Impact of crosscut spacing on recovery and dilution at Jwaneng underground project

Authors: Fuenzalida, M; Dunn, MJ

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DOI https://doi.org/10.36487/ACG_repo/2645_51

Cite As:
Fuenzalida, M & Dunn, MJ 2026, 'Impact of crosscut spacing on recovery and dilution at Jwaneng underground project', in A van As, D Cumming-Potvin & J Wesseloo (eds), Caving 2026: Proceedings of the Sixth International Conference on Block and Sublevel Caving, Australian Centre for Geomechanics, Perth, pp. 1-15, https://doi.org/10.36487/ACG_repo/2645_51

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Abstract:
Jwaneng mine is transitioning from open pit to underground mining using a combination of blasthole open stoping, sublevel retreat, sublevel caving (SLC) and block caving methods. The orebody comprises three kimberlite pipes (North, Central and South), with the Central pipe being the focus of this study. A 3D numerical caving model was developed to evaluate the influence of crosscut spacing on recovery and dilution within the Central pipe. Three spacings (15, 18 and 21 m) were assessed under a common draw strategy. The model incorporates key geomechanical inputs relevant to SLC performance, including fragmentation characteristics and blast ring behaviour, by constraining material flow within each blasted ring. Model results are presented in terms of both recovery and dilution. As crosscut spacing increases, an evident decrease in global recovery is observed, consistent with decreased overlap of adjacent flow zones. Dilution and recovery trends are also evaluated and compared against published benchmarks from established SLC operations, providing context for the expected performance range for the Jwaneng underground project.

Keywords: sublevel caving, recovery, dilution, numerical modelling, Jwaneng underground

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