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
The"three shells"cooperative support technology was proposed herein according to both the large deformation of the rock surrounding large-section chambers in deep mines and the precarious stability of the su...The"three shells"cooperative support technology was proposed herein according to both the large deformation of the rock surrounding large-section chambers in deep mines and the precarious stability of the support structures therein.The development range of the plastic zone in the surrounding rock was controlled by a stress shell to reduce the difficulty of controlling the surrounding rock.Additionally,the residual strength of the rock mass in the plastic zone and the self-bearing capacity of the surrounding rock were improved by a reinforced load-bearing shell.Furthermore,a passive load-bearing shell could restore the triaxial stress state of the surrounding rock on the free surface,reduce the influence of the external environment on the surrounding rock,and reinforce the surrounding rock with the strength of the shell.Reasonable layouts of large-section chambers were determined by analyzing the control effect of the stress shell on the surrounding rock under three kinds of in situ stress fields.The orthogonal test method was applied to reveal the influences of different support parameters in the reinforced loadbearing shell and passive load-bearing shell on the surrounding rock stability.The surrounding rock control effect of the"three shells"collaborative support technology was analyzed through numerical simulation and field monitoring.The results show that the maximum displacement between the roof and floor of the coal preparation chamber in the Xinjulong coal mine was approximately 48 mm,and the maximum displacement between its two sides was approximately 65 mm,indicating that the technology proposed herein could meet the long-term control requirements of the surrounding rock stability for large-section chambers in deep mines.展开更多
As mines go deeper and get larger,mine designs become more fragile largely due to the response of the rock mass to mining.Ground control and rock support become important levers in the mine construction schedule,produ...As mines go deeper and get larger,mine designs become more fragile largely due to the response of the rock mass to mining.Ground control and rock support become important levers in the mine construction schedule,production performance,and excavation health.For example,in cave mines,the production footprint together with associated mine infrastructure are significant investments in a modern caving operation.This investment must be protected and maintained to reduce the risk of ground-related production disruptions.It is necessary to preserve the health of these excavations and their maintenance through an effective rock support design.Rock support thus becomes a strategic element in asset management.This article focuses on support design for brittle ground when displacements induced by stress-fracturing consume much of the support’s capacity.It deals with the functionality of the support in deforming ground.Several interlinked concepts are important when assessing excavation health.Designs must not only account for load equilibrium but also for deformation compatibility and capacity consumption.Most importantly,the support’s displacement capacity is being consumed when the rock mass is deformed after support installation.Hence,it is necessary to design for the support capacity remaining at the time when the support is needed.If support capacity can be consumed,it can also be restored by means of preventive support maintenance(PSM).This concept for cost-effective ground control is introduced and illustrated on operational evidence.Furthermore,how design can impact construction costs and schedule are discussed.Support is installed to provide a safe environment and preserve an operationally functional excavation.It also must assure senior management that investments in high quality support and its maintenance will substantially reduce delays and with it,costs.It is demonstrated that the use of‘gabion-like’support systems can achieve these goals.A technical summary of the‘gabion panel’support system design is presented.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
Under deep and complex geological conditions,severe deformation occurs at intersection points of Y-type roadways with large cross sections during engineering projects in coal mines,especially at junction arches.Based ...Under deep and complex geological conditions,severe deformation occurs at intersection points of Y-type roadways with large cross sections during engineering projects in coal mines,especially at junction arches.Based on in-situ investigations and theoretical studies,we have summarized typical forms of destruction and identified high stress and unrestricted support at both sides of junction arch as its main causes.In this study,we also presented double-directional control bolt support technology for a large Y-type span intersection,applied to deep intersection engineering in the Jiahe Coal Mine,which has proved effective.展开更多
This paper reviews the recent achievements made by our team in the mitigation of rockburst risk. It includes the development of neural network modeling on rockburst risk assessment for deep gold mines in South Af- ric...This paper reviews the recent achievements made by our team in the mitigation of rockburst risk. It includes the development of neural network modeling on rockburst risk assessment for deep gold mines in South Af- rica, an intelligent microseismicity monitoring system and sensors, an understanding of the rockburst evolution process using laboratory and in situ tests and monitoring, the establishment of a quantitative warning method for the location and intensities of different types of rockburst, and the development of measures for the dynamic control of rockburst. The mitigation of rockburst at the Hongtoushan copper mine is presented as an illustrative example.展开更多
