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
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
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
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 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
Gas content serves as a critical indicator for assessing the resource potential of deep coal mines and forecasting coal mine gas outburst risks.However,existing sampling technologies face challenges in maintaining the...Gas content serves as a critical indicator for assessing the resource potential of deep coal mines and forecasting coal mine gas outburst risks.However,existing sampling technologies face challenges in maintaining the integrity of gas content within samples and are often constrained by estimation errors inherent in empirical formulas,which results in inaccurate gas content measurements.This study introduces a lightweight,in-situ pressure-and gas-preserved corer designed to collect coal samples under the pressure conditions at the sampling point,effectively preventing gas loss during transfer and significantly improving measurement accuracy.Additionally,a gas migration model for deep coal mines was developed to elucidate gas migration characteristics under pressure-preserved coring conditions.The model offers valuable insights for optimizing coring parameters,demonstrating that both minimizing the coring hole diameter and reducing the pressure difference between the coring-point pressure and the original pore pressure can effectively improve the precision of gas content measurements.Coring tests conducted at an experimental base validated the performance of the corer and its effectiveness in sample collection.Furthermore,successful horizontal coring tests conducted in an underground coal mine roadway demonstrated that the measured gas content using pressure-preserved coring was 34%higher than that obtained through open sampling methods.展开更多
Despite the long-standing success of waste tailings recycling at shallower lithosphere,heat influx from the stifling environment of deep strata and ground squeezing due to aggravating deposit rheology have posed subst...Despite the long-standing success of waste tailings recycling at shallower lithosphere,heat influx from the stifling environment of deep strata and ground squeezing due to aggravating deposit rheology have posed substantial challenges to traditional mine backfilling.To explore the minefill behavior in difficult geology settings,a new thermo-poroelastic model is developed in this study for characterizing the porepressure evolution in hydrating backfill subjected to coupled thermal perturbation and mechanical deformation.By scrutinizing the undrained pressure responses to a hierarchy of thermo-mechanical loading configurations,we investigated the relative contribution of heat exchange and wall convergence to the macroscopic minefill behavior.The result suggests that the backfill response could exhibit unique rate and path-dependence upon thermal loading due to the competing processes that govern the pressure evolution.Moreover,it shows that while rapid wall convergence would always induce significant pressure,thermal straining via heat exchange might still modulate substantially the pressure distribution when the temperature catalyzes considerable water expansivity.These findings could facilitate understanding of the complex backfill behavior in difficult geology settings,and thus have significant implications for adaptive tailings management to deep mining development.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
Seafloor massive sulfide（SMS） deposits which consist of Au, Ag, Cu, and other metal elements, have been a target of commercial mining in recent decades. The demand for established and reliable commercial mining syst...Seafloor massive sulfide（SMS） deposits which consist of Au, Ag, Cu, and other metal elements, have been a target of commercial mining in recent decades. The demand for established and reliable commercial mining system for SMS deposits is increasing within the marine mining industry. The current status and progress of mining technology and equipment for SMS deposits are introduced. First, the mining technology and other recent developments of SMS deposits are comprehensively explained and analyzed. The seafloor production tools manufactured by Nautilus Minerals and similar mining tools from Japan for SMS deposits are compared and discussed in turn. Second, SMS deposit mining technology research being conducted in China is described, and a new SMS deposits mining tool is designed according to the environmental requirement. Finally, some new trends of mining technology of SMS deposits are summarized and analyzed. All of these conclusions and results have reference value and guiding significance for the research of SMS deposit mining in China.展开更多
