6-Block Modelling 106p

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Product

Surpac™ 6.2

Table of Contents

Introduction 5

Overview 5

Requirements 5

Workflow 6

Block Modelling Concepts 7

Model Space 7

Blocks and Attributes 8

Constraints 9

Estimation 10

Setup for This Tutorial 11

Setting theWork Directory 11

Task: Set theWork Directory (Windows XP) 11

Task: Set theWork Directory (Windows Vista) 12

Displaying the Toolbar and Menubar 13

Task: Display the Block Modelling Toolbar and Menubar 13

Creating a Block Model 14

Create a Block Model 14

Task: Create a Block Model 14

Creating Model Attributes 22

CreateModel Attributes 22

Task: CreateModel Attributes 22

Constraints Within a Block Model 25

Applying Constraints to a Block Model 25

Task: Apply Constraints to a Block Model 26

Estimation or Filling the Block Model 30

Assign Value 30

Task: Fill the Block Model Using Assign Value 30

Nearest Neighbour 34

Task: Fill the BIF Zone Using Nearest Neighbour 34

Inverse Distance 40

Task: Fill the Sand Zone Using Inverse Distance 40

Ordinary Kriging 44

Task: Fill the QPY Zone Using Ordinary Kriging 44

Block Model Reporting 52

Block Model Report 52

Task: Create a Block Model Report 52

Creating Calculated Attributes 56

Task: Create Calculated Attributes 56

Partial Percentage Reporting 60

Partial percent reporting from the block model report 60

Task: Report partial percent using geometric grouping in the block model report 60

Simple Partial Percent Reporting 62

Task: Create Partial Percentage Report 62

Model Reblocking 70

Model Reblocking 70

Task: Perform Model Reblocking 70

Column Processing 72

Workflow 72

Viewing the Data 73

Task: View the Data 73

Classify Blocks 78

Task: Classify Blocks into Ore and Waste 78

Reduction and Dilution 91

Task: Calculate Dilution & Reduction 91

Recoverable Product 93

Task: Calculate Recoverable Product 93

Thicknesses 103

Task: Calculate Column Thickness 103

Introduction

Introduction

OverviewBy working through the examples in this tutorial you will:

l become familiar with Surpac’s block modelling module and the concept of blockmodelling.

l learn to fill a block model from drillhole data from a geological database.l learn to constrain a block model to filter out specific blocks.l learn to report volume, tonnage and grade from a block model.l learn about column processing of a block model.

RequirementsPrior to proceeding with this tutorial, you will need:

l Surpac 6.1 installed, andl The block modelling tutorial data set, andl A good understanding of the basic Surpac concepts of strings, segments, DTMs, and

string tools.

Surpac™ 6.2 Page 5 of 106 Block Modelling

Introduction

Workflow

Note: This workflow demonstrates the steps in this tutorial. There are other ways to achieve aresult.


BlockModelling Concepts

Block Modelling ConceptsThe Block model is a form of spatially-referenced database that provides a means for modelling a 3-Dbody from point and interval data such as drillhole sample data. The Block model consists ofinterpolated values rather than truemeasurements. It provides a method for estimating volume,tonnage, and average grade of a 3-D body from sparse drill hole data.

Model Space3D coordinates spatially define themodel extents.

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

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



Blocks and AttributesThe centroid of each block defines its’ geometric dimensions in each axis, ie. its coordinates, Y, X, andZ. Each block contains attributes for each of the properties to bemodelled. The properties orattributes may contain numeric or character string values. Blocks may be of varying size defined bythe user once the block model is created.

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



ConstraintsAll Block model functions may be performed with constraints. A constraint is a logical combination ofone or more spatial objects on selected blocks. Objects that may be used in constraints are planesurfaces, DTMs, solids, closed strings and block attribute values. Constraints may be saved to a filefor rapid re-use and may themselves be used as components of other constraints.

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

Unconstrained block model in relation to a DTM surface.

Same block model but constrained by the topography (DTM).



