This Crown pillars are essential structural elements for the stability and safety of underground mines, particularly when they separate underground excavations from the surface or an adjacent open pit. At the Fekola gold mine, the transition from open-pit to underground mining of a shallowplugingorebodyled to the formation of a crown pillar with an irregularshape and steep inclination, presenting a particular geomechanical challenge. This study aims to assess the stability of thisatypical crown pillar as part of the plannedmining sequence. The methodology is based on three-dimensional numerical modeling using the Hoek-Brown failure criterion within the MAP3D software. The input parameters were determined from an integrated geotechnical database, including deepborehole logs, laboratory tests (UCS, triaxial, Brazilian), as well as rock mass classification (RMR and Q′). Several mining scenarios, including full extraction and the strategicabandonment of certain sites combined with back filling with cemented rock (CRF), were simulated. The main results show that the complete extraction of all plannedstopes leads to localized instabilities, with safety factors below 1.0. Stability is effectively restored by leaving four stopesunmined, which increases the effective thickness of the pillar and allows for a more favorable stress redistribution. This work confirms the relevance of using advanced 3D numerical modeling, coupled with the Hoek-Brown criterion, for the safe design of complex crown pillars in hybridmining contexts.
