1. Downhole equipment monitoring
1KJ50 PROMOS Monitoring System
Coal mines, especially working faces, are complex environments with the risk of gas and coal dust explosions. Corresponding electrical control systems should be versatile, high-performance, and highly reliable, suitable for various control tasks. However, early relay control systems and other electrical control systems failed to meet these requirements. To address this, the Zhengzhou Coal Design Institute and the Changzhou Science and Technology Development Institute of Yanzhou Mining (Group) Co., Ltd. applied the KJ50 PROMOS monitoring system to the control and protection of the roadway expansion conveyor belt and downhill conveyor belt in the North Fourth Mining Area of Chen Silou Coal Mine, Yongcheng Coal and Electricity Group, as well as the centralized control of mining equipment, roadway conveyor belts, downhill conveyor belts, and coal feeders. This effectively met the needs of production management and design installation.
This system is the result of automation technology from Benbro Electronics GmbH, Germany. It consists of a controller, auxiliary controller, control interface, control conversion interface, coupler, intelligent I/O components, a series of public address telephones with intelligent I/O components, a mining DC regulated power supply, line terminals, and other system-related devices (various switches, buttons, sensors, electric valves, buses, etc.).
The results of the underground application at Chen Silou Coal Mine indicate that the monitoring system has the following main characteristics: ① The system has strong applicability and scalability, and can be configured into different control scales. Its logic control method can be implemented through software programming, making complex logic control simple and easy to implement. ② Many devices in the system are intelligent components, capable of preprocessing input data before transmitting it to the controller for further processing, and communicating with the controller in a reporting manner. In effect, it is a small-scale distributed data control system. ③ The products in the system are connected using simple and quick plug-in connectors, enabling rapid and accurate installation and replacement even in harsh environments. ④ The system has an independent voice communication line, allowing for voice communication wherever possible. ⑤ The system has a specific safety protection loop, which, when connected to the control loop, ensures safe and reliable system control.
2. Development of a comprehensive monitoring and fault diagnosis system for coal mine working faces
The "Comprehensive Monitoring and Fault Diagnosis System for Coal Mine Working Faces," jointly developed by China University of Mining and Technology and Xinglongzhuang Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd., has reached the international advanced level in overall technology. It is of great significance for ensuring the safe production of coal mine working faces and has passed the technical appraisal by experts.
This research project was proposed to adapt to the development of high-yield and high-efficiency fully mechanized longwall mining face production technology in coal mines. The system consists of a surface main unit, an underground central station, nine monitoring subsystems, and corresponding surface and underground communication networks. It has functions such as monitoring the operating parameters of front and rear conveyors and pump stations, monitoring emulsion ratio, monitoring and analyzing support quality and roof pressure, automatic detection of roof delamination, monitoring roadway deformation, monitoring the start-up and shutdown of major equipment in the working face, and statistically analyzing uptime. The system's technical features are mainly reflected in: achieving online real-time monitoring of roof delamination, providing a reliable monitoring method for analyzing the relationship between delamination and mining impacts; using a large-screen intrinsically safe computer for the underground working face condition monitoring system, improving the application level of computer technology in coal mine production; achieving real-time multi-parameter monitoring of emulsion pump stations, providing a basis for concentration adjustment; and achieving online analysis of working face support quality and roof pressure by an expert system, as well as online monitoring of faults in major working face equipment.
This achievement has been put into use in the 5318 high-yield and high-efficiency fully mechanized top coal caving face, a national key technology project implemented at Xinglongzhuang Coal Mine. Practice has shown that the system has a reasonable structure, advanced technology, reliable operation, comprehensive monitoring content, and strong data analysis capabilities. It provides comprehensive monitoring and assurance for the safe operation of high-power equipment in the fully mechanized top coal caving face, and has achieved considerable economic and social benefits. Experts point out that the successful development and application of this achievement has a promising prospect for widespread application in high-yield and high-efficiency mines with large-scale and automated mining equipment in my country, particularly those with one or two faces.
