Calculate the Marginal Cut-Off Grade or the Cut-Over Grade

Source file: how-to-calculate-cut-off-over-strategy.htm

Strategy schedules provide a mechanism for cut-off grade optimisation where blocks are transported to different destinations based on the amount of ore they contain. Cut-off grade optimisation is based around a breakeven point after which a profit can be made. This point is called differently based on the number of processes in the setup:

• Marginal cut-off grade for setups with a single process

• Cut-over grade for setups with more than one process

To calculate the marginal cut-off grade, use the following formula:

where is the processing cost ($ per tonne) of Process 1 and is the direct recovery (%) for cost of Process 1.

For setups with two or more dependent processes, use the following formula to calculate the cut-over grade:

,

where and are the processing costs ($ per tonne) of Process 1 and Process 2 respectively.

Note:  The above formula applies only to the dependent processes (that is, processes with overlapping lithologies).