Abstract:Coal-based green filling materials exhibit component diversity and multi-dimensional performance.Consider-ing the entire solidification process of the backfill and scientifically selecting a multi-component formulation is the primary concern for ensuring mine backfill quality.Accordingly,a Box-Behnken design(BBD)was first employed,with fly ash content(20%‒60%),slurry concentration(82%-86%),and gangue-to-binder ratio(3-7)as independent variables to construct response-surface models for the backfill's overall solidification performance(bleeding rate,setting time,and 28 d uniaxial compressive strength).Analysis of variance indicates that all regression coefficients in the models are statist-ically significant,prediction errors remain within 5%,and the models demonstrate very high fitting accuracy and reliable predictive capability.Fly ash content significantly influences bleeding rate and setting time;increasing fly ash improves slurry stability but delays setting.Slurry concentration is most sensitive to strength enhancement,with higher concentra-tions markedly boosting hydration efficiency.The gangue-to-binder ratio shows significant interactions with both concen-tration and fly ash content regarding strength and setting behavior.Next,the non-dominated sorting genetic algorithm NSGA-II was introduced for multi-objective optimization,yielding over 100 Pareto-optimal formulations.By treating suit-able setting time and controlled bleeding rate as basic constraints,and maximizing backfill strength and coal-based solid-waste utilization as objectives,three representative formulations meeting all constraints were selected,validating the prac-ticality of the NSGA-II approach for filling-material design.This BBD-NSGA-II-based method realizes scientific decision-making for multi-component coal-based green filling materials and can serve as a reference for similar formulation optim-ization.

Abstract:With the advancement of mechanized coal mining,raw coal feed exhibits characteristics of high ash content and clay-rich gangue,resulting in the generation of large quantities of difficult-to-settle high-ash coal slime water during wet coal processing.This high-ash slime is characterized by fine particle size,high clay content,and strong surface electroneg-ativity.Its colloidal stability primarily stems from hydration repulsion caused by surface hydration films and electrostatic repulsion between charged particles.These microscopic interactions severely constrain the sedimentation,clarification,and dewatering efficiency of coal slime water.Therefore,in-depth investigation into the surface hydration properties of coal slime particles holds significant theoretical importance for addressing coal slime water treatment challenges.This pa-per introduces fundamental theories of particle surface hydration,elucidates the formation mechanism of hydration films at water-particle interfaces at micro/nano scales,and discusses their decisive role in determining interfacial properties.It ex-amines the influence of both particle surface characteristics and solution properties on hydration film structure and thick-ness,analyzes surface hydration features of predominant fine particles in coal slime water,and reviews advanced charac-terization techniques including atomic force microscopy,infrared spectroscopy,nuclear magnetic resonance,molecular vi-brational spectroscopy,rheometry,and quartz crystal microbalance,along with research methodologies such as Einstein's viscosity equation and molecular simulations.Finally,it prospects the application potential of hydration film manipulation and advanced characterization technologies in coal slime water treatment.

Abstract:In response to the common problems in the traditional spraying and filling material transportation processes in underground coal mines,such as discontinuous processes,redundant transfer links,high reliance on manual labor,poor stability during long-distance transportation,and high maintenance costs,which lead to a vicious cycle of"excavation first,repair later,repeated instability"and exacerbate the tension in the connection between mining and excavation,through analyzing the current demand for intelligent transportation in underground mines,a green and intelligent pneumatic trans-portation system for long-distance transportation between the surface and the underground was developed based on do-mestic technology.This system adopts a three-level modular architecture of"ground station‒transfer station‒workstation",combined with multi-level pressure dynamic compensation mechanism and optimized technology for dilute-phase gas-sol-id two-phase flow,achieving efficient and sealed transportation of dry-mixed materials over extremely long distances.Through precise metering of premixed materials and the end spraying process,the material gradation and uniformity of mixing are optimized,significantly reducing the rebound rate of spraying.Relying on industrial Ethernet and 5G dual-mode communication technology,a remote collaborative control platform integrating real-time monitoring,dynamic path planning,and intelligent equipment diagnosis was constructed,forming a three-level regulation and transportation system of"surface storage‒underground pressurization‒mobile terminal".The application results of Luan Xing Yuan Coal In-dustry show that compared with the traditional rubber-wheel vehicle transportation method,this system increases the annu-al spraying volume by 106%,reduces the total cost by 41.2%,decreases the number of workers per working face by 80%,and also has the advantages of full enclosure,low energy consumption,and less manpower.This system is the first to achieve 100%domestic equipment integration,providing an innovative solution for intelligent support and green,safe,and efficient production in long-distance coal mining in coal mines.

