工矿自动化

Combined gas drainage practice at upper corner of high-intensity fully mechanized caving face

DUAN Huijun

2020, 46(2): 1-5. doi: 10.13272/j.issn.1671-251x.2019100024

<Abstract>(158) <HTML> (20) <PDF>(15)

Abstract:
In view of traditional single upper corner gas control technology cannot effectively solve problem of severe over-limit of gas at upper corner of high-intensity fully mechanized caving face, taking Wangjialing Coal Mine as engineering background, the paper puts forward a scheme of combined gas drainage by use of upper corner inserted(buried) pipe and high-level directional boreholes. To INSERT INTO (bury) pipe at upper corner, gas drainage pipe is laid in return air lane of working face. The pipe extends along direction of return air lane to upper corner and forms a stable negative pressure zone at the pipe mouth to extract gas at the upper corner. Artificial air flow is formed through suction to disturb cyclotron vortex at the upper corner and reduce gas concentration. At the same time, in drilling site of the return air lane of the working face, the high-level directional borehole is constructed to drill in direction of cutting holes of working face, and the borehole track is extended in fissure zone of goaf through directional drilling technology to extract high concentration gas in the goaf. The application results show that after the combined gas drainage of upper corner inserted(buried) pipe and high-level directional borehole, gas drainage pure volume is stable at 3.40-6.20 m3/min, with an average value of 4.91 m3/min; gas volume fraction in upper corner of the working face decreases in steps, and finally stabilizes at 0.30%-0.52%, with an average value of 0.42%. The gas control effect in upper corner is significant.

Visualized dynamic solution and early warning technology for ventilation network of complex mine

TAN Guowen

2020, 46(2): 6-11. doi: 10.13272/j.issn.1671-251x.17461

<Abstract>(125) <HTML> (16) <PDF>(14)

Abstract:
Traditional manual analysis methods of ventilation network or usual ventilation network solution software used in complex mines with large coal-seam dip angle, complex geologic structure and long mining time have problems of large workload, low efficiency, high error rate, incomplete solution and so on, and cannot well know ventilation safety status of underground roadways real-timely and completely. For the above problems,taking Nantong Coal Mine as a research object, visualized dynamic solution and early warning technology for ventilation network of complex mine was researched from aspects of dynamic solution model and method of ventilation network, measurement of mine ventilation resistance parameters, early warning of abnormal ventilation and visualization of ventilation system according to complex characteristics of the mine ventilation system. A visualized dynamic solution and early warning system of mine ventilation network is developed according to the technology. The applications show that error between solved air quantity of the system and the actual one is less than 10%, and solution results can be displayed real-timely and dynamically. The system realizes precise measurement of mine air speed and air voltage parameters in full range, dynamic solution of whole mine ventilation network and consecutive analysis and early warning of abnormal ventilation.

Design of a mine-used low-voltage leakage protection device

ZHENG Qingle, RONG Xiang, YANG Fan, LI Rui

2020, 46(2): 12-17. doi: 10.13272/j.issn.1671-251x.17505

<Abstract>(70) <HTML> (10) <PDF>(19)

Abstract:
In view of low reliability of leakage protection device of coal mine low-voltage power grid based on line selection principle of zero-sequence power direction, a hardware and software design scheme of mine-used low-voltage leakage protection device was given. Fault line selection is realized according to differences of phase difference between zero-sequence current and zero-sequence voltage in non-fault branch and fault branch when single-phase grounding fault occurs in zero-sequence reactor grounding system with parallel resistance. The simulation and test results show that the device is not affected by zero sequence reactor compensation in power grid, and can operate quickly and reliably when single-phase grounding fault occurs.

