As an important component of mining lifting equipment, steel wire rope is crucial for safe production and the production efficiency of the company.

　　For a long time, the management of steel wire rope has been in an awkward situation of "emphasis but no effective means", and it has been necessary to use manual visual inspection, caliper measurement, experience, feeling and other methods to replace the rope, which has four problems of "unreliability, insecurity, uneconomical and low efficiency". It is urgent to use advanced management and technical means to strengthen the detection of steel wire rope, the assessment of load-bearing capacity, safety management and other work, so as to improve the management level of the lifting equipment in the second mining area as a whole, ensure the safe operation of steel wire rope.

1.The necessity of implementing this project

　　The TCK.W steel wire rope remote network monitoring and control system is currently the most advanced real-time monitoring system for steel wire ropes. Based on weak magnetic detection technology and combined with modern network communication technology, this system can achieve real-time monitoring of online steel wire ropes.

　　The Second Mine District has demonstrated the feasibility and necessity of using the TCK.W steel wire rope remote network monitoring and control system in mine hoisting. This system will be able to achieve the following:

　　(1) Fix the high-sensitivity detection device to the appropriate position of the hoist and connect it to the central control station through wired or wireless communication to achieve real-time monitoring of the online steel wire rope.

　　(2) The central control station can monitor all monitored steel wire ropes in real-time, detect damage and remaining load-bearing capacity, and provide corresponding suggestions for handling measures.

　　(3) The monitoring scope includes the steel wire ropes of the main and auxiliary shafts in the Second Mine District.

2.The Current Situation of Steel Wire Rope Management in Second Mine

　　The management of steel wire rope in the Second Mine District is crucial for the company's safety production and production efficiency. The company has always attached great importance to its management. However, for a long time, due to the lack of appropriate detection equipment and scientific control methods, the management of steel wire rope has remained in the outdated mode of relying on basic manual experience judgments, using methods such as visual inspection, caliper measurement, and feeling to replace the rope.

　　In fact, as early as many years ago, technical personnel from the Second Mine District and relevant departments of the company have been looking for related detection instruments or solutions. In recent years, this effort has never stopped. However, due to the maturity of steel wire rope detection technology, it has not been able to find a steel wire rope detection product that can meet the actual detection requirements. Therefore, the management of steel wire rope has also continued the practice of manual detection and regular replacement of ropes that has been used for decades.

2.1 The main manual inspection method used for steel wire ropes

　　(1) Visual inspection: During the inspection, drive at a rope inspection speed of 0.3-0.5m/s. The inspection personnel inspect the steel wire rope and observe whether there are obvious broken wires, wear, rust, necking, etc. on the surface of the steel wire rope. If there are any abnormalities, stop the machine and conduct a detailed inspection;

　　(2) Caliper measuring necking: Measure the diameter of the steel wire rope with a caliper to ensure that the necking is within the specified range. Manual inspection can be divided into the following types:

　　Shift inspection. According to the special equipment regulations of Jinchuan Company, a shift inspection must be carried out on the main hoisting rope every 12 hours (one shift). During the inspection, the driving speed is generally set at 0.3-0.5m/s. Drive one round trip, and the inspector selects an appropriate observation point to observe the main hoisting rope. If any surface abnormality or damage is found, the inspection will be stopped and further checks will be conducted. Generally, only the main hoisting rope is inspected during the shift inspection, and it is not possible to test the way rope and tail rope in time. These inspections are usually postponed to the weekly inspection. In practice, due to heavy tasks, the time for inspecting the steel wire rope is often sacrificed to ensure production time.

　　Weekly inspection. It is carried out once a week, requiring a detailed inspection of all lifting ropes, way ropes, and tail ropes. The inspection method for the main lifting rope is similar to the shift inspection. For the inspection of the way rope, at least two inspectors need to stand on the lifting container and observe whether there are any abnormalities during the operation of the hoist. Additionally, the tail rope also needs to be inspected. In actual operation, due to the limited daily shutdown time for inspection and maintenance in the main shaft of Erkuo Mine being less than 4 hours, it is not possible to inspect all steel wires in time. Therefore, it is usually necessary to use several weeks of inspection time to inspect different steel wires one by one, i.e., this week mainly inspecting the way rope, and next week mainly inspecting the tail rope, etc.

