The complex stress environment in deep roadways,often exacerbated by thick and hard strata,frequently precipitates coal bursts,posing significant safety hazards.This paper investigates the mechanisms and preventive me...The complex stress environment in deep roadways,often exacerbated by thick and hard strata,frequently precipitates coal bursts,posing significant safety hazards.This paper investigates the mechanisms and preventive methods for coal bursts in the gob-side roadway floor(GSRF)under thick and hard roof in the Ordos region,China.First,the stress-distributing characters of GSRF were analyzed then a stress calculation formula was derived.A mechanical model was developed to determine the critical stress for buckling failure of the roadway floor strata.Criteria for the bursting instability of GSRF were then established.The lateral static load from the adjacent gob,the advancing static load from the working face,and the disturbance load from overlying thick and hard roof fractures combine to transmit high loads and energy to the roadway floor via the“roof→rib→floor”pathway,causing increased stress concentration and energy accumulation.When the conditions satisfy the criteria for bursting instability,coal bursts can occur on the roadway floor.To mitigate dynamic load disturbances,the paper proposes roof regional fracturing and abrasive water jet axial roof cutting.Hydraulic reaming of gutters in the roadway ribs and deep hole blasting at the roadway bottom corners are offered to alleviate the static loads on the surrounding rock.The implementation of targeted prevention measures for dynamic and static loads effectively reduces coal bursts in GSRF.These findings offer an example of preventing and controlling coal bursts in other mines of the Ordos region with comparable geological conditions.展开更多
A microseismic monitoring system was used in the Donggua Shan underground copper mine, and its application was introduced. The spacial distribution of the seismic event was monitored effectively during mining with thi...A microseismic monitoring system was used in the Donggua Shan underground copper mine, and its application was introduced. The spacial distribution of the seismic event was monitored effectively during mining with this system. The distribution of the seismic intensity in different time periods and in the different mining districts was obtained via the clustering analysis of the monitored results, and the different intensity concentration districts of seismicity were compartmentalized. The various characteristics and waveforms of different vibrations in the underground mine were revealed with the help of the micro-seismic monitoring system. It was proved that the construction and application of the micro-seismic monitoring system in the mine not only realized the continuous monitoring of seismicity in the deep mine, but also settled an this system.展开更多
The problem of water preservation in mining and the prevention of water-bursts has been one of the more important issues in deep mining. Based on the concept of water-resisting key strata, the mechanics model of the k...The problem of water preservation in mining and the prevention of water-bursts has been one of the more important issues in deep mining. Based on the concept of water-resisting key strata, the mechanics model of the key strata is established given the structural characteristics and the mechanical properties of the roof rock layers of the working face in a particular coal mine. Four other models were derived from this model by rearranging the order of the layers in the key strata. The distribution characteristics of stress, deformation, pore pressure and the flow vector of all the models are computed using the analytical module of fluid-structure interaction in the FLAC software and the corresponding risks of a water-burst are analyzed. The results indicate that the water-insulating ability of the key strata is related to the arrangement of soft and hard rocks. The water-insulating ability of the compound water-resisting key strata (CWKS) with a hard-hard-soft-hard-soft compounding order is the best under the five given simulated conditions.展开更多
By analyzing the characteristics and the production mechanism of rock burstthat goes with abnormal gas emission in deep coal seams,the essential method of eliminatingabnormal gas emission by eliminating the occurrence...By analyzing the characteristics and the production mechanism of rock burstthat goes with abnormal gas emission in deep coal seams,the essential method of eliminatingabnormal gas emission by eliminating the occurrence of rock burst or depressingthe magnitude of rock burst was considered.The No.237 working face was selected asthe typical working face contacting gas in deep mining;aimed at this working face,a systemof rock burst prediction and control for coal seam contacting gas in deep mining wasestablished.This system includes three parts:① regional prediction of rock burst hazardbefore mining,② local prediction of rock burst hazard during mining,and ③ rock burstcontrol.展开更多
Mineral consumption is increasing rapidly as more consumers enter the market for minerals and as the global standard of living increases. As a result, underground mining continues to progress to deeper levels in order...Mineral consumption is increasing rapidly as more consumers enter the market for minerals and as the global standard of living increases. As a result, underground mining continues to progress to deeper levels in order to tackle the mineral supply crisis in the 21 st century. However, deep mining occurs in a very technical and challenging environment, in which significant innovative solutions and best practice are required and additional safety standards must be implemented in order to overcome the challenges and reap huge eco- nomic gains. These challenges include the catastrophic events that are often met in deep mining engineering： rockbursts, gas outbursts, high in situ and redistributed stresses, large deformation, squeezing and creeping rocks, and high temperature. This review paper presents the current global status of deep mining and high-lights some of the newest technological achievements and opportunities associated with rock mechanics and geotechnical engineering in deep mining. Of the various technical achievements, unmanned workingfaces and unmanned mines based on fully automated mining and mineral extraction processes have become important fields in the 21 st century.展开更多
To predict rock burst in deep mining excavation in Linglong gold mine, systematical laboratory tests of mechanical properties of rock, in situ stress measurement and 3-D FEM analysis on energy distribution in rock mas...To predict rock burst in deep mining excavation in Linglong gold mine, systematical laboratory tests of mechanical properties of rock, in situ stress measurement and 3-D FEM analysis on energy distribution in rock mass surrounding deep mining rooms were carried out. According to various prediction criteria of rock burst, it is concluded that rock burst is liable to occur during deep mining excavation in the mine.展开更多