Design of mine-used real-time video transmission system

LI Wenfeng, LU Jiantong, LEI Wenli, BAI Hui

2020, 46(2): 18-22. doi: 10.13272/j.issn.1671-251x.2019090050

<Abstract>(63) <HTML> (16) <PDF>(11)

Abstract:
A mine-used real-time video transmission system was designed to solve problems of low video definition, unstable transmission rate and poor compatibility in existing underground video transmission system. The system uses 960 nm infrared laser as auxiliary light source, and uses MCCD image sensor to collect video signals, which improves video definition in low light intensity or dark environment. The collected PAL analog video signal is converted into YUV digital signal through video decoding module TVP5150, then the digital signal is compressed and encoded by H.264 through multi format codec, and UDP packet header is added for RTP encapsulation, which improves timeliness of video data transmission. The data is streamed through Live555 streaming media server, RTSP video streaming is encapsulated with ONVIF standard, and real-time video streaming data transmission is realized through Socket network programming, which improves system compatibility and transmission rate stability. The test results show that the system has video transmission rate of 2.190 Mbit/s and packet loss rate of about 1.256%, which meets real-time video transmission requirements.

2020, 46(2): 23-28. doi: 10.13272/j.issn.1671-251x.2019060032

<Abstract>(78) <HTML> (10) <PDF>(12)

Abstract:

Application of short-drilling rapid drainage technology on long-distance excavation face

XIANG Zhencai

2020, 46(2): 29-33. doi: 10.13272/j.issn.1671-251x.2019070008

<Abstract>(87) <HTML> (14) <PDF>(11)

Abstract:
In view of problems of current gas control measures on long-distance excavation face of high gas coal roadway which have high cost and impact excavation speed due to high gas volume fraction in return air flow,it was proposed to apply short-drilling rapid drainage technology on long-distance mining face, that is, the short-drilling was used to conduct rapid and centralized drainage on the mining face during overhaul time.The pressure of excavation face and return air flow is reduced and the excavation speed is increased through high-intensity gas drainage in small areas and a short period of time.The short-drilling rapid drainage technology overcomes the shortcomings of existing technology in terms of time and space, and changes the long-distance and long-time gas drainage into high-efficiency drainage in a short distance and a short time. The application results in the 3605 return air lane of the Holsinghe Coal Mine in Shanxi show that the application of short-drilling rapid drainage technology can increase the cumulative monthly footage of coal roadheading from 170 m to 250 m under the premise of controlling the cost and gas volume fraction in return air flow and the working face, which increases by nearly 50%, and the effective control of gas in long-distance excavation face of low-permeability coal seam has been realized.

Application of long-distance directional drilling gas drainage technology inQinglong Coal Mine

XUE Haiteng, LI Xijian, LIANG Daofu, CHEN Liuyu, MA Shengxiang

2020, 46(2): 34-38. doi: 10.13272/j.issn.1671-251x.2019050022

<Abstract>(68) <HTML> (11) <PDF>(10)

Abstract:
The coal mines in Guizhou Province have complex geological structures, high gas content, and soft coal seams, making gas management difficult. In order to improve gas management level in the area, at the range of 5-205 m forward from Y3 point of the transportation roadway of 21601 working face in Qinglong Coal Mine, the kilometer drilling rig is used for field application of gas drainage technology of long-distance directional drilling along layer. The directional drilling technology and branch drillings control technology are used to ensure drilling trajectory control accuracy and avoid blind drilling and blind pumping. The application results show that the desorbable gas from two coal samples are 1.772 9, 2.191 3 m3/t, and the residual gas content is 4.773 9, 5.170 4 m3/t, both are less than 8 m3/t, which meet the basic gas drainage requirements of mine. The average gas drainage volume reached 1.26 m3/min, which is 12% higher than the original value. Compared with conventional drilling, volume fraction of the gas extracted by directional drilling increased by 50%, and the gas treatment effect is significant.

