Surpac Block_Modelling Tutorial

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BLOCK MODELLING _______________________________________________________________

FILES USED................................................................................................................................................. 3

DISCUSSION................................................................................................................................................ 3 FLOWCHART FOR SIMPLE USE OF BLOCK MODELLING............................................................................... 4

Model Space.......................................................................................................................................... 5 User Block Size ..................................................................................................................................... 5 Sub-blocking ......................................................................................................................................... 5 None...................................................................................................................................................... 5 Standard Sub blocking .......................................................................................................................... 5 Variable Sub Blocking .......................................................................................................................... 6 Attributes............................................................................................................................................... 6 Constraints............................................................................................................................................ 6 Sub-celled Block Model ........................................................................................................................ 6

BLOCKS AND ATTRIBUTES ................................................................................................................... 8 CONSTRAINTS ........................................................................................................................................... 9 ESTIMATION............................................................................................................................................ 10 ANISOTROPY ELLIPSOID PARAMETERS........................................................................................ 11 CREATING BLOCK MODEL ................................................................................................................. 14 CREATING MODEL ATTRIBUTES...................................................................................................... 21 CONSTRAINTS WITHIN A BLOCK MODEL ..................................................................................... 24 FILLING THE BLOCK MODEL ............................................................................................................ 25 ASSIGN VALUE ........................................................................................................................................ 26 INVERSE DISTANCE............................................................................................................................... 27 BLOCK MODEL REPORTING .............................................................................................................. 33 CALCULATED ATTRIBUTES ............................................................................................................... 37 PARTIAL PERCENTAGE REPORTING .............................................................................................. 39 MODEL RE_BLOCKING ........................................................................................................................ 45 BASIC ACTIVITY..................................................................................................................................... 48

1. Add the attribute gold_nn to the block model............................................................................. 50 2. Add the attribute sg to the block model. ..................................................................................... 50 3. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.5 to all blocks below the topography topo1.dtm. ................................................................................................... 50 4. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.9 to all block in the solid ore body ore1.dtm. ....................................................................................................... 51 4. Fill the gold_nn attribute with Nearest Neighbour estimation method................................. 52 6. Create a Block Model Report and report the following:................................................................. 55 Average weighted gold grade.................................................................................................... 55 Average weighted specific gravity............................................................................................. 55 Tonnage (multiplication factor = sg) ........................................................................................ 55 Organized by bench (0,250,10) ................................................................................................. 55 Choose one of the available formats (.csv; .not; .htm; .rtf; .pdf)............................................... 55 Constrain the report to all block within the solid ore1.dtm. ................................................. 55

www.cadfamily.com EMail:[email protected] document is for study only,if tort to your rights,please inform us,we will delete

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ADVANCED BLOCK MODELLING TUTORIAL ............................................................................... 58 1. Open the database DB1.DDB and display the drill holes determine extents and become familiar with the dataset. .................................................................................................................... 61 2. Create an empty block model, ensuring to cover the area required totally. ................................... 62 3. Export the centroid points to a string file and validate the model area.......................................... 63 4. Create a graphical constraint of the qpy1.dtm & bif1.dtm and validate the user block size of your new block model.................................................................................................................................. 64 5. Add the attribute gold to the block model................................................................................... 66 6. Add the attribute sg to the block model. ..................................................................................... 66 7. Add the attribute gold_cut to the block model. ........................................................................... 66 8. Add the attribute orecat to the block model................................................................................ 67 9. Create and save a constraint file for: ............................................................................................. 68 Inside qpy1.dtm save as qpy1.con ............................................................................................ 68 Inside bif1.dtm save as bif1.con .............................................................................................. 68 Inside sand1.dtm save as sand1.con......................................................................................... 68 Combination of all above save as qpy_bif_sand.con................................................................. 68 10. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 0.00 to all blocks above the topography topo1.dtm. ........................................................................................ 69 11. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 1.68 to all blocks below the topography topo1.dtm and above weath_ew1.dtm.......................................... 70 12. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.11 to all blocks below weath_ew1.dtm and above weath_fresh.dtm. ....................................................... 70 13. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.46 to all blocks below weath_fresh.dtm. ...................................................................................................... 70 14. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.9 to all blocks in the ore solid bif1.dtm.................................................................................................................. 70 15. Remove all graphical constraints and then constrain the block model below the topo1.dtm. ...... 71 16. Fill the Gold attribute with the Inverse Distance2 estimation method ..................................... 72 17. Create a Block Model and Report the following:.......................................................................... 78 Average weighted gold grade.................................................................................................... 78 Average weighted specific gravity............................................................................................. 78 Tonnage (multiplication factor = SG) ....................................................................................... 78 Organized by bench (800,1000,10) ........................................................................................... 78 Choose one of the available formats (.csv; .not; .htm; .rtf; .pdf)............................................... 78 Constraints: Inside ore 3DM (bif1.dtm, qpy1.dtm,sand.dtm) .................................................... 78


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BLOCK MODELLING

OBJECTIVES To become familiar with Surpacs Block Modelling module and the concept of

block modelling. To learn to fill a block model from drillhole data from the geological database. To learn to constrain a block model to filter out specific blocks. To learn to report volume, tonnage, & grade from a block model.

FILES USED Files used in this lab exercise are found in the following folder:

C:\GEOLOGY|BLOCKMODEL\DATA C:\GEOLOGY|BLOCKMODEL\ADVANCED_BM (for the advanced tutorial)

DISCUSSION

The Block Model is a form of spatially-referenced database that provides a means for modelling a 3-D body from point and interval data such as drillhole sample data, however it is interpolated values rather than true measurements.It is a method of estimating volume, tonnage, and average grade of a 3-D body from sparse drill data.