EstimationOnce a Block model is created and all attributes defined, themodel must be filled by someestimation method. This is achieved by estimating and assigning attribute values from sample datawhich 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 DistanceAssign block values using an Inverse Distance estimator

Assign ValueAssign an explicit value to blocks in the model

Ordinary KrigingAssign block values using Kriging with Variogram parameters developed froma Geostatistical study

Indicator KrigingFunctions concerned with a probabilistic block grade distribution derived fromthe kriging of indicators

Assign from String

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

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


Setup for ThisTutorial Task: Set theWorkDirectory (WindowsXP)

Setup for This Tutorial

Setting the Work Directory

Task: Set the Work Directory (Windows XP)

1. In the Surpac Navigator, right-click the block_model folder.2. Select Set as work directory.

The name of the work directory is displayed in the title bar at the top of the Surpacwindow.


Setup for ThisTutorial Task: Set theWorkDirectory (WindowsVista)

Task: Set the Work Directory (Windows Vista)

1. In the Surpac Navigator, right-click the block_model folder.2. Select Set as work directory.

The name of the work directory is displayed in the title bar at the top of the Surpacwindow.


Setup for ThisTutorial Task: Display the BlockModelling Toolbar andMenubar

Displaying the Toolbar and Menubar

Task: Display the Block Modelling Toolbar and MenubarWhen working with the Block modelling tools, it is helpful to use the block_model profile. Thisdisplays the Block modelling menubar and toolbar.

1. Right-click in the blank area next to themenus at the top of the Surpac main window.2. From the popup menu, choose Profiles > block_model.


Creating a BlockModel Task: Create a BlockModel

Creating a Block Model

Create a Block Model

Task: Create a Block Model

1. Open ore1.dtm.The solid of the orebody is displayed.

2. Choose View > Zoom out.3. ChooseDisplay > 2D grid.



4. Enter the information as shown, and then click Apply.

The orebody with the 2D in grid in plan view is displayed.

5. Click the icon to show the data in section view.



6. ChooseDisplay > 2D grid.7. Enter the information as shown, and then click Apply.

The orebody in section viewwith a 2D grid is displayed.



Using the previous diagrams you can determine the origin and extents of the block modelwhich will cover the ore solid.

You can also use the string file ore1.str to determine the origin and extents directly fromthe data. This method is described below.

8. Choose Block model > New / Open.9. Enter the information as shown, and then click Apply.

10. Click Apply to confirm creation of the new block model.

11. Tick the box for Get extents from string file.12. Choose ore1.str and click Open.



Themodels coordinates are filled in based on the values in ore1.str.



13. Adjust the values as shown to create a block model which fully covers the extents of theorebody.

14. Click Apply.



15. Enter the information as shown, and then click Create Model.

The block model is created and its name is displayed in the status bar at the bottom ofthe Surpac window.

16. Click the Reset graphics icon .17. Choose Block model > Save to save the block model.18. ChooseDisplay > Display block model.19. Enter the information as shown, and then click Apply.



The block model is displayed.

20. Choose Block model > Close.

Note: To see all of the steps performed in this task run _01_create_model.tcl. You will need toclick Apply on any forms presented.


CreatingModelAttributes Task: CreateModelAttributes

Creating Model AttributesAn attribute contains the information or the properties of themodel space. This can be either anumber with decimal places, an integer or a character code.

Create Model Attributes

Task: Create Model AttributesBefore creating any attributes you will look at the information stored in the drillhole database, anddecide what will be extracted in the compositing.

1. Open training.mdl.2. Open db1.ddb.3. Right-click in the blank area next to themenus at the top of the Surpac main window.4. From the popup menu, choose Profiles > geology_database.5. From the Geology Databasemenu, choose Edit > View table.6. Enter the information as shown, and then click Apply.

7. Click Apply on the blank constraints form to look at the entire table._

8. After looking at the data in the sample table, click Apply. This table data is typical of thedata from a geological database that may be used to fill a block model.

9. ChooseDatabase > Close.10. Right-click in the blank area next to themenus at the top of the Surpac main window.11. From the popup menu, choose Profiles > block_model.12. Choose Attributes > New.




Note: Using real, rather than float, will significantly increase the size of the blockmodel. You would choose float rather than real whenever the attribute will containapproximately 8 significant digits or less.