With comprehensive considerations of the operational safety and collection efficiency for the tracked miner collecting the seafloor poly-metallic nodules, two new improved mining paths for the miner on the deep seaflo...With comprehensive considerations of the operational safety and collection efficiency for the tracked miner collecting the seafloor poly-metallic nodules, two new improved mining paths for the miner on the deep seafloor were proposed. Compared to the conventional mining path, the design principles and superiorities of the two new paths are that the miner turning with relative long radius should avoid large sinkage and high slip, so as to ensure its operational safety, while the space between its straight-line trajectories before and after the turning is optimum, which is designed as the total width of the miner, and collect nodules as more as possible, so as to ensure its collection efficiency. To realize the new mining paths, theoretical designs and quantitative calculations were carried out to determine the exact positions for the speed controls of the miner during its whole operation process. With the new dynamic model of the miner, and through regulations of the speeds of the left and right tracks of the miner on the exact motion positions according to the theoretical calculations, the two new improved mining paths for the miner on the seafloor were successfully simulated, thus the turning radius of the miner in the simulation is about 21.8 m, while the distance between the straight-line trajectories before and after the turning is about 5.2 m. The dynamic simulation results preliminarily prove the feasibility of these two new mining paths, and further can provide important theoretical guidance and useful technical reference for the practical tracked miner operation and control on the seafloor.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 mining method optimization in subsea deep gold mines was studied. First, an index system for subsea mining method selection was established based on technical feasibility, security status, economic benefit, and ma...The mining method optimization in subsea deep gold mines was studied. First, an index system for subsea mining method selection was established based on technical feasibility, security status, economic benefit, and management complexity. Next, an evaluation matrix containing crisp numbers and triangular fuzzy numbers(TFNs) was constructed to describe quantitative and qualitative information simultaneously. Then, a hybrid model combining fuzzy theory and the Tomada de Decis?o Interativa Multicritério(TODIM) method was proposed. Finally, the feasibility of the proposed approach was validated by an illustrative example of selecting the optimal mining method in the Sanshandao Gold Mine(China). The robustness of this approach was demonstrated through a sensitivity analysis. The results show that the proposed hybrid TODIM method is reliable and stable for choosing the optimal mining method in subsea deep gold mines and provides references for mining method optimization in other similar undersea mines.展开更多
Geotechnical properties of red shale encountered in deep underground mining were characterized on both laboratory and field scale to reveal its unfavorably in geoenvironment.Its constituents,microstructure,strength pr...Geotechnical properties of red shale encountered in deep underground mining were characterized on both laboratory and field scale to reveal its unfavorably in geoenvironment.Its constituents,microstructure,strength properties and water-weakening properties were investigated.In situ stress environment and mining-induced fractured damage zone after excavation were studied to reveal the instability mechanism.The results show that red shale contains swelling and loose clayey minerals as interstitial filling material,producing low shear strength of microstructure and making it vulnerable to water.Macroscopically,a U-shaped curve of uniaxial compressive strength(UCS)exists with the increase of the angle between macro weakness plane and the horizon.However,its tensile strength reduced monotonically with this angle.While immersed in water for72h,its UCS reduced by91.9%comparing to the natural state.Field sonic tests reveal that an asymmetrical geometrical profile of fractured damage zone of gateroad was identified due to geological bedding plane and detailed gateroad layout with regards to the direction of major principle stress.Therefore,red shale is a kind of engineering soft rock.For ground control in underground mining or similar applications,water inflow within several hours of excavation must strictly be prevented and energy adsorbing rock bolt is recommended,especially in large deformation part of gateroad.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
To achieve safe and highly efficient mining in the gassy, deep mines of the Huainan collieries simultaneous coal and gas extraction, and the corresponding ventilation methods were developed. This includes a set of min...To achieve safe and highly efficient mining in the gassy, deep mines of the Huainan collieries simultaneous coal and gas extraction, and the corresponding ventilation methods were developed. This includes a set of mining procedures and principles which help insure safe and efficient production. Furthermore, green mining, meaning the comprehensive use of emitted gas, proper treatment of the environment and appropriate mine temperature control, is now standard. The concepts of modem mining and the principles of pressure relief are described. Coal-gas simultaneous ex- traction and multi-pressure relief techniques were developed which require a combination of surface and underground gas extraction. The application of Y-ventilation systems, of roadways retained along goafs, of stress control techniques for highly fragile mine roofs and of powerful, automatic and reliable mining equipment contributes to safe operation of modem deep mines. Operating parameters for these techniques are described and the results of their use discussed.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
