Longwall mining continues to remain the most efficient method for underground coal recovery. A key aspect in achieving safe and productive longwall mining is to ensure that the shearer is always correctly positioned w...Longwall mining continues to remain the most efficient method for underground coal recovery. A key aspect in achieving safe and productive longwall mining is to ensure that the shearer is always correctly positioned within the coal seam. At present, this machine positioning task is the role of longwall personnel who must simultaneously monitor the longwall coal face and the shearer's cutting drum position to infer the geological trends of the coal seam. This is a labour intensive task which has negative impacts on the consistency and quality of coal production. As a solution to this problem, this paper presents a sensing method to automatically track geological coal seam features on the longwall face, known as marker bands, using thermal infrared imaging. These non-visible marker bands are geological features that link strongly to the horizontal trends present in layered coal seams. Tracking these line-like features allows the generation of a vertical datum that can be used to maintain the shearer in a position for optimal coal extraction. Details on the theory of thermal infrared imaging are given, as well as practical aspects associated with machine-based implementation underground. The feature detection and tracking tasks are given with real measurements to demonstrate the efficacy of the approach. The outcome is important as it represents a new selective mining capability to help address a long-standing limitation in longwall mining operations.展开更多
Underground coal mining frequently uses longwalls.The occurrence of a potentially explosive mixture of methane and air is one of the most serious hazards.A large number of papers have applied numerical modeling of met...Underground coal mining frequently uses longwalls.The occurrence of a potentially explosive mixture of methane and air is one of the most serious hazards.A large number of papers have applied numerical modeling of methane propagation in research aimed at this problem.To date,none of the CFD simulations has considered the movement of the shearer in the analyses.This paper proposes an adaptation of a method used for the description of the movement of trains in tunnels to a specific geometry of a longwall district.The flow of the air-methane mixture was calculated using the finite volume method,in particular the k-w SST and SAS turbulence models.Due to the movement of the shearer,moving and deforming meshes were used for simulation of unsteady flows.Examples of solutions for two hypothetical cases are presented.Finally,the drawbacks and advantages of presented methods are discussed.Further development with the application of either local mesh variability or overset meshes is outlined.展开更多
Based on computer graphics principle, technology and 3D graphics software, this paper deals with the 3D part design, assembly and animation of shearer in longwall integrated mechanized coal mining. The matixes of kine...Based on computer graphics principle, technology and 3D graphics software, this paper deals with the 3D part design, assembly and animation of shearer in longwall integrated mechanized coal mining. The matixes of kinetic and geometry relationships and 3 dimension space coordinate systems are built for the cut drums, arms and shearer body. The methods of 3D modeling, dynamic simulation and relative technique problems are discussed.展开更多
Oblique cutting is a working condition in fully mechanized mining whose function is making it possible for coal shearer to cut coal wall.Coal shearer often exhibit large vibration amplitudes in oblique cutting since t...Oblique cutting is a working condition in fully mechanized mining whose function is making it possible for coal shearer to cut coal wall.Coal shearer often exhibit large vibration amplitudes in oblique cutting since the shearer is forced to be bent.In this study,dynamic behavior in oblique cutting for the coal shearer cutting unit gearbox(SCUG)is investigated experimentally based on National Coal Mining Equipment Laboratory of China.A new long wall mining test set-up consists of a test coal shearer and other auxiliary machines is developed for operating long wall coal mining process.Realistic oblique cutting process is developed,and vibration response will be more accurate since both cutting loads and test machine in this experiment are realistic.A data-acquisition system consisting of sensors,channel conditioner and computer is developed to capture three-dimensional vibratory accelerations.A test matrix which included various combinations of key cutting load parameters is executed under realistic oblique cutting loads within a wide parameter range to establish database.Experimental data is analyzed in time,domain and time-frequency domains for investigating the rules of dynamic behavior for SCUG.Beat vibration phenomenon and the coupling of gear mesh frequencies are found in experiment,resulting in local resonance and reduce fatigue life of SCUG.The influence of cutting load on beat phenomenon and frequency coupling is demonstrated at the end,and some conclusions are obtained.展开更多