14. Choose Block model > Summary.



15. After viewing the form, click Apply.16. Choose Block model > Save.

17. Click Yes to write the attributes into the block model.18. Choose Block model > Close.

Note: To see all of the steps performed in this task run _02_create_model_attributes.tcl. You willneed to click Apply on any forms presented.


ConstraintsWithin a BlockModel Task: CreateModelAttributes

Constraints Within a Block Model

Applying Constraints to a Block ModelConstraints are logical combinations of spatial operators and objects. Constraints may be used tocontrol the selection of blocks from which information may be retrieved and/or into whichinterpolations may bemade.

It is possible to apply both simple and complex constraints to the block model to assist in all aspectsofmodelling including:

l Filling the Block model with values .l Producing reports.l Viewing models in graphics.l Loading a constrained portion of a model.

The choices of spatial operators are:

l ABOVE.l INSIDE.l >.l <.l =.

The operator used depends on the nature of the object. In order to reduce the number of spatialoperators, the word NOT is used to imply the opposite of an operation. For example, OUTSIDE wouldbe represented by the expression NOT INSIDE. With the AND statement all conditions must bemetfor the constraint to apply to a block. With the OR statement, just one of the conditions needs to besatisfied.

Create a constraint file

This function allows you to generate constraints without having to perform some other block modelfunction. The key to working with the Surpac block model is in themastering of this form.

One constraint at a timemay be applied to a model, or a series of constraints can be combined andsaved as a constraint (*.con) file.

The types of constraints supported are:

l inside/outside a solid.l above/below a Surface.l satisfy the conditions of a block Attribute.l inside/outside a string.l above/below a defined plane.

As each constraint is defined, click Add .

Note: If a Constraint combination is not defined, Surpac will assume the AND statement is to applyto all constraints, ie. a AND b must be satisfied.


ConstraintsWithin a BlockModel Task: ApplyConstraints to a BlockModel

Task: Apply Constraints to a Block Model

1. Open training.mdl.2. Choose Block model > Display.

Alternatively, click the training button on the status bar at the bottom of the Surpacwindow and chooseDisplay from the popup menu.


The entire block model is shown with no constraints.

4. Choose Constraints > New constraint file.5. Enter the information as shown, and then click Apply.

Note: Once you have constructed the constraint, save it by filling in the Saveconstraint to box and then clicking Apply.

6. Drag and drop oxide.con into graphics.



The blocks below the topography and above the weath_ew1 surface are displayed on thescreen.

You will now repeat the above process to create constraints for the transitional zone andfresh rock zone.

trans.con is aboveweath_fresh1.dtm and belowweath_ew1.dtm.

7. Choose Constraints > Remove last graphical constraint.8. Choose Constraints > New constraint file.9. Enter the information as shown, and then click Apply.

10. Drag and drop trans.con into graphics.



The blocks in the transitional zone are displayed as shown.

fresh.con is belowweath_fresh1.dtm

11. Choose Constraints > Remove last graphical constraint.12. Choose Constraints > New constraint file.13. Enter the information as shown, and then click Apply.

14. Drag and drop fresh.con into graphics.



The fresh rock layer is displayed as shown:


Note: To see all of the steps performed in this task run _03_applying_constaints.tcl. You willneed to click Apply on any forms presented.


Estimation or Filling the BlockModel Task: Fill the BlockModelUsing Assign Value

Estimation or Filling the Block Model

Assign Value

Task: Fill the Block Model Using Assign Value

1. Open training.mdl.2. Choose Estimation > Assign value.3. Enter the information as shown, and then click Apply.


5. Click Yes.

You will now repeat this process of filling the attribute sg. Assign sg a value of 2.6 insidetrans.con and a value of 2.8 inside fresh.con.

6. Choose Estimation > Assign value.





9. Click Yes on the confirmation form.10. Choose Estimation > Assign value.11. Enter the information as shown, and then click Apply.




13. Click Yes on the confirmation form.You will now create another constraint for viewing purposes. The file litho.conwillcontain all the blocks inside the solids sand1.dtm, bif1.dtm and qpy1.dtm.

Note: Be sure to use the OR statement in the constraint combination box as shown.

14. Choose Constraints > New constraints file.15. Enter the information as shown, and then click Apply.

You will now colour the blocks based on numerical attributes.