Ocean mining activities have been ongoing for nearly 70 years,making great contributions to industrialization.Given the increasing demand for energy,along with the restructuring of the energy supply catalyzed by effor...Ocean mining activities have been ongoing for nearly 70 years,making great contributions to industrialization.Given the increasing demand for energy,along with the restructuring of the energy supply catalyzed by efforts to achieve a low-carbon economy,deep seabed mining will play an important role in addressing energy-and resource-related problems in the future.However,deep seabed mining remains in the exploratory stage,with many challenges presented by the high-pressure,low-temperature,and complex geologic and hydrodynamic environments in deep-sea mining areas,which are inaccessible to human activities.Thus,considerable efforts are required to ensure sustainable,economic,reliable,and safe deep seabed mining.This study reviews the latest advances in marine engineering geology and the environment related to deep-sea min-ing activities,presents a bibliometric analysis of the development of ocean mineral resources since the 1950s,summarizes the development,theory,and issues related to techniques for the three stages of ocean mining(i.e.,exploration,extraction,and closure),and discusses the engineering geology environment,geological disasters,in-situ monitoring techniques,envi-ronmental protection requirements,and environmental effects in detail.Finally,this paper gives some key conclusions and future perspectives to provide insights for subsequent studies and commercial mining operations.展开更多
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 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.
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supported by the National Natural Science Foundation of China(Nos.51827901,42477191,and 52304033)the Fundamental Research Funds for the Central Universities(No.YJ202449)+1 种基金the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(No.SKLGME022009)the China Postdoctoral Science Foundation(No.2023M742446).
文摘Gas content serves as a critical indicator for assessing the resource potential of deep coal mines and forecasting coal mine gas outburst risks.However,existing sampling technologies face challenges in maintaining the integrity of gas content within samples and are often constrained by estimation errors inherent in empirical formulas,which results in inaccurate gas content measurements.This study introduces a lightweight,in-situ pressure-and gas-preserved corer designed to collect coal samples under the pressure conditions at the sampling point,effectively preventing gas loss during transfer and significantly improving measurement accuracy.Additionally,a gas migration model for deep coal mines was developed to elucidate gas migration characteristics under pressure-preserved coring conditions.The model offers valuable insights for optimizing coring parameters,demonstrating that both minimizing the coring hole diameter and reducing the pressure difference between the coring-point pressure and the original pore pressure can effectively improve the precision of gas content measurements.Coring tests conducted at an experimental base validated the performance of the corer and its effectiveness in sample collection.Furthermore,successful horizontal coring tests conducted in an underground coal mine roadway demonstrated that the measured gas content using pressure-preserved coring was 34%higher than that obtained through open sampling methods.
基金jointly supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region(Grant No.2022D01E32)Opening Fund of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(Chengdu University of Technology)(Grant No.SKLGP 2023K012)the National Natural Science Foundation of China(Grant No.U20A20266).
文摘Despite the long-standing success of waste tailings recycling at shallower lithosphere,heat influx from the stifling environment of deep strata and ground squeezing due to aggravating deposit rheology have posed substantial challenges to traditional mine backfilling.To explore the minefill behavior in difficult geology settings,a new thermo-poroelastic model is developed in this study for characterizing the porepressure evolution in hydrating backfill subjected to coupled thermal perturbation and mechanical deformation.By scrutinizing the undrained pressure responses to a hierarchy of thermo-mechanical loading configurations,we investigated the relative contribution of heat exchange and wall convergence to the macroscopic minefill behavior.The result suggests that the backfill response could exhibit unique rate and path-dependence upon thermal loading due to the competing processes that govern the pressure evolution.Moreover,it shows that while rapid wall convergence would always induce significant pressure,thermal straining via heat exchange might still modulate substantially the pressure distribution when the temperature catalyzes considerable water expansivity.These findings could facilitate understanding of the complex backfill behavior in difficult geology settings,and thus have significant implications for adaptive tailings management to deep mining development.
