Update concerning The premature discard of 45 mm ropes operating on a Blair multi-rope rock winder

Driefontein Gold Mine installed four 2500 m long 45 mm diameter round strand ropes on the No. 2 Shaft Blair Multi-Rope (BMR) Rock winder, located southwest of Johannesburg. The rope with eight compacted outer strands and a plastic coated steel core was selected for hoisting of ore in a 2043 m deep vertical shaft. In May 2006, two of the ropes on the one BMR drum had to be discarded due to excessive broken wires in the outer strands detected during routine magnetic testing. These ropes, as a pair, had completed only 35,000 cycles. 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 excessive broken wires in the outer strands. This follow–up paper describes: the history of ropes used on the winder prior to the installation of the round strand ropes; the aspects relating to the use of round strand ropes; the findings of the investigators; and, a detailed discussion of the failure mechanism.

Author(s): J. van Rensburg, R. Rontgen, G. Rebel and B. Schmitz