Abstract:The development of mineral resources will inevitably have a certain impact on the environment.The balance between resources and the environment is the core of the green mine construction.It is the decisive internal factor for the orderly development of mineral resources and the high-quality development of the mining industry.It is the fundamental embodiment of the connotation of green mines.Establishing an environmental and resource balance sys-tem is an important means to promote the coordinated development of resource exploitation and environmental protec-tion.As an integral part of the environmental and resource balance system,mineral resource balance plays a signifi-cant role in promoting the sustainable development of mining enterprises.This article explained the definition,signif-icance,transaction flow diagram and relationship diagram of resource balance in the mineral resource development process,as well as resource balance calculation formula,the resource balance table,and the proposal of optimal re-source allocation based on the resource balance mathematical model.Resource balance is the dynamic balance rela-tionship between various factors such as quantity of resource,mining volume,concentrate volume,and tailings volume in the resource development process.It involves the conversion relationship between resource volume,design losses,mining losses and reserves,the mining change relationship between reserves,dilution quantity and raw ore a-mounts,and the transformation relationship of mineral processing among raw ores,concentrates and tailings.The input and output of resource balance were analyzed,the main core technologies involved in the input,intermediate and output ends were introduced.This study established a resource balance calculation formula and explained its physical meaning,designed a resource balance table with a mine data as an example,and gived the suggestions on methods and paths to optimize resource balance based on the formula model.It also explained the relationship be-tween resource development,and environmental protection,and the balance between resource development and eco-nomic benefits.

Abstract:In recent years,digital technologies,including 3D visualization,virtual reality,augmented reality,digital twin,and Cyber physical systems(CPS),has gradually been deeply integrated with longwall mining,thus de-velop a new intelligent operation mode of longwall mining with the integration of virtual and real.Based on the four el-ements of human,machine,environment and method,this paper analyzes the digital longwall mining technology and its integration process,which is divided into four stages:XR 1.0-unidirectional virtual simulation from physical to virtual,XR 2.0-offline industrial data-driven virtual planning and debugging,XR 3.0-real-time data-driven virtu-al monitoring,XR 4.0-bidirectional data-driven virtual reverse control.Five aspects of each stage,including the con-nection between virtual and real way,data using,characteristics for different objects,support technology and typical application,were analyzed.In the 1.0 stage,3D modeling information and expert knowledge are used to establish the virtual working face,and the simulation operation and training of mining personnel are carried out through human-computer interaction technology.In the 2.0 stage,the actual offline data component parameter scenarios are used for virtual planning and virtual debugging.At the stage 3.0,a digital virtual working face containing virtual moni-toring and prediction functions was established.At the stage 4.0,the physical mining system and the virtual sys-tem have been synchronized,and the optimal strategy of virtual decision-making is used to control the real physical process in real time.Finally,the relationship between the four stages of XR was summarized,and the current prob-lems in technological development,key technologies that need to be overcome,and ways to continue promoting the in-tegration of virtual development and actual development in the next step were discussed.

Abstract:Due to the unique characteristics of its roof structure and mining pressure manifestation,shallow buried coal seams have different rock control mechanisms.In response to the problem of subsidence control in shallow buried thick coal seam layered paste filling mining,the top layered filling material is used as a false roof during lower layered min-ing.Due to the dense structure and absence of joints and fissures in the filling material,exploring the overburden con-trol mechanism under the false roof conditions of shallow buried coal seam layered filling material is of great signifi-cance.This article adopts comprehensive research methods such as theoretical analysis,numerical simulation,and engi-neering measurement to construct a direct roof mechanics model for paste filling mining.The critical conditions for di-rect roof fracture instability are analyzed,and the core element for controlling shallow buried coal seam rock layers is proposed as the filling rate.The deformation control mechanism of overlying rock in shallow buried thick coal seam lay-ered paste filling mining is revealed,and a numerical calculation model for shallow buried thick coal seam layered paste filling mining is established.The deformation characteristics of overlying rock and surface movement under differ-ent filling rates are explored,and the stress characteristics and surface movement deformation of the filling body are measured.Research has shown that the ultimate span of the roof rock beam is 17.9 m,with a corresponding deflection of 0.54 m.The mining heights of the upper and lower layers are 4.65 m and 3.65 m respectively.The calculated filling rate of the upper layer is not less than 88％,and the overall filling rate is not less than 93％,which can ensure that the roof will not fracture or become unstable;As the filling rate increases,the stress concentration coefficient and deforma-tion of the overlying rock continuously decrease,the bearing capacity of the filling body gradually increases,and the surface movement deformation gradually decreases.When the overall filling rate of the upper and lower layers reaches 98％,the surface movement deformation can meet the requirements of building protection;After the upper layer filling mining,the stress on the filling body gradually increased and stabilized at around 2.3 MPa.The measured maximum subsidence of the surface was 57 mm,the maximum inclination value was 0.82 mm/m,and the maximum curvature value was 0.03 mm/m2.The surface movement and deformation were all within the range of the Level Ⅰ fortification in-dex,and the filling effect was good.