Abstract:Residual coal resources are abundant and widely distributed,possessing dual value as high-quality energy and strategic underground space.Based on the origins,propagation attenuation,and characteristics of static loading associated with disturbance stress waves during upward mining and underground space utilization in coal mine goafs,this study pro-poses the scientific issue of"low-frequency dynamic disturbance coupled with static pre-stress."A theoretical framework of disturbed rock mechanics was developed to support the synergistic system of residual coal recovery and underground space development.A multi-field coupling servo testing system was independently designed,capable of applying water-gas-temperature conditions along with static and dynamic loads.Drawing on prior studies,this research systematic-ally investigates the dynamic mechanical responses of coal and rock materials under low-frequency disturbances,includ-ing tension,compression,and shear behaviors.The relationship between the number of disturbance cycles and amplitude prior to instability in high-stress coal and rock was quantitatively characterized.Strength degradation behaviors under vari-ous static pre-stress levels were evaluated for sandstone,coal,and backfill materials.Predictive criteria were proposed for the pre-failure identification of high-stress coal-rock systems under disturbance,revealing intrinsic mechanisms linking strength degradation to microcrack evolution.A damage variable and strength criterion incorporating low-frequency dis-turbance effects were derived.Findings indicate that the influence of excavation-induced disturbance must be fully con-sidered in feasibility assessments,stability evaluations,and dynamic instability prevention during residual coal mining.These results provide theoretical guidance and decision support for the safe and efficient development of residual coal and underground resources in mined-out areas.However,challenges remain in achieving safe and green recovery of residual coal and the scientific utilization of goaf spaces,particularly under the compounded risks of water accumulation,gas buildup,dynamic pressure,and spontaneous combustion.The practical application of disturbed rock mechanics in the"re-sidual coal-space development"framework still faces several technical bottlenecks:The dynamic mechanical behavior of coal and rock under complex water-gas-thermal conditions remains unclear;The amplification effect of existing fractures in disturbed coal-rock mass under multiple mining disturbances lacks quantitative characterization;The stability and long-term operation of novel carbon storage/fixing backfill materials and their constructed spaces require further study;The li-thological heterogeneity of sedimentary rocks hinders the development of universal dynamic mechanical models and con-stitutive relationships.To overcome these challenges,it is essential to advance the engineering translation of disturbed rock mechanics theory within the regulatory framework of coal mine safety.This will enable breakthroughs in green,low-car-bon utilization of residual coal resources and the empowered transformation of goaf space,supporting the development and implementation of critical technologies for high-recovery,safe,and sustainable mining of difficult-to-extract coal resources.

Abstract:After open-pit mining of limestone,the resulting exposed slopes and soil depletion exhibit characteristics of desertification,posing key challenges in mine ecological restoration.To optimize ecological restoration technologies for limestone open-pit mines and enhance restoration efficacy,57 typical limestone open-pit mines already treated in Xuzhou are assessed.Using the TOPSIS method,six indicators across three categories—soil quality,vegetation quality,and geo-morphic reconstruction—were evaluated.The findings show that spray seeding greening technology yields the best restor-ation results,followed by slope greening and platform greening.Other methods like retaining soil cofferdams and vegeta-tion holes demonstrate relatively lower effectiveness.Based on these results,parameter optimization for existing restora-tion techniques and design specifications are proposed,providing a practical reference for ecological restoration of similar limestone open-pit mines.

Abstract:The large-scale stockpiling of coal gangue causes issues such as the occupation of arable land and environment-al pollution.Effective methods for the disposal and utilization of coal gangue are urgently needed.To this end,starting from common raw materials,coal gangue and auxiliary materials were used as raw materials to prepare soil-like substrates by mixing them in different proportions.Pot experiments were conducted to observe crop growth under various mixing ra-tios.The optimal substrate composition suitable for crop growth was selected.Based on this,pot experiments were re-peated with the best ratio to evaluate the potential heavy metal risks in the substrate and the safety of agricultural products.Later,field trials were conducted with the same mixture to verify the effectiveness and feasibility of coal gangue-based soil substrates.The results show that reconstructing soil with coal gangue and additives is feasible.The optimal volume ra-tio of coal gangue to additives is 7∶3.The heavy metal content in the soil-like substrates meets national standards.Crops grown in field trials showed no excessive pollution,achieving the effect of"solid waste coordination".It provides a theor-etical basis and technical support for the soil utilization of coal gangue and ecological restoration in mining areas.

