OIPEEC – International Organization for the Study of Ropes

2007 OIPEEC Conference Abstracts-old

How to get the most out of your ropes:
Rope-machine interaction, rope maintenance and lubrication

12 to 14 September 2007
Johannesburg, South Africa

Martin, S. and Hein, N.L. Rope – machine interaction on machine hoists using rope coiling grooves to the LeBus ® pattern, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0803 , 1-13, ISBN: 978-0-9552500-1-9.

This paper investigates various errors that can be encountered in practice due to rope and coiling groove dimensional variations caused by design, manufacture, installation and in-service conditions. The authors mainly cover the effects of these errors on rope coiling and the damage that can be caused to the rope. The groove dimensions, groove pitching and end filler positions and sizes are investigated against varying rope diameters from manufacture and in service changes. For the purpose of discussion and investigation the design is based on the South African code of practice SANS 10294 as is applicable to the performance, operation, testing and maintenance of drum winders relating to rope safety. Although some mining houses have their own internal codes of practice, the authors do not aim to compare the different codes against each other but to use the former as a guide on coiling sleeve design combined with results of rope diameter measurements obtained from eight hoists in the field. The actual measured rope sizes were taken from deep mining double drum and BMR hoists operating with South African manufactured ropes. (2 refs.)

 

Chaplin, C.R., Bradon, J.E. and Ridge, I.M.L. Modelling fatigue damage distribution to inform slip and cut policy for riser tensioner ropes, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0804 , 15-26, ISBN: 978-0-9552500-1-9.

The paper describes a method whereby the distribution of fatigue damage along riser tensioner ropes is calculated, taking account of heave motion, set tension, system geometry, tidal range and rope specification. From these data the distribution of damage along the rope is calculated for a given time period using a Miner’s summation method. This information can then be used to help the operator decide on the length of rope to ‘slip and cut’ whereby a length from the end of the rope is removed and the rope moved through the system from a storage drum such that sections of rope that have already suffered significant fatigue damage are not moved to positions where there is another peak in the distribution. There are two main advantages to be gained by using the fatigue damage model. The first is that it shows the amount of fatigue damage accumulating at different points along the rope, enabling the most highly damaged section to be removed well before failure. The second is that it makes for greater efficiency, as damage can be spread more evenly along the rope over time, avoiding the need to scrap long sections of undamaged rope. (7 refs.)

 

Mostert, S. and Musgrove, P. Winder rope bottom layer (back end) maintenance, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0805 , 27-33, ISBN: 978-0-9552500-1-9.

The purpose of the paper is to describe appropriate maintenance practices for the entire bottom layer on drum winders and in particular the back ends (dead turns). To obtain good rope life it is very important to conduct regular assessments and maintenance. Visual assessments on a regular basis are important as these can identify the first signs of plastic deformation on the crown wires (tram lines). Magnetic rope condition assessments on the day of the back end cut can assist with the decision on the length of rope that needs to be pulled in. Experience over many years has shown that defects develop in this section of the rope and such defects can only be identified and properly assessed when the entire rope is reeled off the drum. The advantage of the back end cut is that it moves the crossover points which have a direct influence on the rope life. (2 refs.)

 

Grimestad, S. and Johansson, B. A method to increase the head rope life of single conveyance friction hoists at hoisting distances up to 2,000 m by reducing the static load range, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0806 , 35-56, ISBN: 978-0-9552500-1-9.

The authors discuss the advantages of reducing the static load range of a single conveyance friction hoist for depths up to 2,000 m. These include: The rope service life for single conveyance friction hoists for deep shafts can be increased, or alternatively the hoisting distance for friction hoists can be increased, by reducing the static load range; the static load range can be reduced by reducing the tail rope mass compared with the head rope mass. This solution can be used for friction hoists with a hoisting distance from about 1,400 m to at least 2,000 m; and, for a single conveyance friction hoist the static load range can be reduced below 11.5 % without exceeding the acceptable margin against rope slip, even if the rope safety factor is as low as 6.0 at hoisting distance S < 1,850 m. (2 refs.)

 

Allner, A. An epic journey into the manufacturing of modern wire rope lubricants with focus on the mining industry, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0807 , 57-72, ISBN: 978-0-9552500-1-9.

This paper takes the end user on an epic journey into the selection of special ingredients used in historic and modern wire rope lubricants, how they are carefully blended into special products and the critical application methodology for rope manufacturers and end users wishing to re-lubricate in service. With a great focus on HSEQ and more especially on moving away from bitumastic / asphalt type lubricants to more modern, safe to use lubricants the author reviews the current market needs both locally and internationally related to the mining industry. Insight into laboratory test methods are shared along with application methods for in-service ropes and rope inspections. (7 refs.)

 

Babendererde, S. and Pusch, J. Managing and lubricating ropes with oil, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0808 , 73-84, ISBN: 978-0-9552500-1-9.