Abstract:In response to the current research status of water conservation coal mining in China and the technical re-quirements for ecological restoration in mining areas,it is proposed to carry out research on ecological function restora-tion of mining-damaged aquifers and incorporate it into the green mining technology system.On the basis of fully elab-orating the concept and connotation of ecological function restoration in mining-damaged aquifers,a theoretical and technical framework was constructed mainly based on the law of water loss in mining aquifers and key technologies for water runoff interception.The current research progress and future research directions were analyzed.The damage,water loss,and ecological function degradation of aquifers are essentially caused by strata movement and crack devel-opment caused by coal mining.Therefore,ecological function restoration research should be carried out on the basis of fully understanding the water loss mechanism of aquifers.Deeply reveal the distribution of water loss paths and the dis-sipation law of water flow dynamics in aquifers,and take the mining affected area with concentrated water loss flow as the key target area for restoration.Reasonably use methods such as"repairing while mining"and"repairing post mining"to implement water flow channel sealing and restoration.At the same time,it is necessary to fully uti-lize the self-healing mechanism of mining-induced rock fractures and its self recovery effect on aquifers,and carry out research and practice on ecological function guided restoration of mining-damaged aquifers;Based on the self-healing and permeability reduction mechanism of chemical precipitation generated by water-gas-rock interactions on wa-ter-conducting fractures,a remediation technology path for ecological function restoration of aquifers is proposed by in-jecting remediation reagents that can produce chemical precipitation with groundwater into the fractured rock mass be-low the aquifer,in order to promote the adsorption consolidation of sediment in the fractures and block the channels.On this basis,the current research status of using iron/calcium chemical precipitation for water conducting fracture re-pair and permeability reduction is elaborated,and it is proposed that future research should focus on developing chemi-cal precipitation induced generation strategies that are conducive to efficient sealing of different types of water flow channels.The research is expected to provide reference for groundwater protection and ecological restoration dur-ing coal mining in ecologically fragile mining areas in the northwest of China.

Abstract:In order to explore the feasibility of implementing CO2-ECBM in heterogeneous coal seams under com-plex geological conditions,taking the No.15 coal seam bifurcation merging area in Xinjing Mining area as an example,the spatial distribution characteristics of coal seams were finely characterized by logging constrained wave im-pedance inversion and time-depth conversion technology,and then integrated fracture prediction was realized by com-bining eigencoherence and intelligent ant technology.The evaluation parameters(thickness,structure,capping condi-tions,etc.)of CO2-ECBM geological favorable area are also described.The results show that the higher the thickness of coal reservoir,the better the effect of CO2 storage.The thickness of No.15 coal seam bifurcation area is small and there is dirt inclusion,and the existence of coal-mudstone system leads to the reduction of reservoir,which is not conducive to the recovery of coalbed gas and CO2 storage.The coal rock thickness in the coalescing area of No.15 is larger than that in the bifurcation area,the geological structure is relatively simple,and the content of coal-bed methane is higher.Starting from the sealing conditions of the surrounding rock,the top and bottom of the No.15 coalseam area develop thick mudstone and limestone,which is poor in permeability,conducive to the large-scale and long-term effective storage of gas,and belongs to a typical closed tectonic environment.In terms of geological structure,the gently inclined coal seam helps to slow down the CO2 escape rate and make CO2 spread more even-ly throughout the coal seam,and the reservoir effect is the best in areas with undeveloped faults,and the reservoir effect in areas with developed reverse faults is better than that in areas with developed normal faults.Therefore,the zone with inclination less than 10°,undeveloped fault or reverse fault development in the No.15 coalseam area is se-lected as the potential favorable area for CO2-ECBM implementation.The study is helpful to promote the application of this technology in similar complex coal seams,and provide a basis for the storage and injection and production of CO2 in complex coal seams.

