Engineering Case of JTK Model Mine Hoist

Engineering Case of JTK Model Mine Hoist

I. Project Background

      During the mining process of an underground mine, the original hoisting equipment was severely aged, suffering from issues such as low operating efficiency and numerous safety hazards. It could no longer meet the mine's growing production demands. To ensure safe production and improve mining efficiency, the mine decided to upgrade the hoisting system and selected the JTK model mine hoist as the core equipment, aiming to create a new, safe, reliable, efficient, and energy - saving hoisting system.

II. Technical Parameters and Configuration of JTK Model Mine Hoist

     The JTK model mine hoist is a single - rope winding hoist. According to the actual needs of the mine, the JTK - 2.5/20 model was chosen. This hoist has a drum diameter of 2.5 meters and a drum width of 1.5 meters. The maximum static tension is 50kN, the maximum static tension difference is 35kN, and the hoisting speed can reach 6m/s, making it suitable for mine hoisting operations within a depth of 600 meters. It is equipped with a YR series wound - rotor three - phase asynchronous motor with a power of 355kW and a speed of 730r/min, which is connected to the drum through a reducer with a gear ratio of 20. Meanwhile, it is equipped with a PLC control system, which can achieve automatic control and precise speed regulation of the hoist operation. Coupled with a high - precision depth indicator, the positioning error does not exceed ±50mm.

     The braking system adopts a hydraulic disc braking device, consisting of a hydraulic station, brakes, and a brake disc. The hydraulic station can automatically adjust the oil pressure according to the operating status of the hoist to provide a reliable braking torque. The braking deceleration meets the requirements of the Coal Mine Safety Regulations. In case of emergency braking, the braking distance does not exceed 5 meters, ensuring quick stopping in case of sudden situations. In addition, the hoist is also equipped with a complete set of safety protection devices, including over - winding protection, over - speed protection, under - voltage protection, speed - limiting protection, etc., to fully guarantee the safety of hoisting operations.

III. Hoisting System Reconstruction Plan

3.1 Installation of Foundation and Mechanical Structure

     In the hoisting machine room, foundation construction is carried out strictly in accordance with the design requirements. High - strength concrete is used to pour the hoist foundation to ensure the stability and bearing capacity of the foundation. During the installation process, high - precision measuring instruments are used to accurately align the main shaft device of the hoist, ensuring that the horizontal error of the main shaft does not exceed 0.1‰, and the verticality error between the axis of the main shaft and the hoisting center line does not exceed 0.15‰. When installing the drum, the difference in the inner diameters of the two flanges of the drum is controlled to be no more than 1mm to ensure uniform winding of the steel wire rope. At the same time, the sheave device is installed, and the ratio of the sheave diameter to the steel wire rope diameter meets the specification requirements to reduce the wear of the steel wire rope.

3.2 Debugging of Electrical and Control Systems

     After correctly connecting the YR series motor to the reducer and drum, electrical circuit laying is carried out. Shielded cables are used to connect each electrical device to reduce electromagnetic interference and ensure stable signal transmission. The PLC control system is programmed and debugged. According to the mine hoisting process requirements, parameters such as the operating speed curve, acceleration and deceleration time, and parking position of the hoist are set. By simulating various working conditions, the reliability of safety devices such as over - winding protection and over - speed protection is tested to ensure that the system can respond quickly in case of abnormal situations and guarantee the safety of hoisting operations.

3.3 Trial Operation and Optimization

     After completion of installation and debugging, no - load trial operation is carried out. The hoist runs at a low speed, and the operation of each component is checked, including whether the drum rotates smoothly, whether the braking system is sensitive and reliable, and whether the electrical equipment works normally. After the no - load trial operation is qualified, load trial operation is carried out. The hoisting load is gradually increased from 25%, 50%, 75% to 100% of the rated load to test the operating performance of the hoist under different loads. Parameters such as the current, voltage, and temperature of the motor, as well as the operating speed and braking effect of the hoist, are monitored. According to the data of the trial operation, the control parameters of the hoist are optimized and adjusted to ensure that it can operate stably and efficiently under various working conditions.

IV. Implementation Results

4.1 Improved Production Efficiency

     After the JTK model mine hoist was put into use, compared with the original equipment, the single - time hoisting capacity increased from 8 tons to 10 tons, the hoisting speed increased by 20%, the number of hoisting times per hour increased from 10 times to 12 times, and the daily hoisting capacity of ore increased from 1,600 tons to 2,400 tons. The annual production capacity of the mine has been significantly improved, effectively meeting the production needs of the mine.

4.2 Enhanced Safety Performance

     The complete safety protection devices and reliable braking system have greatly reduced the safety risks of hoisting operations. Since the equipment was put into use, no safety accidents caused by hoist failures have occurred. Safety devices such as over - winding protection and over - speed protection have been triggered successfully many times in abnormal situations, avoiding serious accidents and providing a solid guarantee for the safe production of the mine.

4.3 Remarkable Economic Benefits

     The efficient operation of the hoist has reduced the equipment's operating time and energy consumption. The YR series motor, combined with the high - efficiency reducer, has reduced the energy consumption of the hoisting system by about 15%. At the same time, the improved reliability of the equipment has reduced the number of maintenance times and maintenance costs, saving about 500,000 yuan in maintenance costs annually. The improvement in production efficiency and the reduction in costs have brought remarkable economic benefits to the mine. The expected investment payback period is 2 - 3 years.

     This engineering case shows that with its reasonable technical parameters, reliable performance, and complete safety configuration, the JTK model mine hoist can effectively solve the existing problems of the mine hoisting system, providing valuable experience and reference for the upgrading and transformation of hoisting equipment in similar mines.