Previous history of block model had limitations to the block size and the resolution was restricted to 512 blocks. Ver 5, the block model now has no limitations and is restricted only by your computer hardware.

A Block Model consists of cells of a specified size which at the core of the block centre contain a a centroid at which all the data is stored in an attribute ie. Grade, sg, rock type. This centroid point is what all data is reported on. If you constrain your data, ie by pit design, the centroid point must lie within the constraint to be used within the calculation.

The effect of this on volumes if you have large parent sized blocks. Generally the law of averages mean that the volume should be relatively accurate, however that is not always the case with some particular deposit geometries. This is where sub-blocking and partial modeling can further refines your volume and reporting values.

Partial modeling checks the percentage of the centroid and writes this percentage of the block inside to an attribute. This gives you a more refined volume for reporting.

Discuss: Block Size What will the model be used for Sub-blocking governed by~1/4 of drill spacing

Effect on Data Integrity


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Flowchart for Simple Use of Block Modelling


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The Block Model comprises of a number of components. Model Space 3D coordinates spatially define the model extents.

Minimum Northing (Y), Easting (X) and Elevation (Z). Maximum Northing (Y), Easting (X) and Elevation (Z).

Schematic diagram showing how a block model space is defined. User Block Size Block size used for interpolation and reporting. Sub-blocking Sub blocking is a method used by the Surpac block model to allow greater precision when applying geometric constraints (surfaces, solid models etc) to the model. Allowing sub blocking allows the model to divide a user block (defined above) into smaller blocks, which will then be used in calculations. All calculations are performed relative to the User block Centroid. None No sub-blocking is applied to the model. The largest and smallest interpolated block is the User Block. Standard Sub blocking Standard sub blocking simply divides the parent block in half in all three dimensions. This creates 8 child blocks (always). This method of sub blocking is used widely when your deposit does not need smaller blocks in one (or two) particular directions.


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Variable Sub Blocking Variable sub blocking allows you to stop sub blocking in one or two directions, while still progressing in the other directions. For example, if you have a user block size of 8x8x8m, standard sub blocking will allow minimum block sizes of 4x4x4, 2x2x2 and 1x1x1 (etc). However, using variable sub blocking, it is possible to have minimum block sizes of 4x4x2, 4x4x1, or even 4x2x1. This method allows you to get much finer resolution in one direction, without having to create potentially large numbers of blocks in the other two directions. This method of sub blocking is particularly useful when modelling thin-seam deposits, as you can effectively model the "thin" direction, while still having fairly large blocks in the other two directions. This saves a lot of memory by creating a smaller number of blocks, but still manages to model the resource very well. Attributes The properties of the model space that are to be modelled are termed attributes. These attributes may be nominal, ordinal, interval or ratio measurements expressed as numeric or character data. Attributes may also be calculated from the values in other attribute fields, for reporting and visualising. Constraints This is the engine of the block model. Constraints are the logical combinations of spatial operators and objects that may be used to control the selection of blocks from which information may be retrieved and/or into which interpolations may be made. Sub-celled Block Model A user block size is specified. A minimum block size is specified. When applying constraints, Surpac applies a centroid rule. Blocks are sub-celled along the egde of the constraint. If the centroid of the parent or of the sub-block is inside a constraint, the entire sub-block or parent block cell volume is reported, or a value is interpolated.


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Schematic diagram showing a constrained block model with parent blocks and sub-blocks NOTE: when Surpac is estimating values for a sub-celled block, the value is estimated on the

original parent centroid and assigned to the sub-celled inside the constraint.


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Blocks and Attributes Records in the Block Model are related to blocks. These are cuboid partitions of the modeled space and are created dynamically according to the operations performed on the Block Model. Each block contains attributes for each of the properties to be modeled. The properties or attributes may contain numeric or character string values. Every block is defined by its geometric centroid and its dimensions in each axis. Blocks may be of varying size defined by the user once the block model is created.

Figure 1: Block model of oil sands coloured by attribute values (bitumen).


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Constraints

All Block Model functions may be performed with constraints. A constraint is a logical combination of one or more spatial objects on selected blocks. Objects that may be used in constraints are plane surfaces, DTMs, Solids, closed strings and block attribute values. Constraints may be saved to a file for rapid re-use and may themselves be used as components of other constraints.

Blocks meet a constraint (e.g.: below a DTM as in the figures below) if its centroid meets that constraint. This is true even if part of the block is above the DTM.

Figure 2: Unconstrained block model in relation to a DTM surface.

Figure 3: Same block model as in Figure 2 but constrained by topography (DTM).


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Estimation

Once a Block Model is created and all attributes defined, they must be filled by some estimation method. This is achieved by estimating and assigning attribute values from sample data which has X Y Z coordinates and the attribute values of interest. The estimation methods that may be used are:

Nearest Neighbour

Assign the value of the closest sample point to a block

Inverse Distance Assign block values using an Inverse Distance estimator

Assign Value Assign an explicit value to blocks in the model

Ordinary Kriging Assign block values using Kriging with Variogram parameters developed from a Geostatistical study

Indicator Kriging Functions concerned with a probabilistic block grade distribution derived from the kriging of indicators

Assign from String

Assign data from the description fields of closed segments to attribute values of blocks that are contained within those segments extended in the direction of one of the principal axes (X, Y or Z)

Import Centroids Assign block values from data in a delimited or fixed format text file


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Anisotropy Ellipsoid Parameters

This function creates an anisotropic ellipsoid, or the zone which a sample must be found to be used to assign a block.