Abstract:Chemical looping combustion is a novel fuel conversion technology that utilizes oxygen carriers to transfer oxygen between the gas and solid to achieve efficient fuel combustion and in-situ CO2 separation.The core of the tech-nology lies in the efficient design of oxygen carriers and reactors.However,the challenges include the low reactivity of oxygen carriers,which is easy to deactivation by sintering;the difficulty in coupling of the reactor and the fuel,and the optimized design and the industrial scale-up technology are not yet mature.Under such context,this paper reviews the research progress on the design and application of oxygen carriers and reactors in chemical looping combustion.Firstly,the current research status and design concepts of oxygen carriers are reviewed.Single metal oxides have a short preparation process and satisfactory high-temperature reactivity,but the stability is limited;multi-composite metal oxides optimize the anti-sintering ability by virtue of intermetallic synergistic effect,which significantly improves the reactivity and cyclic stability of the material.The use of industrial waste as an oxygen carrier shows both environmental and economic value;liquid carriers exhibit good high-temperature adaptability and mixing characteristics,but face cost and stability problems.Secondly,the research status of chemical looping combustion reaction device is introduced in detail,comparing the working principles,advantages and shortcomings of fluidized bed,fixed bed and rotating bed reactors,showing their adaptability to fuel type,reaction conditions and conversion characteristics.Fluidized bed reac-tors have good heat and mass transfer characteristics,but also require high physical properties of oxygen carriers.Fixed bed reactors are simple in structure,but heat transfer efficiency is limited in large-scale applications.Rotating bed re-actors are able to better combine the flexibility and efficiency of the system.Finally,the development and design of ox-ygen carrier and reactor are analyzed and outlooked to provide a basis for the subsequent chemical looping combus-tion technology to provide certain reference for the optimized design and engineering demonstration of the subse-quent chemical looping combustion technology.

Abstract:To investigate the influence of ultrafine solid waste materials on the performance of ultrafine sulfoalumi-nate cement-based grouting material,a considerable amount of ultrafine solid waste fly ash was blended with ultrafine slag and ultrafine sulfoaluminate cement.The compressive strength,setting time,fluidity,water leakage rate and expan-sion rate of the grouting material were tested at the macro level.The hydration products were analyzed by X-ray dif-fraction analysis(XRD),Fourier infrared spectroscopy(FTIR),thermogravimetric analysis,and scanning electron mi-croscopy(SEM),and the effect of two types of ultrafine solid waste materials on the properties of ultrafine sulfoalumi-nate cement was described and the mechanism was analyzed from both macro and micro perspectives.The results dem-onstrated that:① On the basis of adding 20％-40％ultrafine fly ash into the ultrafine sulfoaluminate cement,0-20％ultrafine slag was incorporated.With the addition of ultrafine solid waste and mineral admixtures,the compressive strength of the composite grouting material at each age gradually declined.When the content of ultrafine fly ash was 20％,the 28 d compressive strength reached the maximum of 10.93 MPa.With the addition of ultrafine solid waste ma-terial,the reduction of the grouting materials in each fixed ultrafine fly ash content section was mainly attributed to di-lution,and the variations of setting time and fluidity were different.These two properties were mainly affected by the total proportion of ultrafine solid waste material.With the increase of the total proportion,the coagulation time initially decreased and then prolonged,and the fluidity initially decreased and then increased,reaching the extreme value when the total dosage was 40％.The initial and final coagulation time was approximately 40 min and 50 min,and the variation of the shortening and extension of the fluidity,which was about 200 mm,was caused by the combined action of the nucleation effect and dilution effect.When the condensation time was shortened,the nucleation effect was dominant,while the dilution effect was dominant when the condensation time was prolonged.The decrease in fluid-ity was mainly due to the high surface activity constraint of the ultrafine material.② Materials with a high content of ultrafine slag in terms of strength exhibited higher strength at the later stage due to pozzolanic activity.In terms of compressive strength,with the same content of ultrafine solid waste,grouting materials with a high proportion of ul-trafine slag had higher compressive strength at the later stage due to the pozzolanic activity of ultrafine slag.In terms of fluidity and condensation time,grouting materials with a high proportion of ultrafine slag had higher compressive strength.The proportion of different ultrafine mineral admixtures of solid waste had little influence on the grouting ma-terials.③ The variation in the amount of ultrafine solid waste material did not alter the type of hydration products,and the composite grouting material reacted rapidly within 1 day.In addition to the hydration products such as ettring-ite,monocarbon calcium carboaluminate was also generated.