　　Monthly inspection. A thorough inspection of all types of steel wires is carried out monthly, and a record of the inspection is made as a basis for changing ropes. Due to the limitations and uncertainties of manual inspection, in order to ensure the safety of steel wires, it is necessary to adopt the approach of "sacrifice cost for safety" by regularly replacing steel wires. In other words, as long as it reaches a certain time limit, regardless of the condition of steel wire usage, it will be replaced. The replacement cycle is as follows: main shaft first rope: about 2 years after lifting 6 million tons; main shaft way rope: about 2-3 years after replacement; main shaft tail rope: about 3 years after replacement.

　　In addition, if any obvious broken wire or other damage is found on the steel wire rope during the rope cycle, it is generally safe to replace the steel wire rope immediately.

2.2 Problems in regular rope replacement management

　　In recent years, with the implementation of the concept of "building a digital mine" in the second mining area, many advanced management methods and means have been introduced for the monitoring and management of many major equipment. However, the management of steel wire ropes, which can be said to have been consistent for decades, has not changed at all. Under this backward management mode of steel wire ropes, the four major problems of "unreliable, unsafe, inefficient, and uneconomical" management of steel wire ropes have not been solved.

2.2.l If obvious wire breakage or other damage is found on the steel wire rope during the rope pressing cycle, it is generally necessary to replace the steel wire rope immediately for safety reasons.

　　Due to the following main reasons, manual detection is extremely unreliable for the detection of various injuries:

　　Discontinuity: When inspecting steel wire ropes by visual inspection, it is impossible to ensure that the human eye does not leave the inspection at any moment. In fact, when under the pressure of production tasks, it is only possible to conduct a "shift inspection" at a symbolic speed of 2-3m/s (much higher than the specified inspection speed of 0.3-0.5m/s). This kind of manual visual inspection is even more "perfunctory", and the effect can be imagined. The inspection of the guide rope and tail rope is also the same, and the visibility at the bottom of the well is very poor, so the reliability of manual visual inspection is greatly reduced;

　　Incomplete: limited by the line of sight, only one side of the object can be observed, while the other side cannot be seen;

　　Environmental and light effects: In many cases, the visual inspection is affected by poor lighting conditions, and some inspection locations require personnel to stand at a great distance and rely on lights for detection (such as the observation of a problem with the tail rope by pulling the wire hook up to the front). Therefore, visual inspection has significant limitations.

　　In addition, even if the detection is carried out at a speed of 0.3-0.5m/s, the detection personnel are very careful and the light is very good, the manual detection method can only detect some obvious external damage of the steel wire rope, but cannot detect the internal wear, rust, broken wire, especially fatigue and other damages of the steel wire rope.

　　According to the summary of long-term work and relevant data, the main damages of steel wire ropes in use include the following types, and the types of damages that can be detected by manual inspection account for only about 20%. The effectiveness of manual inspection is analyzed in Table 1.

　　This is an analysis diagram of whether the above types of manual detection can be detected.

　　From the above analysis, it can be seen that most damages cannot be detected by manual visual inspection, caliper measurement, and other methods. In fact, among various damages affecting the load-bearing capacity of steel wire ropes, invisible internal damage has a greater impact than external damage.

　　Generally, when internal damage occurs, the external appearance may not necessarily reflect it. However, once the external appearance can be observed, the internal damage may be very serious. According to a study on steel wire ropes conducted by an expert from the former Soviet Union, when the outer steel wires of a steel wire rope break, the undetected internal broken wires are generally 2.5 times as visible as the external ones.

　　Furthermore, all fatigue is invisible to the naked eye, but its harm is precisely the greatest threat to the safety of steel wire ropes. To illustrate this with a simple example, if a piece of iron wire is bent 100 times, it will break. When bent 99 times, the outer surface of the iron wire does not show any significant abnormalities, but in fact, its load-bearing capacity has already been basically lost. At this point, as long as a slight bending force is applied, it will break. Steel wire ropes are constantly subjected to various bending and tensile fatigue during work. Fatigue has the same impact on steel wire ropes as in this example. However, manual detection cannot detect fatigue. In other words, the daily routine manual inspection in the Second Mine District cannot detect the greatest threat to the safety of steel wire ropes.

2.2.2 Unsafe

　　In summary, the current manual inspection methods are extremely unreliable for ensuring the safe operation of steel wire ropes, and therefore there are many major hidden dangers in production.

