Making the Grade

A mineral resource must have a reasonable prospect for eventual economic extraction (‘RPEEE’). A cut-off grade (‘COG’) provides some information regarding the overlap between grade and economics. A COG represents the minimum grade needed to pay-off most* of the costs of mining and processing that material.

With this tool, I help you calculate the COG for various economic scenarios. You supply the assumptions regarding costs, operating parameters, and metal prices and I’ll handle the rest. Be sure the to select the correct units!

*Caution: Using a COG as a proxy for RPEEE is a bit of an oversimplification. First, there is a spatial component to the economics of mining, which goes uncaptured in a COG. Also, there are geometallurgical complications that can trip us up. A COG is a model: it's wrong, but useful.

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