Mining damage of mine boundary coal pillar in closed mine and its safety evaluatio

ZHANG Wenbin, WU Jiwen, ZHAI Xiaorong, HU Ru, BI Yaoshan, WANG Guangtao

2020, 46(2): 39-44. doi: 10.13272/j.issn.1671-251x.2019060016

<Abstract>(84) <HTML> (16) <PDF>(8)

Abstract:
Mining damage of mine boundary coal pillar in closed mine could weaken its water isolation ability, which easily lead goaf water in the closed mine to adjacent producing mine through damaging the mine boundary coal pillar and affect mine safe production. Taking mine boundary coal pillar between closed Shenzhuang Mine and producing Yuanzhuang Mine in Huaibei mining area as research objects, mining damage width of mine boundary coal pillar between S2Ⅱ313 working face in Shenzhuang Mine and Ⅲ3142 working face in Yuanzhuang Mine was researched by FLAC3d numerical simulation and theoretical calculation method. The mining damage width is determined 13.1 m according to the research results, which shows that the mine boundary coal pillar has been destroyed, and coal seam in boundary of the two adjacent mines has no water blocking capacity. On this basis, safety of the mine boundary coal pillar was evaluated. The conclusion is that there are risks of coal pillar water seeping and collapsing, and some measures should be taken out such as setting water-blocking curtain, grouting reinforcement and so on.

Research on relationship between tailing slurry concentration and ultrasonic attenuation coefficient

WANG Jianxin, CHENG Junhao

2020, 46(2): 45-49. doi: 10.13272/j.issn.1671-251x.2019050038

<Abstract>(93) <HTML> (9) <PDF>(10)

Abstract:
In view of problem that the current tailing slurry concentration measurement method based on ultrasonic method does not directly express correlation between concentration and scattering attenuation coefficients and viscous attenuation coefficients, the attenuation characteristics of ultrasonic wave in tailing slurry were studied by numerical calculation method, and the correlation between acoustic attenuation coefficient and concentration was obtained, and the accuracy of numerical calculation is demonstrated through experimental data. The research results show that within the concentration of 10%, the greater the concentration, the lower the speed of sound; within the concentration of 5%, the attenuation coefficient of ultrasonic wave is approximately proportional to the concentration; when the ultrasonic frequency and particle size are constant, within the concentration of 10%,the greater the concentration, the greater the attenuation coefficient of the ultrasound. The research results provide a basis for the practical application of ultrasound in online monitoring of tailings slurry concentration.

Research on coal mine full scene monitoring system based on fog computing

CAO Jianping, LI Jingzhao

2020, 46(2): 50-53. doi: 10.13272/j.issn.1671-251x.2019050031

<Abstract>(62) <HTML> (11) <PDF>(11)

Abstract:
At present, coal mine full scene monitoring system mainly depends on cloud computing for data processing, storage and decision-making. Cloud computing needs to process massive amounts of monitoring information in real time, which seriously affects timeliness and accuracy of system decision-making layer. In view of the above problem, a coal mine full scene monitoring system based on fog computing was proposed. Fog computing neural network is designed with neuron sensing nodes as a unit to alleviate the pressure of cloud computing data processing. In view of problem of premature convergence and local optimal solution of the node deployment method based on particle swarm optimization algorithm, improved particle swarm optimization algorithm is used to optimize the deployment of neuron sensing node to achieve network structure optimization. Simulation results show that compared with the classic PSO algorithm, the improved PSO algorithm can find the optimal solution faster, and the optimal value, the worst value, and the average value of overall communication coverage have increased by 3.19%, 3.31%, and 3.25%, respectively, which has the advantages of fast and effective convergence, strong adaptability and high stability.

