To give board readers an idea of what is considered good grades, here is a chart. You will find other different interpretations on the web, so don’t take this as gospel.

Gold

Open pit:
0–0.5 g/t gold is low grade
0.5–1.5 g/t gold is average grade
Over 1.5 g/t gold is high grade

Underground:
0–5.0 g/t gold is low grade
5.0–8.0 g/t gold is average grade
Over 8.0 g/t gold is high grade
Gold measured in ounces per tonne is “bonanza” grade.

Silver
Open pit:
0–30 g/t silver is low grade
30–150 g/t silver is average grade
Over 150 g/t silver is high grade

Underground:
0–150 g/t silver is low grade
150–350 g/t silver is average grade
Over 350 g/t silver is high grade
Silver measured in kilos per tonne is “bonanza” grade.