Technical challenges of ground support in a northern permafrost environment: 30 years of operational experience at Raglan mine

Authors: Hammoum, S; Dorion, J-F; Germain, P Download Paper

DOI https://doi.org/10.36487/ACG_repo/2625_01

Cite As:
Hammoum, S, Dorion, J-F & Germain, P 2026, 'Technical challenges of ground support in a northern permafrost environment: 30 years of operational experience at Raglan mine', 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. 1-14, https://doi.org/10.36487/ACG_repo/2625_01



Abstract:
Operating underground mines in permafrost conditions presents unique challenges to ground support design, installation, and long-term performance. This paper draws on 30 years of operational experience at Raglan mine, a high-grade nickel-copper operation in northern Quebec, to document the key technical challenges encountered across all 3 tiers of ground support – primary, secondary, and surface – and the practical solutions developed in response. For primary ground support, inflatable Swellex bolts suffered progressive, corrosion-induced, capacity loss driven by brine water exposure and sulphides, culminating in isolated fall-of-ground events. The solution was a full transition to grouted resin rebar. Cold permafrost temperatures introduced new challenges for resin activation, addressed through heated cartridge storage and in situ thermal monitoring. A monthly QAQC protocol was developed to safely extend resin cartridge service life under arctic storage conditions. For secondary ground support, the introduction of the Cabletec drilling and cementation rig required a new grout formulation. General use Portland Cement combined with SikaSet RHE accelerant was identified as the solution, with performance validated through pull-out and end-beam testing across a wide range of mix proportions and ambient temperatures, and from the in situ performance of stopes. For surface support, locally sourced shotcrete aggregate proved unsuitable due to gradation variability. The mix currently in use – MS-D3 Raglan – was developed specifically for site conditions using brine as the mix water and maintains consistent performance across the full operational range of brine concentrations. Together, these case studies provide practical insights into adapting ground support systems for permafrost environments, with relevance to the growing number of mining operations in arctic and subarctic regions.

Keywords: permafrost, ground support, inflatable bolts, resin rebar, cable bolting, shotcrete, corrosion, arctic mining

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