An increased global supply of minerals is essential to meet the needs and expectations of a rapidly rising world population. This implies extraction from greater depths. Autonomous mining systems, developed through su...An increased global supply of minerals is essential to meet the needs and expectations of a rapidly rising world population. This implies extraction from greater depths. Autonomous mining systems, developed through sustained R＆D by equipment suppliers, reduce miner exposure to hostile work environments and increase safety. This places increased focus on ＂ground control＂ and on rock mechanics to define the depth to which minerals may be extracted economically. Although significant efforts have been made since the end of World War II to apply mechanics to mine design, there have been both technological and organizational obstacles. Rock in situ is a more complex engineering material than is typically encountered in most other engineering disciplines. Mining engineering has relied heavily on empirical procedures in design for thousands of years. These are no longer adequate to address the challenges of the 21st century, as mines venture to increasingly greater depths. The development of the synthetic rock mass （SRM） in 2008 provides researchers with the ability to analyze the deformational behavior of rock masses that are anisotropic and discontinuous-attributes that were described as the defining characteristics of in situ rock by Leopold Mfiller, the president and founder of the International Society for Rock Mechanics （ISRM）, in 1966. Recent developments in the numerical modeling of large-scale mining operations （e.g., caving） using the SRM reveal unanticipated deformational behavior of the rock. The application of massive parallelization and cloud computational techniques offers major opportunities： for example, to assess uncertainties in numerical predictions： to establish the mechanics basis for the empirical rules now used in rock engineering and their validity for the prediction of rock mass behavior beyond current experience： and to use the discrete element method （DEM） in the optimization of deep mine design. For the first time, mining-and rock engineering-will have its own mechanics-based Ulaboratory.＂ This promises to be a major tool in future planning for effective mining at depth. The paper concludes with a discussion of an opportunity to demonstrate the application of DEM and SRM procedures as a laboratory, by back-analysis of mining methods used over the 80-year history of the Mount Lvell Copper Mine in Tasmania.展开更多
To study the mechanism of unsteady heat-moisture transfer of wet surrounding rock in deep mining, a series of experiments with different initial and boundary conditions were carried out. Test results show that rock te...To study the mechanism of unsteady heat-moisture transfer of wet surrounding rock in deep mining, a series of experiments with different initial and boundary conditions were carried out. Test results show that rock temperature decreases quickly at the initial stage, and reduces slowly to be a constant value finally for transient heat-moisture transfer. The quasi-steady surface temperature of wet airway is lower than that of dry airway due to the moisture transfer. The diffusion radius is less than the cooling radius owing to the large diffusion resistance. The outlet airflow enthalpy of wet airway is much larger than that of dry airway. Latent heat caused by the moisture transfer plays a significant role in a deep thermal environment. For periodic heat-moisture transfer, temperature, humidity and enthalpy of outlet airflow and rock temperature also change periodically. The wave amplitude of rock temperature decreases gradually with increasing distance away from the airway surface, and the wave phase of rock temperature is also behind that of airflow. Moreover, direction of the heat-moisture transfer between airway and airflow is bidirectional, which is different from results of transient transfer.展开更多
Based on the characteristic of deep rock layers and the theory of key strata,we analysed elastic mechanical characteristics of key strata by using elastic plate theory.The results show that the deformation and distrib...Based on the characteristic of deep rock layers and the theory of key strata,we analysed elastic mechanical characteristics of key strata by using elastic plate theory.The results show that the deformation and distribution of internal forces of key strata vary with different mine boundary conditions.The boundary values of key strata with three point boundaries and one fixed boundary is greater than that with four fixed boundaries.Considering the rheology of key strata under low stress conditions,we selected a generalized Kelvin model to analyse the rheology characteristics of the key strata and discovered their instantaneous elastic phases.The rate of deformation decreased over time to the point where the key strata reached stability.But over this time,the effect on deformation became very clear. For high stress conditions,we chose a Burgers model and found deformation of key strata in the form of attenuation and steady-state creep and although the rate of deformation remained constant,secondary creep was obvious,causing instability in the system.As well,we analysed the effect of creep buckling and derived a relation between buckling force and time.展开更多
Pump chambers, normally used as dominant structures in mining engineering to insure the safety and production of un-derground coal mines, become generally deformed under conditions of deep mining. Given the geology an...Pump chambers, normally used as dominant structures in mining engineering to insure the safety and production of un-derground coal mines, become generally deformed under conditions of deep mining. Given the geology and engineering condition of Qishan Coal Mine in Xuzhou, the failure characteristics of pump chambers at the –1000 m level show that the main cause can be attributed to the spatial effect induced by intersectional chambers, where one pump is constructed per well. We developed an opti-mized design of the pump room, in which the pump wells in the traditional design are integrated into one compounding well. We suggest that the new design can limit the spatial effect of intersectional chambers during construction given our relevant numerical simulation. The new design is able to simplify the structure of the pump chamber and reduce the amount of excavation required. Based on a bolt-mesh-anchor with a rigid gap coupling supporting technology, the stability of pump chamber can be improved greatly.展开更多