Abstract:After the closure of the mine,due to the influence of various factors such as stress between rock masses and groundwater,the structure of underground rock layers and soil layers in the mining area has changed,resulting in secondary morphological changes on the surface of the goaf.To explore the pattern of surface deformation after mine closure,SBAS-InSAR(Small Baselines Subset InSAR)technology was used to process image data and obtain surface deformation information of the closed mine in Haizi Mining Area,Huaibei City for 5.5 a.Through the analysis of image results,it is indicated that there are 2 obvious subsidence areas in the mining area,distributed in the eastern and southwestern parts of the mining area,with a maximum subsidence rate of 25 mm/a and a maximum subsidence a-mount of 124 mm.Based on previous research by scholars on residual subsidence in closed mine areas,it is speculated that the reasons for its subsidence may be related to factors such as coal seam mining depth,underground water accumulation damaging coal and rock pillars,and surface water accumulation.At the same time,there is a signifi-cant uplift in the central area of the mining area,It is mostly concentrated in Qiji Town and its surrounding area,with a maximum lifting rate of 18 mm/a and a maximum lifting amount of 133 mm.It is speculated that the reason for the lifting may be related to the rise of groundwater and the gravity loading of buildings.It is speculated that groundwater flows into the underground of residential areas,causing the rebound of fractured rock masses,and the gravity of build-ings accelerates this process.The more obvious the lifting in areas with concentrated buildings.After about 4 a of sub-sidence in the mining area,the surface subsidence tends to stabilize,while in residential areas,the surface gradually tends to stabilize after first subsidence and then uplift.Selected characteristic points from the most significant areas of surface deformation and conducted a more detailed analysis based on factors such as coal seam depth,ground-water,and building gravity.Based on the deformation characteristics,the surface deformation over time can be divided into 3 stages:residual subsidence stage,relatively stable stage,and uplift stage;Based on the annual deformation are-a changes in the surface of the mining area,it can be concluded that during the monitoring period,the overall uplift ar-ea of the mining area has increased year by year,while the proportion of subsidence area has gradually decreased.Therefore,it is speculated that the uplift area of the mining area has reached its maximum uplift amount,but the uplift range will further expand.

Abstract:There are 24 mining areas in the Ordos Basin that exploit Jurassic coal seams,with raw coal production ac-counting for about 45%of the national total.With the increase of mining depth,the sandstone aquifer of the Zhiluo Formation in the coal seam roof has become the main source of water inrush in coal mines.The water content of the Zhiluo Formation sandstone aquifer is relatively weak,but the water release effect is significant under mining condi-tions,making it the main source of long-term and sustainable water supply for coal mines.At the same time,the area belongs to an ecologically fragile area with relatively scarce water resources.How to effectively utilize limited water re-sources is undoubtedly an important foundation for the protection of the groundwater system and ecological environment in the mining area.Taking the Yushen mining area and Caojiatan coal mine as examples,this paper proposes the tech-nical route,main research content,and research methods for studying the sandstone aquifer in ancient river channels.Using comprehensive sedimentology,hydrogeology,and mine water prevention and control theory to assist necessary field geological surveys,typical profile measurements,specialized investigations of hydrogeological and environmen-tal geological typical elements,drilling,geophysical logging and sampling testing,numerical simulation,and oth-er methods.We will focus on conducting research on three aspects:the sedimentary evolution and physical character-istics of ancient channel sandstone aquifers,the groundwater system characteristics of ancient channel sandstone aqui-fers,and the mutual feedback mechanism between ancient channel sandstone aquifers and coal seam mining.The re-search practice in Shenfu South District shows that the sand body of the ancient river channel in the lower section of the Zhiluo Formation has a huge scale and good pore and fracture structure characteristics,with good underground water storage and transportation performance.Overall,it is distributed in a NW-SE trending strip along the Hongjian-nao Erlintu Jinjie line as the axis.The fourth and fifth sections of the Yan'an Formation were eroded by the ancient river channel of the Zhiluo Formation.The main river channel area has a stronger water richness than the branch riv-er channel and diversion bay area,and is a high-risk area for mine water inrush.Therefore,water hazard prevention and control should be done well.

Abstract:China's coal mining areas with high underground water level are primarily situated in the densely populated eastern regions.The high-intensity underground mining not only results in the formation of extensive subsidence basins on the surface but is also accompanied by significant subsidence water.A significant portion of arable land and infrastructure is inundated,complicating governance and utilization efforts.This situation leads to various issues,including ecological degradation,land degradation,and conflicts in land use,which have emerged as critical obstacles to the transformation and high-quality development of coal mining cities.To enhance the effective ecological management and sustainable use of coal mining subsidence areas with high underground water level in China,a comprehensive overview of the existing gov-ernance,utilization,and research progress is presented.Firstly,the relevant literature was statistically analyzed by the bib-liometric software VOSviewer.It was found that the ecological management and utilization of coal mining subsidence areas with high groundwater level has garnered significant scholarly interest over the past decade.Research efforts pre-dominantly concentrate on the physical and chemical characteristics of subsidence water and soil,employing a variety of research methodologies.Furthermore,the governance strategies observed indicate a trend towards diversified and integ-rated development.The new progress of basic theory research on the treatment and utilization of subsidence area with high groundwater level is introduced from four aspects:the damage and evolution law of mining strata with high groundwater level,the monitoring and prediction of subsidence,the influence and repair of subsidence on the surface environment,the spatial and temporal evolution of subsidence water and the hydraulic connection with groundwater.On the basis of comb-ing the practice of governance and utilization of coal mining subsidence areas with high groundwater level in the plains of various regions in eastern China,this paper puts forward the coordinated development technology of water and land in subsidence areas with high groundwater level,discusses the technical advantages and challenges of different governance directions and balanced development of water and land,and carries out research prospects,which provides direction and ideas for further realizing the scientific governance and utilization of coal mining subsidence areas with high groundwater level.

