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IMS 1.0

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

Intelligent Mining Software “Solutions” IMS - Model Definitions


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

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Table of Contents

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

WORKING WITH A DEFINITION................................................................................................. 4

Create a New Definition............................................................................................................ 4

Save a Definition......................................................................................................................... 4

Open a Definition........................................................................................................................ 4

Summary of Definitions............................................................................................................ 5

MODEL SETTINGS PROPERTY SHEET......................................................................................6

Main Page...................................................................................................................................... 6

Stratigraphy Page....................................................................................................................... 9

Assays Page................................................................................................................................ 16

MODEL ALGORITHM SETTINGS PROPERTY SHEET..........................................................19

Triangulation Page.................................................................................................................. 20

Inverse (2D And 3D) Page..................................................................................................... 21

Ellipsoidal Page........................................................................................................................ 23

OTHER ALGORITHMS................................................................................................................. 25

Length Weighted Average..................................................................................................... 25

Normal Kriging......................................................................................................................... 25

Log Normal Kriging................................................................................................................. 25

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INTRODUCTION

In IMS, a model is stored in a proprietary binary file that contains a model definition section and a data section. In this manual we consider only the model definition section which is simply a set of parameters relating to a IMS model. These model definitions are used in IMS to identify models, regions, stratigraphic lists, algorithms, and drillhole data files.

The parameters within a model definition include:

A title for output

Base point coordinates

Cell parameters

Algorithms and parameters

Stratigraphic units

Assay / quality lists

Subcrop and barren area plan file names

Trend plan file names

Boundary of interest (region) plan file name

Not all the parameters listed above are required for all definitions. A block model, for example, does not use subcrop, barren area or trend files.

A model definition can be created or modified via the Model Settings property sheet.

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WORKING WITH A DEFINITION

Create a New Definition

IMS provides three ways of accessing the Model Settings property sheet:

1) From the main menu select <File><New><Model…>2) Right click within the required folder in the File Explorer Pane and select <New

Model…>3) Right click in the Loaded Files Pane and select <New Model…>

The Model Settings property sheet appears in all cases with a blank definition. Fill in the parameters as appropriate (see MODEL SETTINGS PROPERTY SHEET).

Save a Definition

When you finish with the Model Settings property sheet simply close it by pressing the <OK> button. If IMS determines that the property sheet was changed in any way then it will prompt you to save those changes (Figure 1).

Figure 1: IMS prompts to save a model definition

Open a Definition

There are two ways of opening a definition:

1. Double click on the definition in the File Explorer Plane2. Drag the definition from the File Explorer Pane to either the 3D Pane or the Loaded File

Pane.

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Summary of Definitions

Right click on a folder in the File Explorer Pane and select <Summary of Model Files>. IMS will display a list of all the definitions in the folder together with a subset of their properties (Figure 2).

Figure 2: A list of all definitions in a folder

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MODEL SETTINGS PROPERTY SHEET

Main Page

Figure 3: Model Settings - Main Page

This page is used to specify the major parameters for a model definition. A model is defined in terms of coordinates, extent and cell sizes. By defining a matrix, it also defines limitation on the area of interest.

The fields on this page are described in the sections that follow.

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File This is the name of the definition and will be used as the filename. Change this name only if you want to store the definition under a different name without creating a new definition.

TitleThis is the definition’s title which is used to identify and describe the definition.

Base pointThis is the lower right-hand (south-east) extremity of the model area before rotation. The model is rotated about this point if a rotation is nominated.

Easting and northing coordinates can be based on any coordinate system, such as AMG or ATM, but should be the same as the system used by the CAD and drillhole data.

The "Datum Elevation" is a convenient elevation far above the highest part of the modelled data so that all plan files and data to be used in the project lies under it. A typical value is 10,000m.

The "Rotation" (in degrees) of the model takes place in the Easting-Northing plane. A positive value rotates the model anti-clockwise about the base point. Rotation enables the model boundaries to more closely approximate an irregularly shaped deposit or allows the model axes to run approximately parallel to the predominant structural features.

CellsThis section specifies the size of a cell and the number of cells in the Easting-Northing plane. The X and Y model dimensions equal the cell size multiplied by the number of cells in the respective directions.

NOTE: A good method of determining the number of model cells required for the model area is to check the extents of the drill data and add 25-50m to those extents (for the purposes of running Lerch-Grossman Pit Optimisation).

Model cells need not be square. Use a smaller cell size in the direction of greatest variation if justified. Smaller cells increase accuracy but also increase computer time and space required for model generation.

There is no limit to the number of cells in the X or Y directions.

Model FrameThis is an optional field used to specify the width of the border (in units of distance) around a model within which drillholes are to be used. It allows you to include in drillhole data that lies outside the model area.

