simulant.This study revealed the evolution laws governing coring and cuttings transport during the self-excavating drilling coring process in lunar regolith simulant,verify-ing the feasibility of the drilling scheme.In view of the harsh working conditions of the lunar base,the drilling load evolution law of differ-ent bit configurations is proved,and the suitable coring bit configuration and drilling procedure parameters were optimized.The test res-ults demonstrate that:① During the self-excavating drilling coring process in lunar regolith simulant,the drill pipe achieves efficient cut-tings evacuation,with the rotational torque constrained within 4 N·m,thereby enabling reliable acquisition of soil core samples;Bore-hole inspection results verify that the boreholes formed by this drilling scheme possess smooth walls and excellent stability.② In boulder and protruding rock drilling scenarios,the PDC bit outperforms the diamond bit in comprehensive drilling performance:it features signi-ficantly lower drilling force and load,a notably higher drilling rate,and a substantial increase in rotational speed can remarkably mitigate the drilling load.③ For lunar soil simulant,an increase in rotational speed can effectively reduce the drilling load,while the coring rate ex-hibits a trend of first decreasing and then increasing with increasing rotational speed.Under the condition of a constant feed rate-to-rota-tional speed ratio,both the penetration rate and rotational speed are positively correlated with significant increases in drilling force/load and the coring rate.This implies that a balance between the coring rate and drilling force/load must be considered when selecting drilling parameters.This study can provide a reference for the future unmanned deep drilling exploration of the moon in China.

Abstract:In order to promote the development of new quality productivity in the open-pit coal mine field,serve the high-quality trans-formation and upgrading of the coal industry,and support the national strategic goal of"dual carbon",a comprehensive study is being con-ducted on the development process of intelligent mining technology and equipment in China's open-pit coal mines.The theoretical founda-tions and applied technological innovations in the areas such as full-lifecycle design,green and efficient mining,intelligent mining and safe mining are investigated,and seven key intelligent mining technologies are proposed,including unmanned intelligent aerial surveying,integrated intelligent design and management,intelligent drilling and blasting with security,unmanned transportation,remote intelligent control of the equipment,slope engineering and geological disaster prevention,and comprehensive safety supervision of personnel and equipment.These address the safe,intelligent and efficient mining technical challenges faced by the intelligent construction of China's open-pit coal mines.The advances in process and technology innovations as well as independent and controllable equipment are systemat-ically elaborated;the breakthroughs in key equipment such as high-cutting-force bucket-wheel excavator,and power transmission systems for huge mining trucks are analyzed;The innovative applications of new energy equipment including the world's first 100-ton autonom-ous dump trucks with the cab-less design,bidirectional operation and pure-electric propulsion and mining trucks with pure electric,battery swapping and hydrogen driven are highlighted;a new intelligent mining mode for open-pit mines has been established,characterized by continuous process innovation,green power system upgrades and the robotization of mining equipment.The achievements and experi-ences from typical intelligent open-pit coal mine projects are condensed.They indicate that the future intelligent developments in open-pit coal mines require deepening the"green,safe,efficient"three core goals,breaking through the independent and controllable bottlenecks in high-end equipment and key components and actively addressing challenges such as flexible mining,dual carbon goals and unmanned mine.These will promote the establishment of a new integrated intelligent decision-making system driven by AI large models,provide the oretical support and technical path for the high-quality development of the industry.