Abstract:China's Xinjiang region is drought and water shortage.As a river with important geographical characteristics and environmental impact in Xinjiang,the Aiweiergou River is of great significance to the economy and ecology of the region.Therefore,when coal mining is carried out under the Aiweiergou River,it is necessary to ensure the safety of the mine and the normal use of the river.The safety of multi-coal seam mining and river protection technology under rivers are studied by means of theoretical analysis and numerical simulation.Under the condition of multi-coal seam mining,the development height of overburden water-conducting fracture zone(11401 working face is 41.9 m,1502 working face is 110 m,11401 working face is 113.8 m)is obtained by theoretical calculation,and the profile diagram is drawn.At the same time,the numerical simulation method is used to determine the development form and height of the water-conducting fracture in the overburden rock.Finally,based on the relationship between the height of the wa-ter-conducting fracture zone(117.8 m)and the minimum coal seam burial depth(191.5 m),it is determined that the mining under the river is safe and feasible.Under the premise of ensuring the safe mining of coal seams under rivers,by analyzing the principle of separation grouting,combined with the characteristic parameters of mining influence and the engineering site,a multi-means based on separation grouting is proposed,supplemented by river seepage prevention and optimized mining design.Precise protection technology for specific surface targets within the scope of mining influ-ence.According to the actual mining geological conditions,the probability integral method is used to calculate the sur-face movement and deformation at the river channel position before and after the mining of the test mining face.The calculation results show that the maximum horizontal deformation value(2 mm/m)of the river channel does not ex-ceed the allowable limit deformation value(2.5 mm/m)of the dam body after the precise protection technology of separation grouting is adopted.Therefore,the precise protection technology of separation grouting can be realized,and the normal use of the river channel can be ensured while the underground mining is safe.Through the analysis and re-search on the safety and protection technology of multi-seam mining under rivers,it provides reference for green min-ing.

Abstract:The ammonia-coal co-combustion technology aligns with China's national energy conditions,where the main status of coal will not fundamentally change in the short term.This technology is crucial for China to achieve carbon emis-sion reduction in the power system and meet the"carbon peaking and carbon neutrality objectives".However,due to the distinct combustion characteristics of ammonia compared to traditional fossil fuels,blending ammonia fuel into coal-fired boilers may result in issues such as reduced combustion stability and elevated NOx emissions.Based on relevant domestic and international research on ammonia-coal co-combustion,the existing problems of ammonia fuel are presented.The im-pacts of variables such as the ratio and injection location of ammonia,air distribution mode,and combustion temperature on the combustion and emission characteristics of ammonia-coal co-combustion are analyzed.Furthermore,changes in the reaction mechanism during ammonia-coal co-combustion are elucidated.The economic analysis of ammonia-coal co-com-bustion technology is also presented,along with future research and application prospects.The results indicate that under a 20%-40%ammonia blending ratio,the combustion and emission characteristics can meet energy conservation and emis-sion reduction engineering requirements through proper fuel staging,air staging,and oxy-fuel combustion.Ammonia-coal co-firing results in a decrease in overall furnace temperature,negatively impacting on fuel burnout and the reduction of NOx by ammonia and coal coke.Additionally,the H2O-rich atmosphere created by ammonia doping could enhance the generation of NOx.At a 20%ammonia co-firing ratio,boiler thermal efficiency remains essentially unchanged,while car-bon emissions can be reduced by approximately 20%.Furthermore,advancements in green ammonia production techno-logy could make the cost of co-combustion competitive with,or even more advantageous than pure coal combustion,fur-ther promoting the construction of China's new energy-based new power system.

