An Investigation into the Permissible Load-Carrying Capacity of Steel Wire Ropes for Hoisting with Special Reference to Deep-Level Winding on the Witwatersrand Goldfields *

Abstract

The aim of the paper is to determine the stresses to which a wire rope is subjected during winding operations, to assess its condition during its operating life, and to correlate its life history with the autographic load-extension diagrams, taken under the statutory periodic tests at the Government Mechanical Laboratory.‡ Theoretical analyses of rope stresses due to different causes are examined in the light of records obtained by decelerometers and cinematographic cameras, and data relating to six hundred ropes, each not less than 1¼ inches in diameter, are analysed statistically. Published reports of British, American, and German investigations are compared and utilized, and the relations of the factor of safety to accident statistics and to the characteristics of the rope are examined. The decrease of the factor of safety with the increase in depth is studied, and the paper concludes by advocating the legalization of a lower factor of safety for deep-level winding, and recommends that this can be best effected by the adoption of the capacity factor method, first proposed by Vaughan.