　　According to the research and analysis of the statistical data of 8,000 steel wire rope laboratories and application sites around the world by the authoritative department of the United States, the conclusion is that more than 12% of the steel wire ropes in use are in a "dangerous or extremely dangerous" state, that is, 10% of the strength loss exceeds 15%, which is in a dangerous state, and another 2% of the steel wire ropes in use have a strength loss of more than 30%, which is in an extremely dangerous state.

　　According to the comprehensive analysis data of the national coal safety production status in 2005, 2004 and 2003 released by the State Administration of Work Safety, in 2005, there were 509 coal transportation and lifting accidents in coal mines nationwide, resulting in 559 deaths; in 2004, there were 556 coal transportation and lifting accidents in coal mines nationwide, resulting in 583 deaths; in 2003, from January to May, there were as many as 215 serious and extraordinarily serious malignant accidents caused by wire rope problems in the national coal system, resulting in 223 deaths, of which the highest death toll was the Wuqi Coal Mine Rope Breaking Accident in Jiaocheng County, Luliang City, Shanxi Province, resulting in 14 deaths and 5 serious injuries.

　　The Second Mine District has also experienced rope breaking accidents or near-accidents in recent years. In April 2004, the #2 tail rope of the #1 machine in the auxiliary shaft hoisting section broke.

　　On the other hand, there is also the possibility of damage to the carrying capacity of steel wire ropes during manufacturing and transportation. Therefore, "new" steel wire ropes do not necessarily equal "good" steel wire ropes. However, due to the lack of means to inspect new steel wire ropes, even if regular rope replacement is adopted, it cannot fully ensure the safe operation of steel wire ropes.

　　Due to limitations in manufacturing processes, materials, and other factors, steel wire ropes are allowed to have a certain degree of unevenness when they are produced. The national standard for the manufacture of steel wire ropes stipulates that the effective metal carrying area can have an allowable error of 5%. The unevenness of the carrying technical area itself will result in unevenness of the carrying capacity. In addition, steel wire ropes may also be corroded or accidentally damaged during transportation and storage, which can affect their carrying capacity. The working conditions of steel wire ropes are complex, often involving uneven loading and impact loading. In particular, the imported ropes used in the Second Mine District are usually stored for a year or even two years before use due to factors such as ordering and transportation. However, the storage period for steel wire ropes is usually not more than six months. Replacing the so-called "new" rope that has been stored for a year or two is actually already a "old" rope that has been corroded and aged with damage.

　　Therefore, even if steel wire ropes are regularly or quantitatively replaced according to regulations, it is impossible to fully ensure their safe use! Many steel wire ropes have not reached the replacement period, but have already experienced rope breaking accidents. According to the incomplete statistics of the book "Detection and Accident Case Analysis of Mine Steel Wire Ropes" (1999, Coal Industry Press), there were more than 17 incidents of new rope breaking accidents in the coal system in Henan Province alone. Steel wire ropes once experience a rope breaking accident, which will inevitably lead to significant hazards, ranging from machinery damage to human casualties.

　　Taking the example of the #2 tail rope breaking accident of #1 machine in the auxiliary shaft hoisting section of Jinchuan Company in April 2004, after the accident, production was stopped for 2 days for equipment repair and mine repair, resulting in direct economic losses of more than 100,000 yuan. Fortunately, the #1 hoist had just been inspected and was in a trial operation at that time, and there were no passengers in the cage. Additionally, the tail rope broke and fell into the shaft without causing damage to other facilities, so the production stoppage lasted only two days.

　　However, whether it is hundreds of thousands or millions of yuan, these economic losses can be measured by numbers, but once there are casualties, the harm caused to the families of the victims by the accident is beyond measurement and cannot be compensated by any amount of money!

2.2.3 inefficiency

　　The efficiency of manual inspection methods is low, wasting a lot of production time. Taking the "shift inspection" in the Second Mine District as an example, the normal running speed of the lifting container during "shift inspection" is generally 0.3-0.5m/s. If each main lifting rope is inspected once per shift, it will take 20 minutes, and there are two shifts every day, which will waste more than 300 hours of valuable production time every year. Based on the current production capacity of 800 tons per hour in the main shaft, this corresponds to a loss of 240,000 tons of production capacity per year, accounting for about 6% of the current total production capacity. The above estimate only calculates "shift inspection", if we also consider "weekly inspection" and "monthly inspection", the loss of efficiency is even more amazing.