Based on a large amount of field investigation and observations, the paper analyzes and summarizes the mining depths and depth distribution of coal mines in China, discusses the characteristics of undrground pressure ...Based on a large amount of field investigation and observations, the paper analyzes and summarizes the mining depths and depth distribution of coal mines in China, discusses the characteristics of undrground pressure appearance in the entries of deep mining, points out some characteristics of surtounding rocks when rHo> =0.5, such as obvious rheologital deformation,and puts forward the main principles of supporting the entries in deep mining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
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
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
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
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
1.Introduction The global transition to green energy has created an unprecedented demand for critical metals and energy resources such as cobalt,nickel,copper,manganese,rare earth elements,and gas hydrates.Against thi...1.Introduction The global transition to green energy has created an unprecedented demand for critical metals and energy resources such as cobalt,nickel,copper,manganese,rare earth elements,and gas hydrates.Against this strategic backdrop,deep-sea mineral and energy resources are increasingly viewed as essential supplements to terrestrial supply bottlenecks and as strategic safeguards for the future low-carbon economy.The international seabed forms a vast strategic resource of global significance,offering great potential to support energy transition and security.Therefore,under sound scientific evaluation and strict regulation,prudent development of this resource should serve both economic needs and the broader goals of sustainable energy transformation[1].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
The stability control of surrounding rock for large or super-large section chamber is a difficult technical problem in deep mining condition.Based on the in-site geological conditions of Longgu coal mine,this paper us...The stability control of surrounding rock for large or super-large section chamber is a difficult technical problem in deep mining condition.Based on the in-site geological conditions of Longgu coal mine,this paper used the dynamic module of FLAC3D to study the response characteristics of deep super-large section chamber under dynamic and static combined loading condition.Results showed that under the static loading condition,the maximum vertical stress,deformation and failure range are large,where the stress concentration coefficient is 1.64.The maximum roof-to-floor and two-sides deformations are 54.6 mm and 53.1 mm,respectively.Then,under the dynamic and static combined loading condition:(1)The influence of dynamic load frequency on the two-sides is more obvious;(2)The dynamic load amplitude has the greatest influence on the stress concentration degree,and the plastic failure tends to develop to the deeper;(3)With the dynamic load source distance increase,the response of surrounding rock is gradually attenuated.On this basis,empirical equations for each dynamic load conditions were obtained by using regression analysis method,and all correlation coefficients are greater than 0.99.This research provided reference for the supporting design of deep super-large section chamber under same or similar conditions.展开更多
Greenhouse gas(GHG)emissions related to human activities have significantly caused climate change since the Industrial Revolution.China aims to achieve its carbon emission peak before 2030 and carbon neutrality before...Greenhouse gas(GHG)emissions related to human activities have significantly caused climate change since the Industrial Revolution.China aims to achieve its carbon emission peak before 2030 and carbon neutrality before 2060.Accordingly,this paper reviews and discusses technical strategies to achieve the“dual carbon”targets in China’s metal mines.First,global carbon emissions and emission intensities from metal mining industries are analyzed.The metal mining status and carbon emissions in China are then examined.Furthermore,advanced technologies for carbon mitigation and carbon sequestration in metal mines are reviewed.Finally,a technical roadmap for achieving carbon neutrality in China’s metal mines is proposed.Findings show that some international mining giants have already achieved their carbon reduction targets and planned to achieve carbon neutrality by 2050.Moreover,improving mining efficiency by developing advanced technologies and replacing fossil fuel with renewable energy are two key approaches in reducing GHG emissions.Green mines can significantly benefit from the carbon neutrality process for metal mines through the carbon absorption of reclamation vegetations.Geothermal energy extraction from operating and abandoned metal mines is a promising technology for providing clean energy and contributing to the carbon neutrality target of China’s metal mines.Carbon sequestration in mine backfills and tailings through mineral carbonation has the potential to permanently and safely store carbon dioxide,which can eventually make the metal mining industry carbon neutral or even carbon negative.展开更多