Abstract:Coal and gas outbursts remain one of the major hazards in deep coal mining in China.With increasing mining depth and intens-ity,the associated influencing factors and their coupling relationships have become increasingly complex,and the combined effects of high in-situ stress,gas pressure,and gas content markedly increase outburst risk,seriously constraining safe and efficient coal production.Ac-curate and reliable monitoring and early-warning technologies and equipment have therefore become an urgent necessity for monitoring and preventing outburst dynamic hazards in deep coal mines.A theoretical model of acoustic and electromagnetic effects induced by the failure of gas-bearing coal under stress was researched,forming the foundation for a multi-signal early warning mechanism based on acoustic,electromagnetic,and gas responses.The response characteristics of acoustic,electromagnetic,and gas signals during outburst evolution were clarified,and an intelligent acoustic-electromagnetic-gas monitoring and early-warning equipment and system were de-veloped.Distributed monitoring methods for acoustic-electromagnetic-gas signals in both roadway development and longwall extraction faces were formulated.The precursor characteristics of acoustic,electromagnetic,and gas signals during the disaster evolution process were analyzed,and an intelligent recognition method for these precursors was established.The time-frequency variation patterns and com-plex evolutionary characteristics of precursor responses and other disturbance signals during outburst development were further investig-ated.A comprehensive technical system for acoustic-electromagnetic-gas monitoring and early warning was constructed,along with a hier-archical multi-signal fusion warning approach.A real-time cloud platform was also developed for the integration and sharing of monitor-ing and warning data.Typical field cases were selected to validate the proposed intelligent acoustic-electromagnetic-gas monitoring and early-warning method in engineering applications.Field validation confirmed that intelligent and accurate identification and early warning of coal and gas outbursts can be achieved through the deployment of specialized equipment,data integration,and comprehensive analysis of signal features and coupling relationships.This work provides theoretical and technical support for the prevention,control,and engin-eering-scale application of coal and gas outburst hazards in deep coal mines.

Abstract:In the aftermath of safety accidents in coal mines,the pervasive phenomenon of roadway collapse and obstruction poses an ur-gent on-site challenge:namely,the expeditious assessment of the internal structure of heterogeneous debris and the creation of rescue channels.At present,there is a paucity of methods to guide the rapid assessment of heterogeneous debris structures,resulting in a signific-ant amount of time spent on-site evaluating these structures.This has the effect of delaying rescue timelines and hindering the rapid estab-lishment of rescue passages.In order to address this issue,a case analysis approach was adopted in order to study the structural character-istics of post-disaster roadway heterogeneous debris and the factors that influence them.A three-dimensional framework was established,comprising disaster type,surrounding rock lithology,and support type.Each dimension was characterised by a set of indicators based on the inherent properties of the disaster.The disaster type dimension includes two categories:gradual failure and triggered failure.The sur-rounding rock lithology dimension includes three categories:hard rock,medium-hard rock,and soft rock.The support type dimension in-cludes four categories:bolt/cable support systems,steel frame support,and composite support.The amalgamation of disparate indicators across these three dimensions engenders 18 distinct types of heterogeneous debris structures and their characteristics,thereby precipitating a rapid three-dimensional classification method for post-disaster roadway heterogeneous debris.The classification results are denoted by alphanumeric codes(111-233),where the first digit indicates the disaster type(1=gradual failure,2=triggered failure),the second digit indicates the surrounding rock lithology(1=hard rock,2=medium-hard rock,3=soft rock),and the third digit indicates the support type(1=bolt/cable support system,2=steel frame support,3=composite support).A detailed analysis was conducted of a roof fall accident in the haulage roadway of the 113101 working face of a specific mine.The rapid three-dimensional classification method was used to cat-egorise the heterogeneous debris left behind by the disaster,resulting in a classification of"131".Key characteristics include uniform and dense accumulation due to the plastic flow of soft rock,bolts scattered within the rock mass and enveloped by it,and stretched metal mesh covering the bottom.Particle flow numerical simulation software was used to simulate the collapse characteristics of the accident.The sim-ulation results indicated plastic failure of the soft rock,as well as deformation or fracture of the bolts and cables within the rock mass and stretched metal mesh covering the surface.These simulation results largely align with the characteristics of the"131"classification.The method was applied to two further cases,resulting in classifications of"121"and"132".The structural characteristics of the heterogen-eous debris in both cases were consistent with the results of the on-site investigation,thereby validating the classification and demonstrat-ing the feasibility of using this rapid,three-dimensional method to classify heterogeneous debris on post-disaster roadways.This method can provide scientific support for rapidly assessing the internal structure of heterogeneous debris and clearing rescue channels during emer-gency response operations in coal mine accidents.

