Failure of rockbolts in underground mines in Australia
- 223 Downloads
Over the last 15 years there has been an increasing incidence of failure in rockbolts used in underground mines in Australia. Failures have also been observed in the United Kingdom where Australian Technology rockbolting is also used. Most of the failures in the United Kingdom were found to be initiated by corrosion pits, but in Australia, the fractures were considered likely to be due to stress corrosion cracking (SCC). This paper reports a metallurgical study of 44 failed rockbolts from four different underground mines in Australia. The study confirmed that failure was generally due to SCC and showed that this was usually initiated by bending of the bolts that occurred due to lateral movement of the rock strata. It also showed that many of the failed bolts had very low toughness with Charpy impact values of 4–7 Joules.
Keywordsfracture mines rockbolts stress-corrosion cracking
Unable to display preview. Download preview PDF.
- 1.P. Gray: “Stress Corrosion Cracking of Rockbolts,”Coal 98 Conference, Wollongong, Australia, Feb 1998.Google Scholar
- 2.D.M. Shutter, W. Geary, and P.F. Heyes: “Engineering Performance of Mining Rockbolts,”29th International Conference on Safety in Mines Research Institutes, Szczyrk, Poland, 8–11 Oct 2001.Google Scholar
- 3.A. Crosky, M. Fabjanczyk, P. Gray, B. Hebblewhite, and B. Smith: “Premature Rock Bolt Failure,” ACARP Project C8008 Final Report, Australian Coal Association Research Program, Aug 2002.Google Scholar
- 4.Australian Standard AS1544.2-1989, “Methods for Impact Tests on Metals, Charpy V-Notch,” Standards Australia, 1989.Google Scholar