This paper discusses the methods and techniques developed for the purpose of protecting and maintaining these valuable assets through a structured wire rope maintenance programme, which includes the value attained through oil lubrication, the methods of application, rope cleaning with dry ice and compressed air, and the ultimate control and management of the programme. It touches on some results achieved in the past and present, for ropes lubricated with oil.

 

Dieng, L., Urvoy, J.R., Siegert, D., Brevet, P., Perier, V. and Tessier, C. Assessment of lubrication and zinc coating on the high cycle fretting fatigue behaviour of high strength steel wires,Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0809 , 85-97, ISBN: 978-0-9552500-1-9.

The fatigue resistance of spiral strands used in civil engineering structures is related to the inter-wire fretting fatigue conditions. In order to get a better understanding of the damage mechanisms, fretting fatigue tests with durations up to 10 7 cycles were carried out. The testing conditions were representative of the contact conditions in spiral strands undergoing free bending deformations at the anchorage and deflection devices. This paper focuses on the assessment of the effectiveness of lubrication and zinc coating in high cycle fretting fatigue conditions in relation to the partial slip regime with relative amplitude of displacement below 10 µm. The experimental results have shown evidence of a dramatic increase in the fretting fatigue limit which reached about twice the experimental value determined for bright wires. Moreover, contrary to obvious expectation, the monitoring of the tangential contact force during the fretting fatigue tests have not shown any lower amplitude of the friction load values after over 50,000 cycles. Some progress in contact mechanics based on elastoplastic finite element modelling and simulations which take into account the anisotropy of the material are reported. (14 refs.)

 

Briem, U. Torque cycle fatigue of wire ropes, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0810 , 99-106, ISBN: 978-0-9552500-1-9.

Running ropes have a limited service life. Material fatigue is caused by oscillating bending stress as the rope runs over sheaves and by pulsating tension-tension stress during service. Oscillating bending stress and fluctuating tension-tension stress may occur simultaneously too. Depending on the application, one of these forms of loading is predominant. In applications with friction winders and high lifting heights such as occur in the mining industry, the rope opens and closes itself in a cyclic manner while running through the shaft. These torque stresses also lead to material fatigue. Beyond a certain shaft depth material fatigue is caused mainly by the torsional stress. In the paper, torque tests are reported and an equation for describing the expected service life introduced. (5 refs.)

 

Gronau, O. Experiences during the magneto-inductive rope testing under application of LF and LMA sensors, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0811 , 107-114, ISBN: 978-0-9552500-1-9.

Since about 1983 DMT has used sensors with which the reduction of the metallic cross section area (LMA) can be determined along with the classic sensors for detection of local faults (LF). The LMA data not only yields information about losses due to corrosion and/or abrasion; it also provides a means to determine the number of wire breaks at a certain rope position. Several wire breaks close to each other superimpose their stray fields and make an exact conclusion as to their number impossible if using only LF data. The LMA caused by corrosion and/or abrasion leads to a reduced breaking strength of hoisting ropes. However this reduction is not equal to the value indicated by the LMA data. Tests on discarded hoisting ropes have made it possible to develop correlations between the measured LMA data and the loss of the breaking strength. (3 refs.)

 

Quirion, C., Couture, G. and McLaughlin, B. The LaRonde Rope Surveillance System,Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0812 , 115-126, ISBN: 978-0-9552500-1-9.

Agnico-Eagle Mines Limited, LaRonde Division, operates the deepest single-lift shaft in the western hemisphere. The shaft reaches a depth of 2,240 m from the surface. In 2000, two rope monitoring systems were purchased. The first was a Rope Load Monitor (RLM), which measures the rope tension at the sheaves at all times. The second was the Continuous Rope Condition Monitor (CRCM). The CRCM magnetically measures the volume of steel going through a large magnetised head and is expected to detect rope flaws that may lead to rope failure before the next rope inspection. Both systems are the first computerised versions of the systems. The RLM is required to take advantage of the lower rope selection factor available with SABS 0294 and the CRCM, while not mandated, is installed as an insurance policy. The computerised RLM was not a good fit with the technology used at the mine and was soon converted to a Programmable Logic Controller (PLC) system. After converting the RLM system, the regulators requested the CRCM system be made functional. The paper describes the testing and modifications to the CRCM to create the LaRonde SSdC (Système de Surveillance des Câbles in French, or Rope Surveillance System in English.) (4 refs.)

 

Young, A. and Delaney, B. Recent advances in automated visual rope inspection, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0813 , 127-136, ISBN: 978-0-9552500-1-9.