Workers exposed to hot and humid conditions suffer from heat stress that affects their concentration and can potentially lead to an increase in workplace accidents. To minimize heat stress, protective equipment may be...Workers exposed to hot and humid conditions suffer from heat stress that affects their concentration and can potentially lead to an increase in workplace accidents. To minimize heat stress, protective equipment may be worn, such as personal cooling garments. This paper presents and discusses the performances, advantages and disadvantages of existing personal cooling garments, namely air-cooled, liquid-cooled, phase change, hybrid, gas expansion and vacuum desiccant cooling garments, and a thermoelectric cooling technology. The main objective is to identify the cooling technique that would be most suitable for deep mining workers. It appears that no cooling technology currently on the market is perfectly compatible with this type of mining environment. However, combining two or more cooling technologies into a single hybrid system could be the solution to an optimized cooling garment for deep mines.展开更多
Shear strain energy is a pivotal physical quantity in the occurrence of earthquakes and rockbursts during deep mining operations.This research is focused on understanding the changes in shear strain energy in the cont...Shear strain energy is a pivotal physical quantity in the occurrence of earthquakes and rockbursts during deep mining operations.This research is focused on understanding the changes in shear strain energy in the context of retreating longwall mining,which is essential for the optimized design and mitigation of rockbursts and seismic events.Through the application of innovative analytical models,this study expands its analytical range to include the variations in shear strain energy caused by fault coseismic slip.An integrated methodology is utilized,taking into account the changes in coseismic and fault friction parameters as well as enhancements in mining-induced stress and existing background stresses.Our numerical investigation highlights the significance of mining location and fault characteristics as key determinants of shear strain energy modifications.The analysis demonstrates significant spatial variability in shear strain energy,especially noting that fault slip near the mining face greatly increases the likelihood of rockburst.This finding emphasizes the need to integrate fault coseismic slip dynamics into the triggering factors of rock(coal)bursts,thus broadening the theoretical foundation for addressing geological hazards in deep mining operations.The results are further corroborated by observational data from the vicinity of the F16 fault zone,introducing the concept of mining-induced fault coseismic slip as an essential element in the theoretical framework for understanding rockburst triggers.展开更多
In a recent article published in Cell,Chowdhury and colleagues apply advanced single-cell mRNA profiling to identify a previously unknown strictly peptidergic neuronal population in the dorsal raphe nucleus(DRN).Promp...In a recent article published in Cell,Chowdhury and colleagues apply advanced single-cell mRNA profiling to identify a previously unknown strictly peptidergic neuronal population in the dorsal raphe nucleus(DRN).Prompted by pathway-enriched genes,the authors show that these cholecystokinin(CCK)-expressing neurons integrate a broad spectrum of food intake-and satiation-related signals and play a robust role in regulating meal sizes during homoeostatic eating(Fig.1).展开更多
Mineral resources exploitation moving deeper into the earth is an inevitable trend with economic and social development.However,the deep high temperature poses a significant challenge to the safety and efficiency of h...Mineral resources exploitation moving deeper into the earth is an inevitable trend with economic and social development.However,the deep high temperature poses a significant challenge to the safety and efficiency of human and machine.The prevention of potential thermal risks in deep mining is critical.Here,the key and difficult issues of humanmachine-environment temperature monitoring are discussed according to the characteristics of deep hightemperature environment.Then,a monitoring and analysis method of human-machine-environment temperature field suitable for deep high-temperature mining areas is proposed.This method covers humanmachine-environment temperature monitoring,data storage and transmission,data processing,results visualization,and thermal risks warning.The monitoring sensor networks are constructed to collect real-time data of miners,machines,and environments.The data is transmitted to the central processing system for storage and analysis using both wired and wireless transmission technologies.Moreover,digital filtering and Kriging interpolation algorithms are applied to denoise and handle outliers in the monitored data,as well as to calculate the temperature field.The temperature prediction model is constructed using Long Short-Term Memory(LSTM)method.Finally,potential thermal risks are identified by combining real-time monitoring and prediction results,thereby guiding management personnels and miners to take appropriate measures.The proposed monitoring and analysis method can be applied to deep mines that affected by high temperature.It not only provides data and methodological support for assessing thermal risks in mines,but also offers scientific basis for optimizing mining operations and implementing safety measures.展开更多
Deep Underground Science and Engineering(DUSE)is pleased to present this special issue on Groundwater and Stability in Deep Mining.As mining operations progress to greater depths to meet the growing global demand for ...Deep Underground Science and Engineering(DUSE)is pleased to present this special issue on Groundwater and Stability in Deep Mining.As mining operations progress to greater depths to meet the growing global demand for mineral resources and energy,the challenges associated with groundwater control and rock mass stability have grown increasingly critical.These challenges are exacerbated by complex geological conditions,structural heterogeneity,and intense mining-induced disturbances.This special issue seeks to address these challenges by showcasing cutting-edge research and technological advancements in the field.展开更多
The publisher regrets that the article type for this publication was incorrectly labeled as a Research Article.The correct designation should be Review Article.This correction does not affect the content or conclusion...The publisher regrets that the article type for this publication was incorrectly labeled as a Research Article.The correct designation should be Review Article.This correction does not affect the content or conclusions of the article.The publisher apologizes for any inconvenience caused.展开更多