16. Choose Display > Display block model.17. Drag and drop litho.con into graphics.18. ChooseDisplay > Colour model by attribute.



19. Enter the values as shown, click Refresh, and then click Apply.


Estimation or Filling the BlockModel Task: Fill the BIF Zone Using Nearest Neighbour

20. ChooseDisplay > Edge and face visibility and ensureDisplay block edges is unticked.

The visual effect is much better, as seen in the image below.


Note: To see all of the steps performed in this task run _04_assign_value.tcl. You will need to clickApply on any forms presented.

Nearest Neighbour

Task: Fill the BIF Zone Using Nearest Neighbour

1. Open training.mdl.2. Choose Block Model > Display.




4. Choose View > Data view options > View by bearing and dip.5. Enter the information as shown, and then click Apply.

6. Choose View > Zoom > Out.The block model is displayed.

7. Choose Constraints > New graphical constraint.




9. Choose Estimation > Nearest Neigbour.10. Enter the information as shown, and then click Apply.







Once the filling has been completed, a report called nearest_neighbour.not is produced.

13. ChooseDisplay > colour by attribute.



14. Enter the information as shown, click Refresh and then click Apply.

The constrained and coloured block model for the bif1 zone is displayed.

15. Choose Block Model > Save.16. Choose Block Model > Close.

Note: To see all of the steps performed in this task run _05a_nearest_neighbour.tcl. You will needto click Apply on any forms presented.


Estimation or Filling the BlockModel Task: Fill the Sand Zone Using Inverse Distance

Inverse Distance

Task: Fill the Sand Zone Using Inverse Distance

1. Open training.mdl.2. Choose Block Model > Display.3. Enter the information as shown, and then click Apply.







9. Choose Estimation > Inverse Distance.10. Enter the information as shown, and then click Apply.








Once the filling has been completed, a report called training_id.not is produced.

14. ChooseDisplay > colour by attribute.


Estimation or Filling the BlockModel Task: Fill the QPYZone UsingOrdinaryKriging


The constrained and coloured block model for the Sand1 zone is displayed.


Note: To see all of the steps performed in this task run _05b_inverse_distance.tcl. You will needto click Apply on any forms presented.

Ordinary Kriging

Task: Fill the QPY Zone Using Ordinary Kriging

1. Open training.mdl.2. Choose Block Model > Display.










9. Choose Estimation > Ordinary Kriging.10. Enter the information as shown, and then click Apply.














When themodel has been filled, a report file callled ordinary_kriging.not is produced.

16. ChooseDisplay > Colour model by attribute.




The constrained and coloured block model for the QPY zone is displayed.


Note: To see all of the steps performed in this task run _05c_ordinary_kriging.tcl. You will need toclick Apply on any forms presented.


BlockModelReporting Task: Create a BlockModelReport

Block Model Reporting

Block Model Report

Task: Create a Block Model ReportYou will now produce a report for the entire deposit.

1. Choose Block model > Report.2. Enter the information as shown, and then click Apply.




Note: The report can be weighted by mass and, in this case, the specific gravityattributemust be supplied.

Note: Grouping Attributes: The results can be grouped based on any attribute or Y, X,Z. If you are grouping by more than one attribute then the order in which they arespecified will have a major influence on the format of the report. In the above example , ifthe attribute GOLD is reported based on the cutoff values of 0;1;3;5;10;999 and thesecutoffs are to be reported on each 50m elevation range between 800 and 1100, youwould enter the Z value first, and the GOLD values second. The results will be divided into50m rl ranges within which the numbers are split into grade ranges.



4. Enter the information as shown, and then click Apply.This will constrain the report to thematerial within the pit and below the topography.

5. Open total_orebody1.not.



The report is displayed.

Note: To see all of the steps performed in this task, run _06_block_model_reporting.tcl. You will need to click Apply on any forms presented.


Creating Calculated Attributes Task: Create Calculated Attributes

Creating Calculated AttributesTask: Create Calculated AttributesIt is possible to create attributes within the Surpac block model that are calculated from values withinother attributes, or from standard values. These attributes, called calculated attributes, are verypowerful tools for generating reportable values. They add no memory size to themodel.

