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.)