The increasing risk of ground pressure disasters resulting from deep well mining highlights the urgent need for advanced monitoring and early warning systems.Ground pressure monitoring,supported by microseismic techno...The increasing risk of ground pressure disasters resulting from deep well mining highlights the urgent need for advanced monitoring and early warning systems.Ground pressure monitoring,supported by microseismic technology,plays a pivotal role in ensuring mine safety by enabling real-time identifi cation and accurate classification of vibration signals such as microseismic signals,blasting signals,and noise.These classifications are critical for improving the efficacy of ground pressure monitoring systems,conducting stability analyses of deep rock masses,and implementing timely and precise roadway support measures.Such eff orts are essential for mitigating ground pressure disasters and ensuring safe mining operations.This study proposes an artificial intelligence-based automatic classification network model for mine vibration signals.Based on conventional convolutional neural networks,the proposed model further incorporates long short-term memory(LSTM)networks and attention mechanisms.The LSTM component eff ectively captures temporal correlations in time-series mining vibration data,while the attention mechanism enhances the models’ability to focus on critical features within the data.To validate the eff ectiveness of our proposed model,a dataset comprising 480,526 waveform records collected in 2022 by the microseismic monitoring system at Guangxi Shanhu Tungsten Mine was used for training,validation,and testing purposes.Results demonstrate that the proposed artifi cial intelligence-based classifi cation method achieves a higher recognition accuracy of 92.21%,significantly outperforming traditional manual classification methods.The proposed model represents a signifi cant advancement in ground pressure monitoring and disaster mitigation.展开更多
Pressure-preserved coring technologies are critical for deep-earth resource exploration but are constrained by the inability to achieve multidirectional coring,restricting exploration range while escalating costs and ...Pressure-preserved coring technologies are critical for deep-earth resource exploration but are constrained by the inability to achieve multidirectional coring,restricting exploration range while escalating costs and environmental impacts.We developed a multidirectional pressure-preserved coring system based on magnetic control for deep-earth environments up to 5000 m.The system integrates a magnetically controlled method and key pressure-preserved components to ensure precise self-triggering and self-sealing.It is supported by geometric control equations for optimizing structural stability.Their structure was verified and optimized through theoretical and numerical calculations to meet design objectives.To clarify the self-triggering mechanism in complex environments,a dynamic interference model was established,verifying stability during multidirectional coring.The prototype was fabricated,and functional tests confirmed that it met its design objectives.In a 300-meter-deep test inclined well,10 coring operations were completed with a 100%pressure-preserved success rate,confirming the accuracy of the dynamic interference model analysis.Field trials in a 1970-meter-deep inclined petroleum well,representative of complex environments,demonstrated an in-situ pressure preservation efficiency of 92.18%at 22 MPa.This system innovatively expands the application scope of pressure-preserved coring,providing technical support for efficient and sustainable deep resources exploration and mining.展开更多
Pressure-preserving controllers(PPCs)are crucial components of in situ pressure-preserving coring(IPP-Coring)devices for deep oil and gas extraction,and their ultimate pressure-bearing(UPB)capability determines the up...Pressure-preserving controllers(PPCs)are crucial components of in situ pressure-preserving coring(IPP-Coring)devices for deep oil and gas extraction,and their ultimate pressure-bearing(UPB)capability determines the upper limit of their ability to acquire oil and gas reserves.However,due to the UPB-capability and sealing challenges,the working pressure typically does not exceed 70 MPa.In this study,the optimal design of a PPC using a self-developed IPP-Coring test platform is presented,and its seal failure mechanism is revealed.Experimental results demonstrate that the designed saddle-shaped PPC achieves a minimal UPB-capability of 140 MPa,which is twice the highest value reported in literature.A numerical simulation method was developed to predict the UPB-capability of the PPC,and its reliability was validated in comparison with experimental results.The simulation results indicate that the sealing failure of the PPC is attributed to a progressive escalation in seal clearance between valve cover and seat,which causes an O-ring extrusion.Under ambient temperature and ultrahigh pressure,the critical threshold for seal clearance in PPC seal failure is approximately 0.2 mm.These results provide significant insights into enhancing deep resource acquisition capabilities.展开更多
The pressure-preserving controller is the key component of deep in situ pressure-preserving coring(IPP-Coring).With increasing drilling depth,the environmental temperature and pressure increase accordingly.However,due...The pressure-preserving controller is the key component of deep in situ pressure-preserving coring(IPP-Coring).With increasing drilling depth,the environmental temperature and pressure increase accordingly.However,due to the strength and sealing problems of pressure-preserving controllers,the coring pressure is generally lower than 70 MPa.Establishing a high-temperature and ultrahigh-pressure test system is highly important for improving the strength and sealing performance of pressure-preserving controllers.This paper introduces a high-temperature and ultrahigh-pressure test system for deep IPP-Coring controller performance analysis.The device includes six parts:an auxiliary air source system,a pressurization system,a temperature control system,a hydraulic system,a data acquisition and electrical control system,and an ultrahigh-pressure vessel.The test system can reconstruct a 150℃ and 200 MPa in situ environment and simulate and test the movement state of the corer and the stability of the pressure-preserving action trigger of the pressure-preserving controller in the deep IPP-Coring process.To verify the performance of this test system,saddle-shaped pressure-preserving controllers made of four different materials were subjected to pressure tests under normal-temperature and high-temperature conditions.The results showed that the ultimate pressure-bearing capability of the pressure-preserving controller greatly varied between normal-temperature and high-temperature conditions.The pressure-preserving ability and sealing performance of the pressure-preserving controller decreased significantly at high temperature,and the pressure-preserving controller exhibited significantly different sealing failure characteristics due to material differences.This study is important for progressing the extraction and evaluation of deep reservoir resources.展开更多
基金financially supported by the National Key Research and Development Program of China(2022YFC3004604)National Natural Science Foundation of China(U23B2093).