Abstract:Deep mining has become a key challenge for China's coal industry,especially under the constraints of high stress,high temperature and high permeability,it is urgent to seek effective mining technology.Filling mining technolo-gy,especially the high-concentration cemented backfill technology using coal gangue as a filling material,has been gradually applied to deep mining and has become an effective means to cope with this challenge.Based on the ex-isting literature,the filling process,influencing factors and control effects of five backfill mining methodswere analyzed.Three types of factors affecting the surface subsidence control effect of deep high-concentration cemented backfill min-ing were summarized:geological mining conditions,filling technical conditions and backfill properties.To further under-stand the uniqueness of deep high-concentration cemented backfill mining,the mechanical interaction model between high-concentration cemented backfill and roof was constructed,and the overburden movement characteristics of high-concentration cemented backfill mining stope with deep long wall were deeply analyzed,and the discrimi-nant conditions for rock stability was clarified.Based on the FLAC numerical simulation results,the main factors affect-ing the control effect of surface subsidence and their order of importance were determined:working face width>filling rate>backfill strength>coal seam thickness.In addition,it was found that the influence of coal seam thickness and working face width on the subsidence effect is negatively correlated,while the influence of filling rate and backfill strength is positively correlated.Finally,combined with the actual data of a mine test mining area,the optimal working face width(100 m),filling rate(90％)and backfill strength(3 MPa)are determined,and the surface subsid-ence data(4-15 mm)are in good agreement with the numerical simulation results through comparative analysis.This research provides a theoretical basis and technical support for surface subsidence in deep mining areas control.

Abstract:Monitoring the vegetation restoration effect on coal mine dumps in fragile ecosystems and pinpointing the drivers of vegetation changes is able to provide crucial technical and data support for the sustainable progress of restoration initiatives.Existing studies using long time-series remote sensing data for vegetation changes in mining areas and their driving mechanisms lack a fine portrayal of the vegetation recovery of the whole life cycle of the dis-charge sites at the mine scale,and lack thematic indicators to quantitatively characterize the vegetation resilience in the dumping site.In order to address the above problems,In this paper,we examined three external dumps at the Pingzhuang West Open Pit Mine,using Landsat images to calculate annual maximum INDV(Normalized Difference Vegetation Index)in this area.We conducted a temporal trend analysis for in-depth monitoring of vegetation changes at these sites over the full cycle.Additionally,we introduced the concept of vegetation restoration force to evaluate the effectiveness of restoration efforts at a regional scale.Finally,the multiple regression residual method is employed to quantitatively assess the effects of two primary driving factors,climate change and human activities,on vegeta-tion changes at waste disposal sites.Experimental findings reveal:① During 2008-2023,the vegetation indices in the three dumping sites showed an increasing trend,with most areas being restored to the level before open-pit mining;② The vegetation recovery force in the dumps exhibits a pattern characterized by an initial increase,fol-lowed by a decrease,and culminating in stabilization.The strongest recovery force is observed in Shanhou dumping site,succeeded by Sanjia dumping site,while Taipingdi dumping site display the weakest recovery force;③The veg-etation improvement areas primarily showcase the predominant influence of human activities and the synergistic impact of human activities and climate change.In areas of vegetation degradation,all three driving modes are present,with Sanjia dumping site notably experiencing a greater combined influence of human activity and climate change.

Abstract:In 2022,the global photovoltaic(PV)industry entered the terawatt(TW)era,with China maintaining its posi-tion as the world's leading PV module producer for 18 consecutive years.Driven by technological upgrades and the end-of-life of early-generation installations,a wave of PV module retirements is imminent in China.These end-of-life modules contain valuable resources—including glass,silicon,aluminum,silver,and copper—with non-ferrous metal grades often exceeding those of primary ores,presenting significant recovery potential.However,they also harbor hazardous elements,such as fluorine and heavy metals.Traditional disposal methods like landfilling and incineration are not only resource-in-efficient but also environmentally detrimental.Consequently,PV module recycling has emerged as a critical pathway for achieving green and sustainable development within the PV industry,gaining broad consensus under supportive national policies.This study comprehensively analyzes the current status and retirement trends of the global and Chinese PV indus-tries.It investigates the resource attributes of various retired PV module types,encompassing the weight distribution and economic value of key components,their potential contribution to future solar material demand,and implications for crit-ical mineral supply security.Concurrently,the environmental risk attributes are evaluated.The research further reviews domestic and international policies and regulations governing valuable element recovery,alongside mainstream recycling technologies(physical,chemical,and thermal processes),critically assessing their latest advancements,technical advant-ages,and persistent challenges.Finally,potential pathways and technological development directions for achieving green,high-value-added recycling of retired PV modules are explored.This work aims to provide theoretical support and novel insights for the efficient resource recovery and circular utilization of PV waste,thereby promoting the development of a closed-loop green supply chain for the photovoltaic industry.