　　Moreover, in order to achieve the five-year strategic plan of Jinchuan Company to increase production capacity to 10 million tons by 2010, the Second Mine District plans to complete a production task of 3.45 million tons next year and a target of 3.63 million tons, and a production task of 4.2 million tons in the following year. The lifting capacity is precisely the bottleneck that determines whether the Second Mine District can complete the production targets set by the company for the next two years. Only by further tapping the lifting potential and breaking through the current lifting bottleneck can we complete the production targets set by the company. Increasing detection efficiency and shortening detection time are important aspects of optimizing lifting time and tapping lifting potential. In this sense, the current low efficiency of manual inspection greatly hinders the extraction of lifting potential.

2.2.4 diseconomy

　　Due to the limitations of detection technology and methods that cannot meet practical needs, in order to avoid steel wire rope accidents, the practice of "trading cost for safety" through regular rope replacement has always been adopted. However, this approach has directly led to an increase in the cost of using steel wire ropes.

　　According to relevant research, a large amount of steel wire ropes that are forced to be replaced are wasted. Japanese statistics show that over half of the ropes that are replaced have a strength of 90% or more of the new rope strength, and some are even higher than 100%, indicating that they are still in the running-in period. A survey conducted by the US found that about 70% of the steel wire ropes that were replaced had little or no strength loss.

　　The former Ministry of Coal once conducted a statistical analysis on the use status of mining steel wire ropes, and found that if the status of steel wire ropes is monitored by instruments and properly maintained, at least 12%-20% less steel wire rope can be used each year, saving 20%-30% of foreign exchange for importing steel wire ropes.

　　In addition, the "inefficiency" also manifests in the increased costs caused by the low-efficiency manual inspection, such as labor costs, power consumption, and other material losses during the inspection process. For example, in terms of power consumption alone: with an average shaft depth of 600m, the total power consumption of the hoist is 5500kw, the rope speed during inspection is 0.3m/s, and it takes 66 minutes to hoist one round trip. Therefore, the power consumption for one inspection is about 6000 degrees, and the cost of industrial electricity is 0.6 yuan per degree. The inspection cost for one time is 3600 yuan. The annual inspection power consumption cost is over 2 million yuan.

　　In short, in steel wire rope management, Jinchuan Company has always had the four major problems of "unreliability, insecurity, uneconomical efficiency and low efficiency", which urgently need to use advanced management methods to strengthen the detection of steel wire ropes, assess their load-bearing capacity, safety management, etc., improve the management level of lifting equipment as a whole, ensure the safe operation of steel wire ropes, fully tap potential, and this is the necessity for implementing this project.

3.The significance of implementing this project

　　To improve the management level of steel wire ropes in Jinchuan Company, optimize lifting efficiency, and overcome the four major challenges in steel wire rope management, it is feasible to implement an online remote network monitoring system for steel wire ropes in the Second Mine. Implementing this system will have the following positive impacts:

　　3.1 Replacing outdated management methods with advanced management practices, and promoting the construction of a digital mine

　　Adopting real-time online monitoring systems for steel wire ropes will completely replace outdated management methods that have been used for decades. In terms of management mode, it changes "qualitative management" to "quantitative management"; in terms of detection time, it changes "shutdown detection" to "online monitoring"; in terms of lifting efficiency, it changes "time loss and productivity loss" to "time and cost savings and increased productivity"; in terms of detection methods, it changes "manual detection" to "real-time monitoring"; in terms of safety assurance, it changes "being worried and anxious" to "safe and reliable"; in terms of rope replacement criteria, it changes "experience estimation" to "scientific judgment"; in terms of cost control, it changes "large waste" to "full utilization".

　　In general, in all aspects, it will greatly improve the company's safety management level and take Jinchuan Company a big step forward towards the goal of "building a digital mine".

3.2 Improving detection efficiency and tapping into potential for improvement fully embodies the innovative concept of seeking efficiency from management and reducing consumption from management

　　The implementation of this system will greatly improve the efficiency of steel wire rope testing, optimize lifting time, and unleash lifting potential. It is not only a technological innovation, but also an innovative management philosophy that emphasizes efficiency, cost reduction, and management for greater benefits.

