[abstract] Analyze and investigate the weak links in the safety supervision of hoist steel wire rope, so that the steel wire rope is in a safe and controlled detection state during the production and operation process. Zhengzhou Coal Group's Zhaojiachai Mine successfully applied the TCK.W steel wire rope online real-time automatic detection system, which is at the international leading level, not only to solve the problem of steel wire rope safety supervision, but also to improve production efficiency, reduce detection energy consumption, and save rope costs, bringing considerable economic benefits to the enterprise.

　　The theory of essential safety believes that due to various environmental influences, the degree of human freedom increases, and safety reliability will deteriorate. Therefore, to ensure safety, it is necessary to adopt a scientific technology that can ensure personal and property safety even in the presence of human errors, so as to achieve "essential safety".

　　The mining hoisting steel wire rope is even more at the throat of the mine. During the operation of the equipment, repeated loading and unloading will lead to irreversible mechanical property loss of the steel wire rope, and for a long time, there is a lack of more reliable prevention methods. Coal mine production often falls into the dilemma of "hidden dangers, waste, and inefficiency" due to the hoisting steel wire rope. Traditional manual inspection is unreliable and difficult to effectively detect hidden dangers in the steel wire rope; regular rope replacement cannot ensure safety and causes a huge waste of steel wire rope usage; excessive overhaul of the steel wire rope occupies production time, resulting in equipment idling energy consumption and low efficiency.

　　1 The Problem

　　Zhengzhou Coal Group's Luco Coal Mine experienced a lifting steel wire rope breakage accident three years ago, resulting in the bucket falling into the shaft and affecting production for 116 hours. Subsequently, Zhengzhou Coal Group's six major mines were each investigated and analyzed, and the results showed that all four multi-rope friction hoists' steel wire ropes were to be used for a maximum of two years and had never experienced a breakage accident. The steel wire rope that was forced to be replaced was also found to have no serious defects. However, the steel wire rope used for the five single-rope winding hoists had an average service life of 2.7 years, and the wear and tear on the steel wire rope was actually quite severe. Multiple times during its normal service life, there were critical situations where the rope almost broke.

　　Based on the results of this investigation, Zhengzhou Coal Group has decided to adopt effective non-destructive testing and scientific evaluation techniques for the in-service steel wire ropes, in order to achieve a fundamental and lasting improvement in mine hoisting and transportation safety.

　　2 Adopt advanced detection technology to address hidden safety hazards in steel wire ropes

　　Zhengzhou Coal Group's various subordinate coal mines have first equipped and used the TCK.W portable non-destructive testing instrument for steel wire ropes. This type of instrument uses weak magnetic detection technology to quantitatively detect internal and external wire breaks, wear and corrosion, fatigue and other damage in steel wire ropes, accurately assessing the remaining load-bearing capacity and service life of the steel wire rope. The instrument integrates multiple advanced technologies, has a clever structure, light weight, good passage ability, simple and convenient operation, safe and reliable use, and is waterproof and resistant to interference, suitable for relatively adverse working conditions.

　　By using advanced detection technology to replace the outdated method of manual inspection, Zhengzhou Coal Group has achieved immediate safety and economic benefits. In the case of Zhengzhou Coal Group's Chaohua Mine, which used to have an imported steel wire rope promised to last for four years but actually lasted less than half a year, a detection was carried out and six serious injuries were detected, with the maximum damage value reaching 10.6%. According to regulations, it was recommended to stop using it immediately. If there had been no detection, the rope could have led to a serious accident at any time. Due to the difficulty of accurately assessing the actual technical status of in-service steel wire ropes, the foreign supplier of steel wire ropes has always been skeptical about the basis for quality claims. The mine provided the TCK.W scientific instrument and TCK.W data report, which finally convinced the foreign supplier of steel wire ropes to acknowledge the detection results and compensate Zhengzhou Coal Group's Chaohua Mine for economic losses of 920,000 yuan.

　　3 Create a new model of safety supervision for steel wire rope

　　Through further exploration and research on the safety supervision methods of steel wire rope, Zhengzhou Coal Group has realized that although the portable non-destructive testing instrument provides a certain technical guarantee for the safe operation of steel wire rope, there is still a significant gap between the actual safety status of mine lifting steel wire rope and the essential safety requirements due to the significant influence of dynamic load on steel wire rope, the continuous operation of high-yield coal mines for 24 hours, the existence of many human factors in instrument operation, and the production time occupied by offline testing. It is necessary to adopt a dynamic and continuous online real-time automatic detection scheme for steel wire rope to ultimately achieve scientific supervision and reliable prevention and control of mine lifting steel wire rope.

　　In 2008, TCK.W steel wire rope weak magnetic detection technology successfully integrated modern high-tech achievements such as Ethernet communication, microelectronic integration, and two-dimensional model analysis to achieve remote monitoring of steel wire rope in major production and public facilities. Zhengzhou Coal Group's Zhaojiazhai Mine immediately organized technical experts to collaborate with TCK.W Company to develop a new technical solution for online real-time automatic detection system for steel wire rope, which can detect various internal and external injuries of mine lifting steel wire rope in a magnetic field environment of 200mT or less and monitor the process without magnetic pollution. The sensor has a lift-off gap of 50mm with respect to the surface of the steel wire rope, and the uncertainty of the metal cross-sectional area loss rate caused by various injuries is less than 0.5%.