Self-positioning of a shearer is the key technology for mining with a man-less working face. In an underground coal mine all radio navigation; satellite positioning or celestial navigation methods have their limitatio...Self-positioning of a shearer is the key technology for mining with a man-less working face. In an underground coal mine all radio navigation; satellite positioning or celestial navigation methods have their limitations. We analyzed an inertial navi-gation system intended to guide the movement a shearer and designed a self-positioning device for the shearer. Simulation tests were also performed on the system. We analyzed the errors observed in these tests to show that the main reason for the low preci-sion of the self-positioning system is accumulated error in the inertial sensor. A Kalman filtering algorithm used in combination with the shearer motion model effectively reduces the measurement errors of the self-positioning system by compensating for gyroscopic drift. Finally, we built an error compensation model to reduce accumulated errors using continuous correction to provide self-positioning of the shearer within a certain range of accuracy.展开更多
Three drums with different helical angles(15°,20°,and 25°) were developed to investigate improved loading performance of the shearer drum.Nine trials were performed at different drum rotation speeds(80,...Three drums with different helical angles(15°,20°,and 25°) were developed to investigate improved loading performance of the shearer drum.Nine trials were performed at different drum rotation speeds(80,100,and 120 r/min) and different haulage speeds(1.5,2.0,and 2.5 m/min) in an orthogonal test design.Loaded coal quantity and cutting power of the drum were the responses measured under the different conditions.The effect of the parameters was determined by means of the extreme difference method.The significance of the effects was determined by analysis of variance.The results indicate that the effect from changes in the helical vane on loading performance of the drum is the largest in magnitude.The haulage speed has the least affect on loading performance.The helical angle has the least affect on cutting power of the drum.Haulage speed has the largest affect on the cutting power of the drum.展开更多
An intelligent shearer height adjusting system is a key technology for mining at a man-less working face. A control strategy for a shearer height adjusting system based on a mathematical model of the height adjusting ...An intelligent shearer height adjusting system is a key technology for mining at a man-less working face. A control strategy for a shearer height adjusting system based on a mathematical model of the height adjusting mechanism is proposed. It considers the non-linearity and time variations in the control process and uses Dynamic Fuzzy Neural Networks (D-FNN). The inverse characteristics of the system are studied. An adaptive on-line learning and error compensation mechanism guarantees sys-tem real-time performance and reliability. Parameters from a German Eickhoff SL500 shearer were used with Matlab/Simulink to simulate a height adjusting control system. Simulation shows that the trace error of a D-FNN controller is smaller than that of a PID controller. Also, the D-FNN control scheme has good generalization and tracking performance, which allow it to satisfy the needs of a shearer height adjusting system.展开更多
Reliability and wear resistance of cutting picks play a significant role in coal mine exploitation with coal shearers.Tool bit separation,blade breaking,severe erosion of the cutting body and fatigue fractures are the...Reliability and wear resistance of cutting picks play a significant role in coal mine exploitation with coal shearers.Tool bit separation,blade breaking,severe erosion of the cutting body and fatigue fractures are the main reasons for failure of cutting picks.We carried out carburization on a 30CrMnMo alloy to synthesize a new cutting pick material with improved mechanical properties and high wear resistance.The results indicated that carburization can effectively strengthen the surface of the 30CrMnMo alloy by forming a thick carburized layer and thus significantly improve the surface hardness and wear resistance.In addition,the excellent toughness of 30CrMnMo alloy as a substrate of cutting picks can prevent brittle ruptures and fatigue fractures under high impact stress conditions.The significant decrease in both frictional coefficient and rate of erosion of this carburized 30CrMnMo alloy suggests that this alloy is a potential material for cutting picks of coal shearers after rational carburization.展开更多
In order to determine the influence of shearer's cutting and neighboring shields' advance on the support resistance variation, leg pressure data of all 235 shields in the panel LW61 of Cumberland coal mine wer...In order to determine the influence of shearer's cutting and neighboring shields' advance on the support resistance variation, leg pressure data of all 235 shields in the panel LW61 of Cumberland coal mine were analyzed. The results show that the relationship between the leg pressure increment and the distance from shield to front drum of shearer is a quadratic function and that the higher leg pressure increment before shield advance tends to be related to adverse roof conditions. In addition, the three proposed leg pressure increment-related parameters and the three traditional parameters(time-weighted average pressure, setting pressure, and final pressure) of approximately 32000 shield supporting cycles were calculated by a self-developed software package to analyze the correlation between them. The results show that there is a powerful connection between them, and that the three proposed leg pressure increment-related parameters could be used as the indexes to evaluate the interaction between shields and the roof, and to identify the periodic weighting.展开更多