1. Choose Block model -- Estimation -- Ellipsoid visualiser and enter the form as shown.

Max search radius: the distance of the major axis of the search ellipse

The ratio of the length of the axis to the length of the semi-major or minor axis is called the anisotropy ratio. If no direction of preference an isotropic model can be used setting bearing, plunge and dip to zero and anisotropy ratio to one

Major axis: is the orientation of greatest continuity of the data set. The azimuth of the major axis sits in an XY plane. The azimuth must be between 0 and 360 decimal degrees inclusive in order to be valid and is rotated about the minor axis.

Semi-major axis: This axis is at right angles to the major axis in the XY plane. This is rotated about the major axis with valid input between -90 and 90 decimal degrees inclusive.

Minor axis: The minor axis is the vertical axis and is mutually perpendicular to the Major and Semi-major axes.


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Bearing: The azimuth of the major axis in the XY plane. The bearing must be between 0 and 360 decimal degrees inclusive in order to be valid.

Plunge: The plunge is the rotation of the major axis around the semi-major axis and must be between -90 and 90 decimal degrees inclusive. For an ellipse that has a bearing of 0 degrees, a positive rotation is a northerly plunge and a negative rotation is a southerly plunge as shown on the diagram below.

N-S Long Section View of ellipse.

Dip: This is the dip above or below the horizontal plane. A valid input is between -90 and 90 decimal degrees inclusive. A positive rotation is to the west and negative rotation is to the east.

E-W Cross sectional view of ellipse.


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The axis and orientation of an ellipsoid may be represented by an aeroplane the main body of the plane represents the major axis. The winds represent the semi-major axis and the tail represents the direction of the minor axis.

2. Select the "Save now" button on the form to save an ellipsoid string file at the specified coordinate origin.

The result is a string file representing the orientation and dimensions specified in the form. When exported at a specified coordinate origin it can be recalled into graphics in close proximity to the data and thus be used for visual confirmation.

3. Recall the file ellipsoid_qpy1.str into a graphics layer of the same name and then recall cmpq1.str into a different layer.

Modify the styles of the cmpq1 layer to display the samples as markers instead of lines

It should now be possible to determine if the anisotropy ellipsoid is sufficient in range in each of the three dimensions (major, semi-major and minor) to find sufficient samples to inform the block model. It is also valuable to determine if the ellipsoid is correctly oriented as it is a common mistake to rotate the ellipsoid in the wrong direction.


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CREATING BLOCK MODEL

1. Open the database surpac.ddb

2. Determine the model area by viewing the topo and drillhole database

From the Database menu, select the Display > Drillholes option.

Just display the drill holes


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Place in plan view Display a grid


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Based on the coordinates you can determine the model area in the X and Y directions.

Origin or the minimum X, Y and Z values for the model. Origin Y 7100 X 1400 Z 820

Minimum and Maximum coordinate. Min co-ord Max co-ord Y 7000 Y 7800 X 1200 X 2100 Z -20 Z 250

Extents. Max Point Y 520 X 580 Z 200

Now that you know your model extents, you can create your block model to cover this area. Something you must keep in mind when creating your model is the smallest block size that you will allow.

In this exercise you will set the block model to have the smallest block at a size as shown in the table below

User Block Y 10 X 10 Z 5

The smallest block size is going to be smaller than your user block size.

Smallest Block Y 10 X 5 Z 2.5


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Click on the Apply button to confirm the creation of the block model.


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If required make changes

This will now be created and displayed in the status bar. SAVE IT

From the Block Model menu, select the Save option.

Once the model is saved you will see it displayed in the file manager on the left of you screen.

It is now possible to display the model in graphics.


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From the block model menu select the Display > Display block model option.

You will be presented with the Draw block model form.

This allows you to select how the model will be displayed in graphics.

In V5 of Surpac you have the option of displaying the blocks as a series of centroid point using the point cloud option.

It is also possible to display the blocks at different sizes.

For this exercise, leave the form unchanged and then click on the Apply button.


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CREATING MODEL ATTRIBUTES

An attribute contains the information or the properties of the model space. This can be either a number with decimal places, a character code, and so on.

Assess what information is stored in the database which needs to be placed into the model Before creating any attributes you will look at the information stored in the drill hole database, and decide what will be extracted in the compositing.

Make sure you have the database open.

From the Database menu, select the Edit > View Table option.

Select the sample table to view, and then click on the Apply button.

You will need to look at the entire table, so will not be using any constraints.

Click on the Apply button without making any changes.


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From the Block Model menu select the Attributes > New option.

You will create four attributes at a single time in this step.

Select Model Summary to view the results


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SAVE the block model


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CONSTRAINTS WITHIN A BLOCK MODEL

Constraints are the logical combinations of spatial operators and objects and may be used to control the selection of blocks from which information may be retrieved and/or into which interpolations may be made.

Filling the Block Model with values Producing Reports Viewing models in Graphics. Loading a constrained portion of a model

The choice of spatial operators you have are:

ABOVE INSIDE >

<

=

The operator you will use will depend on the nature of your objects. In order to reduce the number of spatial operators , the word `NOT' is used to imply the opposite of an operation. For example, OUTSIDE would be represented by the expression NOT INSIDE.

When the word AND is used in a constraint combination, blocks that are common to the ANDed constraints will be selected. When the word OR is used in a constraint combination, all blocks which related to either of the ORed constraints will be shown, not just those that are common.

Create a constraint file

From the Block Modelling menu choose Constraints - New constraint file.

The ENTER CONSTRAINTS form will be displayed. The Make Constraints function allows you to create a constraint without having to perform any other function (ie. filling the model with values). This form consists of a number of different parts which bear examining. The key to working with the Surpac block model is in the mastering of this form. The Constraint Type is the most important part of this form - by selecting a type of constraint to use other parts of the form are turned on and off as required. For example the above form is DTM constraint. If you were using an extended string constraint the data entry fields would be different. You build a constraint up by constructing elements and transferring them over to the table on the right hand side of the constraints form. Once you have constructed your constraint, you save it by filling in the ``Constraint combination box'' and the ``Save constraint to'' box.