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Plan FileThis is a IMS CAD file that delineates a region within the defined model area. All surfaces outside this region are classed as non-existent (flagged out). The polygon(s) in the CAD file must be closed.

<Model Area File…>This button brings up the Model Area File dialog box (Figure 4).

Figure 4: Parameters for the model area file

The dialog box allows you to write two polygons to a IMS CAD file: a polygon that encompasses the entire model area and a polygon that encompasses the area of the cell at the base point. If an ellipsoid is defined for the model then the polygons representing the ellipsoid are also written.

NOTE: The reference RL is typically the elevation of the top bench of the definition or above the highest RL of any data.

<Algorithms…>This button brings up the Algorithms property sheet.

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Stratigraphy Page

Figure 5: Model Settings - Stratigraphy Page

This page allows you to enter the parameters for all the stratigraphic units in the model. All stratigraphic units in the model must be defined here and must be listed in their order of occurrence from the surface.

A stratigraphic unit is defined differently for laminar and block models as follows:

Laminar modelsA stratigraphic unit is defined as seam names in the model or stratigraphic units of interest when accessing drill data.

Each modelled seam (e.g. coal) generally has an interburden seam name (not modelled) nominated between it and the next modelled seam, even if the modelled seams are adjacent, i.e. the interburden has zero thickness. The exception is when the modelled seam is waste in which case the adjacent seams may be either modelled or not modelled. This convention enables all intervals to be referenced in the model reports.

NOTE: if a seam is not modelled then it can have any suitable name; modelled seams, however, should have the same seam name as specified in the drillhole data file(s).

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Block modelsA stratigraphic unit is defined as bench names reflecting the elevations in the model or as a general sample unit (normally defined as “C1”) when accessing drill data.

Each stratigraphic unit refers to a bench, which is normally named according to the elevation of the top of the bench. Each bench should be the same thickness if the Lerch-Grossman pit optimiser is to be run on the model. The bench thickness is specified when creating the block model.

There are different ways of accessing and editing the stratigraphic names; the most appropriate depends on the function. These are discussed in the following sections.

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Multiple StratigraphiesUse the parameters in this section to add multiple benches below a specified (existing) stratigraphy. Each new stratigraphy name is calculated by adding the increment to the name of the stratigraphy above it. This, obviously, works only if the seam names are numeric values as is the case for block models.

Example: In figure 5 we want to add 23 new seams below the stratigraphy named 530. With an increment of -5 the new seams will be 525, 520, 515, …, 430.

Add Stratigraphic UnitsIf there are no existing stratigraphies then select the <Add...> button to add the first stratigraphy. To add a stratigraphic unit when there are existing stratigraphic units:

1. Select an existing stratigraphy.2. Select the <Add below…> or <Add above…> button to insert a new stratigraphic unit below

or above the selected unit.

Or

1. Right click on an existing stratigraphy.2. Select <Insert Strat (Below)…> or <Insert Strat (Above)…> from the context menu to

insert a new stratigraphic unit below or above the selected unit.

Delete Stratigraphic UnitsTo delete one or more stratigraphic units:

1. Select all the required stratigraphic units.2. Select the <Delete> button.

To delete a single stratigraphy follow the procedure above or:

1. Right click on the stratigraphy2. Select <Delete> from the context menu.

Edit a Stratigraphic UnitTo edit a stratigraphy:

1. Select a stratigraphy.2. Select the <Edit…> button.

Or

1. Right click on a stratigraphy.2. Select <Edit Strat…> from the context menu.

Or simply double click on the desired stratigraphy.

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Stratigraphy Selection<Select all> selects all the stratigraphies in the list.

<Select none> resets the selection so that none of the stratigraphies in the list are selected.

<Reverse> reverses the selection so that all previously selected stratigraphies are unselected and the previously unselected stratigraphies are selected.

The standard Windows™ <SHIFT> click and <CTRL> click are also available. See Windows™ help for more details.

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Stratigraphy Parameters

In addition to a common set of parameters, there are specific parameters that differ between laminar and block models.

A Block Model is simple in its construction in terms of stratigraphic units (though not in terms of the grades) so the benches only require a commodity ("C") classification which tells the system that the benches will carry assays/grades. For those benches that are well above the ore body, a waste classification ("W") is acceptable and this will also reduce the size of the model since no assays are carried for waste benches.

A Laminar Model, on the other hand, has a far more complex stratigraphic definition that encompasses additional parameters such as surface files (Figure 6).

Figure 6: Stratigraphic units for a laminar model

Class of MaterialThe stratigraphy can be classed as:

Ore: Truncated by the seam above and truncates the seams below. A surface file name must be specified for model generation.