Abstract:The large amount of coal gangue after washing in Dahaize Coal Mine not only increases the operation cost of the mine,but also causes environmental pollution on the ground to varying degrees.Under special circumstances,the problem of difficult treatment of coal gangue also seriously affects the normal production organization of the mine.In or-der to solve the problem of large amount of coal gangue stored in the coal mine,a million-ton coal gangue overburden isolation grouting backfilling mining technology is carried out in Dahaize Coal Mine.The principle of overburden isola-tion grouting backfilling technology is analyzed in detail,that is,the key layer to control surface subsidence is found in the stratum above the mining area,the grouting filling mining parameters are designed based on the principle of no breakage of the key layer,and the solid waste materials such as coal gangue are used to form a compacted bearing structure to sup-port the key layer,so as to effectively control the movement of rock strata and surface,reduce ground collapse,and Com-bined with the special conditions and challenges of post-mining grouting in Dahaize Coal Mine,the project overview,pro-cess flow,grouting drilling and filling parameters are studied,and the technical,economic,environmental and social bene-fits of the project implementation are evaluated.The overburden isolation grouting backfilling technology of coal gangue overburden rock effectively reduces the ground stacking amount of coal gangue,reduces the occupation of land resources and the pollution to the environment.At the same time,the establishment of a million-ton coal gangue treatment system,the maximum processing capacity of gangue can reach 4000 tons per day,with the completion of the foreign gangue al-location and repair system,the annual processing gangue can steadily reach 1.5 million tons,improving the treatment ca-pacity and efficiency of coal gangue,and realizing the resource utilization of coal gangue.Moreover,reducing the treat-ment price of gangue to less than 60 yuan has great economic benefits,and also innovates a green mining model of"gangue is not discharged,water retention mining,and surface sinking is reduced".This achievement not only provides a new technical path for mining under similar geological conditions,but also contributes effective strategies for environ-mental protection and sustainable development of mining areas.

Abstract:Cemented paste backfill(CPB)technology,serving as a foundational support for green mining,enables the effi-cient utilization of tailings and other solid wastes while controlling underground pressure and reducing environmental pol-lution.It has become a critical method for deep metal mining operations.The CPB pipeline transportation system,acting as the vital link between the surface and underground stopes,has become a major research focus in recent years.The sta-bility,safety,and intelligence of this system directly determine the effectiveness of the backfilling process.The current re-search status of CPB pipeline transportation technology has been systematically reviewed.At the level of fundamental characteristics,it delves into the rheological behavior of CPB slurry(a high-concentration non-Newtonian fluid),elucidat-ing the influence mechanisms of concentration,particle size distribution,temperature,and additives on shear yield stress and thixotropy.Diverse testing methods,including L-pipe tests,loop tests,and Electrical Resistance Rheography(ERR),are employed to evaluate pipeline resistance.In terms of theory and modelling,it summarizes modified Herschel-Bulkley resistance models,particle migration theory,and pipeline wear prediction methods.It emphasizes the critical role of wall slip effects,particle radial migration,and structural time-dependence on pressure drop and wear.Regarding engineering applications,it analyzes optimization strategies for vertical borehole full-pipe flow control technology,gravity flow,high-pressure pumping,and relay pumping for long-distance transportation.It also reviews advancements in core technologies such as air-water coupling pipeline flushing and intelligent pressure monitoring.The research identifies current challenges,including insufficient adaptability for ultra-long-distance transportation in deep mines,complexity in rheological control of multi-source solid wastes,weaknesses in intelligent operation and maintenance,and bottlenecks in the localization of key equipment.Future development trends will focus on digital twin-driven intelligent perception and control systems,green and low-carbon transportation technologies,modular design standard systems,multidisciplinary integration and innova-tion combining rheology,materials science,and control theory.These advancements will provide theoretical support for the safe,efficient,and environmentally sound operation of CPB pipeline systems,thereby boosting the sustainable devel-opment of mining.