Abstract:Regional classification and adapting measures to local conditions were meaningful for the scientific imple-mentation of Ecological Protection and Restoration(EPR).This is due to the regional differences under different types of resource allocation or element combinations.In Xinjiang Province,land degradation issues caused by the spa-tial coupling of large-scale mining disturbance and arid fragile ecological environment have reached a dramatic condi-tion.However,the vast area determined that the differences in ecological issues and the EPR measures in differ-ent mining areas would be inevitable,but there was a lack of clearly classified solutions currently.To this end,this pa-per attempts to classify the mining areas involved in 5 coal bases in Xinjiang from the different combination types of"Coal Resources,Water Resources with Physical Geography&Ecosystem(CR-WR-PGE)".Furthermore,differential strategies for EPR were proposed.Results showed that:① According to the analysis of CR,WR and PGE,the conceptual model of CR-WR-PGE combination type classification based on spatial overlay method were constructed.Then,a simplified division method including 3 aspects and 5 indicators was put forward.② The 5 coal bases were identified and divided into 69 CR-WR-PGE assemblage types.Among them,there are 15,17,25,33 and 24 different combination types in Zhundong,Tuha,Yili,Kubai and Hefeng,respectively.Then the main charac-teristics of the respective combination types of the 5 coal bases were analyzed systematically.③According to different CR-WR-PGE combination types,three Class Ⅰ mining areas in Xinjiang are further summarized,including Gobi Des-ert Mining Area(GDMA),Desert Steppe Mining Area(DSMA),and Oasis Mining Area a(OMA).And they were further divided into 6 number of Class Ⅱ and 17 number of Class Ⅲ.④ The differential strategies of EPR were pro-posed according to the class Ⅰ.In GDMAs,the requirements for vegetation restoration could be properly relaxed and at-tention should be paid to the reconstruction of large-scale gravel layer.In DSMAs,the guided restoration model could be applied to eliminate or reduce the negative disturbance of human activities to promote the self-restoration of land e-cosystem elements.In OMAs,ecological protection still should be controlled by government planning,but social capital should be allowed to invest in ecological restoration of mine ecological restoration with proper guidance and build a di-versified market-oriented restoration mechanism.In the future,the new concept of CR-WR-PGE combination type should be established in the field of EPR in mining area,which can not only provide boundary and guidance for"one mine-one policy",but also provide scientific basis for maintaining regional ecological security.

Abstract:Coal mining causes movement,deformation,and damage of the overlying rock,generating in fissures of differ-ent forms.The determination of the height of vertical thorough fissures is the basis for ensuring safe mining in coal mines,such as setting protective water barrier pillars and formulating measures to prevent roof water damage.This height is also an important parameter required for the application of green mining technologies such as water-preserved mining,gas ex-traction,and isolated overburden grouting filling.This article summarizes the main theoretical methods for predicting the height of fractured water-conducting zone.By comparing the prediction methods under different mining conditions,the need to consider the differences in rock structure to determine the height of fractured water-conducting zone is confirmed.The structure of overburden key strata will have an impact on the developmental characteristics of the height of water-con-ducting fissure zones.Determination based on the location of key strata,which can avoid the shortcomings of lithological homogenization treatment and reflect the differences in engineering conditions,thus has been widely applied in terms of theory and practice.Theoretical prediction methods can serve as reference and guidance for pre-mining safety design and engineering detection schemes.However,due to the differences in mining conditions and the complexity of post mining conditions in China's coal mines,different detection methods are needed to more accurately obtain data of height of frac-tured water-conducting zone and guide engineering practice.This article introduces the different methods and main prin-ciples of direct and indirect detection of height of fractured water-conducting zone,and analyzes their advantages and dis-advantages.Based on the current theoretical calculation methods and commonly used engineering detection methods,problems to be solved and expected development directions for determining the height of fractured water-conducting zone are proposed,such as accurate determination based on new features of detection data in coal measure strata that are rich in water,key technologies for determination under mining with large depth and thickness of coal,research on the correlation between rock strata fracturing and displacement deformation vibration,multi-purpose detection of one hole with collabor-ative analysis and processing of information.This article can provide some reference and inspiration for peers to under-stand the method for determining the height of water-conducting fissure zones and its future directions.

Abstract:In September 2020,China's"Double Carbon Strategy"for the world is not only the inherent requirements of our country's sustainable development,and is also an international obligation responsible for the big country.Shaanxi is a typical energy industry big province,facing the new pressure and opportunities of"double carbon strategy",whether its energy industry can be successfully transformed related to national energy strategic security and the sustainable develop-ment of Shaanxi people's livelihood economy.From the in-depth analysis of three challenges of energy production struc-ture,energy consumption structure,industrial transformation and four challenges of window periods,building a modern energy system,implement new development concept and dual control system,China and the United States strengthen methane reduction cooperation,accurately positioned the transition strategy about the window period before carbon neut-ralization(2021-2030),competition period of twenty years after Peak carbon dioxide emissions(2031-2050),the last ten years transformation attack period before carbon neutral(2051-2060).And then proposed nine transition paths such as strengthen Northern Shaanxi high-end Energy and Chemical base,accelerate the construction of green energy bases,promote diversified stereo carbon-reduction,create a modern energy system,layout zero carbon low carbon negative car-bon technology research relying on Qin-Chuang-Yuan,promoting the industry high-endization,excavating forest grass carbon-fixed potential,optimizing policy system,cultivating carbon neutralization talents,etc.And finally three policy re-commendations are given out,that is,energy industrial ordered transformation,incentive and constraints should be pay at-tention,and create energy technology innovation highland.