The safety factor of roof under deep high stress is a quantitative index for evaluating roof stability.Based on the failure mode of surrounding rock of stope roof,the mechanics model of goaf roof is constructed,and th...The safety factor of roof under deep high stress is a quantitative index for evaluating roof stability.Based on the failure mode of surrounding rock of stope roof,the mechanics model of goaf roof is constructed,and the internal force of roof is deduced by the theory of hingeless arch.The calculation method of roof safety factor(K)under the environment of deep mining is proposed in view of compression failure and shear failure of roof.The calculation formulas of shear safety factor(K1),compression safety factor(K2)and comprehensive safety factor(K)of roof are given.The influence of stope span and roof thickness on roof stability is considered in this paper.The results show that when the roof thickness remains constant,the roof safety factor decreases with the increasing of the stope span;when the stope span remains constant,the roof safety factor increases with the increasing of the roof thickness.The deep mining example shows that when the stope span is 30 m and the roof thickness is 10 m,the roof comprehensive safety factor is 1.12,which indicates the roof is in a stable state.展开更多
In order to obtain a gas seepage law of deep mined coal seams, according to the properties of coalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal se...In order to obtain a gas seepage law of deep mined coal seams, according to the properties of coalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal seams with the Klinkenberg effect was obtained by confirming the coatbed methane permeability in in-situ stress and geothermal temperature fields. Aimed at the condition in which the coal seams have or do not have an outcrop and outlet on the ground, the application of the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields on the gas pressure calculation of deep mined coal seams was investigated. The comparison between calculated and measured results indicates that the calculation method of gas pressure, based on the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields can accu- rately be identical with the measured values and theoretically perfect the calculation method of gas pressure of deep mined coal seams.展开更多
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This work was supported by the Fundamental Research Funds for the Central Universities(No.2019XKQYMS61).
文摘The"three shells"cooperative support technology was proposed herein according to both the large deformation of the rock surrounding large-section chambers in deep mines and the precarious stability of the support structures therein.The development range of the plastic zone in the surrounding rock was controlled by a stress shell to reduce the difficulty of controlling the surrounding rock.Additionally,the residual strength of the rock mass in the plastic zone and the self-bearing capacity of the surrounding rock were improved by a reinforced load-bearing shell.Furthermore,a passive load-bearing shell could restore the triaxial stress state of the surrounding rock on the free surface,reduce the influence of the external environment on the surrounding rock,and reinforce the surrounding rock with the strength of the shell.Reasonable layouts of large-section chambers were determined by analyzing the control effect of the stress shell on the surrounding rock under three kinds of in situ stress fields.The orthogonal test method was applied to reveal the influences of different support parameters in the reinforced loadbearing shell and passive load-bearing shell on the surrounding rock stability.The surrounding rock control effect of the"three shells"collaborative support technology was analyzed through numerical simulation and field monitoring.The results show that the maximum displacement between the roof and floor of the coal preparation chamber in the Xinjulong coal mine was approximately 48 mm,and the maximum displacement between its two sides was approximately 65 mm,indicating that the technology proposed herein could meet the long-term control requirements of the surrounding rock stability for large-section chambers in deep mines.
基金facilitated by financial support from NSERC(Canada’s Natural Sciences and Engineering Research Council)ORF(Ontario Research Fund)。
文摘As mines go deeper and get larger,mine designs become more fragile largely due to the response of the rock mass to mining.Ground control and rock support become important levers in the mine construction schedule,production performance,and excavation health.For example,in cave mines,the production footprint together with associated mine infrastructure are significant investments in a modern caving operation.This investment must be protected and maintained to reduce the risk of ground-related production disruptions.It is necessary to preserve the health of these excavations and their maintenance through an effective rock support design.Rock support thus becomes a strategic element in asset management.This article focuses on support design for brittle ground when displacements induced by stress-fracturing consume much of the support’s capacity.It deals with the functionality of the support in deforming ground.Several interlinked concepts are important when assessing excavation health.Designs must not only account for load equilibrium but also for deformation compatibility and capacity consumption.Most importantly,the support’s displacement capacity is being consumed when the rock mass is deformed after support installation.Hence,it is necessary to design for the support capacity remaining at the time when the support is needed.If support capacity can be consumed,it can also be restored by means of preventive support maintenance(PSM).This concept for cost-effective ground control is introduced and illustrated on operational evidence.Furthermore,how design can impact construction costs and schedule are discussed.Support is installed to provide a safe environment and preserve an operationally functional excavation.It also must assure senior management that investments in high quality support and its maintenance will substantially reduce delays and with it,costs.It is demonstrated that the use of‘gabion-like’support systems can achieve these goals.A technical summary of the‘gabion panel’support system design is presented.