1. Open training.mdl.2. Choose Block Model > Display.3. Enter the information as shown, and then click Apply.





7. Choose Constraints > New graphical constraint.8. Enter the information as shown, and then click Apply.

9. ChooseDisplay > Colour model by attribute.10. Enter the information as shown, click Refresh and then click Apply.



The constrained and coloured block model for the QPY zone is displayed.

11. Choose Attributes > New.You will add a new calculated attribute and in the expression field, entering themathematical formula for calculating the cut grade.


Note: To create a calculated top cut, the expression is iif(gold>20,20,gold) translatingto if gold is greater than 20, then make gold 20, else leave as the existing value of gold.

The new attribute is created.

13. ChooseDisplay > View attributes for one block.



14. Click a few blocks from the upper range to see that the top value for au_cut is now limitedto 20.

15. Choose Block model > Save.16. Choose Block Model > Close.


Partial Percentage Reporting Task: Report partial percent using geometric grouping in the blockmodel report

Partial Percentage ReportingThe traditional constraints functions test all blocks to check whether they are inside or outside theconstraint using the centroid position. This test is done on theminimum size blocks in themodel(sub-blocks).

Occasionally, the centroid may fall outside the constraint, yet a significant part of the block may stillbe inside the constraint (figure A). Usually, this is not a significant issue - the blocks in question are attheminimum block size, and somewill be inside, somewill be outside, and so themodel evens itselfup. 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 valuebetween 0 and 1 as to howmuch of the block is inside the constraint, e.g. 0 is totally out, 1 is totallyin 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, themodel is sub-blocked down to theminimum block size, and then the inside/outside test is performed on the blockcentroid. The partial percentage calculation takes it further. Rather than stopping at theminimumblock size, this function will sub-block further, depending on the Precision Factor that is entered. Thehigher the Precision Factor themore times the block will be sub-blocked past theminimum blocksize.

The function then performs the standard constraint on these smaller blocks, and counts the onesthat are inside and outside the constraint. This count becomes the percentage. The percentage isalways stored in the block at minimum block size. So it becomes a trade-off.

The higher the precision factor, themore precise the partial percentage calculation. However, manymore blocks are created for the higher precision factors, and so the function will be slower. Forexample, a percentage calculation with a precision factor of 5 will create 4096 times the number ofblocks than a calculation at precision 1.

Performing partial percentage calculations on underground models can be very time consumingbecause you would need to create an attribute and run the partial percentage function for eachstope in themodel. An alternative way to determine partial percentage volume is to use thegeometric grouping function in the block model report. The partial percentage volumes, for eachlocation, are then generated in the report. However, the percentage value for each block is notstored as an attribute in the blocks of your model.

Partial percent reporting from the block model report

Task: Report partial percent using geometric grouping in the block model report

1. Open training.mdl.2. Choose Block model > Report.

The Block model report format file form is displayed.



Partial Percentage Reporting Task: Report partial percent using geometric grouping in the blockmodel report

The Block model report form is displayed.


The report opens.


Partial Percentage Reporting Task: Create Partial Percentage Report

Note: To see all of the steps performed in this task run _08a_partial_percentages_report.tcl. Youwill need to click Apply on any forms presented.

Simple Partial Percent Reporting

Task: Create Partial Percentage ReportFirst you will create an orebody solid.



1. Open training.mdl.2. Append bif1.dtm, qpy1.dtm, sand1.dtm into themain graphics layer.

Note: DTM’s are appended to a layer by holding down the control key while draggingand dropping the DTMs into graphics.

The DTMs are displayed.

3. Choose File > Save > string/DTM.4. Enter the information as shown, and then click Apply to save the results to

orebody1.dtm.

5. Choose Attributes > New to create a new attribute to store the partial percentage value.6. Enter the information as shown, and then click Apply.



You will now give the new block attribute a value based on its position relative to theorebody.

7. Choose Estimation > Partial Percentage.8. Enter the information as shown, and then click Apply.

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

The results are a partial percentage volume calculation for the blocks along the edge ofthe orebody.

The precision option determines howmany times the block will be split into smallerblocks for testing to see if it is in or out of the constraint. As an example, a precision of 2would 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 wouldsplit the blocks 3 times in each direction, and so on. The larger the precision value thelonger the process will take.