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.
基金Supported by National Natural Science Foundation of China(Grant No.51074179)National Hi-tech Research and Development Program of China(863 Program,Grant No.2012AA091291)Basic Research Foundation of Shenzhen Science and Technology Innovation,China(Grant No.JCYJ20150929102555935)
文摘Seafloor massive sulfide（SMS） deposits which consist of Au, Ag, Cu, and other metal elements, have been a target of commercial mining in recent decades. The demand for established and reliable commercial mining system for SMS deposits is increasing within the marine mining industry. The current status and progress of mining technology and equipment for SMS deposits are introduced. First, the mining technology and other recent developments of SMS deposits are comprehensively explained and analyzed. The seafloor production tools manufactured by Nautilus Minerals and similar mining tools from Japan for SMS deposits are compared and discussed in turn. Second, SMS deposit mining technology research being conducted in China is described, and a new SMS deposits mining tool is designed according to the environmental requirement. Finally, some new trends of mining technology of SMS deposits are summarized and analyzed. All of these conclusions and results have reference value and guiding significance for the research of SMS deposit mining in China.
基金Project(DYXM-115-04-02-01) supported by the National Deep-sea Technology Project of Development and Research, ChinaProject(2011QNZT058) supported by the Fundamental Research Funds for the Central Universities, ChinaProject(51105386) supported by the National Natural Science Foundation of China
文摘With comprehensive considerations of the operational safety and collection efficiency for the tracked miner collecting the seafloor poly-metallic nodules, two new improved mining paths for the miner on the deep seafloor were proposed. Compared to the conventional mining path, the design principles and superiorities of the two new paths are that the miner turning with relative long radius should avoid large sinkage and high slip, so as to ensure its operational safety, while the space between its straight-line trajectories before and after the turning is optimum, which is designed as the total width of the miner, and collect nodules as more as possible, so as to ensure its collection efficiency. To realize the new mining paths, theoretical designs and quantitative calculations were carried out to determine the exact positions for the speed controls of the miner during its whole operation process. With the new dynamic model of the miner, and through regulations of the speeds of the left and right tracks of the miner on the exact motion positions according to the theoretical calculations, the two new improved mining paths for the miner on the seafloor were successfully simulated, thus the turning radius of the miner in the simulation is about 21.8 m, while the distance between the straight-line trajectories before and after the turning is about 5.2 m. The dynamic simulation results preliminarily prove the feasibility of these two new mining paths, and further can provide important theoretical guidance and useful technical reference for the practical tracked miner operation and control on the seafloor.
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Project(2018dcyj052) supported by Survey Research Funds of Central South University,ChinaProject(51774321) supported by the National Natural Science Foundation of ChinaProject(2018YFC0604606) supported by the National Key Research and Development Program of China
文摘The mining method optimization in subsea deep gold mines was studied. First, an index system for subsea mining method selection was established based on technical feasibility, security status, economic benefit, and management complexity. Next, an evaluation matrix containing crisp numbers and triangular fuzzy numbers(TFNs) was constructed to describe quantitative and qualitative information simultaneously. Then, a hybrid model combining fuzzy theory and the Tomada de Decis?o Interativa Multicritério(TODIM) method was proposed. Finally, the feasibility of the proposed approach was validated by an illustrative example of selecting the optimal mining method in the Sanshandao Gold Mine(China). The robustness of this approach was demonstrated through a sensitivity analysis. The results show that the proposed hybrid TODIM method is reliable and stable for choosing the optimal mining method in subsea deep gold mines and provides references for mining method optimization in other similar undersea mines.
