Scheduling Setup: Quality Constraints

To access this screen:

In the Scheduling Setup screen, select the Quality Constraints tab.

Define constraints for your scheduling scenario that aren't applicable to a particular destination. These are also known as global targets. These targets are defined using target variables.

For example, you can set a global quality target that only applies to a specific combination of rock type, destination and element, such as the g/t target for the transitional mill rock type destination. .

Once the variables are defined, you create one or more global targets, which can be a rate or ratio target.

In summary; a target variable is a rate or ratio of model attributes (rock types, elements) to be kept within specified, possibly time varying, limits over the mine life.

See Target Variables.

To define a quality constraint:

Define your schedule's rock types, destinations and products (elements).
Display the Quality Constraints screen.
Define your target variable context by selecting a rock type Input and Destination.

Variables that consist of only Input and Destination represent the rock mass for this combination of values.

Note: Input lists all ore rock types, stockpiles, external sources, and waste rock types. This is where rock comes from. Destination lists all processing destinations and stockpiles. This is where ore goes to. Waste inputs do not have a destination or element.
To define an input-destination volume constraint, check Volume. Otherwise (to set a non-volume constraint, or any constraint that references an element, uncheck Volume.
Optionally, define a target variable Element (or leave as none to apply the global target to all products).

Variables that consist of Input, Destination and Element represent the contained element mass for the Input/Destination pair. For example:

Example 1: Trans_Mill_ variable is the ore mass from Trans rock type that goes to Mill.

Example 2: Trans_Mill_Au variable is the contained Au mass from Trans rock type that goes to Mill.

This list contains all products, elements, and attributes.

Note: If an element is specified, a volume target cannot be created. If a volume target is required, Element must be none.
If the selected Element is a product; check Recovered if the variable is to represent recovered metal rather than an in situ product (unchecked).

Example: Trans_Mill_Au-R variable is the recovered Au mass from Trans rock type that goes to Mill.
Click Add to generate a new constraint reference using the format Input_Destination_Element.

Note: Once a constraint has an associated Global Target (see below), it cannot be deleted without first deleting the associated targets.
For the input-destination (and optionally -element) constraint, click Add at the bottom of the screen to generate a new Global Target.

The generated target is checked by default, meaning it will be active and considered during scheduling. If a target is unchecked, it is inactive but still reported.

The table on the right updates to show target variable definitions for the defined constraint(s).
On the right, specify a constraint Label to appear in reports and other screens.
Choose the type of target to create; either Rate (either Mtpa or Ktpd, according to the current mining rate definition), or Ratio. See Target Variables.
For each Target variable definition, set the Numerator for the target, that is, the target variable numerator coefficient. Common values are 0, 1, -1 and 100 but any decimal value can be used. For example, if the rate target's variable definition represents the transition of all rock type R1 to stockpile SP1 for element AU, the Numerator is 1 (=100%).
If the constraint relates to a Ratio target, set the Denominator. Common values are 0, 1 and -1.
At this point, it can be useful to review your quality target variable definition. Click Display to show the Display Target Variable popup.
Set the period range for which the target applies by selecting the (inclusive) End Year in the table below.
Define the target variable bounds:
1. For rate targets, set the Minimum or Maximum volume (or both) in mass units.
2. For ratio targets, define the ratio of model attributes in mass units that must be maintained, again as a minimum or maximum (or both).
Save your settings.