　　Additionally, "inefficiency" is also reflected in the increased costs caused by low-efficiency manual inspections, such as labor costs, power consumption, and other material losses during the inspection process. For example, in terms of power consumption alone: with an average shaft depth of 600m, the total power consumption of the hoist is 5500kw, the rope speed during inspection is 0.3m/s, and it takes 66 minutes to hoist one round trip. Therefore, the power consumption for one inspection is about 6000 degrees, and the cost of industrial electricity is 0.6 yuan per degree. The inspection cost for one time is 3600 yuan. The annual inspection power consumption cost is over 2 million yuan.

　　In short, in steel wire rope management, Jinchuan Company has always had the four major problems of "unreliability, insecurity, uneconomical efficiency and low efficiency", which urgently need to use advanced management methods to strengthen the detection of steel wire ropes, assess their load-bearing capacity, safety management, etc., improve the management level of lifting equipment as a whole, ensure the safe operation of steel wire ropes, fully tap potential, and this is the necessity for implementing this project.

3.The significance of implementing this project

　　To improve the management level of steel wire rope in Jinchuan Company, optimize lifting efficiency, and overcome the four major challenges in steel wire rope management, through demonstration of the feasibility of implementing an online remote network monitoring system for steel wire ropes in the Second Mine, implementing this system will have the following positive significance.

　　3.1 Replacing outdated management methods with advanced management practices and promoting the construction of digital mines

　　The implementation of real-time online monitoring systems for steel wire ropes will completely replace outdated management methods that have been used for decades. In terms of management mode, it changes "qualitative management" to "quantitative management"; in terms of detection time, it changes "shutdown detection" to "online monitoring"; in terms of lifting efficiency, it changes "time loss and productivity loss" to "time and cost savings and increased productivity"; in terms of detection methods, it changes "manual detection" to "real-time monitoring"; in terms of safety assurance, it changes "being worried and anxious" to "safe and reliable"; in terms of rope replacement criteria, it changes "experience estimation" to "scientific judgment"; in terms of cost control, it changes "large waste" to "full utilization".

　　In general, in all aspects, it will greatly improve the company's safety management level and take Jinchuan Company a big step forward towards the goal of "building a digital mine".

　　3.2 Improving detection efficiency and ncentive mechanism potential. Fully embodies the management philosophy innovation of seeking efficiency through management, seeking efficiency through management, and seeking efficiency through management.

　　The implementation of this system will greatly improve detection efficiency, optimize lifting time, and tap potential lifting incentives. This is not only a technological innovation, but also a management philosophy innovation that embodies the idea of seeking efficiency through management.

　　Optimizing lifting time and tapping potential lifting incentives. The implementation of this system will replace the current "shutdown manual detection" with "non-stop monitoring", greatly saving detection time for production, so as to achieve the purpose of optimizing lifting time, tapping potential lifting incentives, and overcoming bottlenecks in lifting capacity. This will bring tremendous economic benefits to the group company and lay the foundation for achieving the group company's 5-year plan for 10 million tons of production capacity in 2010. Even if we only save 1/2 of the detection time (which can theoretically save all steel rope detection time), it will at least increase lifting time by 250-375 hours per year, which can increase production capacity by 20-30 million tons.

　　Increase staff efficiency. The implementation of this system will replace manual detection with automatic monitoring by the system, thus freeing up a large number of manpower resources engaged in steel rope detection and alleviating manpower shortages. The company will use these freed-up manpower resources for direct production, saving labor costs on the whole and improving staff efficiency.

　　Reduce blind waste in rope replacement and save costs. The implementation of this system will enable managers to scientifically and objectively evaluate the load-bearing capacity and remaining life of the monitored steel wire rope, reasonably control the time for rope replacement, avoid blindly replacing the rope when the steel wire rope still has sufficient load-bearing capacity, extend the service life of steel wire rope, and save costs on steel wire rope use.

4 conclusion

　　The implementation of an online monitoring system for steel wire ropes will solve the problems of "reliability", "safety", "economy", and "efficiency", and reduce the hidden dangers of major accidents in steel wire ropes.

　　References:

　　L Testing and Accident Case Analysis of Mine Steel Wire Rope (1999, Coal Industry Press)

　　"On-line Nondestructive Quantitative Method and Judgment Rules for Steel Wire Rope (Cable)". MT/T970-2005