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FILLING THE BLOCK MODEL

Several choices available:

Nearest neighbour (Assign the value from the closest sample point to the block centroid) Inverse distance (Interpolate block values using an inverse distance estimator) Assign value (Assign an explicit value to blocks in the model) Ordinary kriging (Interpolate block values using Kriging with Variogram parameters

developed from a geostatistical study) Indicator kriging Assign from string (Assign to all blocks falling within a closed segment, the value from a

description field in that segment.) Import centroids (import block-centroid based data from a text file directly into the current

block model)

some of the more commonly used methods:

Assign Value Nearest Neighbour Inverse Distance

The data to be used for the interpolation/assigning of values will most commonly be in the form of a string file, with northing, easting and elevation stored in the Y, X and Z fields and the values to be interpolated stored in the description fields.


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ASSIGN VALUE This option can be used to assign air blocks a specific gravity of zero.

1. Open training.mdl 2. Block Model | Estimation | Assign Value

Nominate the attribute you wish to fill

3. Repeat this process for the constraints: Fresh, oxide and transitional

4. View this in graphics by constraining the block model by the ore zones qpy and bif and then colour the blocks based on numerical attributes

BLOCK MODEL | DISPLAY | COLOUR MODEL BY ATTRIBUTE


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INVERSE DISTANCE

We will use this function to fill the block model with gold grades within the BIF zone. Downhole composites are stored in cmpb1.str

From the Block Model menu, select the Estimation > Inverse Distance option.

This is the estimation technique that you will use the fill the model.


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Enter the minimum and maximum number of samples as shown in the image.

Enter the maximum search radius as 40metres and a large vertical search distance.

Enter the anisotrophy ratios as shown. If you wish to see the shape of your search ellipse, click on the Ellipsoid Visualiser at the bottom of the form.


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Once you have viewed the ellipsoid, click on the Apply button.

Then click on the Apply button to move to the next stage of setting up the model filling.

Enter the inverse distance power to be used for the filling, and at the bottom of the form, make sure the constraint option is ticked.

Click on the Apply button to be taken to the constraint form.

Descretisation points.

If you leave these fields at 3, 3 and 3, each user block in the model is subdivided into 27 sub-blocks and the grade estimated is at the centroid of each of the sub-blocks. The mean of the grades for the 27 sub-blocks is then calculated and this is the grade assigned to the block. This obviously increases processing time compared to x,y and z being set to 1).Using inverse distance there is often no appreciable benefit in making these extra calculations

On the form, make sure you select to keep the blocks that are partially in the constraint. This will keep all block that have a small part of the block inside the constraint, even if the centroid is outside the constraint.

Once the filling has been completed you will be presented with a report which will summarise the filling parameters.


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Use the Inverse Distance method to fill the block model for the QPY zone. Down hole composites of QPY only are stored in `cmpq1.str'.


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Constrain the interpolation of blocks to QPY only

Also, once the filling has been completed, save the block model.

View the model in graphics to validate that the gold values have been correctly filled.

1. Choose Display - Display block model. 2. Choose Display - New graphical constraint and nominate to view all blocks with a gold value >1.


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Now you can find out the information within an individual block by clicking on it.

From the Block Model menu select the Display > View attributes for one block options.

Then click on any block that you can see on the screen.

You will see that the block has been given values for the attributes.

Click on several blocks to see that each has been given a value for the attributes.


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BLOCK MODEL REPORTING

Report for entire deposit

Based on the filling you have completed, you can now generate a report for the quality within the mine area.

From the Block Model menu select the Block model > Report option.


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Leave the format file name blank, and enter a name for the report in the second field.

Select what format you wish the report to be in, and make sure the report will be constrained.

Click on the Apply button to view the second stage of the reporting.

Report can be weighted by mass (a specific gravity must be supplied)

If there was no density then select the Value for the multiplication factor for volume ie. 2 Volume Adjustment: if the physical volume of a block is different to the volume dimensions, ie expansion factor for mined material.


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Grouping Attributes: If you wish to report by grouped attributes, if you are grouping by more than one attribute then the order in which they are specified will have a major influence on the format of the report.

Ex. If the attribute GOLD is reported based on the cutoff values of 0;1;3;5;9;999 and these cutoffs are to be reported on each 10m elevation range between 0 and 250, you would enter the Z value first, and the GOLD values second.

Ex. REPORTING BY RL

Example, REPORTING BY GRADE RANGE


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Click on the Apply button once you have filled out the form as shown.

Constrain the report to detail the material within the pit and below the topo

Click on the Apply button to generate the report.


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Close the report one you have finished viewing it.

It is important to note, that because you selected to keep blocks partially within the constraint, these blocks will also have been used for the quality reporting, and would not give the same result as a traditional Surpac block model report with the same constraint.

CALCULATED ATTRIBUTES

Simple Calculated Attributes

It is possible to create attributes within the Surpac block model that are calculated from values within other attributes, or from standard values. These attributes, called calculated attributes, are very powerful tools for generating reportable values, and add no memory size the model.

In this example you will create an attribute that will calculate the volume of a block using a calculated attribute.

From the Block Model menu, select the Attributes > New option.

You will add a new calculated attribute and in the expression field, enter the mathematical formula for calculating the volume of a block, width x height x length.


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Enter the name of the attribute and that the attribute type will be calculated. Enter the required number of decimal places, and then in the last field, enter the expression to calculate the volume.

Within the block model there are several special variable that can be used within calculated attributes. The _yext is an example that will give the extent, or length of the block. To see the other options that can be used look at the online help for Block Maths.

Enter the expression as shown in the previous image, and then click on the Apply button.