Underground video pedestrian detection method

LI Xianguo, LI Bin, LIU Zongpeng, FENG Xinxin, LIU Xiao, SONG Jinshui, ZHANG Lei

2020, 46(2): 54-58. doi: 10.13272/j.issn.1671-251x.2019060024

<Abstract>(150) <HTML> (23) <PDF>(18)

Abstract:
For problems of existing pedestrian detection methods based on deep learning such as large computation, detection efficiency relying on hardware performance heavily and so on, the pedestrian detection method based on SSD network was improved. A lightweight convolutional neural network based on DenseNet network is designed as basic network of SSD network to meet real-time detection requirements of underground video pedestrian, and an auxiliary network based on ResNet network is designed to strengthen feature extraction ability and improve correctness of pedestrian detection. An underground video pedestrian detection method based on the improved SSD network has been arranged in embedded platform Jetson TX2 for experiments. The results show that detection accuracy rate of the method for underground video pedestrian is 87.9% as well as nearly 100% for underground low-density pedestrian scene, and calculation speed achieves 48 frames per second, which is about 4.4 times as quick as the pedestrian detection method based on SSD network and meets real-time detection requirements of underground pedestrian.

Construction and application of three-dimensional model of mine ventilation system

ZHANG Ke, YANG Yingdi, LIU Xuetong, JIANG Chenglong

2020, 46(2): 59-64. doi: 10.13272/j.issn.1671-251x.2019070072

<Abstract>(79) <HTML> (10) <PDF>(14)

Abstract:
The existing modeling algorithms of three-dimensional roadway model are complex, and the trend of roadway is directly determined by the coordinate of the endpoints of roadway, which cannot reflect fluctuation of roadway well. In view of the above problems, taking engineering plan of coal mine as basic data, a three-dimensional coal mine roadway model was constructed by using topological relationship between the roadways to collect location points and using algorithm of loading section of center line. Based on the three-dimensional roadway model, a three-dimensional model of mine ventilation system and corresponding database were generated through synchronizing ventilation facility model into the three-dimensional system. The generated three-dimensional map can clearly show overall shape of the mine roadway. Combined with database information management, the intelligent operation such as adding and modification of the mine model can be achieved. The practical application results show that the model can realize fast conversion from two-dimensional drawing to three-dimensional drawing of the mine ventilation system, display information of mine roadway and condition of working face truly, and the database of the mine map can be updated in real time, which provides a good platform for research of mine ventilation network solution and disaster simulation.

Research on control strategy of energy storage converter of mine local ventilator

YUAN Jingbo, JU Yunpeng, YANG Longyue, LYU Chengyang

2020, 46(2): 65-72. doi: 10.13272/j.issn.1671-251x.2019050061

<Abstract>(60) <HTML> (15) <PDF>(8)

Abstract:
For structure of traditional centralized converters cannot meet emergency power supply requirements of mine local ventilators, a two-stage energy storage converter of mine local ventilator integrating charge and discharge was designed. The energy storage converter not only can use as an emergency power source when the power grid is out of power, but also can achieve reactive power compensation function during normal operation of power grid. A control strategy for two-stage energy storage converter was proposed. When dual-circuit power supply line of local ventilator works normally, the energy storage converter is in online operation mode, and the PWM inverter adopts P/Q control strategy, which mainly charges battery and compensates reactive power to the grid. When dual-circuit power supply line of local ventilator fails, the energy storage converter is in emergency supply mode, and the PWM inverter adopts V/f control strategy. A smooth switching control strategy based on state feedback and common current inner loop was put forward. The state of the V/f controller and the output of the P/Q controller are feedback to the input to solve the problem of current impact occurred during the switching of the two operating modes of the emergency power supply and online operation of the energy storage converter, so as to achieve smooth switching of the energy storage converter. The simulation results show that the control strategy enables the converter to operate stably and switch smoothly under two operating modes, which has good steady and dynamic state characteristics.