文摘The complex stress environment in deep roadways,often exacerbated by thick and hard strata,frequently precipitates coal bursts,posing significant safety hazards.This paper investigates the mechanisms and preventive methods for coal bursts in the gob-side roadway floor(GSRF)under thick and hard roof in the Ordos region,China.First,the stress-distributing characters of GSRF were analyzed then a stress calculation formula was derived.A mechanical model was developed to determine the critical stress for buckling failure of the roadway floor strata.Criteria for the bursting instability of GSRF were then established.The lateral static load from the adjacent gob,the advancing static load from the working face,and the disturbance load from overlying thick and hard roof fractures combine to transmit high loads and energy to the roadway floor via the“roof→rib→floor”pathway,causing increased stress concentration and energy accumulation.When the conditions satisfy the criteria for bursting instability,coal bursts can occur on the roadway floor.To mitigate dynamic load disturbances,the paper proposes roof regional fracturing and abrasive water jet axial roof cutting.Hydraulic reaming of gutters in the roadway ribs and deep hole blasting at the roadway bottom corners are offered to alleviate the static loads on the surrounding rock.The implementation of targeted prevention measures for dynamic and static loads effectively reduces coal bursts in GSRF.These findings offer an example of preventing and controlling coal bursts in other mines of the Ordos region with comparable geological conditions.
基金This work was financially supported by the National Key Technologies R & D Program of China (No.2004BA615A-04).
文摘A microseismic monitoring system was used in the Donggua Shan underground copper mine, and its application was introduced. The spacial distribution of the seismic event was monitored effectively during mining with this system. The distribution of the seismic intensity in different time periods and in the different mining districts was obtained via the clustering analysis of the monitored results, and the different intensity concentration districts of seismicity were compartmentalized. The various characteristics and waveforms of different vibrations in the underground mine were revealed with the help of the micro-seismic monitoring system. It was proved that the construction and application of the micro-seismic monitoring system in the mine not only realized the continuous monitoring of seismicity in the deep mine, but also settled an this system.
基金Projects 50490270 supported by the National Natural Science Foundation of China, 50634050 the National Natural Science Foundation of China and 2006A038 SR Foundation of China University of Mining & Technology
文摘The problem of water preservation in mining and the prevention of water-bursts has been one of the more important issues in deep mining. Based on the concept of water-resisting key strata, the mechanics model of the key strata is established given the structural characteristics and the mechanical properties of the roof rock layers of the working face in a particular coal mine. Four other models were derived from this model by rearranging the order of the layers in the key strata. The distribution characteristics of stress, deformation, pore pressure and the flow vector of all the models are computed using the analytical module of fluid-structure interaction in the FLAC software and the corresponding risks of a water-burst are analyzed. The results indicate that the water-insulating ability of the key strata is related to the arrangement of soft and hard rocks. The water-insulating ability of the compound water-resisting key strata (CWKS) with a hard-hard-soft-hard-soft compounding order is the best under the five given simulated conditions.
基金Supported by the National Natural Science Foundation(Instrument)of China(50427401)the National High Technology Research and Development Program of China(2006AA06Z119)+1 种基金the National Key Technology R&D Program in 11th Five Years Plan of China(2007BA29B01)the New Century Excellent Talents in University(NCET-06-0477)
文摘By analyzing the characteristics and the production mechanism of rock burstthat goes with abnormal gas emission in deep coal seams,the essential method of eliminatingabnormal gas emission by eliminating the occurrence of rock burst or depressingthe magnitude of rock burst was considered.The No.237 working face was selected asthe typical working face contacting gas in deep mining;aimed at this working face,a systemof rock burst prediction and control for coal seam contacting gas in deep mining wasestablished.This system includes three parts:① regional prediction of rock burst hazardbefore mining,② local prediction of rock burst hazard during mining,and ③ rock burstcontrol.
文摘Mineral consumption is increasing rapidly as more consumers enter the market for minerals and as the global standard of living increases. As a result, underground mining continues to progress to deeper levels in order to tackle the mineral supply crisis in the 21 st century. However, deep mining occurs in a very technical and challenging environment, in which significant innovative solutions and best practice are required and additional safety standards must be implemented in order to overcome the challenges and reap huge eco- nomic gains. These challenges include the catastrophic events that are often met in deep mining engineering： rockbursts, gas outbursts, high in situ and redistributed stresses, large deformation, squeezing and creeping rocks, and high temperature. This review paper presents the current global status of deep mining and high-lights some of the newest technological achievements and opportunities associated with rock mechanics and geotechnical engineering in deep mining. Of the various technical achievements, unmanned workingfaces and unmanned mines based on fully automated mining and mineral extraction processes have become important fields in the 21 st century.
