The lowest grade worth processing — the dial that decides what counts as ore and what counts as waste.
The minimum grade of mineralization that can be economically mined and processed. Material below the cut-off grade is considered waste, while material above it is classified as ore. Cut-off grades depend on mining costs, processing costs, metal prices, and metallurgical recovery rates.
Cut-off grade is the single most powerful lever in a resource statement. Lower it and tonnage rises while average grade falls; raise it and the opposite. Two companies reporting the same deposit at different cut-offs are not comparable.
Cut-off is set from metal price, recovery and processing cost, so it moves with the market. Resource statements should disclose it; if a release quotes ounces without a cut-off, the number is not interpretable.
Comparing grades across companies without checking cut-offs. It is the most common apples-to-oranges error in junior mining.