Delayed Recovery

To access this screen:

Display the Processing Costs screen.
Sselect a product tab.
Click Delayed Recovery.

Recovery of ore over multiple years may affect the value of each mined block as a compound discounting rate is applied. This panel is used to enter the % recovery of material over successive years, to a sum of 100% for all years.

For example, if 67% of a block is recovered in year 1, but subsequently smaller proportions in later years after extraction, the recovery percentage may be discounted successively on the premise that 100% of the block will not be recovered.

The Delayed Recovery panel is used to specify a 'recovery curve', that is, for each year after extraction and prior to total possible recovery, what is the actual discounted recovery % for each year of recovery when the specified Discount Rate (defined in your Optimization Settings) is applied.

Continuing the example, above, if a 10% Discount Rate has been defined, in the first year, 67% of material is recovered. In year 1, no Discount Rate (10%) is applied, so the Discount Factor is 1. As such, the Discounted % Recovery is 67 x 1 = 67.000.

In year 2, however, the 10% Discount Rate must be applied, and in the second year 17% of the remaining material is recovered. As such, the Discount Factor for year 2 is 0.909 because 0.909 + (12% of 0.909) = 0.9999 (effectively, 1).

To recover 100% of the material over 5 years with a 10% discount rate, for example, could be:

Note the total discounted recovery percentage is 95.090, which is a sum of the discounted rates for all recovery years. The Equivalent Discount Factor then, to be used in recovery formulae, is 0.951.