文摘To predict rock burst in deep mining excavation in Linglong gold mine, systematical laboratory tests of mechanical properties of rock, in situ stress measurement and 3-D FEM analysis on energy distribution in rock mass surrounding deep mining rooms were carried out. According to various prediction criteria of rock burst, it is concluded that rock burst is liable to occur during deep mining excavation in the mine.
文摘An increased global supply of minerals is essential to meet the needs and expectations of a rapidly rising world population. This implies extraction from greater depths. Autonomous mining systems, developed through sustained R＆D by equipment suppliers, reduce miner exposure to hostile work environments and increase safety. This places increased focus on ＂ground control＂ and on rock mechanics to define the depth to which minerals may be extracted economically. Although significant efforts have been made since the end of World War II to apply mechanics to mine design, there have been both technological and organizational obstacles. Rock in situ is a more complex engineering material than is typically encountered in most other engineering disciplines. Mining engineering has relied heavily on empirical procedures in design for thousands of years. These are no longer adequate to address the challenges of the 21st century, as mines venture to increasingly greater depths. The development of the synthetic rock mass （SRM） in 2008 provides researchers with the ability to analyze the deformational behavior of rock masses that are anisotropic and discontinuous-attributes that were described as the defining characteristics of in situ rock by Leopold Mfiller, the president and founder of the International Society for Rock Mechanics （ISRM）, in 1966. Recent developments in the numerical modeling of large-scale mining operations （e.g., caving） using the SRM reveal unanticipated deformational behavior of the rock. The application of massive parallelization and cloud computational techniques offers major opportunities： for example, to assess uncertainties in numerical predictions： to establish the mechanics basis for the empirical rules now used in rock engineering and their validity for the prediction of rock mass behavior beyond current experience： and to use the discrete element method （DEM） in the optimization of deep mine design. For the first time, mining-and rock engineering-will have its own mechanics-based Ulaboratory.＂ This promises to be a major tool in future planning for effective mining at depth. The paper concludes with a discussion of an opportunity to demonstrate the application of DEM and SRM procedures as a laboratory, by back-analysis of mining methods used over the 80-year history of the Mount Lvell Copper Mine in Tasmania.
基金Foundation item： Project（2012CB026103） supported by the National Basic Research Program of China Project（51204170） supported by the National Natural Science Foundation of China+2 种基金 Project（2011M500974） supported by Postdoctoral Science Foundation of China Project （2011QNA16） supported by Fundamental Research Funds for the Central Universities, China Project（PDll01） supported by Postdoctoral Foundation of State Key Laboratory for Geomechanics and Deep Underground Engineering, China
文摘To study the mechanism of unsteady heat-moisture transfer of wet surrounding rock in deep mining, a series of experiments with different initial and boundary conditions were carried out. Test results show that rock temperature decreases quickly at the initial stage, and reduces slowly to be a constant value finally for transient heat-moisture transfer. The quasi-steady surface temperature of wet airway is lower than that of dry airway due to the moisture transfer. The diffusion radius is less than the cooling radius owing to the large diffusion resistance. The outlet airflow enthalpy of wet airway is much larger than that of dry airway. Latent heat caused by the moisture transfer plays a significant role in a deep thermal environment. For periodic heat-moisture transfer, temperature, humidity and enthalpy of outlet airflow and rock temperature also change periodically. The wave amplitude of rock temperature decreases gradually with increasing distance away from the airway surface, and the wave phase of rock temperature is also behind that of airflow. Moreover, direction of the heat-moisture transfer between airway and airflow is bidirectional, which is different from results of transient transfer.
基金supported by the National Natural Science Foundation of China(No.50904065)the Program for New Century Excellent Talents in University(No.NCET-09-0728)
文摘Based on the characteristic of deep rock layers and the theory of key strata,we analysed elastic mechanical characteristics of key strata by using elastic plate theory.The results show that the deformation and distribution of internal forces of key strata vary with different mine boundary conditions.The boundary values of key strata with three point boundaries and one fixed boundary is greater than that with four fixed boundaries.Considering the rheology of key strata under low stress conditions,we selected a generalized Kelvin model to analyse the rheology characteristics of the key strata and discovered their instantaneous elastic phases.The rate of deformation decreased over time to the point where the key strata reached stability.But over this time,the effect on deformation became very clear. For high stress conditions,we chose a Burgers model and found deformation of key strata in the form of attenuation and steady-state creep and although the rate of deformation remained constant,secondary creep was obvious,causing instability in the system.As well,we analysed the effect of creep buckling and derived a relation between buckling force and time.
基金supported by the Major Project of the National Basic Research Program of China (No2006CB202200)the Program for New Century Excellent Talents in Uni-versity (NoNCET07-0800)the Special Fund for Basic Research and Operating Expenses of the China University of Mining & Technology, Beijing and the Academician workstation in enterprise of Jiangsu Province (No.BM2009563)
文摘Pump chambers, normally used as dominant structures in mining engineering to insure the safety and production of un-derground coal mines, become generally deformed under conditions of deep mining. Given the geology and engineering condition of Qishan Coal Mine in Xuzhou, the failure characteristics of pump chambers at the –1000 m level show that the main cause can be attributed to the spatial effect induced by intersectional chambers, where one pump is constructed per well. We developed an opti-mized design of the pump room, in which the pump wells in the traditional design are integrated into one compounding well. We suggest that the new design can limit the spatial effect of intersectional chambers during construction given our relevant numerical simulation. The new design is able to simplify the structure of the pump chamber and reduce the amount of excavation required. Based on a bolt-mesh-anchor with a rigid gap coupling supporting technology, the stability of pump chamber can be improved greatly.