基金Projects(51774058,51674047)supported by the National Natural Science Foundation of ChinaProjects(cstc2016jcyjA1861,cstc2018jcyjA3320)supported by Chongqing Basic Science and Cutting-edge Technology Special Projects,ChinaProject(2015M570607)supported by Postdoctoral Science Foundation of China
文摘Geotechnical properties of red shale encountered in deep underground mining were characterized on both laboratory and field scale to reveal its unfavorably in geoenvironment.Its constituents,microstructure,strength properties and water-weakening properties were investigated.In situ stress environment and mining-induced fractured damage zone after excavation were studied to reveal the instability mechanism.The results show that red shale contains swelling and loose clayey minerals as interstitial filling material,producing low shear strength of microstructure and making it vulnerable to water.Macroscopically,a U-shaped curve of uniaxial compressive strength(UCS)exists with the increase of the angle between macro weakness plane and the horizon.However,its tensile strength reduced monotonically with this angle.While immersed in water for72h,its UCS reduced by91.9%comparing to the natural state.Field sonic tests reveal that an asymmetrical geometrical profile of fractured damage zone of gateroad was identified due to geological bedding plane and detailed gateroad layout with regards to the direction of major principle stress.Therefore,red shale is a kind of engineering soft rock.For ground control in underground mining or similar applications,water inflow within several hours of excavation must strictly be prevented and energy adsorbing rock bolt is recommended,especially in large deformation part of gateroad.
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Projects 2001BA803B04 and 2004BA803B01 supported by the National Key Projects for Tackling Scientific and Technological Problems during the 10thFive-Year Plan
文摘To achieve safe and highly efficient mining in the gassy, deep mines of the Huainan collieries simultaneous coal and gas extraction, and the corresponding ventilation methods were developed. This includes a set of mining procedures and principles which help insure safe and efficient production. Furthermore, green mining, meaning the comprehensive use of emitted gas, proper treatment of the environment and appropriate mine temperature control, is now standard. The concepts of modem mining and the principles of pressure relief are described. Coal-gas simultaneous ex- traction and multi-pressure relief techniques were developed which require a combination of surface and underground gas extraction. The application of Y-ventilation systems, of roadways retained along goafs, of stress control techniques for highly fragile mine roofs and of powerful, automatic and reliable mining equipment contributes to safe operation of modem deep mines. Operating parameters for these techniques are described and the results of their use discussed.
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.
基金Funding for this research was provided by the National Natural Science Foundation of China (42022052,42277138,and 52108337)the National Key R&D Program of China (2022YFC2803800)+1 种基金the Shandong Provincial Natural Science Foundation (ZR2020YQ29)UCL's Department of Civil,Environmental and Geomatic Engineering,and Ocean University of China.
文摘Ocean mining activities have been ongoing for nearly 70 years,making great contributions to industrialization.Given the increasing demand for energy,along with the restructuring of the energy supply catalyzed by efforts to achieve a low-carbon economy,deep seabed mining will play an important role in addressing energy-and resource-related problems in the future.However,deep seabed mining remains in the exploratory stage,with many challenges presented by the high-pressure,low-temperature,and complex geologic and hydrodynamic environments in deep-sea mining areas,which are inaccessible to human activities.Thus,considerable efforts are required to ensure sustainable,economic,reliable,and safe deep seabed mining.This study reviews the latest advances in marine engineering geology and the environment related to deep-sea min-ing activities,presents a bibliometric analysis of the development of ocean mineral resources since the 1950s,summarizes the development,theory,and issues related to techniques for the three stages of ocean mining(i.e.,exploration,extraction,and closure),and discusses the engineering geology environment,geological disasters,in-situ monitoring techniques,envi-ronmental protection requirements,and environmental effects in detail.Finally,this paper gives some key conclusions and future perspectives to provide insights for subsequent studies and commercial mining operations.