Saving a partial percentage result to a file allows it to be used again without the need forrunning the estimation function. It also allows for several variables to be filled at onetime.

Once completed, a report can be generated to give the volume in the orebody. This isdone by using the partial attribute as a weighting attribute.



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

9. Select Block model > Report.10. Enter the information as shown, and then click Apply.


This will generate a report for the volumewithout making use of the partially filled blocks.




Surpac generates the report and displays it as shown.

13. Choose Block model > Report.








Note:Make sure that this time you click the checkbox to keep the blocks partially inthe constraint at the bottom.


You should see that the difference between the two reports in terms of volume is about0.6%, and in terms of the gold content, 0.4 in true value (or 5.2% of the grade). If theblocks were larger (eg. 20x20x20) partial percentages would show a greater effect on theresult.

17. Choose Block model > Save.




Note: To see all of the steps performed in this task run _08b_partial_percentages.tcl. You willneed to click Apply on any forms presented.


ModelReblocking Task: PerformModelReblocking

Model Reblocking

Model Reblocking

Task: Perform Model ReblockingIn Surpac you can create a newmodel with different block sizes from those in the current model byre-blocking.

In this example, you will reblock themodel in all 3 directions.

1. Open training.mdl.2. Choose Block model > Reblock.3. Enter the information as shown, and then click Apply.

Themodel training_reblock is created with the specified block size and becomes theactivemodel.

4. Choose Block model > Summary.


ModelReblocking Task: PerformModelReblocking

Themodel summary is displayed. Notice that the new block size is 20 x 20 x 10.

Note: To see all of the steps performed in this task run _09_model_reblocking.tcl. You will needto click Apply on any forms presented.


Column Processing Task: PerformModelReblocking

Column ProcessingIn this section you will take an existing block model and use Surpac's block model column processingfunctions to evaluate the economics of the block model.

The data is a block model containing only one attribute, grade, and a DTM representing surfacetopography.

Workflow


Column Processing Task: View the Data

Viewing the Data

Task: View the Data

1. Open blockmodel.mdl.2. Choose Block model > Display.3. Enter the information as shown, and then click Apply.


The block model is displayed.

6. ChooseDisplay > Colour model by attribute.



7. Enter the information as shown, click Refresh, and then click Apply.

8. ChooseDisplay > New graphical constraint.9. Enter the information as shown, and then click Apply.




Themodel is displayed.

The blocks in this model are 35metres in the x and y dimensions and 3metres high. Because the vertical extent of this model is limited compared to the horizontal extent,you will vertically exaggerate this model by a factor of 5.

12. Choose View > Data view options > View scale factors.13. Enter the information as shown, and then click Apply.

After exaggerating themodel five times, to get the view at a bearing of 330 degrees and adip of -20 degrees, you need to set the View by Bearing function to a dip of -4; the dip youwant divided by the vertical exaggeration.




Themodel is displayed.

16. Open block_topo1.dtm.Note the separation between the topography and the highest blocks with any grade. Thisseparation is called the overburden.

You will now slice themodel to see the internal structure.

17. In the Layers pane, right-click on the layer blocktopo1.dtm and chooseDelete layer.18. Choose View > Zoom > All.

This moves the data back to plan view

19. Click theDefine section icon .



20. Enter the information as shown below on the Section Method tab.

21. Enter the information as shown on the Section Block Model tab, and then click Apply.


Column Processing Task: ClassifyBlocks into Ore andWaste

The first section through the block model is displayed.

22. Click theNext section icon to view the following sections (there are 5).You should now have a good idea of how the block model looks and are ready to startthe economic modelling process.

23. Choose Block model > Close

24. Click Exit graphics .

Note: To see all of the steps performed in this task run _10_viewing_the_data.tcl. You will needto click Apply on any forms presented.

Classify Blocks

Task: Classify Blocks into Ore and Waste

1. Open blockmodel.mdl.2. Choose Column processing > Column tops.3. Enter the information as shown, and then click Apply.




This will search down through the block model extracting a point at the top of the firstblock in each column where the grade is greater than 8.

The result will be a string file called top_cutoff1.str. The nominal value above top valuefrom the Tops of columns form is the default elevation which will be assigned if no blocksin the column satisfy the constraint. As a rule of thumb, when extracting upper surfaces,the nominal z elevation should be set to an elevation below your model and whenextracting lower surfaces it should be set to an elevation above your model.