The authors indicate that the failure of hydraulic systems of shearers can drop greatly, its’ reliability and service life can be increased by the use of a field oil contamination analyser and filter device to contro...The authors indicate that the failure of hydraulic systems of shearers can drop greatly, its’ reliability and service life can be increased by the use of a field oil contamination analyser and filter device to control the oil contamination of the hydraulic systems of shearers. Experimental provement of silting theory contamination analyser are carried out.The filter effect of portable hydraulic driving oil filter model YLJ 21 is examinationed in laboratory and field experiment. From January to August 1992, on site experimental research using a silting theory contamination analyser and oil filter model YLJ 21 to control the oil contamination was carried out in the Datong Coal Mining Bureau.展开更多
In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried ou...In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried out using a numerical simulation package(Fluent) based on gas-solid coupling dispersed multiphase flow model and field measurement to research different technology modes, dust distribution law at different intervals where shearers work in opposite directions on the lower 9303 face, No. 2 Jining Mine,Yankuang Coal Mining Co. Results show that the concentration of dust 3–6 m away from the shearers working in the same directions was large, while the impact area of respirable dust near the shearer increased significantly to 5–6 m with the distance between two shearers working in opposite directions.The concentration of dust on a double-shearer face was considerably higher than that of a face with one shear under the combined effect of wind speed on the face and disturbed wind around the shearer, while the dust concentration near the shearer on the return side was considerably higher than that on the inlet side. The concentration of dust on a double-shearer face along the airflow declined slowly so that dust was hard to control. Simulation results confirmed the results of field measurement, which could provide reference for dust prevention design.展开更多
The pressure signal in the lifting cylinder of the shearer is selected as feature signal, its mean-square deviation is extracted as the feature variable in this paper. The authors put forward a new method of recognizi...The pressure signal in the lifting cylinder of the shearer is selected as feature signal, its mean-square deviation is extracted as the feature variable in this paper. The authors put forward a new method of recognizing the shearer’s cutting state based on pattern recognition. According to this, the completed controI software produced a satisfactory experiment result on the artificial longwall face in the laboratory, Finally the authors look forward to the prospect of the introduction of the artificial neural network theory into this field.展开更多
In order to realize the memory cutting of a shearer, made use of the memorizedcutting path and acquisitioned cutting parameters, and realized the teaching and playbackof the cutting path.In order to optimize the memor...In order to realize the memory cutting of a shearer, made use of the memorizedcutting path and acquisitioned cutting parameters, and realized the teaching and playbackof the cutting path.In order to optimize the memory cutting path of a shearer, took intoaccount the constraints of coal mining craft, coal quality and the adaption faculty of coalmining equipments.Genetic algorithm theory was used to optimize the memory cutting ofshearer and simulate with Matlab, and realized the most valuable mining recovery rate.The experimental results show that the optimization of the memory cutting path of ashearer based on the genetic algorithm is feasible and obtains the most valuable memorycutting path, improving the ability of shearer automatic cutting.展开更多
Several damaged distributors of the shearer’s main pump have been analyzed. Lubricated abrasive wear was found to be the cause of distributor failure. On the basis of selecting reasonably materials and surface strent...Several damaged distributors of the shearer’s main pump have been analyzed. Lubricated abrasive wear was found to be the cause of distributor failure. On the basis of selecting reasonably materials and surface strenthening methods of distributors, pump’s function tests under the condition of contamination were performed with actual distributors. The results showed that wear resistance and contaminant wear lifetime of TiN coated high-speed steel W18Cr4V distributor is the best and TiN coating technology can be used in manufacturing of pump’s distributor.展开更多
