Open Pit Geotechnics: Designing Slopes for a Very Deep Hole

Abstract

For most hard rock surface mining operations, the development of an open pit is required to extract the ore resource. In designing an open pit, the challenge is to develop the most cost-effective pit slopes that can be mined safely. Pit slope designs can be fairly complex, particularly with many open pit depths exceeding 300 m and the deepest open pits exceeding 1,000 m. The process of developing a safe but optimized pit slope angle is the same regardless of the pit scale; however, the greater stress changes and increased highwall exposures associated with deeper pits tend to correlate with an increased risk of instability.