Research on acoustic emission characteristics of prefabricated fissure rock under uniaxial compressio

NIU Xingang

2020, 46(2): 73-77. doi: 10.13272/j.issn.1671-251x.2019120017

<Abstract>(78) <HTML> (16) <PDF>(16)

Abstract:
In order to research acoustic emission (AE) characteristics during instability and failure of prefabricated fissure rock, uniaxial compression AE test of prefabricated fissure rock with different inclination angles was carried out, and deformation and failure characteristics of prefabricated fissure rock and variation law of AE signals were analyzed. The results show that with the decrease of prefabricated fissure inclination angle, compressive strength of rock specimens gradually decreases, time to reach the peak stress gradually shortens, axial strain during rock failure gradually decreases, and specimen changes from tensile splitting failure to shear sliding failure. With the decrease of prefabricated fissure inclination angle, the time when the peak of AE energy and ringing count first appear in specimen is advanced and the axial stress required for loading decreases. The cumulative AE ringing count shows a nonlinear upward trend with the increase of loading time, and the smaller the prefabricated fissure inclination angle is, the faster the cumulative AE ringing count rises.

An improved trilateration positioning algorithm

GAO Li, YANG Xuemiao

2020, 46(2): 78-81. doi: 10.13272/j.issn.1671-251x.2019120032

<Abstract>(170) <HTML> (11) <PDF>(15)

Abstract:
Aiming at the problem that trilateration positioning algorithm based on weighted least squares (WLS) lost positioning information in linearization process, an improved trilateration positioning algorithm was proposed. In the algorithm, WLS algorithm is used to roughly estimate coordinates of unknown nodes, and lost positioning information is used to construct positioning model, so precise positioning is achieved by solving the positioning model. The simulation results show that positioning accuracy of the proposed algorithm is obviously higher than that of the trilateration positioning algorithm based on WLS, and the larger the length-width ratio of roadway is, the better the positioning performance of the proposed algorithm is.

Underground signal recognition method based on higher-order cumulants and DNN model

WANG Anyi, LI Li

2020, 46(2): 82-87. doi: 10.13272/j.issn.1671-251x.2019100064

<Abstract>(97) <HTML> (14) <PDF>(7)

Abstract:
In view of complex and heterogeneous wireless environment of mine, an underground signal recognition method based on higher-order cumulants and DNN model was proposed to realize automatic modulation recognition of underground digital signals of BPSK, QPSK, 8PSK, 2FSK, 4FSK, 8FSK, 32QAM, 64QAM, OFDM. Theoretical values of high-order cumulants of the 9 kinds of digital signals were obtained by analysis, and the signal identification was improved by Fourier transform. The influence of underground small-scale fading channels on high-order cumulants were analyzed, high-order cumulants calculation expression of the signal after passing through the underground channel was derived, and signal recognition was realized using characteristic parameters constructed according high-order cumulants to train DNN model. The simulation analysis results show that the method has excellent modulation recognition performance in mine Nakagami-m fading channel, average correct recognition rate is more than 89.2% when the signal-to-noise ratio is -5 dB, and the average correct recognition rate is 100% when the signal-to-noise ratio is 5 dB or more. The method provides a new idea for signal recognition and detection in special and complex environments.

Numerical simulation research on effective influence radius of hydraulic punching in inclined coal seam

HUA Mingguo, YAO Banghua, LI Jianwei

2020, 46(2): 88-93. doi: 10.13272/j.issn.1671-251x.2019070040

<Abstract>(54) <HTML> (12) <PDF>(7)

Abstract:
Current research on hydraulic punching technology seldom considers that pressure relief range of hydraulic punching in inclined coal seam varies with direction and influence of coal seam inclination on the effective radius of hydraulic punching pressure relief. In view of the above problem,taking the coal seam No.3 of a coal mine as research object, the effective influence radius for inclined coal seam under hydraulic punching was numerically simulated by using multi-physics coupling numerical simulation software COMSOL Multiphysics. The effective extraction radius of borehole in different directions was studied. The numerical simulation results show that under the action of punching, the range of extraction influences continues to increase with the increase of extraction time, but the expansion speed decreases with time. Due to the stress relief under punching, the permeability of coal seam is greatly increased, and the influence range around the borehole is approximately elliptic. After 90 days of continuous extraction, the influence radius is about 6 m in the upper direction, the influence radius is about 4 m in the lower direction and the influence radius is about 5 m in the horizontal direction. In order to reach the gas extraction standard, the horizontal drilling arrangement spacing of the hydraulic drilling tunnel of the coal seam is about 3.5 m, and the longitudinal drilling arrangement spacing is about 4.0 m. The research results have important practical significance for optimizing hydraulic punching process parameters, guiding the accurate layout of extraction boreholes, and enhancing the gas control effect of the mine.