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supported by the National Basic Research Program of China (No.2006CB202200)the Major Program of the National Natural Science Foundation of China (No.50490270)the Innovative Team Development Project of the Ministry of Education of China (No.IRT0656)
文摘Under deep and complex geological conditions,severe deformation occurs at intersection points of Y-type roadways with large cross sections during engineering projects in coal mines,especially at junction arches.Based on in-situ investigations and theoretical studies,we have summarized typical forms of destruction and identified high stress and unrestricted support at both sides of junction arch as its main causes.In this study,we also presented double-directional control bolt support technology for a large Y-type span intersection,applied to deep intersection engineering in the Jiahe Coal Mine,which has proved effective.
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China （51621006, 413200104005, and 11232014）.
文摘This paper reviews the recent achievements made by our team in the mitigation of rockburst risk. It includes the development of neural network modeling on rockburst risk assessment for deep gold mines in South Af- rica, an intelligent microseismicity monitoring system and sensors, an understanding of the rockburst evolution process using laboratory and in situ tests and monitoring, the establishment of a quantitative warning method for the location and intensities of different types of rockburst, and the development of measures for the dynamic control of rockburst. The mitigation of rockburst at the Hongtoushan copper mine is presented as an illustrative example.
文摘Based on a large amount of field investigation and observations, the paper analyzes and summarizes the mining depths and depth distribution of coal mines in China, discusses the characteristics of undrground pressure appearance in the entries of deep mining, points out some characteristics of surtounding rocks when rHo> =0.5, such as obvious rheologital deformation,and puts forward the main principles of supporting the entries in deep mining
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.
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 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.
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financial support from the National Key R&D Program of China(No.2024YFC2815400)the Young Taishan Scholars Program(No.TSQN202507107)+1 种基金the Shandong Natural Science Foundation(No.ZR2025MS647)the European Commission(HORIZON MSCA-2024-PF-01,101200637).
文摘1.Introduction The global transition to green energy has created an unprecedented demand for critical metals and energy resources such as cobalt,nickel,copper,manganese,rare earth elements,and gas hydrates.Against this strategic backdrop,deep-sea mineral and energy resources are increasingly viewed as essential supplements to terrestrial supply bottlenecks and as strategic safeguards for the future low-carbon economy.The international seabed forms a vast strategic resource of global significance,offering great potential to support energy transition and security.Therefore,under sound scientific evaluation and strict regulation,prudent development of this resource should serve both economic needs and the broader goals of sustainable energy transformation[1].
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.
基金Project(2018YFC0604703)supported by the National Key R&D Program of ChinaProjects(51804181,51874190)supported by the National Natural Science Foundation of China+3 种基金Project(ZR2018QEE002)supported by the Shandong Province Natural Science Fund,ChinaProject(ZR2018ZA0603)supported by the Major Program of Shandong Province Natural Science Foundation,ChinaProject(2019GSF116003)supported by the Key R&D Project of Shandong Province,ChinaProject(SDKDYC190234)supported by the Shandong University of Science and Technology,Graduate Student Technology Innovation Project,China。
文摘The stability control of surrounding rock for large or super-large section chamber is a difficult technical problem in deep mining condition.Based on the in-site geological conditions of Longgu coal mine,this paper used the dynamic module of FLAC3D to study the response characteristics of deep super-large section chamber under dynamic and static combined loading condition.Results showed that under the static loading condition,the maximum vertical stress,deformation and failure range are large,where the stress concentration coefficient is 1.64.The maximum roof-to-floor and two-sides deformations are 54.6 mm and 53.1 mm,respectively.Then,under the dynamic and static combined loading condition:(1)The influence of dynamic load frequency on the two-sides is more obvious;(2)The dynamic load amplitude has the greatest influence on the stress concentration degree,and the plastic failure tends to develop to the deeper;(3)With the dynamic load source distance increase,the response of surrounding rock is gradually attenuated.On this basis,empirical equations for each dynamic load conditions were obtained by using regression analysis method,and all correlation coefficients are greater than 0.99.This research provided reference for the supporting design of deep super-large section chamber under same or similar conditions.
