http://www.gold.org/investment/why_how_and_where/faqs/#q023The...

http://www.gold.org/investment/why_how_and_where/faqs/#q023


The grade of ore refers to the proportion of gold contained in the ore of a particular mine and is quoted in grams per tonne (g/t). This varies greatly from mine to mine. For example, at a rough estimate, the larger, more efficient South African underground operations may extract ore averaging 8-10g/t) while the other South African underground mines produce grades nearer 4-6g/t. Many of the operations elsewhere in the world are open pit mines, which run at lower grades, from as little as 1g/t up to around 3-4g/t. Perhaps a more significant piece of information for investors than average ore grade is cost per ounce, which is an indicator of both grade quality (grams/tonne) and production cost (USD/tonne).