Grade uncertainty in stope design- Improving the optimisation process

Abstract

Decisions in the mining industry are made in the presence of uncertainty whether it is in the form of technical, financial or environmental risk. In recent years, the main focus of uncertainty has been the mineral resource. Methods for assessing and quantifying grade risk in open pit operations has lead to the ability to forecast problems and improve the design and planning process by integrating this risk. This paper successfully implements these risk-based methods in an under- ground stoping environment using data from Kidd Creek Mine, Ontario, Canada. Risk is quantified in terms of the uncertainty a conventional stope design has in contained ore tonnes, grade and economic potential. A mathematical formulation optimising the size, location and number of stopes in the presence of uncertainty is introduced and applied. The implementation of different geostatistical simulation methods to the optimisation formulation is discussed briefly and observations made.