On the basis of the model experiments, a software for optimum design of the shearer drum has been developed, and the main parameters of a shearer drum also have been optimized. The combination of the techniques of opt...On the basis of the model experiments, a software for optimum design of the shearer drum has been developed, and the main parameters of a shearer drum also have been optimized. The combination of the techniques of optimization with the mod el experiment makes the designing and theoretical systems of the shearer drum more perfect.展开更多
基金the Australian Coal Association Research Program(ACARP)for their invaluable support that enabled new research and development into longwall shearer automation
文摘Longwall mining continues to remain the most efficient method for underground coal recovery. A key aspect in achieving safe and productive longwall mining is to ensure that the shearer is always correctly positioned within the coal seam. At present, this machine positioning task is the role of longwall personnel who must simultaneously monitor the longwall coal face and the shearer's cutting drum position to infer the geological trends of the coal seam. This is a labour intensive task which has negative impacts on the consistency and quality of coal production. As a solution to this problem, this paper presents a sensing method to automatically track geological coal seam features on the longwall face, known as marker bands, using thermal infrared imaging. These non-visible marker bands are geological features that link strongly to the horizontal trends present in layered coal seams. Tracking these line-like features allows the generation of a vertical datum that can be used to maintain the shearer in a position for optimal coal extraction. Details on the theory of thermal infrared imaging are given, as well as practical aspects associated with machine-based implementation underground. The feature detection and tracking tasks are given with real measurements to demonstrate the efficacy of the approach. The outcome is important as it represents a new selective mining capability to help address a long-standing limitation in longwall mining operations.
基金The results presented in this paper are the result of the PICTO research project titled"Production Face Environmental Risk Minimization in Coal and Lignite Mines”,No.800711,financed by the Research Programme of the Research Fund for Coal and Steel(RFCS)and Polish MNiSW No W93/FBWiS/2018 and the statutory research funds of the Institute.
文摘Underground coal mining frequently uses longwalls.The occurrence of a potentially explosive mixture of methane and air is one of the most serious hazards.A large number of papers have applied numerical modeling of methane propagation in research aimed at this problem.To date,none of the CFD simulations has considered the movement of the shearer in the analyses.This paper proposes an adaptation of a method used for the description of the movement of trains in tunnels to a specific geometry of a longwall district.The flow of the air-methane mixture was calculated using the finite volume method,in particular the k-w SST and SAS turbulence models.Due to the movement of the shearer,moving and deforming meshes were used for simulation of unsteady flows.Examples of solutions for two hypothetical cases are presented.Finally,the drawbacks and advantages of presented methods are discussed.Further development with the application of either local mesh variability or overset meshes is outlined.
文摘Based on computer graphics principle, technology and 3D graphics software, this paper deals with the 3D part design, assembly and animation of shearer in longwall integrated mechanized coal mining. The matixes of kinetic and geometry relationships and 3 dimension space coordinate systems are built for the cut drums, arms and shearer body. The methods of 3D modeling, dynamic simulation and relative technique problems are discussed.
基金This paper was supported by the National Basic Research Program of China(2014CB046303).
文摘Oblique cutting is a working condition in fully mechanized mining whose function is making it possible for coal shearer to cut coal wall.Coal shearer often exhibit large vibration amplitudes in oblique cutting since the shearer is forced to be bent.In this study,dynamic behavior in oblique cutting for the coal shearer cutting unit gearbox(SCUG)is investigated experimentally based on National Coal Mining Equipment Laboratory of China.A new long wall mining test set-up consists of a test coal shearer and other auxiliary machines is developed for operating long wall coal mining process.Realistic oblique cutting process is developed,and vibration response will be more accurate since both cutting loads and test machine in this experiment are realistic.A data-acquisition system consisting of sensors,channel conditioner and computer is developed to capture three-dimensional vibratory accelerations.A test matrix which included various combinations of key cutting load parameters is executed under realistic oblique cutting loads within a wide parameter range to establish database.Experimental data is analyzed in time,domain and time-frequency domains for investigating the rules of dynamic behavior for SCUG.Beat vibration phenomenon and the coupling of gear mesh frequencies are found in experiment,resulting in local resonance and reduce fatigue life of SCUG.The influence of cutting load on beat phenomenon and frequency coupling is demonstrated at the end,and some conclusions are obtained.
