Critically evaluate techniques for the in situ testing of steel tendon grouting effectiveness as a basis for reducing fall of ground injuries and fatalities

Abstract

The quality of installation and grouting of rock reinforcing tendons is seen as a serious problem by the mining industry. Up to half of all full-column grouted steel tendons or rock bolts installed in South African gold and platinum mines are not effective as they should be, owing to defects such as incomplete grout coverage or incorrect water to cement ratio; or post installation deterioration due to corrosion or rock deformation. This problem is recognised wherever fully grouted rock reinforcement is used, and over the past 20 years a number of research efforts have been made, both in south Africa and overseas to develop a non-destructive test method for assessing grouted tendon effectiveness in situ-with partial success in one case and no success in the others. The aim of this project was to review that work in order to understand the reasons for failure, and then taking into account more recent technology advances, recommend the most promising directions for future development that finally solve the problem