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IMS 1.0

Produced by W.S. Mart and G. MarkeyFor MineMap Pty Ltd

Intelligent Mining Software “Solutions” IMS - Working With Seams In Laminar

Models

Intelligent Mining Software “Solutions” IMS - Working With Seams In Laminar Models

Copyright © 2013 by William Seldon Mart and Geoff Markey. All rights reserved.

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Table of Contents

INTRODUCTION........................................................................................................3

MODIFYING SEAMS..................................................................................................4

VIEWING AND EDITING SEAMS............................................................................9

APPENDIX A: REQUIRED FILES.........................................................................11

APPENDIX B: CREATING A ‘TOPO’ SURFACE FILE.......................................12

APPENDIX C: OVERTURNED SEAMS/ REVERSE FAULTS...........................13

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INTRODUCTION

A surface file in a laminar model contains matrices representing the roof, floor and assays for one stratigraphic unit and is only used in laminar modelling applications such as coal, heavy minerals, bauxite and alluvial deposits. This document, therefore, uses the word "seam" when referring to stratigraphy.

The facility to modify surface files is useful for deposits such as coal, where very steeply dipping or overturned seams occur. The modelling methods used in building the surface files (via the <Model><Laminar Model Operations...><Building Surface Files...> menu item) may not adequately describe the seam structure so, in such cases, it is necessary to manually edit the generated model.

IMS provides the functionality to alter seam structure, thickness, and assays from either contour plan/ triangulated file of the seam(s), or interactively at the cell level of the model, using the keyboard.

Each cell having an X, Y coordinate, a single elevation and thickness assigned to it, represents the structure within a surface file. Multiple values (repeats) can occur where a seam is overturned or has a reverse fault. In these cases, separate matrices (seam names) must be assigned to the upper, middle and lower portions of the seam where they occur together.

NOTE: The surface files are modified directly on the disk so it is best to make a backup copy of the surface files before running any of the options discussed in this document.

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MODIFYING SEAMS

This option should be used to globally modify the qualities (structural properties such as roof elevation, floor elevation and thickness, or assay values) of a seam related to laminar modelling with respect to an IMS CAD layer and/or basic mathematical formulae incorporated with regional boundary limitations.

To modify a seam:

1. Load a model file by dragging it from the File Explorer Pane to either the 3D View Pane or the Loaded File Pane (Figure 1). If you are going to modify a seam by using a triangulation or a contour string set then load the relevant IMS CAD file too.

Figure 1: Loaded model and CAD file.

2. Select the <Model><Laminar Model Operations><Modify Surface Files...> menu item to display the first page of the “modify surface files” wizard (Figure 2).

3. Choose the name of the required seam.

4. Select the quality that will be modified.

NOTE: Choose the ‘roof and floor’ option to create a zero thickness seam.

5. Select the item that will be used to modify the quality selected in step 4.

a. Using a triangulation

Select the required triangulation from the list of triangulations. The elevation of the triangulation is calculated for each cell centre and this value is used to modify the quality selected in step 4.

IMS only updates the cells with centres inside the triangulation region. For a new surface file, if the triangulation does not cover the entire model area, update the surface file with a constant first to provide a suitable background value.

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Figure 2: Selecting options of modifying

b. Using a contour

Select the required IMS CAD file from the list of CAD files. PIC00000019All strings and polygons in the file are used as contours.

At any given point IMS searches from the location of the point in each of the four cardinal directions (north, south, east and west) until it finds a line segment. The elevation of each of these segments is calculated at the point of intersection and these (up to four) values are combined into a distance weighted average. The final value is used as the elevation of the surface at that point.

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Cells that are not covered by the contour data may be updated if they lie due north, due south, due east or due west of the data. During the four-way search, if even one direction contains a segment, a value is calculated and applied. The contour file, therefore, must contain valid data across the entire model area.

NOTE: Using a contour is slower and less precise than using a triangulation. Additionally, a triangulation has a clearly defined boundary so it can be used to update a portion of the model area.

c. Using a constant

Enter the value of the constant that will be used to update quality selected in step 4.

6. Select the method used to modify the quality selected in step 4 with the value of the item selected in step 5.

7. Press the <Next> button to display the Region page (Figure 3).

Figure 3: Setting the region

8. Select the extents of the model region that will be modified.

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9. Use an additional region by entering the name of an IMS CAD file. All polygons in the file are used as the region. Leave the name of the region file blank to disable the additional region.

