Stochastic mine planning-Methods, examples and value in an Uncertain World

Abstract

Conventional approaches to estimating reserves, optimising mine planning and production forecasting result in single, often biased, forecasts. This is largely due to the non-linear propagation of errors in understanding orebodies throughout the chain of mining. A new mine planning paradigm is considered herein, integrating two elements: stochastic simulation and stochastic optimisation. These elements provide an extended mathematical framework that allows modelling and direct integration of orebody uncertainty to mine design, production planning, and valuation of mining projects and operations. This stochastic framework increases the value of production schedules by 25%. Case studies also show that stochastic optimal pit limits: • can be about 15% larger in terms of total tonnage when compared to the conventional optimal pit limits, while • adding about 10% of net present value (NPV) to that reported above for stochastic production scheduling within the conventionally optimal pit limits. Results suggest a potential new contribution to the sustainable utilisation of natural resources.