Nguyen, T, Dempers, G, Seymour, C & Harris, M 2023, 'Using drone photogrammetry to optimise geotechnical analysis through efficient data collection ', in PM Dight (ed.), SSIM 2023: Third International Slope Stability in Mining Conference, Australian Centre for Geomechanics, Perth, pp. 477-490, https://doi.org/10.36487/ACG_repo/2335_31 (https://papers.acg.uwa.edu.au/p/2335_31_Seymour/) Abstract: This paper presents the application of drone photogrammetry to acquire high-resolution data to conduct geotechnical analysis. The application of this technology enables the collection of data with significant time and cost savings when compared to conventional methods. The employment of drones in mapping and pit inspection services yields many advantages. Whether through manual flight or pre-planned flight paths, efficient data collection becomes possible; covering areas that are inaccessible for visual inspection by personnel. Furthermore, the acquisition of high-resolution data through drone photogrammetry enhances the quality and quantity of gathered information. By leveraging the collected photogrammetric data, 3D textured meshes of pit walls can be generated, facilitating the identification and mapping of defects as well as significant large-scale structures. Drone photogrammetry ensures operator safety by enabling geotechnical data collection from secure locations. Operators can remotely gather data without the need for physical mapping, thereby eliminating exposure to potential hazards. Additionally, drones can operate at altitudes that do not interfere with ongoing pit operations, minimising disruptions and sustaining productivity. The methodology employed in drone photogrammetry for open pit mines can be extended to other largescale excavations with restricted access. Inactive quarries, road cuttings and cliff faces are prime examples of scenarios where drone-based geotechnical analysis can prove invaluable, providing detailed information that could not otherwise be obtained. Keywords: drone photogrammetry, open pit, quarry