Whittle 4D Interface

Exporting to Whittle 4D

This section gives information on the following parts of the Whittle 4D interface:

prerequisites
calculate variables
regularise the block model
export model
making a 4D parameter file

Prerequisites

The Whittle 4D model requires that the units of metal (or product) be used rather than grade. This means that some preprocessing is necessary before the model can be dumped. You must compute (using a script) at least the following:

TONS (total tons in the block)
Then for each ore type you must create variable field(s)
xxxxMET (units of metal)
If you have a sub-block model and need to regularise it you will also need
xxxxTONS (tons of ore)

The 4D model must have regular sized blocks (all blocks the same size), so if you have a Vulcan sub-block model, you need to regularise it.

Calculate Variables

This can be performed using a script file. The script file must be run prior to regularising the block model to ensure the correct computation of partial block tonnages. A generic example to calculate contained metal is shown below.

Example - Script File:Metal.bcf

# comment:calculate metal based upon cut-off grade, oxidation and stored tons 
(8-Mar-1999) KAF
if (au_ok ge NNN and au_ok lt NNN and oxidation eq MMM) then
       dpadoxmet = ton * au_ok / 1000
endif
if (au_ok ge NNN and oxidation eq MMM) then
       rpadoxmet = ton * au_ok / 1000
endif
if (au_ok ge NNN and au_ok lt NNN and oxidation ne MMM) then
       dpadsulmet = ton * au_ok / 1000
endif
if (au_ok ge NNN and oxidation ne MMM) then
       millsulmet = ton * au_ok / 1000
endif
end

where NNN = required cut-off limit, MMM = oxidation code.

During the calculations it may be possible to end up with negative metal content. The following script should be used to reset any negative values to zero.

Example: Script File:Reset.bcf

#comment: set negative metals to zero if < 0 (8-Mar-1999, KAF)
if (dpadox lt 0.0) then
       dpadoxmet = 0.0
endif
if (dpadsul lt 0.0) then
       dpadsulmet = 0.0
endif
if (rpadox lt 0.0) then
       rpadoxmet = 0.0
endif
if (millsul lt 0.0) then
       millsulmet = 0.0
endif
end

Regularise the Block Model

The regulariser converts a sub-blocked model into a regular block model. The contents are a merged representation of the sub-blocked model. This operation is carried out through the Block > Transfer > Regularise Model option, which is used to create or edit a block definition file to be used in regularising a block model.

Limitations
To correctly calculate the tonnage and metal content of partial blocks, it is essential that you compute these columns for each ore type, before you regularise the block model.

Export Model

Block -> Whittle 4D -> Export Model

This option performs the export of information from the regularised Vulcan model into the 4D format (model file).

Limitations
The current version of the interface checks whether the model is regular or sub blocked. If it is a regular model, the rock codes must be supplied explicitly. They are not taken from any block model variable. You must set up columns containing both metal content and, optionally, tons of ore in advance. These are then defined as different ore type in the second panel of the interface.

Example

   Code               Units              Tons
   DPOX               dpadoxmet          dpadoxton
   RPOX               rpadoxmet          rpadoxton
   DSUL               dpadsulmet         dpadsulton
   MSUL               millsulmet         millsulton

where Code = name to be used in 4D and must be supplied by you, Units = name of the variable to be used to export the parcels units of product/metal, and can be chosen from a list, Tons = the name of the variable which contains the ore parcel's tonnage for the particular ore type, and can also be chosen from a list.

Making a 4D Parameter File

Block -> Whittle 4D -> Edit Parameters

This option can be used to prepare "skeleton" Parameter File that matches the block model you have exported. The current interface has several panels into which the details required by 4D can be entered. A value must be entered into every empty box before you can move to the next screen. It is recommended that you enter "1" for both Mining and Milling (processing) CAFs (cost adjustment factors), even if you do not intend to use them. You should also enter "0" (zero) for the Threshold Grade and Minimum Cutoff Grade, even if they are not being used. Take care to maintain consistency between the settings in the various panels.

The file produced needs to be updated by 4D for use with Rev 3.02. The simplest method is to load the parameter file into FDED (the parameter file editor in 4D) which can read the old parameter file formats and convert them to the new format. While you have the file open in FDED, you can also add or change any of the settings in the Parameter file. It is also recommended that you use FDED's facility to check the validity of the parameters before saving.

After performing all these steps you are ready to run the 4D program.