Abstract:Aiming at the roof control problem of super-large mining height in near-shallow buried thick unconsolidated layers represented by Yushen Mining Area,the theoretical analysis,numerical simulation and field measurement are used to analyze the pressure law,roof structure and strong dynamic load control method of 10 m super-large mining height fully mechanized mining face.The results show that:The roof breaking form of super-large mining height in near-shallow buried thick unconsolidated layers is a combination of"low canti-lever beam(equivalent direct roof)+high masonry beam(key layer structure group)".The instability load of high masonry beam is posit-ively correlated with the thickness of unconsolidated layers,and decreases with the increase of bearing capacity of bedrock layer.When the base-load ratio Jz≤1.5,the influence range of"vertical stress relief zone"and"horizontal stress concentration zone"in the overlying strata will expand with the increase of the base-load ratio,and the bearing capacity and structural stability of the high-level"key stratum struc-ture group"will gradually increase,which is conducive to the increase of the overall weighting step distance and the weakening of the weighting strength of the working face.When the base load ratio Jz>1.5,the influence of the base load ratio on the stress environment of the roof strata is weakened,the load of the high bedrock layer structure and the loose layer tends to be balanced,and the risk of strong dy-namic load pressure in the working face is significantly reduced.According to the characteristics of roof structure and the pressure law of working face,the prevention and control measures of strong mine pressure are put forward:in the area of base load ratio Jz≤1.5,improv-ing the bearing capacity of high-level"key stratum"structure is the key to reduce the pressure strength of working face.The location of the key layer should be accurately determined to avoid regional weakening measures for the key layer of the bearing structure.When the base load ratio Jz>1.5,reducing the mining height and regional weakening of the low-position thick and hard roof to improve the filling rate of the goaf will more effectively reduce the pressure strength of the working face.The research conclusion has been verified and applied in the industrial practice of fracturing strong mine pressure prevention and control in the roof area with super large mining height,and has achieved ideal results.

Abstract:Coal is the"ballast stone"for China's energy security,but hidden disaster-causing factors and the"three highs and one low"problems in deep underground environments pose threats to the safe,efficient and green mining of coal mines.Currently,the detection of hidden disaster-causing factors in mines mainly relies on geological surveys,drilling and geophysical exploration methods,but these meth-ods have problems such as limited data acquisition,high costs and narrow coverage.Distributed optical fiber sensing technology(DOFS),with its advantages of distributed sensing,long-distance coverage,high-precision measurement and anti-electromagnetic interference,can monitor multiple parameters such as stress,temperature,seepage and vibration in real time,thereby significantly enhancing the detection capability of hidden disaster-causing factors.This paper systematically reviews the core technologies and parameter indicators of DOFS in the monitoring of hidden disaster-causing factors in mines,including fiber Bragg grating(FBG),optical time-domain reflectometry(OT-DR),optical frequency-domain reflectometry(OFDR),Brillouin optical time-domain reflectometry(BOTDR),Brillouin optical time-do-main analysis(BOTDA),Brillouin optical frequency-domain analysis(BOFDA),Raman optical time-domain reflectometry(ROTDR),Ra-man optical frequency-domain reflectometry(ROFDR)and distributed acoustic sensing(DAS).A comparative analysis of the above tech-nologies is conducted from multiple perspectives such as monitoring capabilities,applicable scenarios and selection criteria,and typical engineering cases are combined to discuss the application advantages of DOFS in aspects such as the stability analysis of coal mine sur-rounding rock,health monitoring of support structures,gas disaster early warning,evolution of the temperature field in roadways and state assessment of belt conveyors.The current situation of DOFS technology in precise acquisition of multi-field data,intelligent interpretation of massive data,effective representation of sensing data and joint monitoring with multiple means is analyzed,and optimization schemes are proposed,including clarifying the feedback mechanism between optical fiber sensing data and disaster-causing factors,optimizing the construction of multi-source and multi-field coupling systems,establishing a disaster evolution model based on spatio-temporal big data mining,and promoting the construction of intelligent monitoring and real-time early warning systems.Based on the three-layer architec-ture of"physical space,sensing space and decision-making space",this paper proposes a conceptual model of the monitoring and early warning system for hidden disaster-causing factors in mines,and combines DOFS with artificial intelligence technology to achieve intelli-gent matching and autonomous regulation,thereby providing theoretical and technical support for mine disaster early warning and the con-struction of smart mines.

