Sormunen, M, Saiang, D & Lapcevic, V 2026, 'Gravity-flow modelling to evaluate caving alternatives for Leveäniemi iron ore mine', 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. 1-17, https://doi.org/10.36487/ACG_repo/2645_103
(https://papers.acg.uwa.edu.au/p/2645_103_Sormunen/)
Abstract: The Leveäniemi open pit operation at Svappavaara, Sweden, is a part of LKAB’s iron ore mining portfolio. The main alternatives for continued mining are expanding the open pit operation followed by later a transition to underground mining using caving methods, or transitioning directly from the current state to underground mining using sublevel caving (SLC) or block caving without further pit expansion. The trade-off between these alternatives is driven by expected tonnage-grade profiles and the capital expenditures required for the associated production infrastructure, both surface and underground. The tonnage-grade profiles are also strongly influenced by the chosen draw strategies. To support comparison of these alternatives, a PGCA gravityflow model (Power Geotechnical Cellular Automata) was developed that can be adapted to the various draw strategies and trade-off scenarios considered in this study. 
The initial SLC flow model was generated from a large number of rings, and a preliminary tonnagegrade profile was produced using basic scheduling dependencies. Alternative draw strategies were then evaluated by adjusting shut-off and draw-call criteria and refining the ring-selection process within an iterative modelling workflow. 
The primary objective of this paper is to identify and recommend a preferred caving alternative for the continued mining at Leveäniemi. The recommendation is based on the resulting tonnage-grade profiles, technical feasibility, strategic considerations of each mining option, and long-term social and economic considerations. Based on the gravity‑flow modelling results and the associated trade‑off analysis, the authors recommend a direct transition from the present state to underground mining. Among the evaluated options, the life of mine (LOM) 30 and LOM 30 crown pillar (CP) scenarios offer the most favourable outcomes, delivering strong caving performance metrics, substantial underground tonnage, and dilution levels comparable to LKAB’s existing SLC operations. These scenarios also provide the potential to extend the life of the Leveäniemi operation significantly, while reducing waste‑rock stripping requirements and minimising surface‑disturbance impacts.

Keywords: LKAB, Leveäniemi mine, underground transition, gravity-flow modelling, PGCA