Waste: Truncated by the seam above and truncates the seams below. A surface file is not required but can be specified, e.g. "surface seam", toxic material, intrusions, etc.

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Basement: Truncates the seams above. A surface file is required for model generation. This class of material is useful in limiting the extrapolation of overlying seams.

Surface File NameEach modelled seam is generated separately and stored in a separate file. The name specified here is the unique part of the full model file name for the surface being generated. Select the name carefully so as not to overwrite a previously generated surface file which you may want to use again. The seam name is usually used with an extra letter or two to indicate the purpose of the model.

Enter a name here only for seams that are to be modelled (i.e. containing ore). If no surface file name is specified then the seam will not to be modelled so will be a waste unit.

Trend File Name (Optional) The application of a trend in seam generation superimposes the structure defined in the trend file (a IMS CAD file) with respect to the elevations of the modelled seam. Trends are a powerful and flexible modelling tool in laminar modelling.

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Subcrop/Barren Files (Optional)These are IMS CAD files which are used predominantly in laminar modelling and have very little use in block modelling.

Figure 7: Stratigraphic units with subcrop and barren files

Subcrop files contain closed polygons that define the limits of ore for the seam. All material outside the limits is defined as non-existent. The limits may be real or arbitrary. The plan outline can extend outside the model boundary.

Barren files are similar to subcrop files but all material inside the limits is defined as non-existent. This is useful for excluding reserves sterilised by shafts, buildings, etc.

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Assays Page

This page lists all the assays and qualities that are in the model. It also has a direct link to the algorithm manager (see MODEL ALGORITHM SETTINGS PROPERTY SHEET).

The fields on this page are described in the sections that follow.

Add AssayTo add an assay press the <Add…> button and enter the assay properties in the resulting dialog box. The assay properties are:

Figure 8: Adding an assay

Assay NameEnter a new assay name or select one of the assays from the drop down list.

PrecisionThis is the number of decimal places used when grades are reported. It does not affect the actual value stored.

AlgorithmSelect the modelling algorithm from the drop down list.

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Search DistanceThis is the radius from the model cell centre undergoing the algorithmic calculation, within which drillhole data will be included. It is used by all algorithms except “Triangulation” and “Ellipsoidal 3D IDW”.

UseSelect the assay usage from the drop down list. IMS provides the following assay usages (Table 1):

Table 1: Assay usages

Assay Use Definition

Assay A quality (updated by drillhole data or other methods) which is weighted in <Grade Tonnage Reporting> reports by relative density.

Relative Density A quality used to weight assays and calculate tonnages in <Grade Tonnage Reporting>.

Dollar Value A quality used by <Lerch-Grossman Pit Optimisaton>. The value represents the value of a model cell (ore value – cost of mining).

Variance A quality used to store the value generated by the Kriging interpolation algorithm representing the variance of the model cell value from the surrounding drillhole samples.

Primary Material A quality used to weight other model qualities.

E.G. Heavy mineral percent (HM%) with respect to constituent concentrate mineral contents such as ilmenite (ilm%) and zircon (zr%). In a 1tonne block of mineral sands with 10wt%HM, the concentrate represents 80% ilm and 20% zr. <Grade Tonnage Reporting> would report 8%ilm and 2%zr as contents of these minerals in real terms using this weighting.

Minimum Sample Distance

A quality used to store the distance from a model cell centre to the nearest drillhole sample used to calculate the model cell.

Number of Samples

A quality used to store the number of samples used to calculate the value of a model cell.

Weight by Primary

A quality that uses the ‘Primary Material’ defined quality to determine a weighted average in <Grade Tonnage Reporting>.

EG: Constituent concentrate mineral contents such as ilmenite (ilm%) and zircon (zr%) in HM% are reported as % of model cell weight rather than concentrate weight percentages.

RD of Lerch Ore Percent

A quality used to store the relative density of the ‘ore’ in a cell – used for laminar models that have been converted to block models.

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Weighted Sample Distance

A quality that is only used with IDW interpolation algorithms. It is defined as a weighted average sample distance of all samples inside an IDW field of influence from a cell being updated.

Ore Proportion A quality used to store the proportion of ‘ore’ material in a model cell, denoted as a number between 0 and 1 where 0 is no ore and 1 is 100% ore material (for use with IK model conversions). See LNK00000020Selecting the Assays for more information.

NOTE: This is only used by <Lerch-Grossman Pit Optimisaton> and <Grade Tonnage Reporting>.

Lerch dollar value A quality used to store dollar values (revenue, cell value, mining cost, etc.) generated by <Lerch-Grossman Pit Optimisaton>

Lerch Recovery A quality used to store the recovered assay content.

