Target Variables

Your application utilizes the concept of target variable to define optimization constraints wherever they are needed; for example:

Pit Optimizer in “blending” mode uses target variables to formulate blending targets.
Scheduler uses target variables to formulate scheduling targets.

Rates and Ratios

The Rate variable has the form:

V = A*x + B*y + C*z + ..

The Ratio variable has the form:

V = (A*x + B*y + C*z + ̤ )/(D*x + E*y + F*z + ..)

Where A, B, C, D, E, F etc. are user defined coefficients and x, y, z etc. are model variables. The model variable sets may differ depending on the context; for example, they represent mass of non monetary Economic Model fields in Pit Optimizer and Scheduler.

Note: (A*x + B*y + C*z + .. ) is called the Numerator and (D*x + E*y + F*z +..) is called Denominator.

Target and Limits

The purpose of optimization is to optimize an objective keeping the target variables within certain limits or, sometimes, exactly at a target value. You may be required to define one, two or all three of the following parameters, any one of which may vary over time:

Target (Ideal Value)
Lower Limit
Upper Limit

Which parameters are required depends on the context:

Pit Optimizer’s blending: upper and lower limits must be defined.
Scheduler – All three parameters must be defined although only the Target of the target variable chosen as the “primary optimization objective” will actually be used.