The new attribute will be created, and you can now use the Display properties for a single block to see the volume.

You will use the constraint that was saved in the previous exercise, and then click on the Apply button to generate the report.

To create a calculated top cut


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The expression is iif(gold>30,30,gold) translating to if gold is greater than 30, then make 30, or else leave as gold

Partial Percentage reporting

The traditional constraints functions test all blocks to check whether they are inside or outside the constraint using the centroid position. This test is done on the minimum size blocks in the model (where required).

Occasionally, the centroid may fall outside the constraint, yet a significant part of the block may still be inside the constraint (figure A). Usually, this is not a significant issue - the blocks in question are at the minimum block size, and some will be inside, some will be outside, and so the model evens itself up. However, for some reporting, such as volume reconciliation, this is not accurate enough.

The partial percentage function tests these 'inconclusive' blocks and determines a fractional value between 0 and 1 as per how much the block is inside the constraint, e.g. 0 is totally out, 1 is totally in and 0.4 is 40% inside (figure B). These values are stored inside a specified attribute.

How the percentage is calculated is very simple. With traditional constraints, the model is sub-blocked down to the minimum block size, and then the inside/outside test is performed on the block centroid. The partial percentage calculation takes it further. Rather than stopping at the minimum block size, this function will sub-block further, depending on the Precision Factor that is entered. The higher the Precision Factor the more times the block will be sub-blocked past the minimum block size.

The function then performs the standard constraint on these (much) smaller blocks, and counts the ones that are inside and outside the constraint. This count becomes the percentage. The percentage is always stored in the block at minimum block size. So it becomes a trade-off. The higher the precision factor, the more precise the partial percentage calculation. However, many more blocks are created for the higher precision factors, and so the function will be slower. For


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example, a percentage calculation with a precision factor of 5 will create 4096 times the number of blocks than a calculation at precision 1.

Simple Partial Percent Reporting

1. First create an attribute to store the partial percentage value.

Make sure you have your block model open, and then select the Attribute > New function.

This will allow you to create a new attribute in the model, and as you will be storing a percentage value for a block to be inside or outside of a constraint you must make the attribute a real or float value.

Fill out the new attribute form as shown below and then clock on the Apply button.

The next step is to give the new attribute a value based on its position relative to a constraint, in this example a DTM surface.

From the Block Model menu select Estimation > Partial Percentage

With the constraint you will assign a value based on the position of a block below the topography.

Any block that is completely above the topography will have a value of 1, and any block below the seam will have a value of 0.

It is possible to use a string, DTM surface, 3D model or several other options.


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Select the constraint type, and set it to DTM.

Set the precision option to 3.

Select the partial attribute to be assigned a value, in this example partial.

Enter the name of the DTM surface to be used, in this case topo1.dtm, and make sure that you will be filling only those blocks below, or not above the DTM surface.

At the bottom of the form, tick the option to save the partial percentage result to a file, and give the file a name.

The precision option determines how many time that the block will be split into smaller blocks for testing to see if it is in or out of the constraint.

As an example, a precision of 2 would split the block into two parts in each direction, almost as if it were sub blocking, and then testing these smaller blocks against the DTM surface. A precision of 3 would split the blocks 3 times in each direction, and so on. The larger the precision value the longer the process will take.

Saving a partial percentage result to a file allows it to be used again without the need for running the estimation function again. It will also allow for several variables to be filled at one time.

Once the filling has completed, a report can be generated to give the volume below the topography. This is done by using the partial attribute as a weighting attribute.

You will now generate two reports to see the difference, once without making use of the partial attribute, and then a second time using the partial attribute as a weighting field.

2. From the block model menu, select the Report function


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Give the output report a name, and make sure you will be using a constraint at the bottom of the form.

Click on the Apply form when complete.

Fill out the Block Model Report form as shown above to generate a report for the volume without making use of the partially filled blocks.

Select the attribute to be reported.

Either select a density attribute or set a default density of 2 will be used to give a tonnage.


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Select to constrain the model using the topo1.dtm file. Make sure you only report the blocks below this DTM surface.

Click on the Apply form without making any further changes.

Surpac will generate the report and display it on the screen.

3. Create another block model report, this time making use of the partially filled blocks

Select the Block Model > Report function


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AS in the previous exercise, enter a name for the report, and select to constrain the model, then click on the Apply button .

As with the previous exercise, select the attribute to report, and then select the Use volume adjustment option.

In the Attribute field, select the partial attribute, and as before enter a value of 2 for the density.

Click on the Apply button once you have filled out the form.


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Fill out the constraints form as before, making sure that this time you select to keep the blocks partially in the constraint at the bottom.

Click on the Apply button once you have filled the form out as shown above.

As before the report will be displayed on the screen.

You should see that the difference between the two reports in terms of volume is a fraction over 1%, and in terms of the CaO content, 0.09 in true value.

Model Re_Blocking

Surpac will allow you to create a new model with different block sizes that is in the current model by re-blocking.

This is a very good toll where you have modelled your deposit with small blocks in a certain direction, such as for the elevation, but now wish to create a design where your bench height is much larger.


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In this example, you will re-block the model in all 3 directions.

From the Block Model menu, select the Block model > Reblock option

Enter the name you wish to give to the new model, and a description for the model.

Select the advanced reblocking option from the reblocking type field, and then enter in the new block sizes.

Enter the new minimum block sizes to be the same as the use block size, and make the SG attribute blank, as you do not have one you can use.


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You have three options that can be used for determining the new value for a larger block.

In this case you will use the first option which will treat any negative values as a 0.

Include all attributes, and then click on the Apply button to create the new model.

The new model will be created, and can now be viewed in the normal way.