Abstract:The influence mechanism of polyacrylamide(PAM)residue on the flotation of low rank coal during coal slurry water treatment is investigated using low rank coal from the Panji and Pan Yidong Coal Processing Plants in the Huainan Mining Area.A model of the characteristic structural unit of low rank coal is constructed using X-ray diffraction and infrared spectroscopy.Density Functional Theory(DFT)calculations are employed to study the adsorption interactions between water molecules,dodecane,PAM adsorption structural units,and the characteristic structural units of low rank coal.The DFT results are validated through flotation tests conducted with varying PAM dosages to assess the impact of PAM residue on flotation performance.The DFT results indicate that the average adsorption energies of water molecules,dodecane,and PAM adsorption units with the characteristic structural units of low rank coal are-0.35,-0.39,and-0.50 eV,respectively.The adsorption stability follows the order:polyacrylamide(PAM)>dodecane>water molecules.This indicates that in the competitive adsorption system,PAM has formed a more stable adsorption configuration on the surface of low-rank coal,rendering it diffi-cult for dodecane to effectively displace the pre-adsorbed PAM molecules.Among the three PAM adsorption structural units,P-DAC shows the strongest adsorption with the low rank coal characteristic structural unit,significantly reducing both the adsorption sites and ca-pacity of dodecane.This results in decreased overall adsorption stability in the competitive adsorption system,weakening the trapping ef-fect of dodecane.The adsorption mechanism between low rank coal characteristic units and water molecules is mainly governed by hydro-gen bonding and van der Waals force,with hydrogen bonding being the dominant driving force.In contrast,the adsorption of low rank coal units with dodecane and PAM is primarily driven by van der Waals force,with P-AM and P-AA assisting adsorption through hydro-gen bonding with-C=O groups.PAM molecules influence the charge transfer between collecting agents and low rank coal units,further weakening the adsorption effect and reducing adsorption stability.Flotation tests reveal that while PAM enhances fine coal yield,it signi-ficantly increases the ash content of fine coal,reduces flotation recovery and performance indices,leading to an overall deterioration in flotation efficiency.The combined DFT and experimental findings suggest that the polar groups in PAM have low selectivity,causing both coal and gangue minerals to be floated simultaneously.Furthermore,the flocculation effect of PAM interferes with the effective adsorp-tion of collecting agents and hinders the hydrophobicization of coal particles,further compromising flotation performance.This study provides a theoretical basis for optimizing flotation processes and the rational use of flocculants through DFT simulations and flotation tests.

Abstract:The efficient and intelligent production in coal mining necessitates more precise detection of hidden underground disaster-caus-ing factors.Rapid excavation faces challenges in the accuracy and efficiency of detecting coal-rock interfaces,geological structures,and water-bearing anomalies ahead of the working face.To address issues such as limited construction space,strong electromagnetic interfer-ence,and long distance detection anomalies,this study proposes an integrated advanced borehole detection system combining drilling and geophysical methods for areas ahead of tunneling.To enhance radial long distance detection range and anomaly imaging precision,a virtu-al wavefield full-waveform inversion algorithm for pseudo-acoustic media based on wavefield inverse transformation and a three-compon-ent spatial positioning algorithm were developed.These enable borehole Transient Electromagnetic(TEM)methods to achieve intelligent inversion and 3D imaging of concealed water-bearing anomalies near the borehole.Innovative techniques were also introduced for bore-hole radar,including an in-situ method for determining coal-seam radar wave velocity and a spatially constrained migration imaging meth-od guided by borehole trajectory,significantly improving the identification accuracy of coal-rock interfaces and geological structures.To overcome the limitations of single-method detection,a multi-parameter,multi-component integrated borehole detector was developed,combining borehole TEM,radar,and natural gamma methods.The compatibility of simultaneous multi-frequency electromagnetic wave detection was verified.A multi-source data fusion and interpretation platform with multi-borehole comparison and multi-parameter link-age analysis functions was established.This platform enhances geological interpretation accuracy and lithological resolution through col-laborative data inversion,reducing interpretation ambiguity and forming a complete intelligent borehole advance detection and identifica-tion system.Field applications demonstrate that this technology is suitable for rapid excavation in coal mining.It enables precise detection within a radial range of 30 meters over advance distances exceeding 1 000 meters in a single drilling run.This effectively resolves the con-flict between exploration and excavation sequences,significantly improves roadway driving efficiency and safety,and provides robust geo-logical support for the green and high-efficiency development of coal mines.

