The necessity of 3D analysis for open-pit rock slope stability studies: Theory and practice

Geotechnical models developed during the planning stages of open pit mines are three-dimensional so as to capture spatial variation in lithological, structural, hydrogeological, and geomechanical conditions. Geological that describe lithological structural (faulting folding) characteristics a deposit always 3D. Likewise, boreholes piezometers used develop properties groundwater drilled at offsets across understand lateral vertical characteristics. Yet when geotechnical analysis is completed, often geological, well geometrically complex 3D mine designs for optimizing economic mineral recovery overburden removal simplified two-dimensional sections. In this paper we demonstrate simplification can lead wrong failure mechanism being identified, analysed, and/or conservative factor safety calculated hence an over-estimation slope stability. Through case studies show how methods more suited rock slopes, particularly those with anisotropic material strength, singularities such geological faults present, nonlinear geometry. When same slopes analysed two dimensions, fundamentally incorrect. The further reveal three dimensions not higher than safety.