Calculator
Contained metal
How much metal a resource contains, from tonnage and grade. Contained metal is a geological figure, not a forecast of production.
The formula
Contained metal = tonnage x grade. For g/t, divide by 31.1035 to get troy ounces. For a percentage grade, multiply tonnage by grade divided by 100 to get tonnes of metal.
What it assumes
- Tonnage and grade are taken exactly as you enter them, with no allowance for the confidence category they came from.
- A percentage grade is treated as a mass percentage of the ore.
- Where you enter a recovery, recoverable metal is contained metal multiplied by that recovery.
Where it stops being reliable
- Contained metal is not recoverable metal. Processing never captures all of it, and the shortfall is often substantial.
- It is not economic value either. Mining costs, dilution, mining losses, royalties and the metal price all sit between this number and any revenue.
- Inferred material is a low-confidence estimate. Including it in a contained metal figure makes that figure low-confidence too.