Abstract:Coal flotation is a critical stage in modern coal preparation,and its intelligentization plays a key role in the overall transforma-tion of coal-washing plants.The ash content of the flotation concentrate directly reflects product quality and impurity removal efficiency.Precise control of concentrate ash not only guides reagent dosing and process optimization,but also supports maximal coal recovery and economic returns.To address the challenges of delayed ash-content measurements and the underutilization of heterogeneous data,we pro-pose an intelligent detection method for flotation coal ash based on multi-source information fusion.The method integrates X-ray fluores-cence(XRF)spectral data,real-time flotation process variables,and tailings imagery features.We use continuous projection and multiple linear regression for spectral dimensionality reduction and apply the Hilbert-Schmidt independence criterion(HSIC)for time-series align-ment to handle asynchronous data streams.A regularized Random Vector Functional-Link network with dynamic node adjustment is then developed to model nonlinear relationships between multi-source data and ash content.Experimental results show that the root mean square error is 0.113,the coefficient of determination is 0.787,and the pass rate is 100%when the absolute error of ash content is 0.3.The developed intelligent ash-content detection system has been successfully deployed on-site,achieving real-time,high-precision measure-ments that meet the production process requirements.This system provides comprehensive technical support and decision-making data for the flotation process,enhancing detection accuracy and process control.

Abstract:The surface subsidence caused by coal mining threatens the living environment and infrastructure safety in mining areas.Reas-onable control of the subsidence range can alleviate the conflict between the safety of pro-tected objects and the recovery of constrained re-sources,which is of significant practical importance for the rational planning and sustainable development of mines.Addressing the un-clear transmission path of stress damage from coal pillar side mining in the coal seam-overburden-surface system,as well as the unclear control mechanism of surface subsidence boundaries due to pre-splitting of thick hard rock layers,this study clarifies the propagation ef-fect of stress damage in thick hard rock layers based on theoretical research and mechanical analysis.It analyzes the conduction path of stress damage in the overburden and constructs a mechanical transmission model for surface subsidence boundaries.On this basis,it re-veals the control mechanism of surface subsidence boundaries based on pre-splitting of thick hard rock layers,subsequently proposing an optimization method for subsidence boundaries and validating its effectiveness.The research results indicate that the sus-pended beam formed after the fracture of thick hard rock layers bears additional loads,causing stress damage to shift deeper into the original rock.Pre-splitting at specific locations of thick and hard rock layers can improve the load and stress concentration above the coal rock mass,thereby reducing the range of surface subsidence.Notably,the offset is positively correlated with the additional load,while the pre-splitting pres-sure relief capacity is negatively correlated with the subsidence range.By combining engineering examples,the protective coal pillar widths under pre-splitting of thick and hard rock layers at different levels are determined:185.5 m for pre-splitting only the upper thick hard rock layer,176.1 m for only the lower thick hard rock layer,and 148.3 m for pre-splitting both upper and lower thick hard rock layers.Compared to the unpre-splitting scheme,this allows for the liberation of 6.0%,10.8%,and 24.9%more constrained coal pillar resources on the outer side of the pro-tective zone,respectively.After pre-splitting the lower hard rock layer on-site,the measured surface subsidence range decreased by 20 m,validating the accuracy of the model and method.The research results can serve as a beneficial supplement to the traditional theoretical system for retaining protective coal pillars and hold certain reference value for damage prevention and production continuity in mining areas.

