Cost ranking: a strategic planning tool

摘要

A summary of the systematic steps used to determine economic reserves available for open cut, underground and highwall mining and the optimum delineation between them is provided below.Undertake open cut marginal cost ranking to determine the economics of open cut mining.Undertake an underground marginal cost ranking exercise to determine economic limits of underground mining.Confirm that the remaining reserves are amenable to underground mining and of sufficient extent to support the level of capital investment required.Establish and evaluate which drivers most affect the open cut, underground and highwall mining limits. The cost margin ranks can be re-run to calculate changes to these limits e.g. changes to the revenue stream through price or exchange rate movements may narrow or increase the highwall mining areas.Overlay the graphical results of both cost ranking exercises to highlight: zones which are uneconomic by either open cut or underground systems; the zone of economic overlap, which provides a first pass delineation between open cut and underground.Determine a unit cost for highwall mining and compare this with the cost ranking results.Use the resultant combined cost ranking results to assist in generating the mine designs and resultant production schedules.Analyse the resultant cashflow results using discounted cash flow techniques to determine the economically optimum delineation of reserves between open cut, underground and highwall mining methods.The final delineation between open cut, highwall mining and underground mining will be very site specific, but can be readily determined by adopting the systematic methodology as outlined in this article.