　　The steel wire rope online real-time automatic detection system is equipped with five technical units including mode combination detection, intelligent data acquisition and conversion, photoelectric distance measurement and speed measurement, self-controlled acoustic-visual alarm, and multi-channel terminal control. It adopts an expert data platform and system embedded control program, and has advanced functions such as unattended full-time automatic detection, automatic data integration, and automatic generation of detection reports. It can achieve multiple pre-set functions such as "data sequence/damage curve/statistical chart pre-set", "background data calculation", "automatic file establishment", "system self-check", and "fault analysis", and generate a treatment plan. It is closely integrated with the actual working ecology and safety operation needs of the mine hoist, and can detect the steel wire rope online during normal hoisting. The system maximizes the avoidance of human influence in the monitoring process, and extends the monitoring range to cover areas that were previously difficult for inspectors to reach, enabling full-cycle online real-time automatic monitoring of the steel wire rope and becoming the most advanced steel wire rope safety solution for safe operation.

　　Currently, Zhengzhou Coal Group's Zhaojiazhai Mine has installed the TCK.W-SC type 4-rope 8-measure point steel wire rope online real-time automatic detection system in the main and auxiliary shafts, with the detection head fixed alongside the path of the mine hoist steel wire rope. During normal lifting operations, it can complete corresponding online detection based on the travel distance. In the event of encountering a serious injury signal during the detection process, it will automatically emit an acoustic-visual warning in the first instance, and the computer system will also provide equipment handling plans such as "enhanced maintenance", "shutdown review", or "immediate replacement of the rope" to the equipment operator based on the detection data in real-time.

　　Some maintenance personnel at the mine initially expressed doubts about the data detected by the system. However, through detailed field testing, comparison, and parameter adjustment, the technical indicators have been fully validated, and its accuracy is beyond the reach of daily manual inspections and traditional detection techniques.

　　4 Effect

　　In July 2009, the Zhaojiazhai Mine's main and auxiliary shaft wire rope online detection system was put into operation. After a period of on-site verification, coal production significantly increased, rope costs were controlled, and energy consumption for detection was close to zero. The small investment of the enterprise has brought great returns, and has become a new model for safety supervision of important steel wire ropes.

　　(1) The steel wire rope is always in a safe and controlled state during production and operation. The application of the TCK.W steel wire rope online real-time automatic detection system greatly improves on-site safety monitoring, production process control, and scientific management level. The system ensures that the operation of the steel wire rope is always closely monitored for safety, fundamentally eliminating various hidden dangers and ensuring the safety of the hoist, making it the most important management innovation achievement of Zhengzhou Coal Group Zhaojiazhai Mine.

　　(2) Production efficiency significantly increased: According to the regulations of the "Coal Mine Safety Regulations", the lifting rope and guide rope must be inspected once a day. Under this requirement, the Zhaojiazhai Mine had to spend 1.5 hours per day for manual inspection of the steel wire rope. After adopting the steel wire rope online real-time automatic monitoring system, the steel wire rope inspection was completed during normal production, integrating production and inspection processes. The time previously used for manual inspection of steel wire rope became effective production time, resulting in an annual increase of at least 180,000 tons of coal production.

　　(3) Eliminate equipment detection-induced idle energy consumption: The main and auxiliary shafts of the Zhaojiazhai Mine have a lifting height of 446m and 465m, respectively, with motor powers of 2800kW and 850kW. During manual inspection, the rope speed is 0.3 to 0.5m/s, the equipment idle power consumption is 235kW, and it takes 4 inspectors 1 hour to complete a manual inspection simultaneously, consuming 350kW·h of electricity. Based on 330 effective working days per year, the annual idle energy consumption for steel wire rope inspection is at least 11.6 million kW·h. By using the steel wire rope safety supervision system for lifting, the equipment idle energy consumption dedicated to steel wire rope detection is almost zero, resulting in a power saving benefit of nearly 100,000 yuan.

　　(4) Rational utilization of steel wire rope remaining service life: The replacement cycle of the main and auxiliary shaft lifting machines in Zhaojiazhai Mine was 2 years in the past, with a material cost of 780,000 yuan per time and a maintenance labor cost of 250,000 yuan. The production was stopped and adjusted for 3 days to shorten the start-up time, resulting in an annual replacement cost of 510,000 yuan. After using the steel wire rope online real-time automatic detection system, the main and auxiliary shaft lifting steel wire rope can be used to full service life, and even extended for one year, reducing the annual replacement cost to 340,000 yuan, and the cost of using the rope is also reduced to one-third of the original.

　　5 Conclusion

　　Zhaojiazhai Mine of Zhengzhou Coal Group has implemented the transformation of the work mode of safety supervision of mine lifting steel wire rope through the application of the TCK.W steel wire rope online real-time automatic detection system, achieving the goal of online real-time monitoring and dynamic continuous effective monitoring of steel wire rope. This not only solves the problem of steel wire rope safety supervision, but also can create direct economic benefits of 81.27 million yuan per year in improving production efficiency, reducing detection energy consumption, and saving rope costs, thereby truly achieving the three-way management goals of safe, economical, and efficient operation of mine lifting steel wire rope.

       Author Introduction:

　　Liu Shidong, male, born in May 1963, graduated from the former Jiaozuo Mining College (now Henan Polytechnic University) in 1985, is a senior mechanical and electrical engineer, currently serving as the deputy general manager of Henan Xinzheng Coal and Electricity Co., Ltd. He has published more than ten papers and mainly engaged in the research of mechanical and electrical equipment technology and on-site management in mines.