Special MappingIf the assay affects another quality then select that quality from the drop down list.

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MODEL ALGORITHM SETTINGS PROPERTY SHEET

IMS provides the following algorithms for interpolating values for assays and qualities:

1. Triangulation

2. 2D and 3D Inverse Distance

3. Ellipsoidal

All the stratigraphic units use the same algorithm and same set of algorithmic parameters for a nominated assay. Each assay, however, can have its own unique algorithm. If different algorithms or algorithmic parameters are required for a selection of stratigraphic units or assays, then multiple definitions are required.

In addition to the assays and qualities defined for the model there is also a "structure" quality. Here “structure” refers to the elevation and thickness of a seam. It is always included in the list of assays and qualities.

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Triangulation Page

This algorithm triangulates the data points in a surface file and is only used in laminar modelling.

Figure 9: The triangulation algorithm

The extrapolation option only applies to the triangulation method of interpolation. If the modelled parameter (usually "structure", i.e. seam elevations) is extrapolated, cell values are generated beyond the boundaries of available drillhole data, following the slope of the outermost triangle at the location.

The aspect ratio test will determine the extent of extrapolation with the external triangles formed.

Extrapolation is useful but should be treated with caution, and the triangles may require some editing.

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Inverse (2D And 3D) Page

This algorithm uses weighting based on direction.

Figure 10: The inverse (2D and 3D) distance algorithm

The fields on this page are:

Minimum Number of SamplesThis is the minimum number of drillhole samples that lie within the search radius (an assay property specified when defining the assay) from the cell centre before a parameter value is generated for that cell. If this minimum is not satisfied then the cell is "flagged out" for that parameter.

Weighting Factors – Horizontal PlaneThere are sixteen sectors defined in the horizontal plane with the north being the centre of sector one. Sector numbers increase clockwise. All parameters must be specified; use a value of 1.0 in each of the 16 sectors for no weighting. Values between 2.0 and 3.0 are generally appropriate.

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Weighting Factors - Vertical PlaneThese are only used in the 3D algorithm and must be specified even for the 2D case (use a value of 1.0 for no weighting). The values for each three-dimensional direction are the product of the horizontal and vertical sectors that enclose the direction of interest.

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Ellipsoidal Page

This algorithm uses an ellipsoid to limit the search for data.

Figure 11: The ellipsoidal algorithm

The fields on this page are:

Minimum Number of Samples This is the minimum number of drillhole samples that lie within the search radius (an assay property specified when defining the assay) from the cell centre before a parameter value is generated for that cell. If this minimum is not satisfied then the cell is "flagged out" for that parameter.

Weighting FactorThis is the power used to weight samples within the ellipsoidal envelope. This power is applied over all directions within the ellipsoid. Use a power of 2.0 for inverse distance squared weighting.

SizeThis is the size of the ellipsoid in each of the three directions. The radii define the size and shape of the ellipsoidal search envelope which determines the search distance and direction for the inclusion of sample data in a given direction.

The x, y and z directions are related to the easting, northing and elevation as follows:

1. Plan view: x = easting, y = northing, z = elevation.

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2. Section view: x = easting, y = elevation, z = northing.

The search directions used in the ellipsoidal algorithm are shown in Figure 12.

Figure 12: Ellipsoidal search parameters

RotationThis is the orientation of the ellipsoid. It is used to allow for the strike, dip and plunge of the ore body. All rotations are in degrees, clockwise when looking towards the origin from the positive axis. The Z rotation then represents the strike, Y the dip and X the plunge. E.g. an ore body that is plunging at 10 degrees to the north (i.e. deeper at the northern end of the ore body) would have an X rotation of +10 degrees.

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OTHER ALGORITHMS

Length Weighted Average

This algorithm uses a weighting on the length of data and is appropriate for use when doing polygonal grade calculations.

The only parameter required for this algorithm is the search distance which is specified on the assay properties page. For modelling, the search distance refers to the radius from the model cell centre undergoing the algorithmic calculation, within which drillhole data will be included. However, this algorithm is primarily used for grade determinations of polygons, and is not recommended for modelling.

If the search distance is zero, then the algorithm searches to 'infinity' (i.e. it uses all samples on screen). For grade calculations, the search distance is restricted to being within the polygon.

A “C1” definition, specifying the length weighted average algorithm, is recommended for use with polygonal grade calculations.

Normal Kriging

This algorithm uses Kriging when modelling. The parameters are set via the VARIOGRAM EDITOR.

Log Normal Kriging

This algorithm uses logarithmic Kriging when modelling. The parameters are set via the VARIOGRAM EDITOR.

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