This paper describes recent advances in automated visual rope inspection for double drum and friction winders that provides 360° rope inspection at full speed. In many jurisdictions, daily visual rope inspections are carried out to meet regulatory requirements. These visual inspections are generally done at slow speed in order to give the rope inspector an opportunity to detect possible rope defects. During manual inspection, for safety reasons it is common practice for the mine to suspend muck hoisting activities. The paper describes an automated double drum visual rope inspection system installed at Xstrata Copper Kidd mine in Timmins Canada. It describes how the system was installed, the problems encountered and the benefits the mine expects to achieve as a result of using the system. The paper also points to how the installed technology might be adapted to friction winders.

 

Winter, S., Moll, D. and Wehking, K.-H. Innovative visual rope inspection method for maintenance, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0814 , 137-143, ISBN: 978-0-9552500-1-9.

When in operation for example in aerial ropeways, cranes or mines the ropes run over rollers and are deflected by sheaves. On the one hand the rope is subjected to tensile and bending loads and to torsion, and on the other hand additional stresses occur due to the helix-shaped structure of the rope. Running ropes of ropeway plants, cranes and mines have a finite service life. For this reason safe operation is only possible when the ropes are tested regularly and damage which necessitates the replacement of the rope is recognised reliably and in time before a hazardous operating state is reached. The authors describe the development of a visual inspection tool which simultaneously images a length of rope from fours sides. The data may be stored and reviewed at a later time to allow a thorough inspection and record of the external condition of the rope. (8 refs.)

 

Vorontsov, A., Volokhovsky, V., Halonen, J. and Sunio, J. Prediction of operating time of steel wire ropes using magnetic NDT data, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0815 , 145-154, ISBN: 978-0-9552500-1-9.

A strength assessment model is proposed for predicting the residual working time of wire ropes that have deteriorated. The distributed losses of the metallic sectional area and local wire breaks as measured by a magnetic flux detector are used as input data for the strength evaluation. A residual safety index for the damaged rope is treated as the parameter for the working capacity. The subsequent rope inspection and the corresponding strength state relative to the empirical permissible level are predicted. Examples of the forecasting procedure are presented. (4 refs.)

 

Greyling, P., Rontgen, R., Rebel, G. and Schmitz, B. Premature discard of 45 mm ropes operating on a Blair Multi-Rope rock winder, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0816 , 155-174, ISBN: 978-0-9552500-1-9.

In September 2005, Driefontein Gold Mine, located west of Johannesburg, installed four 2500 m long 45 mm diameter CASAR Duroplast ropes on the No. 2 Shaft electrically coupled Blair Multi‑Rope (BMR) rock winder. This was the first time a rope with eight compacted outer strands and a plastic coated steel core was used by the mine for deep vertical shaft mine hoisting. At the end of May 2006, two of the ropes on one BMR drum had to be discarded due to broken wires in the outer strands at the drum end, detected during routine magnetic testing. These ropes, as a pair, had completed 35,000 cycles (i.e. hoisted 70,000 skips or 604,000 tonnes of rock). The two ropes on the other BMR drum showed no damage at this time. On 20 June 2006 the remaining two ropes were discarded at 38,000 cycles also due to broken wires in the outer strands at the drum end. The average standard rope life previously achieved on the same winder was circa 66,000 cycles. This paper describes the full operating history of the ropes, the lubrication used and the general maintenance practices. A detailed description of the rope failure mechanisms is given including SEM micrographs. Finally, recommendations are made as to how this situation can be avoided in the future. (8 refs.)

 

Dubuisson, J. and Cantin, M. Study on mechanical conditions of the looseness of the outer wires of ropeway haulage ropes, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0817 , 175-193, ISBN: 978-0-9552500-1-9.

In 1991, the haulage rope of the “Aiguille du Midi” ropeway in Chamonix had to be replaced some weeks after it had been put into operation. It could not be used any longer because scattered over several hundreds of metres of rope were dozens of loose outer wires. The replacement rope was subjected to the same phenomena after nine years of operation. The authors report on a study designed to measure and calculate wire stresses in order to try to determine the mechanical conditions causing the looseness of the outer wires of a test rope subjected to tension and torsion. The calculation results showed that the helical outer wires formed into the rope structure are subjected to a bending stress, which corresponds to their straightening, resulting in a compressive force and a linear “back pushing” load. The measurement results showed that a few outer wires have in fact a rather variable behaviour in the rope structure as far as the lowest tensions are concerned and that some of these wires are even subjected to a bending stress greater than the value of the conventional stress to the limit of elasticity. (6 refs.)

 

Kleynhans, J., Kapp, J., Rebel, G. and Schmitz, B. A case study of 54 mm ropes operating on a double drum rock winder, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0818 , 195-205, ISBN: 978-0-9552500-1-9.

