How Ore Grade Is Calculated
Contained Metal = Tonnage x Grade
Recoverable Metal = Contained Metal x Recovery Rate
In-Situ Value = Recoverable Metal x Metal Price
Cutoff Grade = Total Costs / (Metal Price x Recovery)
Understanding Ore Grade
Ore grade measures the concentration of a valuable mineral in rock. For precious metals like gold and silver, grades are expressed in grams per tonne (g/t). For base metals like copper and iron, grades are expressed as a percentage of the ore weight.
The cutoff grade is the minimum grade that can be mined economically, below which the cost of extraction exceeds the value of the metal recovered.