Abstract:The movement,deformation,fracture,and stress changes of overlying strata caused by coal mining are the main reasons for the weighting on the longwall face and surface ecological damage.Studying the movement laws and damage mechanisms of overlying strata during mining is the core issue in solving underground safety production,aquifer protec-tion,surface construction facilities,and ecological protection.It is the theoretical basis for achieving green and safe min-ing in coal mines.To fully understand the conduction mechanism of mining damage,taking the overburden"arch shell"structure as the core,the current research results of overburden movement are systematically reviewed.According to the difference of overburden combination and medium characteristics,the arch in mining field are divided into loose layer arch and bedrock arch.Bedrock arches can be further divided into fracture arches and stress arches.On this basis,the re-search progress and existing problems of bedrock arch are discussed according to the arch shell evolution mechanism and research methods:The theoretical model can give the arch trace equation and judge the bearing characteristics of the arch.However,there are some problems,such as simplification of boundary stress conditions,assumption of rock stratum ho-mogeneity,assumption of arch trace and calculation of arch thickness.Numerical simulation can well give the location,thickness and evolution characteristics of arch shell.However,the stress arch shell simulated by finite element ignores the influence of rock fracture,while the stress or fracture arch shell simulated by discrete element depends on the division of blocks.Similar simulation can only qualitatively observe the development characteristics of fracture arch,and it is diffi-cult to determine the range of stress arch.The existing applications based on overlying rock arch shells focus on predict-ing and preventing longwall face weighting and surface subsidence through arch shell evolution models.However,there are relatively few methods for actively regulating overlying rock arch shells.Based on this,this paper summarizes three methods for regulating overlying rock arch shells:source preset arch shell method,process control arch shell method,fi-nal stability control arch shell method.Finally,based on the existing achievements,a theoretical calculation model and simulation method for mining damage arch shell theory based on the law of energy conservation were further proposed.It provided the theoretical support and research methods for the evolution characteristics of the overlying rock fracture struc-ture stability in the longwall face and the treatment of surface subsidence.

Abstract:Uranium,as a pivotal strategic resource,holds significant importance in the fields of national defense and en-ergy.With the depletion of shallow resources,the deep earth strategy emerges as a crucial means to ensure resource secur-ity.Sandstone uranium ore leaching mining,a method that harnesses natural conditions by injecting leaching solutions to chemically react with ores,transforming uranium from solid phase to liquid phase,has garnered global attention due to its advantages of low cost,short cycle time,pipelining,and unmanned operation.Nevertheless,deep sandstone uranium leaching confronts the"three highs and one disturbance"complex environment of high well depth,high geothermal tem-perature,high geostress,and intense disturbance,where the multi-scale nature of ore layer pore-fracture structures leads to multi-stage solution seepage,intricate seepage paths,and difficulties in uniform permeation.To tackle these challenges,re-searchers have extensively delved into pore-fracture structure characterization,seepage behavior visualization,as well as targeted intervention and macro-control in deep sandstone uranium mines.This paper delves into the current research status of pore fracture-seepage transparency characterization and directional intervention in the in-situ leaching system for deep uranium mining.Specifically,the transparency characterization of pore fracture structures is primarily categorized in-to physical characterization methods and 3D reconstruction technologies.The visualization of seepage processes encom-passes studies on seepage experimental behaviors,the preparation of transparent rocks,and the application of numerical simulation techniques in enhancing seepage visualization.Furthermore,the paper explores the mechanisms of directional intervention and regulation within the in-situ leaching system for deep uranium mining,encompassing strategies such as physical control,biochemical regulation,and sandstone uranium reservoir modification.These research efforts have signi-ficantly improved uranium leaching efficiency,mitigated environmental impacts associated with mining,and propelled the development of green and sustainable uranium resources.Lastly,the paper identifies the bottlenecks and challenges faced in the research on pore-fracture-seepage transparency characterization and directional intervention for the in-situ leaching of deep sandstone uranium deposits.Looking ahead,it is imperative to deepen our understanding of the leaching mechan-isms in such systems,optimize and refine the technologies for transparent characterization of pore-fracture structures and visualization of seepage behaviors,and innovate more efficient and environmentally friendly strategies for directional in-tervention and regulation.