Abstract

Increasing demand for various metals, including gold and silver, has initiated a favorable cycle for mining investors. However, mining projects remain risky due to the significant investments required and project-specific technical factors that are subject to geological uncertainty. Specifically, narrow vein mining suffers from a lack of geometrical freedom in the advance of the excavation; therefore, mine planners must compensate by controlling stockpile and blending and metallurgical process variables. Nonetheless, this lack of geometrical freedom makes it possible to link geological uncertainty to dynamic functioning of the process and ultimately to the net present value and internal rate of return. Discrete rate simulation is an effective approach to dynamic mass balancing, in which geometallurgical relationships can be implemented considering geostatistically variable incoming combinations of andesitic and rhyolitic ore in the case of narrow vein Au-Ag mining. The limited geometrical freedom is conducive to a simple mining sequence, easily implemented within a discrete rate simulation that includes a stochastic representation of the narrow vein orebody based on sequential indicator simulation. The resulting tool uses the apparently disadvantageous geometry of narrow veins and is effective at capturing project-specific metallurgical variables within economic prefeasibility and feasibility studies.