Abstract:Open-pit mining is recognized as one of the direct factors affecting the degradation of vegetation and the ecolo-gical environment surrounding mining areas.The disturbance of vegetation during the process of open-pit mining is mainly characterized by two processes:damage and restoration.Monitoring vegetation changes through the temporal vari-ation of vegetation indices is a commonly employed method to evaluate the ecological restoration status of mining areas.Seven frequently used vegetation indices were screened:Normalized Differential Vegetation Index(NDVI),En-hanced Vegetation Index(EVI),Green Normalized Difference Vegetation Index(GNDVI),Ratio Vegetation Index(RVI),Difference Vegetation Index(DVI),Modified Soil Adjustment Vegetation Index(MSAVI),Redness Index(RI)and a comparative analysis was then conducted to evaluate their effectiveness in extracting vegetation disturbance in the Shen-dong Coal Base over a long timespan(1990-2021).The findings reveal a correlation between vegetation coverage and the identification accuracy of various vegetation indices at the scale of individual mining areas.At the coal base scale,NDVI,GNDVI,and DVI are all suitable indices for extracting vegetation disturbances in the Shendong Coal Base.In identifying three types of disturbances—restored after damage,damaged without restoration,and undamaged—except for RI,all other indices effectively extracted the disturbance types within the mining area,achieving an overall identification accuracy exceeding 80%.Furthermore,for the extraction of disturbance timing,NDVI,GNDVI,and DVI demonstrated superior recognition effectiveness,with extraction accuracies for damage timing at 82%,80%,and 76%,respectively,and for restoration timing at 95%,91%,and 88%.Large-scale mining in the Shendong Coal Base began after 2005,followed by significant restoration efforts initiated after 2010.The integration of various restoration measures post-extraction has led to improvements in the ecological environment of the mining area.This research provides data support and scientific basis for the optimal selection and application of vegetation indices.A reasonable selection of vegetation indices is crucial for grasping the overall ecological status of mining areas,making it of great significance for monitoring the ecological im-pacts of open-pit coal mining and supporting the formulation of restoration measures.

Abstract:Under the global trend of green and low-carbon transition,China's mining enterprises face dual pressures of economic growth and ecological protection,which necessitates in-depth research on their green transition efficiency and spatial imbalance.This study takes listed mining enterprises from 2008 to 2024 as samples,constructs a Super-SBM mod-el incorporating desirable and undesirable outputs to measure green transition efficiency,and analyzes regional disparities based on spatial economics.The results show:Policy cycles significantly influence transition efficiency and exhibit a fluc-tuating pattern of"policy-driven—technology lag—institutional restructuring",with comprehensive efficiency ranging between 0.35 and 0.39.Leading enterprises,such as PetroChina(601857),achieved efficiency leaps through clean energy substitution;A"dual paradox"exists between technical efficiency(mean 0.82)and scale efficiency(mean 0.46).While 90%of enterprises are in increasing returns to scale,fragmented resource allocation persists regionally.Spatial heterogen-eity is prominent,with core regions(e.g.,Beijing-Tianjin-Hebei,Yangtze River Delta)driving efficiency improvements in neighboring areas through technology spillovers,while western resource-rich regions lag by over 30%due to technologic-al bottlenecks and insufficient ecological compensation.Policy recommendations include enhancing technical collabora-tion standards,optimizing regional compensation mechanisms,and promoting industrial chain integration to foster bal-anced green transition in the mining sector.

Abstract:The construction of green mines is an inevitable requirement for changing the mode of development of the mining economy and promoting the high-quality development of the mining industry,which is also the crucialfo-cus and inherent requirement for helping the goal of"dual carbon".However,there is a lack of in-depth analysis of the logic,core principles,and action plans of green mining construction under the context of carbon neutrality.Therefore,starting from the policy evolution process of green mine construction,this article explores the underlying logic of green mine construction in the context of carbon neutrality,analyzes its essence,and points out its specific action plans.Research has shown that after nearly two decades of practical exploration,China's green mine construction has been through the concept formation,practical exploration consolidation,and enhancement of the three phases and a-chieved specific results,gradually moving towards scale,normalization,refinement and standardization.As global cli-mate change intensifies,mining production and processing construction,life safety,and ecological environment protec-tion face significant impacts.Green mining construction,as an important lever to achieve transformation and develop-ment of mines,urgently needs to achieve sustainability,low-carbon,and intelligence.Therefore,green mine construction in the context of carbon neutrality has always adhered to the underlying logic of harmlessness,non-waste,and digitali-zation.At the same time,starting from the production factors,structural processes,and technological equipment of the mining industry,we should explore a construction system for carbon control,energy carbon reduction,and tech-nological sink enhancement.We should focus on green design throughout the entire life cycle,industry models with pan-energy boundaries,and technological innovation for promoting human welfare.We should continuously build mate-rial green mines from hardware support,strengthen the engineering practice environment,conduct scientific research and construction of theoretical green mines,enhance emergency management capabilities and policy improvement,and build cultural green mines.We should strengthen digital governance models to promote the systematic development of multiple subjects and factors,accelerate the formation of new productive forces in mining,and help achieve the goats of carbon neutrality vision.

