Refurbishment: then versus now – pumpable resin systems for enhanced ground support in extremely poor ground conditions

Authors: Pereira, D; Gabriel, J; Wyink, U; Bray, P Download Paper

DOI https://doi.org/10.36487/ACG_repo/2625_42

Cite As:
Pereira, D, Gabriel, J, Wyink, U & Bray, P 2026, 'Refurbishment: then versus now – pumpable resin systems for enhanced ground support in extremely poor ground conditions', in D Cumming-Potvin & J Wesseloo (eds), Ground Support 2026: Proceedings of the 11th International Conference on Ground Support in Mining, Australian Centre for Geomechanics, Perth, pp. 1-13, https://doi.org/10.36487/ACG_repo/2625_42



Abstract:
With increasing mining depth, the in situ stress levels usually increase, inducing greater damage to the rock mass and a higher load on the ground support. This increase often renders previously adequate ground support systems ineffective. Fully encapsulated resin cartridge rebar bolts are among the most widely used reinforcement systems and perform reliably in fair to very good, Q-value > 4, ground conditions. However, their performance becomes inconsistent in poor to exceptionally poor ground, Q-value < 4. This is primarily attributed to over-drilling, resin volumetric losses into fractures and voids, and other installation-related challenges. In addition to technical limitations, operational inefficiencies arise in such conditions. Installation rates decrease due to the need for hole cleaning or re-drilling, while increased bolt density is required to compensate for reduced reliability. This leads to extended ground support cycle times and reduced excavation longevity, often caused by sub-optimal installation quality. Consequently, the frequency of refurbishment increases, resulting in significant costs associated with consumables and production downtime, and in some cases restricting access to valuable ore. An effective alternative for such challenging ground conditions is the use of self-drilling anchor (SDA) systems combined with a pumpable (bulk) resin grout. These systems eliminate issues related to over-drilling and re-drilling by integrating drilling and installation into a single-step process. Furthermore, the low-viscosity resin can penetrate fractures and voids, ensuring effective encapsulation and load transfer. Field applications have demonstrated up to a 60% increase in installation rates, along with near-complete installation reliability. In addition, pumpable resin systems enable a bolts full bearing capacity within minutes, in contrast to the extended curing times required for cementitious grouts used in conventional SDA systems. The performance of pumpable resin systems is highly dependent on the use of appropriately designed installation equipment. Mechanised bolting rigs such as the Epiroc Boltec series are specifically engineered to support high-quality, repeatable installation of self-drilling anchors with pumpable resin. Such equipment integrates automated drilling, resin pumping, and bolt installation into a controlled and standardised process. This ensures consistent resin dosing, proper mixing, and accurate placement, which are critical parameters for achieving reliable encapsulation and load transfer in fractured ground. Moreover, mechanised systems improve operator safety by reducing manual handling and exposure to unsupported ground. They also contribute to higher productivity through optimised cycle times and reduced variability between installations. The combination of suitable equipment and pumpable resin technology therefore represents a system-based approach, where both components are essential to fully realise the performance benefits in poor ground conditions.

Keywords: self-drilling anchors, poor ground conditions, over-drilling, installation reliability, pumpable resin grout, mechanised bolting equipment

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