3. Ji'er Mine monitors underground equipment to ensure safety.
The KJ95 mine safety production monitoring system installed at Jining No. 2 Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd. can comprehensively monitor the underground production working environment and the operation of some production equipment, and promptly alarm when the monitored values exceed the safety production regulations.
The system consists of a server, switches, and user terminals. Eighteen gas sensors, nine wind speed sensors, four carbon monoxide sensors, four temperature sensors, and two negative pressure sensors were installed underground. After several years of use, the original system was recently upgraded. The system monitors environmental parameters such as conveyor belt operation, overhead personnel carrier operation, damper operation, temperature, negative pressure, local fan operation, and carbon monoxide and gas concentrations via sensors. The data is transmitted directly to the server via the mine's local area network (LAN). The server processes and analyzes the collected data, generating graphs and reports. The provided mine monitoring charts are displayed clearly on the user's desktop. This system achieves mine-wide networking through the LAN, allowing mine leaders, departments, and work teams to view the relevant data.
4. Development of a Visual Control System for Tunneling Faces
The fully mechanized tunneling face visual control system, jointly developed by Xinglongzhuang Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd. and Tianjin Tianning Mining Electronic Equipment Factory, is a control and communication system that integrates communication, control, detection and protection. It can centrally control and dynamically detect the operation of equipment within a 3km range.
When used underground, each control point only needs a power supply, a public address telephone, and cables to enable communication and early warning. Configuring controllers, intelligent input/output systems, and various sensors allows for equipment operation control. The controller, equipped with a large-screen color LCD display, is the core of the control system. The intelligent input/output system, serving as a local control substation for each belt conveyor or scraper conveyor, has four inputs and four outputs. Output nodes control motor start/stop, while input nodes connect to protection sensors and local start/stop buttons.
After configuration according to site requirements, the system can perform the following main functions: ① Sequential start-up and shutdown. The scraper conveyor and belt conveyor can be started sequentially against the coal flow direction and stopped sequentially with the coal flow direction via the start and stop buttons on the controller. A voice alarm is triggered before startup, and the startup interval is adjustable. ② Emergency stop. In case of emergency, pressing the interlock button on any public telephone along the tunneling face will immediately stop all controlled equipment on the tunneling face. ③ Local individual start and stop. Individual start and stop buttons are installed near each controlled piece of equipment. When the controller's "operating mode selection" is set to "local," pressing this button will allow individual startup and shutdown of that equipment. ④ Equipment protection. Each piece of equipment is equipped with coal pile protection, and belt conveyors also have protection against deviation, smoke, temperature, and speed. ⑤ Along-line communication and alarm. Every telephone along the line can make calls to other telephones, and the equipment has a voice alarm before each start-up, which improves the safety of equipment operation and avoids various serious accidents.
5. Coal Mine Safety Monitoring and Control System Based on GIS
The Qinglong Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd. has high coal seam gas content and large emission volume, which seriously threatens the lives of miners. In order to prevent problems before they occur, they have established a coal mine safety monitoring and control system based on GIS, which makes mine safety management intuitive and fast, and effectively reduces potential accident hazards.
Mine information is closely related to spatial location information; therefore, they introduced a software platform that combines spatial location and attribute data in the coal mine's information system construction. This system uses MapInfo's Java 4.5 product, leveraging its comprehensive map operation functions, positioning, map navigation, thematic maps, and various statistical analysis functions to achieve visualized production scheduling, safety scheduling, and safety monitoring. It can arbitrarily select and display target coal mines and corresponding mining engineering maps, freely query and browse mining engineering maps and other production relationship maps, transparently overlaying them for spatial analysis; it can directly measure distances on the map, directly generate warning and supervision orders at boundary crossing locations on the digital mining engineering map, and promptly issue them via the network. The safety monitoring sub-functions include online detection, gas exceedance monitoring, curve analysis, global monitoring, data query, historical curve analysis, and email processing.
