Cut-Off Grade - The Impact of Getting it Right!


Gary Poxleitner, SRK Consulting; Joe Rowland, SRK

This paper will first define, at a high level, what a cut-off grade is. It will then delve into the linkage between COG and how it supports, or hinders, attaining your overall corporate objectives.  The importance of fully understanding and defining these objectives should be well understood and communicated before venturing down a cut off grade practice. We will then explore  what goes into a cut off grade calculation and the impact that this has on your reserves base,  mine plan, cashflow and overall sustainability of your operation. Presented will be a summary of what various cut off grade policies and inclusions  are used in the industry (based on a survey of nearly one hundred projects and operations). Finally it will be understood that the selection of a cut-off grade is essentially a trade-off off study exploring a multitude of scenarios that reflects your own project or operations objectives.
Keywords: COG Cut-off Grade, Mine Optimization, best practices, mine reserves, mine resources