The Unfold Wizard

The Unfold Wizard provides a structured means of unfolding a stratified geological unit using a series of tabs. After specifying an orebody wireframe and samples file containing desurveyed drillhole data, the wizard allows you to divide the wireframe into sections. These are defined by specifying hangingwall and footwall strings, and additional tag strings, if required. The UNFOLD process is then used to transform the X,Y,Z coordinate data associated with the samples into an Unfolded Coordinate System (UCS).

The parameters file produced by the Unfold Wizard can then be specified as an input to the Estimate process, and configured using the Unfolding tab in this process. Variogram analysis is done using the Unfolded Coordinate System, with the parameters of the variogram model calculated in the Unfolded Coordinate System. A model with cells and subcells within the folded stratified unit can then be defined using the world coordinate system.

The Unfold Wizard provides the following advantages:

Ability to model the mineralization in a stratabound deposit more accurately.
Provides better understanding of the mineralization.
True stratigraphic distances between points are calculated.
Experimental variograms are more accurate and easier to model.
More accurate grade estimates and resource/reserve classification.

Folded and Unfolded Distances

The main purpose of unfolding strata is to calculate the stratigraphical distances between points. This is demonstrated in the image below, showing two drillhole samples either side of an anticline. Although the standard geometrical distance between them is a straight line, the distance separating them, from a geological point of view, is a line following the anticline structure. It is this distance, called the stratigraphical or unfolded distance, (shown as a dashed line) that is used in variogram calculation and grade estimation.

Folded Distance: standard geometrical distance between points A and B, calculated from standard orthogonal X, Y, Z axes.
Unfolded Distance: stratigraphical distance between points A and B, calculated from Unfolded Coordinate System (UCS) axes.

The Unfolded Coordinate System (UCS)

This unfolding technique transforms the standard coordinates (orthogonal X,Y,Z axes) of each sample to an Unfolded Coordinate System (UCS). The UCS axes are not straight lines, and are not orthogonal to each other. This is demonstrated in the following example of a folded orebody.

The image below shows four sections through a stratified deposit, showing the strike of an orebody in plan view.

A section of the same deposit is shown below.

The axes of the Unfolded Coordinate System (UCS) are defined using A, B and C coordinates. This is demonstrated with reference to this orebody as follows:

A: across strike (in the hangingwall-footwall direction, perpendicular to the orebody). The UCSA coordinate represents a location on the A axis.
B: down-dip (along the centre line between hangingwall and footwall). The UCSB coordinate represents a location on the B axis.
C: along strike. The UCSC coordinate represents a location on the C axis.

Running the Unfold Wizard

As theUnfold Wizardprovides a step-by-step approach to unfolding and validating a folded orebody, it comprises a series of tabs associated with each phase of the unfolding operation. As each tab is dependent on the proceeding one, they must be completed in order, from left to right. Each tab comprises multiple groups of buttons; when you click Save in a particular group, the next group is activated and all your changes are saved, even if you click Cancel. This allows you to continue running the wizard at a later time, from a particular point. Click Files and Settings to view your progress through the wizard in the Files and Settings dialog.

Define Sections: the groups described below enable you to select the required files, and define the sections of the folded orebody.

User Files and Current Section: allows you to load the wireframe and samples files that are processed by the Unfold Wizard, and specify a parameters file. The parameter file is created when theFinishbutton on theValidatetab (see below) is selected.

The orientation of the view in the3Dwindow can also be defined.
Strike String: create a strike string in the3Dwindow, and save it.
Section Strings: create and save section strings of a specified length (target interval). These can be added and removed, and their orientation and position adjusted using the buttons provided.
Create Section Definitions: define the clipping interval, specify whether the section strings follow the direction of the strike string, and save the section definitions.

HW and FW: the groups described below allow you to view the wireframe sections, create section slice, hangingwall and footwall strings, and create additional tag strings. These strings can then be validated and converted.

Sections: allows you to view each wireframe section in the3D window, and choose whether clipping is used.
Section Slice Strings: create a section slice string in the plane of each section string, around the outside of the wireframe. Section slice strings can also be deleted and saved in this group.
HW End Strings: allows you to automatically create a string that joins the hangingwall end points, edit it and save it. Change the view of the end points using theZoom LeftandZoom Rightbuttons.
HW and FW Strings: create individual hangingwall and footwall strings in the plane of each section string, and save them. Saving the edited strings automatically creates tag strings that mimic the shape of the wireframe.
Additional Tag Strings: allows you to automatically insert a specified number of Within-Section tag strings, as well as manually insert Between-Section and Within-Section tag strings. After saving the tag strings, you must clickValidate and Convert Tagsin order to proceed to the next tab.

Unfold: the groups described below allow you to specify whether quads only, strings or samples are unfolded. Coordinate fields and parameters can also be set before the Unfold operation is run.

Unfold Mode: allows you to specify that quads only, strings or samples are unfolded. Unfold Samples would typically be selected.
Sample Coordinate Fields: select the WCS coordinates from the samples file. If likely coordinate fields are identified, then they are automatically selected in each dropdown list.
Parameters: allows you to specify whetherLink Modeis selected, and define the type of coordinates used for each axis of the Unfolded Coordinate System (UCS). The tolerance, UCSA limit and UCSB origin tag can also be specified. After entering the required parameters, clickUnfold Samplesto run theUnfold process. A dialog is shown to confirm that the Unfold operation ran successfully.

Validate: the group described below allows you to view samples and quads in the World Coordinate System, view samples in the Unfolded Coordinate System, and edit tag strings in theHW and FWtab.

Validate: specify whether to display samples in theWorld Coordinate System, or Unfolded Coordinate System. Samples are shown in the 3D window whenDisplayis clicked.
- IfWorld Coordinate Systemis selected, then you can specify the display of quads, according to their type, as well as samples which were successfully and/or unsuccessfully unfolded.
- IfUnfolded Coordinate Systemis selected, then only samples that were successfully unfolded are shown.

Tag strings can be edited in theHW and FWtab by clickingEdit Strings, and new samples and quads viewed using theValidatetab. Ensure that any changes madein theHW and FWtab are saved,Validate and Convert Tagsis clicked, and theUnfoldoperation is run again before you return to theValidatetab. Click Finish to complete and close the Unfold Wizard.

The following buttons are provided at the bottom of the wizard:

Files and Settings: launches the Files and Settings dialog. This dialog allows you to configure the Unfold Wizard and view the names of the files created.
Prev: shows the previous tab.
Next: shows the next tab.
Finish: only available in the Validate tab. Saves any changes made in the Unfold Wizard, creates the parameter file that you specified in the Define Sections tab, and closes the wizard.
Cancel: cancel the Unfold wizard

	Related Topics
	Defining Sections Create Unfolding Strings Unfolding Samples Validating Results Files and Settings Dialog Estimate Dialog - Unfolding The Unfold process