Significance of Mobile Machine Damage on Resin-Grouted Bolts
- Proceedings
- EUROCK 2026
- Pages
- 929-934
- Submitted
- 28 January 2026
- Accepted
- 15 June 2026
- Published
- 12 August 2026
Summary
Abstract
Full-column resin-grouted bolts are widely used to provide ground support in underground shallow-depth tabular hard-rock mines. Self-Propelled Mobile Machines (SPMMs) often damage these bolts in narrow reefs, leading to mandatory bolt replacements that halt production and increase costs. This investigation was prompted by the lack of evidence regarding whether such bolts lose structural integrity or post-impact effectiveness. No work has been done to determine the extent of damage that such collisions have on the bolts. Laboratory and field studies were conducted to quantify the damage. The work included bolts that were grouted in suitably prepared steel pipes and embedded in the rock wall of a stope. Subsequently, the bolts were intentionally impacted by Load-Haul-Dump vehicles, driving at normal, accepted speeds. The pipe assemblies of the damaged bolts were retrieved, cut into 100 mm segments and visually examined. Each segment was subjected to push tests to measure bond strength. The results were compared to undamaged control samples. The results show that when the annulus between the bolt and borehole wall was 4.5 mm or less, damage to the resin column did not extend beyond 100 mm in from the rock wall. The bond strength in the subsequent segments remained the same as the control samples. Where the annulus exceeded 4.5 mm, resin degradation extended up to 400 mm, accompanied by poor mixing and gloving, resulting in significant reductions in bond strength. The study concludes that full-column resin-grouted bolts damaged by SPMMs do not require replacement if the annulus is 4.5 mm or less. In contrast, bolts with larger annuli should be replaced due to poor resin mixing.
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References
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