Uniform Conditioning - UC Model Reports

To access this dialog:

Activate the Estimate ribbon and click Uniform ConditioningSelect the UC Model Reports panel on the left.

The UC Model Reports screen, part of the Uniform Conditioning wizard, is used to apply kriged grade estimates at the panel scale into the model file selected on the Input Data screen.

The inputs to Uniform Conditioning are:

The kriged panel estimate of raw grades (either from a samples file or an input geological model)
The dispersion variance of estimated models
A point anamorphosis (transformation) function
A variogram model

The output from this phase is an updated geological model file containing grade estimates relevant to predefined panel and Selective Mining Unit (SMU) dimensions - this is referred to as the 'Panel Model'. This captures the proportion of the SMU distribution above each cut-off grade. This is done by transforming the panel estimate and cutoff grade to Gaussian units, then calculating the tonnage of the mining units that are above the cutoff but within the target panel. The metal quantity is also calculated above the same cutoff grade.

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The size of each SMU is determined by specifying a number of mining units in the X, Y and Z directions. You also use this screen to define the grade 'bins' for the panel model, using a simple process of defining the minimum grade and size of interval. The grade cutoffs will represent areas of interest for analysis. These could be chosen based on economic or mining parameters (e.g. low, medium, and high grade cutoff values).

You can choose to calculate kriged panel estimates using the input data model (and predefined search volumes located in a Search Volume Parameter File) or to use existing kriged values that are already held within the input model file. If you choose the latter option, you will also need to select the kriged estimate and kriged variance column using the available drop-down lists.

The remainder of the screen is used to define panel size and SMU parameters to prepare for the generation of the panel block model. The SMU size will be based on the deposit type and mining equipment limitations. The panel size should be based on drillhole/sample spacing.

How to Calculate Dispersion Variance

Dispersion variance (Variance of Z*) is an approximation of the variance of estimated block grades.

Using COKRIG or advanced estimation, Dispersion variance can be calculated directly by setting the field “Variance of Z*. This is calculated when field VARZSTR is set in the COKRIG field parameter file.

Dispersion variance can also be calculated from the Kriging Variance, Block Variance (BLOCKVAR) and Lagrange parameter(LAGRANGE); where DISPVAR= BLOCKVAR – VAR + (2*LAGRANGE).

Field Details:

The Panel Block Model Reports screen contains the following fields:

Calculate kriged values: if you wish to calculate kriged panel estimates 'on the fly', you can select this option and a predefined Search Volume Parameter file.

Use kriged values from input model: use kriged values created from a previously kriged model, as found in the Input Model defined on the Input Data screen. You will need to define the Kriged estimate and Dispersion variance data columns.

Panel Size: this read-only section of the screen shows the dimensions in XYZ of the input model parent cell size.

SMUs per panel: enter a value or use the spin buttons to specify the number of SMUs in each of the XYZ directions within each panel. This is used to determine the size of the Selective Mining Unit (SMU)

SMU size: the calculated size in XYZ of the SMUs within each panel.

Define Cutoffs: this section is used to define either:

The number (and by implication, range) of grade intervals to report. Minimum is an editable field that can be used to specify a starting grade from which to create subsequent grade intervals. By default, it is zero. The Maximum value is automatically calculated based on the No. of cutoffs specified, and the size of each Interval. For example, a Minimum setting of '0', an Interval of '2' and No. of cutoffs of '6' will generate a Maximum cutoff grade of '10' (zero is classed as an interval).

To set up cutoffs this way, select the Use fixed cutoffs radio button.
If you have a list of cutoff values in an external file (this file must contain at least one numeric attribute - CUTOFF, and at least one record), you can load it using the Use custom cutoffs option, and selecting an appropriate file.

UC block model: displays the name of the temporary model file created on disk that contains the kriged panel model with dispersion variance data appended.

Create UC block model: generate the panel model on disk when you are happy the parameters you have specified are correct.

UC block model summary: display summary information relating to the generated panel model in the Studio Output window.

View UC block model: load the generated panel model into Studio and display it. You will then have access to the full range of Studio's visualization options to represent the panel model in 2D and/or 3D.