Abstract:The green development of China's economy is a necessary way to achieve the national strategic goal of"carbon peak and carbon neutral",promote high-quality development,build a beautiful China,and construct an eco-logical civilization.However,a series of theoretical issues,such as the connotation of economic green development,the evolution of China's green development policies,the evaluation methods,influencing factors and realization paths of economic green development,have not reached a consensus,and urgently need to be further explored and answered,in the hope of making fundamental theoretical contributions to a profound understanding of China's economic green development,and providing theoretical references to China's implementation of the new development concept,the promotion of high-quality development and the construction of an ecological civilization.This paper first discusses the connotation of economic green development,secondly,it compiles China's green development poli-cies,then it reviews the methods of evaluating the level of economic green development,and finally it discusses the in-fluencing factors and realization path of China's economic green development.The following four main conclusions are drawn:First,there are no consensus definitions of green development and economic green development,and people have their own understanding to the definitions,but there is basically a consensus on its core connotation.Sec-ond,the evolution of China's green development policies could be divided into two phases:the period from 1973 to 2010 is the budding and starting phase of policies;and the period from 2011 to the present is the accelerated phase of policy formulation.Third,there are three main evaluation methods on the level of economic green development:green GDP accounting,measurement of green economic efficiency and comprehensive evaluation of economic green de-velopment.Fourth,China's economic green development is jointly influenced by economic,environmental and social factors.Comprehensive measures must be taken to realize green economic development by enhancing scientific and technological innovation capacity,promoting industrial structure upgrading,accelerating the transformation of the energy mix,and improving the institutional mechanism of green development.

Abstract:Quantitative analysis of the impact of human activities such as coal mining and land reclamation on the envi-ronment can provide a basis for environmental protection in mining areas.Based on Landsat images from 1990 to 2022,remote sensing ecological index(RSEI)was used to evaluate the temporal and spatial dynamic evolution charac-teristics of the ecological environment in Shendong mining area.The relationship model between temperature,rainfall and RSEI was further established by using random forest model,and the predicted value of R'SEI under climatic condi-tions was obtained.Residual analysis and Landtrendr algorithm were combined to quantitatively assess the impact of human activities.The results show that:①The average RSEI of mine scale and mine scale is higher,but the average RSEI of mine scale is lower than mine scale.From 2018 to 2022,the RSEI decline rate of the photovoltaic area is-0.027,slightly lower than that of the control area,indicating that the overall ecological environment of the Shen-dong mining area has been slightly improved,but the ecological environment quality at the mine scale is lower than that at the mining area,and the construction of the photovoltaic area has played a role in improving the ecological environment.② The correlation coefficient R2 between the actual RSEI before(1990-1996)and after(1996-2022)mining in Shendong Mining area is 0.61.The ecological environment of the mining area has a good trend un-der the influence of climate factors only.③After mining(1996-2022),the average residual δ of mining area scale is 0.07,and the part of δ＜0 is mainly concentrated in the mine concentration area in the north of the mining area and its surrounding areas,accounting for 39.74%of the total area.When new mining activities are added to the mining area,the proportion of δ＜0 area will increase significantly.The overall δ-value of mine scale showed a decrea-sing trend from 1996 to 2000,an increasing trend from 2000 to 2012,and a decreasing trend from 2012 to 2022.④ From 1990 to 2022,the mean values of scale disturbance and recovery intensity in mining area are 0.45 and 0.37,respectively,while the mean values of mine scale disturbance and recovery intensity are 0.43 and 0.37,respectively.The intensity of mine scale disturbance is lower than mine scale but similar to mine scale recovery intensity.After min-ing(1996-2022),the proportion of disturbance and restoration area both increased first and then decreased,indica-ting that disturbance and restoration behavior of mining area always occur together,and the disturbance caused by coal mining can be offset by self-restoration and human reclamation behavior after ecological damage.The maxi-mum duration of disturbance in the mining area is 1 a,and the maximum duration of recovery is 16 a,indicating that the mining disturbance in the study area is a sharp mining disturbance event.After the occurrence of temporary mining disturbance,there will be recovery events,and the artificial restoration behavior of the mining ar-ea is long-term and sustainable.To sum up,coal mining behavior has a strong negative impact on the ecological envi-ronment of the mining area,but it can be repaired by various measures taken by human beings and the restoration a-bility of the environment itself.This study is helpful to understand the impact of coal mining on the ecological environ-ment of the mining area,and provides a scientific basis for the restoration and improvement of the ecological environ-ment quality of Shendong Mining Area.