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Basic Activity FILES USED

Files used in this lab exercise are found in the following folder:

C:\GEOLOGY|BLOCKMODEL\DATA

1. Open the block model block_model.mdl 2. Add the attribute gold_nn to the block model. 3. Add the attribute sg to the block model. 4. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.5 to all

blocks below the topography topo1.dtm. 5. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.9 to all

block in the solid ore body ore1.dtm. 6. Fill the gold_nn attribute with Nearest Neighbour estimation method. Use the following

estimation parameters: I. Composite file = samples1.str II. Maximum search radius = 500m III. Maximum vertical search distance = 9999 IV. Bearing of major axis = 0 V. Plunge of major axis = 0 VI. Dip of semi-major axis = 0 VII. Anisotropy Ratios

i. major / semi-major = 1 ii. major / minor = 1

VIII. Constraints: Inside 3DM (ore1.dtm)

7. Create a Block Model Report and report the following: I. Average weighted gold grade II. Average weighted specific gravity III. Tonnage (multiplication factor = 11) IV. Organized by bench (0,250,10) V. Choose one of the available formats (.csv; .not; .htm; .rtf; .pdf) VI. Constraints: Inside 3DM (ore1.dtm)


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USEFUL TOOLBAR ICONS BLOCK MODELLING

Open Block Model

Close Block Model

Display Block Model

Add New Graphical Constraint

Remove Last Graphical Constraint

Remove All Graphical Constraint

Edit Block Model Constraint

Block Edge and Face Visibility

Add Slicing Plane Constraint

Remove Slicing Plane Constraint

Colour Model by Attribute

Remove Block Colours

Add Block Model Attribute

Delete Block Model Attribute

Edit Block Model Attribute

Block Maths

Identify Block Values

Block Model Report


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PROCEDURE

1. Add the attribute gold_nn to the block model. a. Make sure youre connected to the block model first. From the Navigator, click

and drag the block model block_model.mdl into the view port to connect to it. Notice the special icon and name of the block model that appears in the status bar.

b. From the Block Model menu, choose Attribute, New. c. Fill the subsequent form as follows:

2. Add the attribute sg to the block model. d. From the Block Model menu, choose Attribute, New. e. Fill the subsequent form as follows:

3. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.5 to all blocks below the topography topo1.dtm.

f. From the Block Model menu, choose Estimation, Assign value. g. Fill the subsequent forms as follows:


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4. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.9 to all block in the solid ore body ore1.dtm.

h. From the Block Model menu, choose Estimation, Assign value. i. Fill the subsequent forms as follows:


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4. Fill the gold_nn attribute with Nearest Neighbour estimation method. Use the following estimation parameters:

I. Composite file = samples1.str II. Maximum search radius = 500m III. Maximum vertical search distance = 9999 IV. Bearing of major axis = 0 V. Plunge of major axis = 0 VI. Dip of semi-major axis = 0 VII. Anisotropy Ratios


VIII. Constraints: Inside 3DM (ore1.dtm)

j. From the Block Model menu, choose Estimation, Nearest neighbour. k. Fill the subsequent forms as follows:


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Please note that the above form specifies source data. In this case the gold grades are contained in the file samples1.str in the second description field (D2). Feel free to open this string file and from the Inquire menu use Point Properties to view the description information contained in the D fields of each sample point.


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6. Create a Block Model Report and report the following: Average weighted gold grade Average weighted specific gravity Tonnage (multiplication factor = sg) Organized by bench (0,250,10) Choose one of the available formats (.csv; .not; .htm; .rtf; .pdf) Constrain the report to all block within the solid ore1.dtm.

l. From the Block Model menu, choose Block model, Report. m. Fill the subsequent forms as follows:


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Advanced Block Modelling Tutorial FILES USED

Files used in this lab exercise are found in the following folder: C:\GEOLOGY|BLOCKMODEL\ADVANCED_BM (for the advanced tutorial)

Open Database 1. Open the database DB1.DDB and display the drillholes determine extents and become

familiar with the dataset.

Block Model Validation 2. Create an empty block model, ensuring to cover the area required totally.

3. Export the centroid points to a string file and validate the model area.

4. Create a graphical constraint for qpy1.dtm, bif1.dtm and a combination of both, then validate the user block size of your new block model.

Create Attributes 5. Add the attribute gold to the block model.

6. Add the attribute sg to the block model.

7. Add the attribute gold_cut to the block model (apply a 20g/t cutoff).

8. Add the attribute orecat to the block model.

Apply constraints to model 9. Create constraint files for:

1. Inside qpy1.dtm 2. Inside bif1.dtm 3. Inside sand1.dtm 4. Combination of all above

Fill Block Model with SG Values 10. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 0.00 to all

blocks above the topography topo1.dtm.

11. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 1.68 to all blocks below the topography topo1.dtm and above weath_ew1.dtm.

12. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.11 to all blocks below weath_ew1.dtm and above weath_fresh.dtm.

13. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.46 to all blocks below weath_fresh.dtm.

14. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.9 to all blocks in the ore solid bif1.dtm.

Display the block model by SG Attribute 15. Remove all graphical constraints and then colour display the block model on SG

attributes.


