In mining, the cut-off grade is the concentration of mineral "Grade (mining)") that is used to discriminate the mineral from sterile waste. The waste material goes to a landfill "Landfill (garbage)") while the ore goes to the next stage in the processing chain.[1]​ There are several types of cut-off grades as well as ways to calculate them. In general, the calculation of the cut-off grade is made based on economic, geological and operational considerations.[1]​ A corporate cut-off grade policy can cause the cut-off grade to vary during the useful life of a mine.[1]​.

A widely used algorithm to calculate the cut-off grade is that of Lane from 1964.[2]​[1]​.

Formula of the Critical Court Law:[2]​[1]​.

Where γ is the Critical Cut-off Law, m is the mining cost, c is the processing cost, s is the price of the product, r is the cost of sale and y the metallurgical recovery.[1]​ This formula can be simplified by eliminating m once the blocks to be mined have been selected with the complete equation.[2]​.

The delineation of the cut-off grade to identify the mineralized bodies to be extracted can be done in several ways and there is no single correct way.[3]​ In some cases the cut-off grade may be higher for smaller deposits on the periphery of the main deposit given that their exploitation has a higher proportion of associated expenses.[4]​.

The size of underground mines depends directly on the cut-off grade,[5]​ while for open pit mines the cut-off grade has less influence than the selection of optimal cones&action=edit&redlink=1 "Cone (mining) (not yet written)") in their design.[5][6]​.

The critical cut-off grade is that which determines which is the poorest mineral that can be extracted for economic benefit.[2]​.

The volume cut-off law is also sometimes distinguished from the limit cut-off law. One difference is that the first estimates the effects of dilution&action=edit&redlink=1 "Dilution (mining) (not yet written)") in its calculation.[4]​.

In estimating the cut-off grade in polymetallic ores, it is necessary to calculate the price of the extracted material as the sum of the products of the "Grade (mining)") of each mineral times its market price.[7]​.

The implementation of new techniques in mineral processing such as the classification of bulk minerals can allow the reduction of cut-off grades, thus increasing mineral resources and reserves.[8]​[9]​ These cut-off grades impacted by classification can increase the value of a mine, and make viable exploitation projects that were previously discarded.[9]​.

• - Composite of witnesses.

• - Predatory mining.

• - Clearance ratio.