基金supported by the Chinese Academy of Engineering(No.2019-XZ-16)National Natural Science Foundation of China(No.L1824042)Fundamental Research Funds for the Central Universities,USTB(No.FRFIDRY-20-032)。
文摘Greenhouse gas(GHG)emissions related to human activities have significantly caused climate change since the Industrial Revolution.China aims to achieve its carbon emission peak before 2030 and carbon neutrality before 2060.Accordingly,this paper reviews and discusses technical strategies to achieve the“dual carbon”targets in China’s metal mines.First,global carbon emissions and emission intensities from metal mining industries are analyzed.The metal mining status and carbon emissions in China are then examined.Furthermore,advanced technologies for carbon mitigation and carbon sequestration in metal mines are reviewed.Finally,a technical roadmap for achieving carbon neutrality in China’s metal mines is proposed.Findings show that some international mining giants have already achieved their carbon reduction targets and planned to achieve carbon neutrality by 2050.Moreover,improving mining efficiency by developing advanced technologies and replacing fossil fuel with renewable energy are two key approaches in reducing GHG emissions.Green mines can significantly benefit from the carbon neutrality process for metal mines through the carbon absorption of reclamation vegetations.Geothermal energy extraction from operating and abandoned metal mines is a promising technology for providing clean energy and contributing to the carbon neutrality target of China’s metal mines.Carbon sequestration in mine backfills and tailings through mineral carbonation has the potential to permanently and safely store carbon dioxide,which can eventually make the metal mining industry carbon neutral or even carbon negative.
基金Projects(51974135,51704094)supported by the National Natural Science Foundation of ChinaProject(2016YFC0600802)supported by the National Key Research and Development Program of ChinaProject(2020M672226)supported by the China Postdoctoral Science Foundation。
文摘The safety factor of roof under deep high stress is a quantitative index for evaluating roof stability.Based on the failure mode of surrounding rock of stope roof,the mechanics model of goaf roof is constructed,and the internal force of roof is deduced by the theory of hingeless arch.The calculation method of roof safety factor(K)under the environment of deep mining is proposed in view of compression failure and shear failure of roof.The calculation formulas of shear safety factor(K1),compression safety factor(K2)and comprehensive safety factor(K)of roof are given.The influence of stope span and roof thickness on roof stability is considered in this paper.The results show that when the roof thickness remains constant,the roof safety factor decreases with the increasing of the stope span;when the stope span remains constant,the roof safety factor increases with the increasing of the roof thickness.The deep mining example shows that when the stope span is 30 m and the roof thickness is 10 m,the roof comprehensive safety factor is 1.12,which indicates the roof is in a stable state.
基金support of the Open Fund of State Key Laboratory of Oil and Gas Reser-voir Geology and Exploitation (Southwest Petroleum University) (PLN0610)the Opening Project of He-nan Key Laboratory of Coal Mine Methane and Fire Prevention (HKLGF200706)+3 种基金 the National Natural Science Foundation of China (No. 50334060, 50474025, 50774106)the National Key Fundamental Research and Development Program of China (No. 2005CB221502)the Natural Science Innovation Group Foundation of China (No. 50621403)the Natural Science Foundation of Chongqing of China(No. CSTC, 2006BB7147, 2006AA7002).
文摘In order to obtain a gas seepage law of deep mined coal seams, according to the properties of coalbed methane seepage in in-situ stress and geothermal temperature fields, the gas seepage equation of deep mined coal seams with the Klinkenberg effect was obtained by confirming the coatbed methane permeability in in-situ stress and geothermal temperature fields. Aimed at the condition in which the coal seams have or do not have an outcrop and outlet on the ground, the application of the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields on the gas pressure calculation of deep mined coal seams was investigated. The comparison between calculated and measured results indicates that the calculation method of gas pressure, based on the gas seepage equation of deep mined coal seams in in-situ stress and geothermal temperature fields can accu- rately be identical with the measured values and theoretically perfect the calculation method of gas pressure of deep mined coal seams.