Abstract:Promoting green development of mining through the construction of standard systems is an important symbol of mining governance in the new era,as well as an important driving force and development direction for green devel-opment of mining.At present,China is in the initial stage of constructing a standard system for green development in the mining industry,and has initially formed a standard system framework guided by national and industry stand-ards,based on local standards,supplemented by enterprise and group standards.The article summarizes the character-istics of standard construction for international mining green development,and based on the standardization construction of China's mining green development,proposes three challenges:Insufficient synergy,low public partici-pation,and low internationalization.The article proposes that the standardization construction of green development in mining in the new era presents four trends:More market-oriented participation,more chained coverage,more diver-sified value pursuit,and more internationalized evolution path.The article emphasizes the importance of connecting with international advanced technologies and concepts,emphasizing the new formats and models of the mining industry brought about by new technologies such as big data and new concepts of environmental and social governance,reflec-ting the new characteristics of industry management at different stages of development.Handle the focus and synergy between national standards,industry standards,local standards,group standards,and enterprise standards,improve the coordination and matching between standards,and effectively play the guiding role of standards in the green development of mining.Accelerate the construction of a standard system for green development of China's mining industry,break away from the inherent thinking of"governance theory",improve the top-level design of stand-ardization for green development of mining industry,promote the application and demonstration of new technologies in green development of mining industry,establish a standard list system for green development of mining industry,and promote the internationalization of the standard system for green development of mining industry.Promote the standard-ization and standardization of the entire process of green development of mining industry,and comprehensively en-hance the efficiency and level of green governance of mining industry.

Abstract:Solving the contradiction between coal mining and soil and water conservation is a major scientific issue and strategic demand for ecological protection and high-quality development in the upper and middle reaches of the Yellow River.On the basis of systematically combing the relevant research progress,it is pointed out that insufficient under-standing of the regional characteristics of coal mining subsidence areas,incomplete understanding of the key factors of soil erosion in the process of coal mining subsidence,lack of research on soil erosion effect of different mining dam-age types in coal mining subsidence areas are the main problems in the research of soil erosion effect and prevention and control in coal mining areas in China.The sharp contradiction and development trend between coal mining and soil and water conservation in the seven national coal bases in the upper and middle reaches of the Yellow River are analyzed.The focus of the contradiction is mainly manifested in:first,the high overlap between the coal mining con-centration area and the key control area of soil and water loss leads to the double pressure of energy security supply and soil and water loss prevention;second,the background of regional natural soil erosion leads to a small and difficult space to solve the contradiction between coal mining and soil and water conservation.Third,the continuously expanding coal mining subsidence area during the 14 th Five-Year Plan period will become the main battlefield for soil and water conservation.It is proposed that the spatial and temporal evolution law and mechanism of soil erosion under the coupling of underground mining+underground overburden+surface natural micro-topography,the soil ero-sion effect of different damage types and the spatial and temporal evolution law and mechanism,and the key technology system of precise prevention and control of soil erosion in the whole life cycle under the strategy of underground joint surface are the key research directions for the prevention and control of soil erosion effect in the coal mining subsid-ence area in the upper and middle reaches of the Yellow River in the future.It is hoped to provide a useful reference for solving the contradiction between coal mining and soil and water conservation in the upper and middle reaches of the Yellow River and supporting the ecological protection and high-quality development of the upper and middle reaches of the Yellow River.