It can monitor the operational status of all sensors and underground equipment in a single coal mine in real time using graphical methods. The graph displays the current gas concentration of each sensor and the on/off status of the equipment, with audible alarms for exceeding gas limits and corresponding displays for communication interruptions. The ventilation system provides real-time processing and analysis of data such as wind speed, air volume, wind direction, and trends, enabling real-time display and querying of collected data and automatic over-limit alarms. Curve analysis allows for real-time, minute-by-minute, and hourly data queries of coal mine gas conditions and can generate graphical curves for partial data from a single gas sensor. The subsystem provides real-time processing and analysis of gas concentration and trends, automatically generating corresponding thematic maps based on the collected data and issuing over-limit alarms.
Application of 6Profibus-DP bus in coal mine equipment monitoring system
Recently, Shandong University of Science and Technology successfully applied Profibus-DP bus technology to the monitoring system of air compressors, fans and water pumps in the East Wind Shaft Square of Xinglongzhuang Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd., which is of great significance for ensuring the safe production of coal mine and maintaining the efficient and economical operation of equipment.
Profibus is an international, open, and device-independent fieldbus standard increasingly widely used in industrial automation. It has three compatible versions, among which Profibus-DP is a high-speed (data transfer rate up to 12 Mbit/s) and economical device-level network primarily used for communication between field controllers and distributed I/O. This system consists of one Profibus-DP master, three Profibus-DP slaves, and field devices including fans, air compressors, and various transmitters.
The master station is located in the main monitoring room, and the slave stations are located at the field sites of each monitored device. All slave devices are connected via a Profibus-DP bus. The master station uses an industrial computer as the host computer, connected to the fieldbus via a fieldbus interface card, enabling the industrial computer to connect to the fieldbus network and form a complete control network system capable of configuration, operation, and control. Slave station 1 monitors the operation of four 300kW air compressors, slave station 2 monitors the operation of five water pumps in the ventilation shaft area, and slave station 3 monitors two ventilation fans in the ventilation shaft and parameters such as ventilation shaft pressure, gas, and dust. Because the three slave stations are relatively far from the master station, a human-machine interface (HMI) is designed at each slave station. Detailed operating parameters of the field devices can be displayed via an LCD touchscreen, and the operation of the corresponding devices at each slave station can also be controlled. This type of centralized equipment monitoring system uses the Profibus-DP fieldbus to achieve distributed control and has been running stably in the field for over one year. Operational practice at Xinglongzhuang Coal Mine has proven that this bus technology improves system stability and reliability, has strong anti-interference capabilities, and reduces system costs.
7. Mine Locomotive Transportation Monitoring System
The KJ15A mine locomotive transportation monitoring system, jointly developed by Nantun Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd. and Hefei University of Technology, is technologically advanced, highly adaptable, reliable, and easy to operate and maintain, and has great potential for widespread application.
The system mainly consists of three parts: a ground dispatch station, remote control substations, and the telemetry and control field. The ground dispatch station includes a main control computer, display equipment, printers, management computers, and intelligent communicators; the remote control substations include explosion-proof power supply boxes and control substations; and the telemetry and control field includes track axle counters, underground transceivers, dynamic signals, and electric switch machines. The industrial control network used by the KJ15A system is a two-level network with a multi-layer bus-star hybrid structure. The main control room is located on the ground, and the main control computer uses an Advantech series industrial control computer. Four network communication cables are led from the main control room to the underground. The control substations are installed on the shaft wall in the tunnel and use self-developed dedicated industrial control computers. Each network communication cable can connect 15 control substations. The control substations are dedicated field intelligent substations composed of high-end industrial control microcomputers, directly managing sensing and execution equipment. Each control substation is equipped with a dedicated power supply box and can manage four telemetry and control points. Each control point includes one pair of axle counting sensors, one receiver, one signal, and one electric switch.
This achievement introduces intelligent control technology and explores a series of flexible scheduling algorithms, solving problems such as forward and backward uncertainty in dynamic target tracking, dynamic linking of train paths, automatic determination of signal interlocking relationships, and adaptive reorganization of topology when equipment is damaged. It enhances traditional route scheduling methods by using task and task string scheduling, achieving automated scheduling. A track axle counter has been successfully put into use, adaptable to various locomotives and capable of detecting information such as train speed, direction of travel, and number of wagons. Replay software has been developed, capable of reproducing the transportation process at arbitrary speeds within a selected time period. The underground equipment adopts a modular structure, adaptable to mines of different sizes. After the basic system is installed, users can easily expand and modify the system themselves.
