Topographic deformation and geomorphic instability of mine dump slopes: A UAV-based multi-scale analysis framework

The structural integrity of mine dump slopes within open-pit excavations constitutes a multifaceted geomechanical phenomenon, wherein dynamic interactions between anthropogenic perturbations and intrinsic geomorphological parameters dictate stability thresholds. Catastrophic slope failures have profound repercussions, encompassing occupational hazards, substantial capital losses, and perturbations in extraction continuity. This study employs a hybridized, multimodal analytical paradigm to investigate the spatiotemporal evolution of dump slope stability by integrating unmanned aerial vehicle (UAV)-facilitated photogrammetric reconstruction, multi-scale model-to-model (M3C2) topographic displacement approach, and high-fidelity numerical simulations grounded in the Limit Equilibrium Method (LEM) within a Multi-Modal Optimization (MMO) framework. High-resolution UAV-derived orthophotography, acquired in January 2023, has enabled the generation of dense three-dimensional topographic models. Computational modelling delineated geotechnically compromised zones 1 (FOS = 1.17) and 2 (FOS = 1.11), exhibiting subcritical stability indices. M3C2 differential analysis elucidated pronounced mass displacement phenomena, registering peak translational vectors of 23.77 m and 18.08 m within Zones 1 and 2, respectively, over a four-month temporal window. These slope deformations are predominantly attributable to progressive overburden deposition-induced loading, which is compounded by the destabilizing effects of haul road modifications and decommissioning sequences. The results substantiate the profound interdependence between engineered interventions and slope deformation mechanics, reinforcing the need for real-time geotechnical surveillance and adaptive mitigation strategies. This study advances the discourse on UAV-integrated geospatial analytics as a pivotal instrument for enhancing predictive stability assessments, facilitating pre-emptive risk abatement, and augmenting the resilience of extractive operations within open-pit mining environments.