5. Choose Column processing > Column tops.6. Enter the information as shown, and then click Apply.

This time the search is in the Z direction (positive Z is up) and the nominal elevation is setto 400.

7. Enter the information as shown below, and then click Apply.



You will now use the string files top_cutoff1.str and bot_cutoff1.str to create DTMs.

8. Choose Surfaces > DTM File functions > Create DTM from string file.9. Enter the information as shown, and then click Apply.

10. Choose Surfaces > DTM File functions > Create DTM from string file.




12. Choose Block model > Display.13. Enter the information as shown, and then click Apply.

14. Choose View > Data view options > View scale factors.




16. ChooseDisplay > Colour model by attribute.17. Enter the information as shown, click Refresh and then click Apply.

18. Open top_cutoff.dtm and bot_cutoff.dtm.The block model with top and bottom cutoffs is displayed.



19. Click the blockmodel button on the status bar at the bottom of the screen.A popup menu appears.

20. ChooseHide.You will see the following image which shows the upper and lower cutoff DTM surfaces.

21. Click the blockmodel button on the status bar at the bottom of the screen and chooseDisplay from the popup menu.




The block model is redisplayed.

23. In the Layers pane, double click the bot_cutoff1.dtm layer to make it the active layer.24. Right-click the bot_cutoff1.dtm layer and untick the Visible option from the popup

menu.Notice that the visibility icon changes from to (ie. greyed out) to show that thelayer is no longer visible in graphics.

25. Repeat the above step for the top_cutoff1.dtm layer.Only the block model is now visible.

The next step is to add two attributes to themodel which will be filled in the Ore/Wastediscrimination function.

26. Choose Attributes > New.




Note: Right-click on the number 1 to add a row to the table.

The ore_waste_flag is a flag which will signify an ore block if set to 1 and a waste block ifset to 0. The composite_grade attribute will store the grade for a contiguous set of oreand waste blocks in a column.

28. Choose Column processing > Ore/Waste discrimination.29. Enter the information as shown, and then click Apply.

Note: You are specifying minimum mining thicknesses of ore and waste of 6metresand a cutoff grade of 8. This function classifies blocks as ORE orWASTE according to acutoff grade and minimum thickness criteria.



The ore/waste classification is stored as an integer value in the ore_waste_flag attributewhich facilitates colouring themodel on ore/waste. Amaster attribute is specified (grade)and an attribute to store the composite grade for each resulting ore and waste layer.


Note: It is very important that this function be applied using the above constraint. Thisway no outlying sub-grade waste blocks will be included in the top or bottom ore layers.This constraint file is saved for future processing.

A summary is shown below.

You will now colour themodel on the ore_waste_flag attribute. Ensure you are viewingonly the blocks within your new constraint file - top_bot_cutoff.con.




33. ChooseDisplay > Colour model by attribute.34. Select ore_waste_flag for Attribute to colour by, and then click Scan.



The form is redisplayed.

35. Click the down arrow on row 1 to bring up the Colour chooser.36. Click the Crayola tab, type in blue and then click OK.

The waste blocks are now coloured blue.

37. Click the down arrow on row 2 to bring up the Colour chooser.38. Click the Crayola tab, type in yellow and then click OK.

The ore blocks are now coloured yellow.



39. Click Apply on the Block Colours form.

40. Click the toggle display polygon & triangle edges icon to turn edges off.This will colour themodel as shown:

Note that theminimum mining thickness of 6metres (2 blocks in elevation) has beentaken into account.



41. ChooseDisplay > View attributes for one block and click on a block to select it.The composite grade will be reported. This is the average grade for all contiguous ore orwaste blocks in that column. If you select a block above or below this block in the samelayer, it will have the same composite grade. All ore layers have a composite grade greaterthan 8 and all waste layers have a composite grade less than 8. You will now display wasteblocks only so you can see their distribution in themodel.


The waste blocks are displayed.

44. Choose Block model > Save.45. Choose Block model > Close.

Note: To see all of the steps performed in this task run _11_classify_blocks.tcl. You will need toclick Apply on any forms presented.


