A Unified 4D UAV Photogrammetry Methodology for Mine Dump Slope Monitoring, Displacement Analysis and Time Dependent Factor of Safety Evaluation

Abstract

Landslides of mine dump slopes are recognized as high-consequence hazards in surface mining. They occur due to the rapid construction from heterogeneous waste materials, the continuous evolution of their geometry during dumping, and the strong influence of foundation conditions and hydromechanical triggers on stability. Uncrewed aerial vehicles (UAV) photogrammetry has increasingly been adopted for the frequent acquisition of high-resolution 3D representations of dump morphology, enabling safer and more efficient monitoring and engineering assessment. Nevertheless, deformation mapping derived from multitemporal point cloud differencing is commonly treated independently from mechanistic stability analysis, thereby limiting its value for predictive hazard interpretation. In this study, a unified 4D (x,y,z,t) framework is proposed in which multitemporal UAV point cloud comparison is integrated with displacement estimation procedures, together with 3D limit equilibrium and strength reduction numerical modeling for time-dependent factor of safety (FoS), evaluation, and operational warning tier definition. The framework is conceived in a form suitable for software-based implementation and is intended for the direct use of site point clouds and geotechnical parameters. Through further research and targeted programming development, it could be translated into an executable workflow capable of generating outputs such as spatial displacement fields, volumetric change distributions, FoS surfaces, and risk classifications to support proactive dump slope management and hazard mitigation.