文摘Workers exposed to hot and humid conditions suffer from heat stress that affects their concentration and can potentially lead to an increase in workplace accidents. To minimize heat stress, protective equipment may be worn, such as personal cooling garments. This paper presents and discusses the performances, advantages and disadvantages of existing personal cooling garments, namely air-cooled, liquid-cooled, phase change, hybrid, gas expansion and vacuum desiccant cooling garments, and a thermoelectric cooling technology. The main objective is to identify the cooling technique that would be most suitable for deep mining workers. It appears that no cooling technology currently on the market is perfectly compatible with this type of mining environment. However, combining two or more cooling technologies into a single hybrid system could be the solution to an optimized cooling garment for deep mines.
文摘Shear strain energy is a pivotal physical quantity in the occurrence of earthquakes and rockbursts during deep mining operations.This research is focused on understanding the changes in shear strain energy in the context of retreating longwall mining,which is essential for the optimized design and mitigation of rockbursts and seismic events.Through the application of innovative analytical models,this study expands its analytical range to include the variations in shear strain energy caused by fault coseismic slip.An integrated methodology is utilized,taking into account the changes in coseismic and fault friction parameters as well as enhancements in mining-induced stress and existing background stresses.Our numerical investigation highlights the significance of mining location and fault characteristics as key determinants of shear strain energy modifications.The analysis demonstrates significant spatial variability in shear strain energy,especially noting that fault slip near the mining face greatly increases the likelihood of rockburst.This finding emphasizes the need to integrate fault coseismic slip dynamics into the triggering factors of rock(coal)bursts,thus broadening the theoretical foundation for addressing geological hazards in deep mining operations.The results are further corroborated by observational data from the vicinity of the F16 fault zone,introducing the concept of mining-induced fault coseismic slip as an essential element in the theoretical framework for understanding rockburst triggers.
基金supported by the SFB 1461(Project-ID 434434223)to P.W.
文摘In a recent article published in Cell,Chowdhury and colleagues apply advanced single-cell mRNA profiling to identify a previously unknown strictly peptidergic neuronal population in the dorsal raphe nucleus(DRN).Prompted by pathway-enriched genes,the authors show that these cholecystokinin(CCK)-expressing neurons integrate a broad spectrum of food intake-and satiation-related signals and play a robust role in regulating meal sizes during homoeostatic eating(Fig.1).
基金supported by the National Science Foundation for Distinguished Young Scholars of China(Grant No.52425403)。
文摘Mineral resources exploitation moving deeper into the earth is an inevitable trend with economic and social development.However,the deep high temperature poses a significant challenge to the safety and efficiency of human and machine.The prevention of potential thermal risks in deep mining is critical.Here,the key and difficult issues of humanmachine-environment temperature monitoring are discussed according to the characteristics of deep hightemperature environment.Then,a monitoring and analysis method of human-machine-environment temperature field suitable for deep high-temperature mining areas is proposed.This method covers humanmachine-environment temperature monitoring,data storage and transmission,data processing,results visualization,and thermal risks warning.The monitoring sensor networks are constructed to collect real-time data of miners,machines,and environments.The data is transmitted to the central processing system for storage and analysis using both wired and wireless transmission technologies.Moreover,digital filtering and Kriging interpolation algorithms are applied to denoise and handle outliers in the monitored data,as well as to calculate the temperature field.The temperature prediction model is constructed using Long Short-Term Memory(LSTM)method.Finally,potential thermal risks are identified by combining real-time monitoring and prediction results,thereby guiding management personnels and miners to take appropriate measures.The proposed monitoring and analysis method can be applied to deep mines that affected by high temperature.It not only provides data and methodological support for assessing thermal risks in mines,but also offers scientific basis for optimizing mining operations and implementing safety measures.
文摘Deep Underground Science and Engineering(DUSE)is pleased to present this special issue on Groundwater and Stability in Deep Mining.As mining operations progress to greater depths to meet the growing global demand for mineral resources and energy,the challenges associated with groundwater control and rock mass stability have grown increasingly critical.These challenges are exacerbated by complex geological conditions,structural heterogeneity,and intense mining-induced disturbances.This special issue seeks to address these challenges by showcasing cutting-edge research and technological advancements in the field.
文摘The publisher regrets that the article type for this publication was incorrectly labeled as a Research Article.The correct designation should be Review Article.This correction does not affect the content or conclusions of the article.The publisher apologizes for any inconvenience caused.