Abstract:The south exploration block of Wuxiang County in Qinshui Basin of Shanxi Province is one of the important coalbed methane resource rich areas in China.However,its complex geological structure features,especially the alternating distribution of folds and faults,greatly restrict the efficient development of CBM.Therefore,combined with the regional geodynamic background,the structural character-istics of folds and faults in this block are systematically analyzed,on the basis of detailed interpretation of 3D seismic,logging and drilling data,a 3D model of fault and coal seam in the study block is constructed,and the correlation of sedimentary and structural characteristics with the variation of coal thickness and CBM content in this block is analyzed emphatically.From the researched results,it can be con-cluded that:Firstly,according to the structural composition and occurrence characteristics,four different distribution regions are divided,and the nature,elements and distribution characteristics of the main structures in each region are discussed,which provides a scientific basis for the systematic classification of regional geological structures;Secondly,according to the structural geometry and dynamic classi-fication method,the block coal-controlling structural styles are divided into 3 structural types(extension,extrusion,strike-slip fault)and 9 subtypes,and the influence mechanism of structure on CBM enrichment is further refined.Thirdly,through the analysis of sand-mud ratio,sediment,lithology and geological structure characteristics of Shanxi Formation and Taiyuan Formation,the correlation between sediment-ary environment,lithology of top and floor and changes of coal seam thickness and gas content is briefly discussed,revealing that sedi-mentary environment has a direct control effect on the thickness of coal seam,and the thickness of coal seam further affects the distribu-tion of gas content.The controlling effect of structure on gas abundance is further studied.On this basis,three CBM enrichment areas in No.3 and No.15 coal reservoirs are delineated respectively,and the distribution characteristics of CBM enrichment areas are drawn.The research results can provide a basis for the scientific selection of efficient CBM development in this block.

Abstract:Coal mine gas explosion accident will not only produce a huge shock wave,but also produce a large number of toxic and harm-ful gas CO,which seriously affects the mine safety production environment.In order to achieve the dual protection of explosion suppres-sion and gas ablation,CuO-CeO2 composite oxide was used as CO catalyst and CaO was used as CO2 adsorbent.The catalytic adsorption composite powder CuO-CeO2/CaO doped with CaO was prepared by the combination of solid phase impregnation and thermal dispersion.The effects of H2O and CaO doping amount on the catalytic adsorption performance were investigated by heating and isothermal gas reac-tion experiments.The physical and chemical structures of CuO-CeO2/CaO were characterized by X-ray diffractometer,X-ray photoelec-tron spectrometer,Raman spectrometer and scanning electron microscope.The explosion suppression and gas ablation properties of differ-ent powders were analyzed by 20 L spherical explosion tester and gas chromatograph.The results show that the doping of CaO reduces the negative effects of H2O and CO2 on CuO-CeO2/CaO,promotes the formation of surface oxygen vacancies and the interaction between Cu-Ce,and then improves the CO catalytic performance,so that it can completely oxidize CO at about 120℃.When the doping amount of CaO is 15%,its CO catalytic performance and CO2 adsorption are the highest.Compared with equal mass Al2O3 and CuO-CeO2 powders,CuO-CeO2/CaO composite powders have stronger explosion suppression and gas ablation ability.The specific performance is that after adding CuO-CeO2/CaO,the maximum explosion pressure,maximum pressure rise rate and deflagration index of gas explosion reach the lowest,which are 0.483 MPa,7.60 MPa/s and 2.1 MPa·m/s,respectively,and the elimination rates of CO and CO2 reach the highest,which are 89.1%and 95.3%,respectively.The study confirmed that the composite powder CuO-CeO2/CaO can eliminate CO and CO2 by its catalytic adsorption,and reduce the gas explosion pressure by interrupting the chain reaction,dilution asphyxiation and endo-thermic effect of adsorption products,which provides a new idea for reducing the risk of gas explosion.