10. Press the <Next> button to display the Assays page (Figure 4).

Figure 4: Setting assay values

11. Enter the background values for each assay in the list. These values are assigned to cells that do not get updated during the modelling process.

12. Press the <Finish> button to build the modified seam. IMS will display a summary of the results at the end of the operation (Figure 5).

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Figure 5: Summary of the modification

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VIEWING AND EDITING SEAMS

To view or edit individual cell qualities of surface files:

1. Load a model file by dragging it from the File Explorer Pane to either the 3D View Pane or the Loaded File Pane (Figure 6).

Figure 6: Loaded model file

2. Select the <Model><Laminar model operations><View/ Edit Surface Files...> menu item to display the View/ Edit Surface Files dialog box (Figure 7).

Figure 7: Viewing/ editing surface files

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3. Select the required Seam, Row and Quality from the dropdown lists. The values of the selected quality will be displayed for each column of the selected row.

4. Edit values by clicking on the value cell and entering a new value.

5. Repeat steps 3 and 4 as required saving or rejecting the edited cells when prompted (Figure 8).

Figure 8: Requesting confirmation of editing

6. When all the cells are edited as required press the <Close> button to finish editing.

NOTE

1. Assay values can be flagged out by filling the Cells of Value field with blanks.

2. IMS uses a left handed coordinate system when it refers to the rows and columns of a model. Columns are numbered run from right (east) to left (west) in the model while rows are numbered run from the bottom (south) to the top (north) of the model.

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APPENDIX A: REQUIRED FILES

1. A model definition containing the model and matrix parameters.

2. Surface files for the model are used if present. If a required surface file is not present an empty one is created automatically.

The actual model data need not exist for the Modify Surface Files and View/Edit Surface Files options since IMS is only concerned with the surface files that are used to build the model, but the model definition must exist. The model definition stores a table containing:

i. The seams of interest

ii. The names of seam surface files

iii. The matrix size (dimension and number of cells), and

iv. The number and type of assays

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APPENDIX B: CREATING A ‘TOPO’ SURFACE FILE

The Topo surface is important since it truncates all underlying seams and does not get created from the drillhole data used to construct the seam/ore surface files.

To create a Topo surface:

1. Load the required model by dragging the model from the File Explorer Pane to the File Loaded Pane or the 3D View Pane.

2. Load the triangulated IMS CAD file by dragging the model from the File Explorer Pane to the File Loaded Pane or the 3D View Pane. The CAD file must contain a triangulation that covers the entire model area file,

3. Select the <Model><Laminar Model Operations><Modify Surface Files…> menu item to display the first page of the “modify surface files” wizard (Figure 2).

4. Select the top stratigraphic unit (Surf/Topo/etc).

5. Select the ‘roof and floor’ option. This will create a seam that has the roof and floor at the same elevations. This is a zero thickness seam.

6. Select the ‘triangulation’ option and select the required triangulation from the list.

7. Select the ‘replacing’ option. All values in the surface will be replaced with the value from the triangulation.

8. Press the <Next> button to display the Region page (Figure 3).

9. Select <All Rows> and <All Columns> to include the entire model but leave the Region File blank.

10.Press the <Next> button to display the Assays page (Figure 4).

11.Set the Values of all qualities to zero or any other value. The value is meaningless for zero thickness seams.

12.Press the <Finish> button to modify the selected seam.

13.Weathering zones, topsoil, overburden or similar units that run semi-parallel to the surface can be modified in subsequent runs if required. Keep the roof elevation constant on the surface while adjusting the thickness or floor elevation.

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APPENDIX C: OVERTURNED SEAMS/ REVERSE FAULTS

The surface modelling technique employed by IMS, for a given modelled surface, allows for only one vertical value for each point in the horizontal plane. Consequently, when seams are repeated due to either reverse faulting or being overturned by folding, they cannot be handled using the techiniques discussed elsewhere in this document. The solution in such cases is to use different seam names for each part of a seam that is repeated and to delineate the seams accordingly.

EXAMPLE

For an overturned seam name the seams as follows:

Upper arm of the seam: seam 1A

Overturned portion: seam 1B

Lower arm: seam 1C

Apply sub-crop files to each seam so that their extremities coincide. Reverse faulting is handled similarly but requires only two seam names.

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