基金Financial support for this work, provided by the National Natural Science Foundation of China (No.50504014), is gratefully acknowledged
文摘Self-positioning of a shearer is the key technology for mining with a man-less working face. In an underground coal mine all radio navigation; satellite positioning or celestial navigation methods have their limitations. We analyzed an inertial navi-gation system intended to guide the movement a shearer and designed a self-positioning device for the shearer. Simulation tests were also performed on the system. We analyzed the errors observed in these tests to show that the main reason for the low preci-sion of the self-positioning system is accumulated error in the inertial sensor. A Kalman filtering algorithm used in combination with the shearer motion model effectively reduces the measurement errors of the self-positioning system by compensating for gyroscopic drift. Finally, we built an error compensation model to reduce accumulated errors using continuous correction to provide self-positioning of the shearer within a certain range of accuracy.
基金support for this work was provided by the National Natural Science Foundation of China (No. 51005232)the China Postdoctoral Science Foundation (No. 20100481176)
文摘Three drums with different helical angles(15°,20°,and 25°) were developed to investigate improved loading performance of the shearer drum.Nine trials were performed at different drum rotation speeds(80,100,and 120 r/min) and different haulage speeds(1.5,2.0,and 2.5 m/min) in an orthogonal test design.Loaded coal quantity and cutting power of the drum were the responses measured under the different conditions.The effect of the parameters was determined by means of the extreme difference method.The significance of the effects was determined by analysis of variance.The results indicate that the effect from changes in the helical vane on loading performance of the drum is the largest in magnitude.The haulage speed has the least affect on loading performance.The helical angle has the least affect on cutting power of the drum.Haulage speed has the largest affect on the cutting power of the drum.
基金support for this work, provided by the National High Technology Research and Development Program of China (No2008AA062202)China University of Mining & Technology Scaling Program
文摘An intelligent shearer height adjusting system is a key technology for mining at a man-less working face. A control strategy for a shearer height adjusting system based on a mathematical model of the height adjusting mechanism is proposed. It considers the non-linearity and time variations in the control process and uses Dynamic Fuzzy Neural Networks (D-FNN). The inverse characteristics of the system are studied. An adaptive on-line learning and error compensation mechanism guarantees sys-tem real-time performance and reliability. Parameters from a German Eickhoff SL500 shearer were used with Matlab/Simulink to simulate a height adjusting control system. Simulation shows that the trace error of a D-FNN controller is smaller than that of a PID controller. Also, the D-FNN control scheme has good generalization and tracking performance, which allow it to satisfy the needs of a shearer height adjusting system.
基金the Youth Foundation of China University of Mining & Technology (No.2009A056)the Tribology Science Fund from State Key Laboratory of Tribology at Tsinghua University (No.SKLTKF08A01)+1 种基金the National Natural Science Foundation of China (Nos.50905180 and 51005234)the National Science and Technology Pillar Program in the Eleventh Five-Year Plan Period (No.2008BAB36B02)
文摘Reliability and wear resistance of cutting picks play a significant role in coal mine exploitation with coal shearers.Tool bit separation,blade breaking,severe erosion of the cutting body and fatigue fractures are the main reasons for failure of cutting picks.We carried out carburization on a 30CrMnMo alloy to synthesize a new cutting pick material with improved mechanical properties and high wear resistance.The results indicated that carburization can effectively strengthen the surface of the 30CrMnMo alloy by forming a thick carburized layer and thus significantly improve the surface hardness and wear resistance.In addition,the excellent toughness of 30CrMnMo alloy as a substrate of cutting picks can prevent brittle ruptures and fatigue fractures under high impact stress conditions.The significant decrease in both frictional coefficient and rate of erosion of this carburized 30CrMnMo alloy suggests that this alloy is a potential material for cutting picks of coal shearers after rational carburization.
