Optimising paste backfill at the LZ5 plant, LaRonde Complex

Authors: Eloundou Bana, J; Arcila-Gut, S; Beland, F

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DOI https://doi.org/10.36487/ACG_repo/2655_28

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Eloundou Bana, J, Arcila-Gut, S & Beland, F 2026, 'Optimising paste backfill at the LZ5 plant, LaRonde Complex', in AB Fourie, M Horta, M Oliveira & S Wilson (eds), Paste 2026: Proceedings of the 28th International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 1-15, https://doi.org/10.36487/ACG_repo/2655_28

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Abstract:
This paper presents the optimisation process of the paste backfill system at the LZ5 plant of LaRonde Complex, operated by Agnico Eagle Mines in Abitibi-Témiscamingue, Quebec, Canada. In collaboration with Sika Canada, a customised admixture was developed and fully integrated into the plant’s dosing system. Since implementation, several trials have demonstrated significant improvements in performance, overall operating cost and sustainability of the paste backfill. Sill plug fill trials achieved a significant binder reduction of 17–33%, while simultaneously reducing pipeline pressure onsurface by up to 62% and underground by up to 29%. This binder reduction translates to a reduction in global warming potential of up to 348 tonnes CO₂ eq per year, supporting the mine’s efforts to reduce its environmental footprint while reducing over 8% in net annual binder costs. Additionally, the substantial pressure reduction trials allowed an increase in backfill throughput of up to 49% in complex long horizontal pumping areas. During those trials, the pumping pressure observed was lower than those estimated by an engineering pressure simulation model. The admixture demonstrated its efficiency at low dosages, with only 1% by mass of binder addition required to achieve the observed effects even when working with mixes having binder contents as low as 2.2%. This optimisation has provided LaRonde Complex with a cost-effective and scalable solution to backfill remote and previously inaccessible areas. As the mine continues to extend both vertically and horizontally, this advan supports operational continuity and resource recovery, while aligning with cost and environmental objectives.

Keywords: paste backfill, sustainable mining, admixture optimisation, binder reduction, CO₂ emissions reduction, throughput increase

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