Abstract:Under the background of global climate change and resource shortage,realizing the goal of"double carbon"has become the common pursuit of all countries,and the exploitation and utilization of mine underground space has become an important way to achieve sustainable development.As an important prerequisite for the exploita-tion and utilization of underground space,fine detection of underground space has attracted extensive attention from the academic community,and is the basis for ensuring the safe and efficient exploitation of underground space.This paper expounds the method principle and current development status of underground space detection technology in mines,systematically combs the underground space detection technology from two dimensions of"air(sky)-ground-well-roadway"and"gravity-magnetic-electric-seismic".Through in-depth analysis and comparison of the differences of ge-ophysical exploration methods in detection range,detection depth,cost effectiveness and anomalous body sensitivity,the applicability of different mining underground space exploration methods to different application scenarios is analyzed,and the advantages and limitations of each exploration method are summarized.The typical ap-plication of underground space exploration in mines is studied.By analyzing the exploration results of practical engi-neering application,the application value of each exploration technology in practical engineering is highlighted,and the practical basis is provided for the future technology optimization.In addition,the development trend of mine under-ground space detection technology in the future is discussed,and the feasibility and necessity of integrated robot re-search on multi-space and multi-dimensional joint detection and underground space perception detection is expounded,which is expected to further improve the accuracy and efficiency of mine underground space detection,and reduce the detection cost and risk of mine underground space detection under complex geological environment.It pro-vides a reference for the future development direction of underground space detection technology in mines.

Abstract:The development of mineral resources has promoted the improvement of human social productivity and the development of civilization,especially after entering the stage of industrialization,the large-scale development of natural mineral resources and the development of mineral processing technology have also made great progress.The progress of mineral processing technology is inseparable from the deep understanding of ore properties,the innovation of mineral processing technology and equipment technology.Among them,mineral processing equipment plays an im-portant role as a carrier,and it is an important research field to promote the innovation and development of mineral processing technology.Research progress on mineral processing equipment technologies at home and abroad is reviewed in this paper,mainly including typical equipment in the fields of physical separation,surface physical and chemical separation,and composite force field separation.The results indicate that although extensive improve-ments of modern mineral processing equipment has been achieved day by day,there is a gap between the application level and development prospects of different types of mineral processing equipment.The early gravity separation equip-ment has been developed and applied rapidly,the development of magnetic separation equipment is also unprecedent-edly prosperous in the middle and late stages,recently the sensor-based sorting equipment is a hot spot in research,at present,the traditional physical separation equipment technology development tends to be slow;the application range of flotation equipment is constantly expanding,and recently the flotation machine has achieved remarkable development in large-scale,efficient,diversified and intelligent.Overall,new technologies such as advanced automated control,flu-id measurement,and CFD simulation are rapidly promoting the iterative upgrading of traditional mineral processing e-quipment and the development of new equipment.In the future,facing the new situation of lower-grade complex ore and green development of the mining industry,it is necessary for all parties to strengthen collaborative innovation,ac-celerate multidisciplinary cross-theoretical research,and continue to promote the in-deep integration of industry,acade-mia and research,so as to develop more efficient mineral processing equipment technology.

Abstract:The Shendong and Shaanbei coal bases are located in the arid and semi-arid regions of the western region,and are the most prominent areas in China where the contradiction between coal resource development and groundwater resource protection is prominent.The impact assessment of coal mining on groundwater resources is an important part of the environmental impact assessment.It is the basic work for the coal mine to optimize the water conservation min-ing technology according to the requirements of groundwater resources protection and establish the coal develop-ment mode of"determining production by water resources".By systematically analyzing the geological and hydrogeo-logical conditions of Northern Shaanxi and Shendong coal bases,the differences in mining hydrogeological structure,water conservation target layer,water barrier key layer and groundwater loss mode in different mining areas are summa-rized in this paper.The research shows that in the middle to shallow mining areas,the main target layer for water re-tention is the loose aquifer of the Quaternary system,with the loess layer of the Lishi Formation of the Quaternary sys-tem and the red soil layer of the Baode Formation of the Neogene system as the key layers for water retention.In deep mining areas,the loose pore aquifer of the Quaternary system and the pore fracture aquifer of the Cretaceous system jointly constitute the water retention target layer for deep coal resource development,with the sandy mudstone layer of the Anding Formation at the bottom of the Cretaceous system as the key water barrier layer.Based on the com-bination relationship between coal seam mining induced by water conducting fractures and key water blocking layers and water retention target layers in different coal mining areas,five water loss modes of water retention target layers in the Shaanbei and Shendong coal bases are summarized.We have sorted out the relevant requirements and regula-tions for evaluating the impact of coal mining on groundwater resources,combined with the differences in groundwater loss patterns in different mining areas of Shaanbei and Shendong coal bases,and analyzed the technical status and lim-itations of relevant evaluation methods.Finally,in response to the technical requirements for evaluating the impact of scientific coal mining on groundwater resources,we put forward the generalization and numerical treatment of mining induced water conducting fracture zone,the construction method of coal water collaborative dynamic platform model for dynamic calculation of groundwater loss,and three evaluation indexes of the impact of coal mining on ecological water level,water retaining aquifer structure and groundwater resources,so as to provide reference for scientific evalua-tion of the impact of coal mining on groundwater resources and the coordinated development of coal water resources under the situation of"determining production by water resources".

