Block Model Operations

Intelligent Mining Software “Solutions” IMS - Block Model Operations

Table of Contents

Introduction 4

THE Block Model Operations MENU 5

BuildING Empty Block Models 6

The Elevations Page 6

The Assays Page 8

Generating Cells 9

The Stratigraphies Page 10

The Regions Page 11

The Drillhole Flagging Page 12

The Mapping Page 13

SplitTING CellS 14

Raising the Topography Of a model 15

DILUTING ASSAYS 16

The Region Page 16

The Dilution Page 17

DumpING CELLS as Vertical Drillholes 18

The Stratigraphies Page 19

The Region Page 20

The Assay Ranges Page 21

DumpING CELLS as Horizontal Drillholes 22

The Stratigraphies Page 23

The Region Page 24

The Assay Ranges Page 25

AdjustING Cells With a Constant 26

The Region Page 26

The Update Method Page 27

Mining Cells 29

Introduction

Block models are created and manipulated via several menu items. In particular:

i) The assay and quality values can be updated (<Model<Updating>) or generated (<Model<Block Model Operations<Generate Cells>).

ii) External data can be imported into the model (<Model<Import/Export Cells> <Import>).

iii) The model can be exported (<Model<Import/Export Cells<Export).

iv) A model can undergo further examination using <Model<Grade Tonnage Reporting> where volumes, tonnes and average qualities can be calculated en masse or using plan files.These plan files can contain contours and triangulated surfaces, regions or pit design files created in IMS.

v) The statistically built model can be reviewed using the 3D Lerch's-Grossmann algorithm for final pit optimisation under nominated economic parameters.

vi) The model can be exported as an IMS drillhole file.This quasi drillhole file can be used interactively within IMS.

vii) Section or plan file plots of the values inserted into the model can be produced using <Tools<Section View Publisher> and <Tools< Plan View Publisher>.

A block model can be created only if a model definition already exists. This definition identifies the parameters with which the model is formed (see the MODEL DEFINITIONS manual).

THE Block Model Operations MENU

1. Load the required model definition, drillhole and CAD files into the 3D View Pane.

2. Select the <Model<Block Model Operations> menu item to display a sub-menu containing the available operations (Figure 1).

Items in the sub-menu are enabled if all the necessary files are loaded. In particular:

a. <Build Empty Block Model…>, <Raise Topography…>, <Dilute Assays…>, <Dump As Vertical Drillholes…> and <Dump As Horizontal Drillholes…> only require a model definition.

b. All remaining operations except for <Generate Cells…> are enabled if the loaded model definition has model data attached.

c. <Generate Cells…> requires a model definition, an IMS drillhole file and a CAD layer containing a wireframe.

Figure 1 : Block Model Operations menu

BuildING Empty Block Models

Select the <Model<Block Model Operation<Build Empty Block Model…> menu item to display the first page of the Empty Block Model wizard.

The Elevations Page

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Figure 2: Elevations property page

This page allows you to enter the elevations of the roof of each stratigraphic unit specified in the model definition. IMS makes an initial guess at these elevations by inspecting the stratigraphy names. Make corrections as required by typing the correct elevation.

If none of the elevations are correct then you can manually enter all the values or use the automatic features presented on the page. To use the automatic features fill in the parameters in the Automatic Fill section as follows:

1. Enter the elevation of the first stratigraphic unit in the list.

2. Enter the thickness of the stratigraphic unit.

3. Press the fill button.

NOTE: Lerch-Grossman pit optimisation requires that all benches in the model have the same thickness.

The Assays Page

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Figure 3: Assays property page

Enter the background value for the assays in the list or leave blank as required. The background value is most commonly used to identify waste or low-grade areas of the model. If background value is blank then they will be flagged out and reported as non-existing.This can be useful to export assay values and stratigraphic units from one model and import those values into another model.

HINT: To define waste material in the model, use negative background values such as -1.

Generating Cells

This is the main method used to generate the assays and qualities defined in the block model. It allows you to update a block model within a wire frame. A grade value is calculated (using the drillhole data and algorithm selected for the model) and stored for each model cell that is inside the wire frame.

To generate cells:

1. Load a block model (not just a definition), an IMS CAD layer containing a wireframe and a drillhole file.

Select the <Model<Block Model Operation<Generate Cells…> menu item to display the first page of the Generate Cells wizard.

The Stratigraphies Page

Figure 4: Selecting stratigraphies

1. Select all the required stratigraphic units from the list.

2. Use the buttons on the right hand side of the list for quick selections of ore, etc. For example, if you want to select everything but stratigraphy 520 then:

Press the <Select None> button to clear the list.
Select stratigraphy 520.
Press the <Reverse> button to reverse the selection.

The Regions Page

Figure 5: Selecting solids for delimiting drillholes and cells.

1. Select the solid to delimit the model cells. Only model cells in this solid are considered.

2. Select the solid to delimit the drillhole samples. Only samples in this solid are considered. This solid can be the same as the solid delimiting the model cells.

The Drillhole Flagging Page

Figure 6: Flagging drillholes.

Drillholes can be flagged and written to another file so that you can determine which samples were in the wireframe and which were outside. To flag drillholes:

1. Enter the name of the output drillhole file.

2. Select the required flagging check boxes.

3. Enter the name that will be written to stratigraphic units that are inside the wireframe or leave blank if you do not want to flag them.

4. Enter the name that will be written to stratigraphic units that are outside the wireframe or leave blank if you do not want to flag them.

The Mapping Page

Figure 7: Mapping assays.