8. DC traction network monitoring system for underground overhead line locomotives in coal mines
Based on the characteristics of DC power supply in underground coal mines and the characteristics of underground locomotive transportation, Baodian Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd. has developed an underground overhead line locomotive DC traction network monitoring system. This system not only ensures the normal power supply of the DC traction network, but also enables rapid power restoration after a fault, thereby improving the transportation efficiency of locomotives and placing it at a leading level in China.
The system allows centralized operation of all switches on-site from the control panel; it also allows for independent operation and control of individual zone switches without interlocking; each switch can also be operated locally. The 550V DC overhead line uses a serial power supply method, as does the 660V operating power supply of the zone switches. Each switch controls the next, and the control panel communicates with each zone switch via an encoding method. When supplying power to the overhead line, the control panel first scans the system, sequentially sending the codes for each switch. Each zone switch, upon receiving its coded command, returns its operating status information to the control panel for analysis and displays accordingly. Indicator lights illuminate, indicating a normal zone switch has its DC contactor closed and is energized. Fault lights illuminate, the DC contactor cannot close, and the overhead line is de-energized; the fault should be checked and rectified. In the event of a power outage caused by human error or a fault on-site, the control panel displays various faults, and power can be directly restored to a specific zone switch from the dispatch room. Power can be quickly restored in cases of locomotive grounding, short circuits, or intentional power outages, avoiding the hassle of searching each switch individually.
Its features are as follows: ① It adopts a new type of Hall element sensor to sample DC current. The signal is processed by a microcontroller to achieve various protections. The switch has an opening and closing interlock function, preventing operation both locally and remotely during switch maintenance, ensuring safety during maintenance. ② It has a DC leakage current interlock function. Before the zone switch closes, the insulation performance of the overhead 550V DC line is tested. If the line insulation value is lower than the set standard value, the leakage current interlock circuit activates, preventing the zone switch from closing and providing line protection. If the line insulation value is higher than the set insulation value, the leakage current interlock circuit does not activate, allowing the zone switch to close normally for power supply. Considering the importance of the leakage current interlock circuit, a leakage current interlock circuit test circuit for self-testing is also designed to verify its reliability.
9. Monitoring of Support Position and Support Quality in High-Yield and High-Efficiency Coal Seams
The coal seam thickness of the 23-01 longwall mining face at Jining No. 2 Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd. is medium to thin, with well-developed faults. They implemented support position and support quality monitoring, which included monitoring the elevation and depression angles of the support roof beams, the balance jacks, coal wall spalling, and end face roof collapse, to ensure the reasonable position of the supports and the quality of the support.
Monitoring and analysis show that the elevation range of the support beam is -1° to 9°, with an average of 3.7°. This ensures the support maintains a good position even when the working face crosses faults or experiences significant changes in mining height. The beam is essentially horizontal, maintaining good contact with the roof, which is beneficial for the support function of the columns. Statistical results show that the maximum angle between the beam and the shield beam is 174.5°, the minimum is 146°, the average is 159.37°, and the sample standard deviation is 6.94°. Based on the design dimensions and stroke of the balancing jacks, the maximum design angle between the support beam and the shield beam is 199.225°, the minimum is 134.528°, and the average is 167.23°. Therefore, the angle between the beam and the shield beam is within a reasonable range during support operation. The above analysis indicates that, from the perspective of the balancing jacks' working condition, the support is in good working order, adapting to changes in the working face's mining height and providing good roof support.
