Grade Targets

Grade targets allow the user to specify a strict grade range, and place penalty multipliers on deviation from the Target.

Different Destinations may have different Grade targets.

Adding Grade Targets for Stockpiles and Crushers

Configure Crusher Grade Target

Specifying Grade Targets

Grade Limits and Grade Targets are explained in the tables below.

Input	Description
Grade Lower Limit	The final weighted average grade cannot be below this value. Individual feed blocks can be lower than the minimum. If multiple destinations are listed, individual destinations can be lower than the minimum.
Grade Upper Limit	The final weighted average grade cannot be above this value. Individual feed blocks can be higher than the maximum. If multiple destinations are listed, individual destinations can be higher than the maximum.

Input

Description

Grade Lower Limit

The final weighted average grade cannot be below this value.

Individual feed blocks can be lower than the minimum.
If multiple destinations are listed, individual destinations can be lower than the minimum.

Grade Upper Limit

The final weighted average grade cannot be above this value.

Individual feed blocks can be higher than the maximum.
If multiple destinations are listed, individual destinations can be higher than the maximum.

Note: Grade Limits applied to Product Specifications > StockpileGradeTarget are the weight average of the material added to the Stockpile over a Period.

To take into account material already present on the stockpile, tick on ‘Is Content of Stockpile”:

Input	Description
Grade Target	The difference between the Actual grade and the Target grade is subject to a penalty multiplier specified by the user. Net grade penalty = \|(Content Deviation Penalty) * (actual grade - target grade) * 100 * (total tonnes)\| The result of this formula is an absolute (always positive) value. If Crusher A and Crusher B have different grade targets, then a single block will incur a different penalty depending on the destination. This penalty is summed with the Cash Flows to determine the reward or cost of blending materials into each destination.
Content Deviation Penalties	The value of the content deviation penalty should be considered relative to other grades, and relative to the Cash Flow values. If the net grade penalty is greater than the crusher cash flow, then the crusher won't feed. If the Fe grade penalty is greater than the Al grade penalty, then the optimiser may blow out Alumina to keep Iron on spec. This is because the penalty of dirtying Al is lower than the penalty of dirtying Fe.

Input

Description

Grade Target

The difference between the Actual grade and the Target grade is subject to a penalty multiplier specified by the user.

Net grade penalty = |(Content Deviation Penalty) * (actual grade - target grade) * 100 * (total tonnes)|

The result of this formula is an absolute (always positive) value.

If Crusher A and Crusher B have different grade targets, then a single block will incur a different penalty depending on the destination. This penalty is summed with the Cash Flows to determine the reward or cost of blending materials into each destination.

Content Deviation Penalties

The value of the content deviation penalty should be considered relative to other grades, and relative to the Cash Flow values.

If the net grade penalty is greater than the crusher cash flow, then the crusher won't feed.
If the Fe grade penalty is greater than the Al grade penalty, then the optimiser may blow out Alumina to keep Iron on spec. This is because the penalty of dirtying Al is lower than the penalty of dirtying Fe.

Fields

Select one or more fields to be used as targets.

Selecting multiple will create separate targets for each.

Input Method and Destinations

Select an option to control how grade targets are created. Separately will create individual targets for each selected destination. Combined will create a single target applied to the selected destinations.

Blend Targets