The assays in the model must be mapped to their equivalents in the drillhole data. IMS makes an initial guess at this mapping based on the names of the assays. Correct any incorrect guesses by dragging assays to the correct position as follows:

1. Drag incorrect assays off the model assays list and drop them in the drillhole assays list. If all the guesses are incorrect then press Ignore All to remove all the maps.

2. Drag assays from the drillhole assays list and drop them on the correct model assays.

3. Click on <Auto Map> to instruct IMS to guess again.

SplitTING CellS

This option splits each cell in the loaded model to create smaller cells and writes those cells to a new file. The loaded model remains unchanged.

To split cells:

1. Load a block model (not just a definition).

Select the <Model<Block Model Operation<Split Cells…> menu item to display the Split Model Cells dialog box.

Figure 8: Splitting model cells

Enter the name of the new model file.

Select the number of splits for each cell.

Raising the Topography Of a model

This option resets the areas of model surfaces that that have been mined off. This is useful for volume reporting.

To raise the topography of a model:

1. Load a block model (not just a definition).

Select the <Model<Block Model Operation<Raise Topography…> menu item to display the Model Region dialog box.

Figure 9: Defining the region of interest.

Enter the starting and ending rows and columns to define the region of interest in the model.

If a CAD layer is loaded then you can further restrict the cells to those that are inside a solid in that CAD layer.

DILUTING ASSAYS

This option modifies the values of assays in a cell by diluting the values with a proportion of the values in adjacent cells which are within given extents. The cell size of the model does not change so the number of ore and waste cells remains constant.

To dilute assays:

1. Load a block model (not just a definition).

Select the <Model<Block Model Operation< Dilute Assays …> menu item to display the first page of the assay dilution wizard.

The Region Page

Figure 10: Defining the region of interest for assay dilution.

Enter the starting and ending rows and columns to define the region of interest in the model.

IMS models use a local coordinate system such that column one is at the right hand edge and the columns increase to the left. This is important in the determination of cell positions (column and row numbers) and their respective coordinates.

If a CAD layer is loaded then you can further restrict the cells to those that are inside a solid in that CAD layer.

NOTE: IMS models use a local coordinate system such that column one is at the right hand edge and the columns increase to the left. This is important in the determination of cell positions (column and row numbers) and their respective coordinates.

The Dilution Page

Figure 11: The assay dilution parameters.

1. PIC0000003AEnter the name of an output model file.

2. Enter the dilution extents in the easting/northing plane and the elevation axis.

3. Select the assays that you want to dilute.

4. Enter a value for negative assays or leave it blank to use the negative values as is.

DumpING CELLS as Vertical Drillholes

This option exports the model as quasi drillhole data to an IMS drillhole file. All the cells located at each row and column, are treated as vertical drillhole samples with a sample spacing that is the same as the cell dimensions.

The drillhole collar coordinates at each row and column are derived as follows:

1. The xy-coordinates are the coordinates of the row and column.

2. The z-coordinate is the elevation of the roof of the first selected stratigraphy at the row and column (Figure 12).

Drillhole samples take the values of the cells and the centre of the sample corresponds to the centre of the cell.

To dump cells as vertical drillholes:

1. Load a block model (not just a definition).

Select the <Model<Block Model OperationsDump As Vertical Drillholes…> menu item to display the first page of the export wizard.

The Stratigraphies Page

Figure 12: Selecting stratigraphies for dumping cells as vertical drillholes.

1. Select all the required stratigraphic units from the list.

2. Use the buttons on the right hand side of the list for quick selections of ore, etc. For example, if you want to select everything but stratigraphy 520 then:

Press the <Select None> button to clear the list.
Select stratigraphy 520.
Press the <Reverse> button to reverse the selection.

The Region Page

Figure 13: Selecting the region of interest for dump cells as vertical drillholes.

Enter the starting and ending rows and columns to define the region of interest in the model.

If a CAD layer is loaded then you can further restrict the cells to those that are inside a solid in that CAD layer.

The Assay Ranges Page

Figure 14: Specifying assay ranges.

1. Enter the name of the drillhole file that will contain the vertical drillholes.

2. Enter the minimum value for each assay in the model or leave the value blank. If a value is specified then assay values that fall below this value will be flagged out.

To exclude a particular assay from the drillhole file simply set its minimum value to a large number (e.g. 999 if assay is reported as ppb, g/t etc.).

3. If samples should be excluded instead of being flagged out then select the check box.

DumpING CELLS as Horizontal Drillholes

This option exports the model as quasi drillhole data to an IMS drillhole file. All the cells in each row are treated as horizontal drillhole samples with a sample spacing that is the same as the cell dimensions.

The drillhole collar coordinates at each row are derived as follows:

3. The xy-coordinates are the coordinates of the row and column one.

4. The z-coordinate is the elevation of the roof of the first selected stratigraphy at the row and column one (Figure 15).

Drillhole samples take the values of the cells and the centre of the sample corresponds to the centre of the cell.

To dump cells as horizontal drillholes:

1. Load a block model (not just a definition).

2. Select the <Model<Block Model OperationsDump As Horizontal Drillholes…> menu item to display the first page of the export wizard.

The Stratigraphies Page

Figure 15: Selecting stratigraphies for dumping cells as horizontal drillholes.

1. Select all the required stratigraphic units from the list.

2. Use the buttons on the right hand side of the list for quick selections of ore, etc. For example, if you want to select everything but stratigraphy 520 then:

Press the <Select None> button to clear the list.
Select stratigraphy 520.
Press the <Reverse> button to reverse the selection.

The Region Page