In mid November 2004, Lonmin Platinum at their Marikana Operations, northwest of Johannesburg, installed two 1100 m long 54 mm diameter CASAR Turboplast ropes on the Karee No. 3 Main Shaft double drum rock winder. This was the first time a rope with eight compacted outer strands and a plastic coated steel core was used by the mine for vertical shaft mine hoisting. At the time of completion of this paper (June 2007) the ropes had completed 220,000 cycles and hoisted a total of 440,000 skips or 7.0 million tonnes of rock. The most recent magnetic non-destructive test showed that the ropes do not have any broken wires. The current operating life is approximately double the standard triangular strand rope life achieved previously on the same winder. This paper describes the full operating history of the ropes, the lubrication system used and the general maintenance practices. Through collaboration between the mine and the rope manufacturer, it has been possible to safely increase the number of cycles between backends (drum crops) from the standard 10,000 cycles to 30,000 cycles. This change, combined with fewer rope changes, has significantly benefited production efficiency and shaft safety. (4 refs.)

 

Louw, L. Difficulties with long ropes (3,400 m) and new approach on how to extend winder rope life – Twin Shaft BMR rock winder, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0819 , 207-224, ISBN: 978-0-9552500-1-9.

Established methods exist for computing and determining rope life for various hoisting applications in the mining industry. In the late 1980’s an extensive study was done by the CSIR on 99 winder installations and the 711 ropes discarded from these winders. A key driver in budgeting for rope expenditure is the ability to determine an estimated rope life in advance in the absence of rope history. This is critical to eliminate unnecessary spare rope but even more critical to ensure that ropes are available for rope changes when required. During the design and commissioning of winders, careful consideration is given to all aspects pertaining to ensuring and improving rope life. There are on site rope maintenance and care practices that are essential in ensuring that winder ropes reach and exceed their predicted rope life. In the case of the unique Twin Shaft rock winder installation this predicted rope life is still only a calculated time span. The on-site mining team in conjunction with the manufacturer is involved in several initiatives to extend the present rope life. The contents of this paper focus mainly on one of the innovative techniques to ensure that maximum rope life is obtained. (2 refs.)

 

Ridge, I.M.L., O’Hear, N., Verreet, R., Grabandt, O. and Das, C.A. High strength fibre cored steel wire rope for deep hoisting applications, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0820 , 225-240, ISBN: 978-0-9552500-1-9.

The concept of combining high strength fibre with steel to make lightweight ropes for deep shaft hoisting applications is not new. However, until now development of serviceable ropes has been hindered by technological feasibility. This paper reports on the progress in the development of such ropes being made as a joint project between fibre and steel wire rope manufacturers. An important objective in the design of such a “composite” rope is to ensure that fibre and steel elements take a proportional share of the load so that both fibre and steel components are used to their full potential. With these issues in mind, composite ropes have been designed and manufactured. Results are presented for initial strength measurements on ropes which show that a previously unattained strength to mass ratio is achievable. Some preliminary fatigue data is also included. Finally the authors discuss the further work needed before these ropes may be employed in winder installations. (13 refs.)

 

Vogel, W., Schönherr, S. and Wehking, K.-H. Alternative wire material for suspension means used in goods handling and flow systems, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0821 , 241-248, ISBN: 978-0-9552500-1-9.

Alternative materials for suspension means like high strength fibre ropes, belts with steel or fibre cords as well as ropes with stainless steel wires (1.4401 or 1.4436/AS/316) are applied in goods handling and flow systems. For the use of alternative suspension means, safety relevant requirements such as sufficient service life as well as criteria for accurate and reliable discard have to be guaranteed, independent of the material. To date, due to the absence of experience and research, lifetime prediction of stainless steel ropes running over sheaves and drums as well as the dimensioning of rope drives with stainless steel ropes are normally based on the experiences with carbon steel ropes. However, the lifetime of stainless steel ropes under fluctuating tension and fluctuating bending stresses is in some cases smaller than with traditional suspension means by a factor of 3 to 8. This may result in both economic and safety problems. This paper reports experiences with stainless steel ropes in different applications and presents the results of bending fatigue tests with stainless steel ropes. (3 refs.)

 

Voigt, P.-G. Eight-strand ropes for surface mining and rope rotation combined with lay length changes for Koepe hoist winders, Proceedings of the OIPEEC Conference ‘How to get the most out of your ropes’, September 2007, Johannesburg, paper no. ODN 0822 , 249-262, ISBN: 978-0-9552500-1-9.

The first part of this paper describes how the eight-strand rope construction was introduced for draglines with excellent results but also how mistakes in rope design from different suppliers gave poor results; because small differences in rope design and manufacturing can determine whether performance is good or poor. The second half considers self rotation of a rope in a Koepe hoist as the deeper the shaft gets (distance travelled by the cage) the more turns in the rope will show, despite both rope ends being guided and fixed. Depending on the rope construction, the number of self rotations can be higher than 50 turns in one direction and then the same number in the other direction. The ways in which self rotation can be reduced are discussed. (15 refs.)