To analyze the force distribution of the balancing jacks and determine their reasonable force range, statistical analysis was conducted on the pressure data collected from the working face. Under relatively low mining heights, the roof movement was relatively stable. The balancing jacks could adjust the center of force of the roof beam according to the roof movement, enabling them to effectively support the roof. Due to the influence of gravity along the inclined direction, the movement of the overlying strata varied in different parts of the working face, which was clearly reflected in the resistance distribution of the balancing jacks. This indicates that the balancing jacks can automatically adjust the working state of the support according to different pressure conditions at the working face, maintaining overall coordination while adapting to changes in internal pressure along the inclined direction.
2. Ground Equipment Monitoring
1. Ground-based waste disposal multimedia locomotive monitoring system
The ground-based multimedia locomotive monitoring system selected by the Dongtan Coal Mine of Yanzhou Coal Mining (Group) Co., Ltd. not only ensures locomotive speed but also guarantees transportation safety, effectively solving the problem of locomotive throughput in the transportation yard and creating significant benefits.
The system consists of indoor centralized control equipment and field signaling equipment. The signaling equipment controlling locomotive operation is located on-site, including electric switch machines, signals, sensors, and cameras. The switch machines change the locomotive's direction, the signals indicate the locomotive's start and stop, the sensors track and monitor the locomotive's position, and the cameras monitor train occupancy in the depot. The indoor equipment consists of an operation control console, relay cabinet, power supply cabinet, lightning protection cabinet, and a large-screen display. The system's main unit, the 984-385 control software, adopts a modular structure, with the entire program divided into two sections. The first section contains the core components: system reset, sensor short-circuit detection, and route status control. This program controls route query, occupancy/unlocking transitions, signal opening, some prompt signals, and automatic control signals for the switch machines. The second section includes route sending and unlocking procedures, electric switch machine control and alarm procedures, and data transmission procedures.
The system has the following features: it uses a programmable logic controller (PLC) of internationally advanced level from the United States as the system control host, enabling three control modes: programmable control, centralized control, and manual operation; it provides image monitoring of the operation of the waste rock washing bin, waste rock sorting bin, level crossing, and hoisting cage, displaying information such as locomotive number, train position, route occupancy, signal display, and switch machine tip position; it provides audible and visual alarms for broken signal bulbs, switch machine tip misalignment, and sensor electrical faults; when a locomotive runs a red light, a red light strip flashes in the red light area; it counts the number of waste rock cars in the waste rock washing bin, waste rock sorting bin, level crossing, and hoisting cage, and prints various data for vehicle dispatching and management according to production needs; it has interfaces for connecting to the mine network and underground locomotive monitoring system; and the gap rail sensor used for the first time has shockproof, waterproof, and impact-resistant functions, with stable and reliable performance.
A new type of coal bunker coal level transmission and display system was developed.
The industrial television monitoring system at Yanzhou Coal Mining (Group) Co., Ltd.'s Baodian Coal Mine has been extended from the surface to underground. However, due to environmental factors and technical limitations, the coal levels in the mine's bunkers, both above and below ground, have not been included in the networked management system, preventing the dispatch system from understanding the coal storage status. To address this, with the assistance of China University of Mining and Technology, they integrated one raw coal bunker, two gangue bunkers, and three underground coal bunkers from the coal preparation plant into the dispatch monitoring system. This enabled automatic monitoring of coal levels in the bunkers, reducing downtime, startup, and standby time for belt conveyors and providing a scientific basis for coal washing, processing, and sales decisions.
The system consists of three parts: a coal preparation plant substation, an underground substation, and a mine dispatch center mainframe. Compared to the mine's local area network (LAN), it is both a self-contained system and a distributed subsystem. The coal preparation plant substation measures and displays the coal level in the 30m-high raw coal and gangue bunkers, then transmits this information to the mine dispatch center mainframe. Due to less interference from surface transmission, shielded twisted-pair cable and Bitbus bus protocol error correction are used to save investment, resulting in a transmission error rate of less than 10⁻⁶, ensuring reliable data transmission. The underground substation measures and displays the coal level in the 25m-high coal bunker, provides low and high level alarms, and converts the measurement signals into optical signals for fiber optic transmission. The mine dispatch center mainframe handles information acquisition, drives the display substations, and transmits information to the LAN.