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Fill the Gold attribute with the Inverse Distance2 estimation method 16. Use the following estimation parameters:

For QPY1.DTM ore solid VII. Composite file = cmpq1.str VIII. Maximum search radius = 100m IX. Maximum vertical search distance = 9999 X. Bearing of major axis = 40 XI. Plunge of major axis = 0 XII. Dip of semi-major axis = 42 XIII. Anisotropy Ratios


XIV. Constraints: Inside 3DM (qpy1.dtm) XV. Ellipsoid Origin: Y:7260 X:1560 Z:900

For BIF1.DTM ore solid XVI. Composite file = cmpb1.str XVII. Maximum search radius = 100m XVIII. Maximum vertical search distance = 9999 XIX. Bearing of major axis = 50 XX. Plunge of major axis = 0 XXI. Dip of semi-major axis = 55 XXII. Anisotropy Ratios


XXIII. Constraints: Inside 3DM (bif1.dtm) XXIV. Ellipsoid Origin: Y:7350 X:1840 Z:1000

For SAND1.DTM ore solid XXV. Composite file = cmps1.str XXVI. Maximum search radius = 100m XXVII. Maximum vertical search distance = 9999 XXVIII. Bearing of major axis = 27 XXIX. Plunge of major axis = 0 XXX. Dip of semi-major axis = 0 XXXI. Anisotropy Ratios


XXXII. Constraints: Inside 3DM (sand1.dtm) XXXIII. Ellipsoid Origin: Y:7335 X:1760 Z:1000

Create a Block Model Report 17. Create a Block Model Report and report the following

1. Average weighted gold grade 2. Average weighted specific gravity 3. Tonnage (multiplication factor = SG) 4. Organized by bench (800,1000,10) 5. Choose one of the available formats (.csv; .not; .htm; .rtf; .pdf) 6. Constraints: Inside ore 3DM (bif1.dtm, qpy1.dtm,sand.dtm)


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Files required:

USEFUL TOOLBAR ICONS BLOCK MODELLING

Open Block Model

Close Block Model

Display Block Model

Add New Graphical Constraint

Remove Last Graphical Constraint

Remove All Graphical Constraint

Edit Block Model Constraint

Block Edge and Face Visibility

Add Slicing Plane Constraint

Remove Slicing Plane Constraint

Colour Model by Attribute

Remove Block Colours

Add Block Model Attribute

Delete Block Model Attribute

Edit Block Model Attribute

Block Maths

Identify Block Values

Block Model Report


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PROCEDURE Open Database

1. Open the database DB1.DDB and display the drill holes determine extents and become familiar with the dataset.

a. Open the db1.ddb and display the drill holes (DATABASE | DISPLAY | DRILLHOLES)

b. Open the topography file TOPO1.DTM

c. Plot a 2D grid (PG) and determine the minimum and maximum co-ordinates of the area.

d. The co-ordinates to adequately cover the block model would be approximately: Northing: 7100 -7620 Easting: 1200 - 2000 RL: 820 -1050

Block Model Validation


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2. Create an empty block model, ensuring to cover the area required totally.

a. Select Block Model | New/Open

b. Enter the minimum and maximum co-ordinate as determined above and select a user block size and variable sub-celling size. The block size should reflect the drill hole spacing, mining equipment to be used and the structure of the ore.


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c. Apply through the following form, if required, you can change the block size if needed.

d. The block model has now been created and the name of the block model will appear on the status bar.

e. Save the block model.

3. Export the centroid points to a string file and validate the model area.

a. Select Block Model | Export | Block centroids & dimensions to string file

b. View the file centroids1.str


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4. Create a graphical constraint of the qpy1.dtm & bif1.dtm and validate the user block size of your new block model.

a. Select Constraints | New graphical constraint and complete the form as shown below there is no need save this constraint.

b. Drag and drop QPY1.dtm and validate the user block size of your new block model.

c. Select Constraints | Remove all graphical constraints.

d. Select Constraints | New graphical constraint and complete the form as shown below there is no need save this constraint.

e. Drag and drop BIF1.dtm and validate the user block size of your new block model.


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f. Select Constraints | New graphical constraint and complete the form as shown below there is no need save this constraint. Combine both the BIF1.DTM and the QPY1.DTM. Note the constraint combination (a or b).


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Create Attributes

5. Add the attribute gold to the block model.

a. Make sure youre connected to the block model first. From the Navigator, click and drag the block model blockmodel.mdl into the view port to connect to it. Notice the special icon and name of the block model that appears in the status bar.

b. From the Block Model menu, choose Attribute, New.

c. Fill the subsequent form as follows:

6. Add the attribute sg to the block model.

a. From the Block Model menu, choose Attribute, New.

b. Fill the subsequent form as follows:

7. Add the attribute gold_cut to the block model.




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8. Add the attribute orecat to the block model.



View the new attributes and values created above by having the block model displayed and then selecting Attribute | View attributes for one block and then select a block.


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Apply constraints to model

9. Create and save a constraint file for: Inside qpy1.dtm save as qpy1.con Inside bif1.dtm save as bif1.con Inside sand1.dtm save as sand1.con Combination of all above save as qpy_bif_sand.con

Select Block Model | Constraint | New Graphical Constraint and complete constraints for the above.

Example given below for qpy1.con constraint, repeat for bif1.dtm and sand1.dtm

Example given below for the combination constraint.


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Fill Block Model with SG Values

10. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 0.00 to all blocks above the topography topo1.dtm.

a. From the Block Model menu, choose Estimation, Assign value.

b. Fill the subsequent forms as follows:


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11. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 1.68 to all blocks below the topography topo1.dtm and above weath_ew1.dtm.

12. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.11 to all blocks below weath_ew1.dtm and above weath_fresh.dtm.

13. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.46 to all blocks below weath_fresh.dtm.

14. Fill the sg attribute with the Assign Value method. Assign a specific gravity of 2.9 to all blocks in the ore solid bif1.dtm.


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Display the block model by SG Attribute

15. Remove all graphical constraints and then constrain the block model below the topo1.dtm.

Colour display the block model on the SG attribute by selecting Block Model | Display | Colour By Attribute

View the new attributes and values created above by selecting Attribute | View attributes for one block and then select a block.