基金supported in part by the National Science Fund for Distinguished Young Scholars under Grant (42025403)the National Key Research and Development Plan of China (2021YFA0716800)the National Key Research and Development Plan of China (2022YFC2903804)。
文摘The increasing risk of ground pressure disasters resulting from deep well mining highlights the urgent need for advanced monitoring and early warning systems.Ground pressure monitoring,supported by microseismic technology,plays a pivotal role in ensuring mine safety by enabling real-time identifi cation and accurate classification of vibration signals such as microseismic signals,blasting signals,and noise.These classifications are critical for improving the efficacy of ground pressure monitoring systems,conducting stability analyses of deep rock masses,and implementing timely and precise roadway support measures.Such eff orts are essential for mitigating ground pressure disasters and ensuring safe mining operations.This study proposes an artificial intelligence-based automatic classification network model for mine vibration signals.Based on conventional convolutional neural networks,the proposed model further incorporates long short-term memory(LSTM)networks and attention mechanisms.The LSTM component eff ectively captures temporal correlations in time-series mining vibration data,while the attention mechanism enhances the models’ability to focus on critical features within the data.To validate the eff ectiveness of our proposed model,a dataset comprising 480,526 waveform records collected in 2022 by the microseismic monitoring system at Guangxi Shanhu Tungsten Mine was used for training,validation,and testing purposes.Results demonstrate that the proposed artifi cial intelligence-based classifi cation method achieves a higher recognition accuracy of 92.21%,significantly outperforming traditional manual classification methods.The proposed model represents a signifi cant advancement in ground pressure monitoring and disaster mitigation.
基金supported by the National Key Research and Development Program of China(No.2023YFF0615401)Joint Funds of the National Natural Science Foundation of China(No.U24A2087)+1 种基金Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(No.SKLGME022009)the National Natural Science Foundation of China(No.42477191)。
文摘Pressure-preserved coring technologies are critical for deep-earth resource exploration but are constrained by the inability to achieve multidirectional coring,restricting exploration range while escalating costs and environmental impacts.We developed a multidirectional pressure-preserved coring system based on magnetic control for deep-earth environments up to 5000 m.The system integrates a magnetically controlled method and key pressure-preserved components to ensure precise self-triggering and self-sealing.It is supported by geometric control equations for optimizing structural stability.Their structure was verified and optimized through theoretical and numerical calculations to meet design objectives.To clarify the self-triggering mechanism in complex environments,a dynamic interference model was established,verifying stability during multidirectional coring.The prototype was fabricated,and functional tests confirmed that it met its design objectives.In a 300-meter-deep test inclined well,10 coring operations were completed with a 100%pressure-preserved success rate,confirming the accuracy of the dynamic interference model analysis.Field trials in a 1970-meter-deep inclined petroleum well,representative of complex environments,demonstrated an in-situ pressure preservation efficiency of 92.18%at 22 MPa.This system innovatively expands the application scope of pressure-preserved coring,providing technical support for efficient and sustainable deep resources exploration and mining.
基金support from National Natural Science Foundation of China(Grant Nos.52304146 and 52225403)the China Postdoctoral Science Foundation(Grant No.2023M742460).
文摘Pressure-preserving controllers(PPCs)are crucial components of in situ pressure-preserving coring(IPP-Coring)devices for deep oil and gas extraction,and their ultimate pressure-bearing(UPB)capability determines the upper limit of their ability to acquire oil and gas reserves.However,due to the UPB-capability and sealing challenges,the working pressure typically does not exceed 70 MPa.In this study,the optimal design of a PPC using a self-developed IPP-Coring test platform is presented,and its seal failure mechanism is revealed.Experimental results demonstrate that the designed saddle-shaped PPC achieves a minimal UPB-capability of 140 MPa,which is twice the highest value reported in literature.A numerical simulation method was developed to predict the UPB-capability of the PPC,and its reliability was validated in comparison with experimental results.The simulation results indicate that the sealing failure of the PPC is attributed to a progressive escalation in seal clearance between valve cover and seat,which causes an O-ring extrusion.Under ambient temperature and ultrahigh pressure,the critical threshold for seal clearance in PPC seal failure is approximately 0.2 mm.These results provide significant insights into enhancing deep resource acquisition capabilities.
基金funding support from National Natural Science Foundation of China(Grant Nos.52225403,51827901,and 52304146).
文摘The pressure-preserving controller is the key component of deep in situ pressure-preserving coring(IPP-Coring).With increasing drilling depth,the environmental temperature and pressure increase accordingly.However,due to the strength and sealing problems of pressure-preserving controllers,the coring pressure is generally lower than 70 MPa.Establishing a high-temperature and ultrahigh-pressure test system is highly important for improving the strength and sealing performance of pressure-preserving controllers.This paper introduces a high-temperature and ultrahigh-pressure test system for deep IPP-Coring controller performance analysis.The device includes six parts:an auxiliary air source system,a pressurization system,a temperature control system,a hydraulic system,a data acquisition and electrical control system,and an ultrahigh-pressure vessel.The test system can reconstruct a 150℃ and 200 MPa in situ environment and simulate and test the movement state of the corer and the stability of the pressure-preserving action trigger of the pressure-preserving controller in the deep IPP-Coring process.To verify the performance of this test system,saddle-shaped pressure-preserving controllers made of four different materials were subjected to pressure tests under normal-temperature and high-temperature conditions.The results showed that the ultimate pressure-bearing capability of the pressure-preserving controller greatly varied between normal-temperature and high-temperature conditions.The pressure-preserving ability and sealing performance of the pressure-preserving controller decreased significantly at high temperature,and the pressure-preserving controller exhibited significantly different sealing failure characteristics due to material differences.This study is important for progressing the extraction and evaluation of deep reservoir resources.
