Glossary · Geology
Cut-off grade
The minimum grade at which material is considered ore rather than waste.
Cut-off grade is the threshold concentration of the commodity below which a block of rock is treated as waste rather than ore. It is set by the economics of the operation — mining cost, processing cost, recovery, commodity price — so a higher commodity price typically lowers the cut-off (more material becomes economic) and a lower price raises it. Resource estimates are always reported at a stated cut-off; changing the cut-off changes the tonnes and grade of the resource.