基金provided by the National High Technology Research and Development Program of China(No.2012AA062100)the Program for New Century Excellent Talents in University of China(No.NCET-10-0770)
文摘In order to determine the influence of shearer's cutting and neighboring shields' advance on the support resistance variation, leg pressure data of all 235 shields in the panel LW61 of Cumberland coal mine were analyzed. The results show that the relationship between the leg pressure increment and the distance from shield to front drum of shearer is a quadratic function and that the higher leg pressure increment before shield advance tends to be related to adverse roof conditions. In addition, the three proposed leg pressure increment-related parameters and the three traditional parameters(time-weighted average pressure, setting pressure, and final pressure) of approximately 32000 shield supporting cycles were calculated by a self-developed software package to analyze the correlation between them. The results show that there is a powerful connection between them, and that the three proposed leg pressure increment-related parameters could be used as the indexes to evaluate the interaction between shields and the roof, and to identify the periodic weighting.
文摘The authors indicate that the failure of hydraulic systems of shearers can drop greatly, its’ reliability and service life can be increased by the use of a field oil contamination analyser and filter device to control the oil contamination of the hydraulic systems of shearers. Experimental provement of silting theory contamination analyser are carried out.The filter effect of portable hydraulic driving oil filter model YLJ 21 is examinationed in laboratory and field experiment. From January to August 1992, on site experimental research using a silting theory contamination analyser and oil filter model YLJ 21 to control the oil contamination was carried out in the Datong Coal Mining Bureau.
基金the National Natural Science Foundation of China (No.51404249)the Basic Research Program of Jiangsu Province (No.BK20140201)the Priority Academic Program Development of Jiangsu Higher Education Institutions for financial support provided during this research
文摘In order to understand the migration law of respirable dust and gain reasonable design parameters for dust control on a super-long double-shearer fully mechanized working face, this paper describes research carried out using a numerical simulation package(Fluent) based on gas-solid coupling dispersed multiphase flow model and field measurement to research different technology modes, dust distribution law at different intervals where shearers work in opposite directions on the lower 9303 face, No. 2 Jining Mine,Yankuang Coal Mining Co. Results show that the concentration of dust 3–6 m away from the shearers working in the same directions was large, while the impact area of respirable dust near the shearer increased significantly to 5–6 m with the distance between two shearers working in opposite directions.The concentration of dust on a double-shearer face was considerably higher than that of a face with one shear under the combined effect of wind speed on the face and disturbed wind around the shearer, while the dust concentration near the shearer on the return side was considerably higher than that on the inlet side. The concentration of dust on a double-shearer face along the airflow declined slowly so that dust was hard to control. Simulation results confirmed the results of field measurement, which could provide reference for dust prevention design.
文摘The pressure signal in the lifting cylinder of the shearer is selected as feature signal, its mean-square deviation is extracted as the feature variable in this paper. The authors put forward a new method of recognizing the shearer’s cutting state based on pattern recognition. According to this, the completed controI software produced a satisfactory experiment result on the artificial longwall face in the laboratory, Finally the authors look forward to the prospect of the introduction of the artificial neural network theory into this field.
基金Supported by the High-Tech Research and Development Program of China(2008AA062202)Fok Ying Tung Education Foundation(114003)New Teacher Foundation for the Doctoral Program of Ministry of Education(20070290538)
文摘In order to realize the memory cutting of a shearer, made use of the memorizedcutting path and acquisitioned cutting parameters, and realized the teaching and playbackof the cutting path.In order to optimize the memory cutting path of a shearer, took intoaccount the constraints of coal mining craft, coal quality and the adaption faculty of coalmining equipments.Genetic algorithm theory was used to optimize the memory cutting ofshearer and simulate with Matlab, and realized the most valuable mining recovery rate.The experimental results show that the optimization of the memory cutting path of ashearer based on the genetic algorithm is feasible and obtains the most valuable memorycutting path, improving the ability of shearer automatic cutting.
文摘Several damaged distributors of the shearer’s main pump have been analyzed. Lubricated abrasive wear was found to be the cause of distributor failure. On the basis of selecting reasonably materials and surface strenthening methods of distributors, pump’s function tests under the condition of contamination were performed with actual distributors. The results showed that wear resistance and contaminant wear lifetime of TiN coated high-speed steel W18Cr4V distributor is the best and TiN coating technology can be used in manufacturing of pump’s distributor.
文摘On the basis of the model experiments, a software for optimum design of the shearer drum has been developed, and the main parameters of a shearer drum also have been optimized. The combination of the techniques of optimization with the mod el experiment makes the designing and theoretical systems of the shearer drum more perfect.