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16. Fill the Gold attribute with the Inverse Distance2 estimation method

Use the following estimation parameters:

For QPY1.DTM ore solid I. Composite file = cmpq1.str II. Maximum search radius = 100m III. Maximum vertical search distance = 9999 IV. Bearing of major axis = 40 V. Plunge of major axis = 0 VI. Dip of semi-major axis = 42 VII. Anisotropy Ratios

ii. major / semi-major = 2 iii. major / minor = 10

VIII. Constraints: Inside 3DM (qpy1.dtm) IX. Ellipsoid Origin: Y:7260 X:1560 Z:900

For BIF1.DTM ore solid X. Composite file = cmpb1.str XI. Maximum search radius = 100m XII. Maximum vertical search distance = 9999 XIII. Bearing of major axis = 50 XIV. Plunge of major axis = 0 XV. Dip of semi-major axis = 55 XVI. Anisotropy Ratios

iv. major / semi-major = 3 v. major / minor = 10

XVII. Constraints: Inside 3DM (bif1.dtm) XVIII. Ellipsoid Origin: Y:7240 X:1670 Z:870

For SAND1.DTM ore solid XIX. Composite file = cmps1.str XX. Maximum search radius = 100m XXI. Maximum vertical search distance = 9999 XXII. Bearing of major axis = 27 XXIII. Plunge of major axis = 0 XXIV. Dip of semi-major axis = 0 XXV. Anisotropy Ratios

vi. major / semi-major = 4 vii. major / minor = 10

XXVI. Constraints: Inside 3DM (sand1.dtm) XXVII. Ellipsoid Origin: Y:7335 X:1760 Z:1000


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EXAMPLE: For QPY1.DTM ore solid

Fill the gold attribute with Inverse Distance2 estimation method. Use the following estimation parameters:

I. Composite file = cmpq1.str II. Maximum search radius = 100m III. Maximum vertical search distance = 9999 IV. Bearing of major axis = 40 V. Plunge of major axis = 0 VI. Dip of semi-major axis = 42 VII. Anisotropy Ratios

viii. major / semi-major = 2 ix. major / minor = 10

VIII. Constraints: Inside 3DM (qpy1.dtm) IX. Ellipsoid Origin: Y:7260 X:1560 Z:900

a. From the Block Model menu, choose Estimation, Inverse distance .

b. Fill the subsequent forms as follows:

Please note that the above form specifies source data. In this case the gold grades are contained in the file cmpq.str in the second description field (D1). Feel free to open this string file and from the Inquire menu use Point Properties to view the description information contained in the D fields of each sample point.


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Select the Ellipsoid Visualiser button to view the ellipsoid.

To gain a visual representation of your ellipsoid save it by entering a string file name and string file origin co-ordinates.

Select save now prior to applying the form.


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Once you have viewed the ellipsoid, click on the Apply button.

Then click on the Apply button to move to the next stage of setting up the model filling.

Enter the inverse distance power to be used for the filling, and at the bottom of the form, make sure the debug output report and constraint option is ticked.

Click on the Apply button to be taken to the constraint form.

Descretisation points.

If you leave these fields at 3, 3 and 3, each user block in the model is subdivided into 27 sub-blocks and the grade estimated is at the centroid of each of the sub-blocks. The mean of the grades for the 27 sub-blocks is then calculated and this is the grade assigned to the block. This obviously increases processing time compared to x,y and z being set to 1).Using inverse distance there is often no appreciable benefit in making these extra calculations

On the form, make sure you select to keep the blocks that are partially in the constraint. This will keep all block that have a small part of the block inside the constraint, even if the centroid is outside the constraint.


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Once the filling has been completed you will be presented with a report which will summarise the filling parameters.

*Use the Inverse Distance method to fill the block model for the BIF and SAND zones.

Using the following estimation parameters:

For BIF1.DTM ore solid X. Composite file = cmpb1.str XI. Maximum search radius = 100m XII. Maximum vertical search distance = 9999 XIII. Bearing of major axis = 50 XIV. Plunge of major axis = 0 XV. Dip of semi-major axis = 55 XVI. Anisotropy Ratios

x. major / semi-major = 3 xi. major / minor = 10

XVII. Constraints: Inside 3DM (bif1.dtm) XVIII. Ellipsoid Origin: Y:7350 X:1840 Z:1000

For SAND1.DTM ore solid XIX. Composite file = cmps1.str XX. Maximum search radius = 100m XXI. Maximum vertical search distance = 9999 XXII. Bearing of major axis = 27 XXIII. Plunge of major axis = 0 XXIV. Dip of semi-major axis = 0 XXV. Anisotropy Ratios

xii. major / semi-major = 4 xiii. major / minor = 10

XXVI. Constraints: Inside 3DM (sand1.dtm) XXVII. Ellipsoid Origin: Y:7335 X:1760 Z:1000


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Remove all graphical constraints and then constrain the block model by qpy_bif_sand.con

Colour display the block model on the gold attribute by selecting Block Model | Display | Colour By Attribute

View the inverse distance estimation in the gold attribute by selecting Attribute | View attributes for one block and then select a block.


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Create a Block Model Report

17. Create a Block Model and Report the following: Average weighted gold grade Average weighted specific gravity Tonnage (multiplication factor = SG) Organized by bench (800,1000,10) Choose one of the available formats (.csv; .not; .htm; .rtf; .pdf) Constraints: Inside ore 3DM (bif1.dtm, qpy1.dtm,sand.dtm)

a. From the Block Model menu, choose Block model, Report. b. Fill the subsequent forms as follows:

To determine the overall grade of the deposit


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Apply no constraints to give the average volume and tonnes for each grade range.

To determine the gold and grade in each solid (eg qpy1.dtm) then complete the form as follows:


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Apply no constraints.


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If required the report can also break up the grade ranges for each bench to be mined, complete the form as follows:


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Documents

Surpac Block_Modelling Tutorial