The system has a measurement range of 0–35 m, a measurement accuracy of less than 0.5% of the range, and a display accuracy of 0.1 m. Signals between the coal preparation plant, the mine shaft, and the mine control room are transmitted via fiber optics, providing strong anti-interference capabilities. The coal preparation plant control room and the underground central control room are equipped with digital display instruments. The displays are key-operated 4-digit 20.3-inch high-resolution LED displays with a basic error of 0.5% and a resolution of 0.01. The analog transmission current is 4–20 mA (with a load resistance of 500 Ω), allowing operators to clearly see the exact location of the coal level in the coal bunker.
This achievement replaces the previous two displays for high and low coal levels, featuring both digital and bar chart displays on the main unit in the mine dispatch room, which is both intuitive and aesthetically pleasing. Furthermore, it fully considers future system expansion needs, reserving 15 storage bin transmission interfaces to integrate all 18 coal bins in the coal preparation plant into the system, forming an independent coal bin level transmission and display network.
The Xinglongzhuang Coal Preparation Plant's operating condition monitoring system is effective.
The "Xinglongzhuang Coal Preparation Plant Operating Condition Monitoring System" project, jointly completed by the Xinglongzhuang Coal Mine Coal Preparation Plant of Yanzhou Coal Mining (Group) Co., Ltd. and the School of Information and Electrical Engineering of China University of Mining and Technology, has reached the advanced level in China and has passed the technical appraisal of experts.
The Xinglongzhuang Coal Preparation Plant's operational monitoring system can be divided into one main system and five subsystems. Its primary equipment utilizes the "KJ28 Coal Mine Above-Ground and Underground Fiber Optic Industrial Television Monitoring System" series, researched and manufactured by the School of Information and Electrical Engineering of China University of Mining and Technology. Television images within each subsystem are transmitted via coaxial cable, while data and images between subsystems and between subsystems and the main system are transmitted entirely via fiber optic cable. The entire system is equipped with 35 cameras, allowing for numerous centralized monitoring points to be set up in the four technical operation rooms and the clean coal transportation system of the coal preparation plant. This enables monitoring by each subsystem, as well as fixed-point or cyclical monitoring of all images from the plant dispatch room and relevant plant leadership offices. Furthermore, it can monitor the entire loading process of coal trains and the cleanliness of the wagons.
After careful installation and debugging, the system was officially put into operation, and it is estimated that it replaced the workload previously undertaken by at least 60 on-duty drivers. To date, the system has been running for several years, and its practical operation has powerfully demonstrated that the industrial television monitoring system at Xinglongzhuang Coal Mine's coal preparation plant is reliable, provides clear and stable images, and offers flexible and convenient operation and control. The system's functions and technical specifications have all met the design requirements.
Experts believe that this achievement will take a significant step forward in the modernization of my country's mining industry's ore dressing plants, and has considerable promotional value, which can be applied in ore dressing plants with similar conditions.
4. Baodian Mine's fiber optic industrial television system passed technical appraisal.
The KJ28 fiber optic industrial television system, jointly developed by Yanzhou Coal Mining (Group) Company Baodian Coal Mine and China University of Mining and Technology, has passed the technical appraisal of experts.
It is understood that the KJ28 fiber optic industrial television system mainly consists of two parts: underground fiber optic television in the mine and ground-based office automation. It enables 24/7 monitoring of key production processes and equipment in coal mines, as well as monitoring of their status data. Practical application shows that images from the field can be transmitted via fiber optic cable to the ground control room and the offices of relevant leaders. More than 20 terminal devices have AV/TV signal switching capabilities, are easy to operate, and offer flexible and reliable control. They are fully capable of independently viewing all types of images, either in a fixed location, cyclically, or selectively.
Experts point out that even under the limited lighting conditions underground in coal mines, the images transmitted through this system remain stable, clear, and interference-free. This allows mine leaders and dispatchers to intuitively and promptly understand the coal production, transportation, and hoisting conditions at each coal mining face underground. It plays a vital role in ensuring safe production in coal mines and in scientific dispatching and command, and has high promotional value.
