The optimal design configuration of an open pit mine is critical in achieving maximum value for stakeholders. In this paper, we focus on how to reduce design uncertainty in mine planning and geotechnical engineering by improving handover processes. Typically, one slope design is provided to mine planning to use for pit optimization and pit design. What is less clear are the assumptions on the project risk profile that the geotechnical team has made. Is the provided design based on what the rock mass can achieve, or based on what the technical team believes is achievable? What are the assumptions made about implementation, and are these reasonable and in line with expectations? Understanding where the design slope angles are relative to the range of possible slope angles defines how aggressive or conservative a design may be.
The risks to a project can be significant if overly steep designs are provided and not achievable. The geotechnical risks taken on a project can be better quantified by considering a range of possible slope angles that may exist and evaluating these using pit optimization software. Understanding the sensitivity of the profitability of the project to the slope angles allows for a range of options to manage geotechnical risk. This paper demonstrates some case studies of how understanding the profitability and tonnage for a range of slope angles can inform how geotechnical risk can be managed.