Abstract:The water environment governance and restoration in closed coal-mine areas serves as a vital foundation for the sustainable de-velopment of the mining area's ecological environment.The key lies in the identification of characteristic pollutants within the groundwa-ter environment of the mining area.In the Junlian Mining Area on the southern margin of the Sichuan Basin,the Longtan Coal-measure is exploited.The overlying Triassic and underlying Permian strata are both distributed with relatively thick carbonate rocks.The discharge of pollutants in the water gushing from the Longtan Coal-measure strata of closed mines has exerted an impact on the karst groundwater en-vironment.A characteristic pollutant identification system for closed coal-mine areas is established.Through hydrochemical characterist-ic analysis methods,hydrogen-oxygen isotope methods,and principal component analysis methods,the source-indicating properties of pollution indicators in the water gushing from the Longtan Coal-measure strata are analyzed and quantified.The pollution attributes are quantified using the analytic hierarchy process,and the pollution degree is quantified by the sub-item pollution index method.The quanti-fication results are weighted and integrated by the subjective-objective comprehensive weighting method for comparative analysis,thereby enabling the identification of characteristic pollutants among the pollution indicators of the water gushing from closed mines.The results indicate that the pollution indicators in the water gushing from closed mines mainly originate from the water-rock interaction res-ulting from the weathering and dissolution of carbonate rocks,silicate rocks,and their ore-bearing components,as well as the residues of mining activities.In the study area,the pollution indicators iron and manganese possess attribute characteristics such as strong toxicity,non-degradability,and weak mobility.Their enrichment is likely to have an impact on the local water environment,while CODCr and sulfate with relatively high migration intensity are prone to polluting the regional water environment.Among the pollution indicators,iron,manganese,CODCr,and sulfate exhibit significant pollution degrees.Ultimately,iron,manganese,CODCr,and sulfate,which have a relat-ively large proportion of the comprehensive weight,are identified as the characteristic pollutants in the water gushing from closed mines in the study area.They require key monitoring and treatment.Meanwhile,by combining the identification results with the karst hydrogeolo-gical conditions,four genetic models of characteristic pollutants are proposed,namely the"coal gangue leaching and infiltration type",the"goaf water-rock interaction type",the"oxidation of mining facilities type",and the"composite type".This research plays a guiding role in the groundwater pollution treatment in the Junlian mining area on the southern margin of the Sichuan Basin and also provides ideas for the identification of characteristic pollutants in groundwater-polluted areas of similar mining regions.

Abstract:The working conditions of the scraper conveyor are complex,and the excessive wear of the sprocket will lead to an increase in the failure rate of the scraper conveyor meshing transmission system,affecting the production efficiency and service life,and even threat-ening the life safety of the operator.Inspired by the control chain tension of the sprocket center distance adjusted by the tail of the telescop-ic machine,the mechanical drive structure of the double electric cylinder of the head and tail was designed,and the sprocket shaft adopted a segmented structure,and a test platform for simulated loading and vibration wear detection of the meshing transmission system was built.The chain tension model and the differential equation of vibration wear of the meshing transmission system are established,the influence of sprocket wear and chain tension on the vibration displacement of the transmission system is clarified,and the control method for con-trolling chain tension based on vibration displacement monitoring is designed.Based on the relationship between the center distance of the sprocket and the chain tension,a multi-working condition simulation method of scraper conveyor was designed,and the downhole load characteristics of the scraper conveyor were simulated,and the influence of sprocket wear on thevibration displacement of the meshing transmission system under half-load,full-load,half-load impact and full-load impact conditions was analyzed,and the vibration displace-ment test of sprockets with different wear amounts was carried out.The results show that the chain tension increases with the increase of sprocket center distance,and the vibration displacement of the meshing transmission system increases with the increase of chain tension and sprocket wear.