Application of microservice in development framework of coal mine monitoring software series

JING Cheng, WANG Aijun

2020, 46(2): 94-99. doi: 10.13272/j.issn.1671-251x.2019070056

<Abstract>(108) <HTML> (19) <PDF>(11)

Abstract:
Development of coal mine monitoring software series faces version confusion, repeated development and maintenance difficulties, and the customized modification of software makes communication between different monitoring software series of coal mine difficult. In order to solve the above problems, a development framework of coal mine monitoring software series adopting microservice architecture was proposed. The development process of coal mine monitoring software series is optimized by standardizing development process, simplifying technology stack and adopting microservice architecture. The basic business is solidified in the development framework, and the proprietary business is loaded and run by means of microservice, which reduces the repetitive coding of the basic code and makes the proprietary business reusable. Sandbox operation mode makes the deployment of microservices not affected by the running environment, easy to deploy, and has strong cross-platform portability, microservice hosting platform can carry out unified version management of microservices. The practical application results show that coal mine monitoring software series using microservice architecture can minimize repeated development of software functions by splitting common functions into microservices. The data storage efficiency of microservice is higher than that of the existing vertical architecture, and the software installation process is more convenient when Docker image is used for deployment, which provides a more efficient development mode for monitoring software series development.

Design of roadheader control system based on embedded soft PLC

ZHU Wei, WANG Hong, LI Shoubin, ZHAO Wensheng

2020, 46(2): 100-106. doi: 10.13272/j.issn.1671-251x.2019070067

<Abstract>(97) <HTML> (16) <PDF>(23)

Abstract:
In order to solve problems of high development cost, large maintenance and difficult cross-platform transplantation of existing coal mine roadheader control system taking ordinary PLCs and dedicated controllers as cores, a roadheader control system based on embedded soft PLC technology was designed. The functional requirements and implementation principles of the system were analyzed. The control system architecture taking embedded soft PLC as the core was put forward. The system realizes basic logic control, full-function remote control and automatic cutting function of the roadheader through the customization of real-time operating system, transplantation of the soft PLC runtime system and the development of the drive components. The system also can real-time monitor status of the roadheader, and can realize full-function remote control through the remote control, automatic cutting and shaping of the roadway section by setting parameters such as section shape, path type, roadway height, roadway width and cutting interval. Compared with the control system with PLC and dedicated controller as the core, the roadheader control system based on embedded soft PLC can better realize unified standard and system's configuration and development of roadheader equipment, which has good cross-platform portability.The test results show that basic control function and remote control operation of the system are good, and the maximum error of automatic cutting surface boundary is less than 10 cm.

Transmission delay elimination method of abnormal signal in coal mine electromechanical monitoring system

DONG Guangmi

2020, 46(2): 107-110. doi: 10.13272/j.issn.1671-251x.2019040093

<Abstract>(132) <HTML> (13) <PDF>(8)

Abstract:
In view of problems of short life cycle and low delay elimination probability of existing abnormal signal transmission delay elimination methods, a transmission delay elimination method of abnormal signal in coal mine electromechanical monitoring system was proposed. In the method, FIR digital filter is used to filter abnormal signal and then detect abnormal signal transmission delay. Abnormal signal aggregation tree model is constructed by use of dynamic tree to mark signal that has not been eliminated by delay, calculate time slot of all marked signals, select signal with the smallest time slot, and eliminate delay of the signal. The simulation results show that the proposed method has a long life cycle and high efficiency in eliminating abnormal signal transmission delay.

2020 Vol. 46, No. 2

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