Abstract:With the gradual increase in the depth and intensity of coal mining in China,the threat of rock burst to the safety and efficient production of coal mines is becoming increasingly severe.While backfill mining technology can re-alize green mining by restricting overburden movement through backfill body in the goaf,which can prevent rock burst accidents induced by hard roof.Focusing on the prevention of hard roof induced rock burst by backfill mining technol-ogy,this thesis reviews the research progress of dynamic characteristics of backfill body consisted of loose backfill ma-terials and cemented backfill materials from three aspects:the dynamic characteristics,energy transfer mechanism and relevant numerical simulation.At present,the research on the dynamic characteristics and energy transfer mechanism of granular filling materials and cemented filling materials is mainly conducted by using drop hammer impact test and Hopkinson pressure bar test.PFC and ANSYS are widely used to study the dynamic load characteristics of backfill ma-terials.It is concluded that the mechanism of rock burst induced by hard roof is that the sudden collapse of roof causes rapid release of accumulated energy in roof and coal seam,and then causes rock burst.From the point of view of filling rate and energy mechanism,the interaction mechanism between hard roof and backfill body is expounded.It is revealed that backfill body can effectively reduce energy accumulation,slow down energy release and reduce energy transfer efficiency in coal strata,and its effect mainly depends on the filling rate.This thesis also elaborates on the sol-id backfill and cemented backfill mining technology for the prevention and control of hard roof induced rock burst.The engineering cases of solid backfill in the 6304 working face of Jisan Coal Mine and cemented backfill in the 1123 working face of Gucheng Coal Mine is analyzed.The measured microseismic data show that the filling mining technolo-gy can obviously reduce the frequency and energy level of microseismic events in the mining process of the working face,and can effectively prevent the occurrence of rock burst of hard roof type.In the future,the rock burst prevention and control by backfill mining technology will require in-depth research in basic theories such as:studying the move-ment and energy evolution of rock strata,achieving precise control of rock strata and accurate prediction of energy evo-lution,and developing new energy absorbing backfill materials for reducing rock burst impact.

Abstract:Geodynamic disasters in coal mines often cause the collapse and blockage of the excavation space roadway,which seriously threatens the safety of underground workers in coal mines.The mechanical structure and accumulation form of the loose and broken accumulations formed by the collapse are very complicated,so how to quickly clear the collapsed accumulations and construct the rescue passage is an urgent scientific problem to be solved.On the basis of analysing the current situation and problems in research on the structural transport laws of catastrophic col-lapsed bodies and the construction of rescue routes,and in view of the complexity of the mechanism of pile blocking of collapsed piles and the uncertainty of the laws of disturbance and deformation.Firstly,a two-dimensional computa-tional model of the collapsed pile was constructed based on the particle flow numerical simulation software,and the motion characteristics of the particles in the process of constructing the rescue channel inside the collapsed pile were investigated,and the disturbance law of its excavation was clarified;Secondly,the stress redistribu-tion characteristics in the pile under the conditions of constructing the rescue channel in different areas were analysed,and the construction location of the rescue channel in the collapsed pile was preferred;Finally,according to the me-chanical characteristics of the collapsed pile and the pile morphology,a new rapid construction method of the res-cue channel is proposed.The results show that:under the influence of the disturbance of excavation to build the res-cue channel,the rock body of the collapsed pile has a tendency to move towards the excavation space,and the farther away from the excavation position,the smaller the influence of the disturbance is;the secondary collapse of the col-lapsed pile to the excavation space is mainly in the vertical direction,and the horizontal direction is secondly;the col-lapsed pile is in the shape of a"trapezoid"after the excavation is stabilised in the lower left,and in the shape of"V"after the excavation is stabilised in the middle and lower parts of it;Considering the influence of secondary disturbance,the stability of the supporting structure and the source structure of the collapsed pile,it is appropriate to choose the location of the rescue channel in the middle of the collapsed pile.