Column Processing Task: Calculate Dilution &Reduction

Reduction and Dilution

Task: Calculate Dilution & Reduction

1. Open blockmodel.mdl.2. Choose Attributes > New.3. Add an attribute called diluted_grade as shown:

4. Choose Column processing > Dilution and reduction.5. Enter the information as shown, and then click Apply.


Column Processing Task: Calculate Dilution &Reduction


7. Click Yes on the following form.




Column Processing Task: Calculate Recoverable Product

Note: To see all of the steps performed in this task run _12_dilution_and_reduction.tcl. You willneed to click Apply on any forms presented.

Recoverable Product

Task: Calculate Recoverable Product

1. Open blockmodel.mdl.2. Choose Estimation > Assign value.3. Enter the information as shown, and then click Apply.

4. Enter the information as shown below, and then click Apply.

This will assign those blocks above the top of our ore, and below the topography (ie. theoverburden) blocks to waste.

5. Click Yes.



Note: Before you run the Recoverable product function, you should add the attributeswhich will store the results of this function.

The attributes do not have to be added ahead of time in this function. If the attributesspecified to store the results do not exist, they will be created.

However it is a better practice to add them first for two reasons:

l If they are added by the function, they are created as real attributes and notfloats and therefore will require double the storage space.

l You have control of the background values when adding them yourself. Fordata management reasons you will want to standardize your backgroundvalues. In this tutorial you are using a background value of -99.

6. Choose Attributes > New.7. Enter the information as shown, and then click Apply.

Unlikemost other attributes, the ratio attributes are given a high background value. Ahigh value of the ratio of volume to product denotes less economic material. You will besearching for the first value below a certain value. If you picked a low background value,when searching for the first block below a certain value using the column tops function,you would always find the top or bottom of themodel because this is outside of ourconstraint and so remains at the background value.

8. Choose Column processing > Recoverable product.9. Enter the information as shown, and then click Apply.




Note: You would expect an ore layer with only a small amount of overlying waste tohave a lower individual ratio than an ore layer with a higher thickness of overlying waste.Also, you would expect the uppermost ore layer to have the same value for the individualand cumulative ratios.

10. Choose Block model > Display.11. Choose View > Data view options > View by bearing and dip.12. Enter the information as shown, and then click Apply.

13. ChooseDisplay > Colour model by attribute.14. Select ore_waste_flag for Attribute to colour by, and click Scan.



The Block Colours form is as displayed.

15. Click Apply.16. Choose View > Data view options > View scale factors.17. Enter the information as shown, and then click Apply.

18. Drag and drop top_bot_cutoff.con into graphics.19. ChooseDisplay > Edit attributes for one block.20. Click an ore block.



You should see results similar to those shown below.

The final steps of the process are to extract and create surfaces representing the top andbottom of economic ore. The bottom of economic ore will be a surface created whensearching up through themodel, using the Column Tops function, for the first blockwhere both individual and cumulative ratios are below a cutoff ratio. For this exercise youwill use a cutoff ratio of 12.






26. Click and drag bot_ore12.dtm from the Navigator into graphics.



27. View the block model from below, as shown.The economic bottom of orematches the lowest occurrence of ore in all parts of themodel except for the southwest.

The top of the ore will simply be the first occurrence of ore searching down through themodel (ie. the ore_waste_flag =1). If this ore is not economic, as in the southwest of themodel, it will be excluded by the fact that the economic bottom of ore is at an elevation of400 here. This is a reason why the nominal values are important when using the ColumnTops functions.






A block model report can now be generated to calculate volume, tons, average grade andrecoverable product of the economic ore.

33. Choose Block Model > Report.





Note: Right-click on the “a” in the first row to add another row to the table.




The resulting report is shown.



Column Processing Task: Calculate Column Thickness

Note: To see all of the steps performed in this task run _13_recoverable_product.tcl. You willneed to click Apply on any forms presented.

Thicknesses

Task: Calculate Column Thickness

1. Open blockmodel.mdl.2. Choose Column processing > Thickness.3. Enter the information as shown, and then click Apply.




A report is generated as shown:

Note: In the resultant string file, String 1 contains the ore thickness and averagediluted grade in the first and second description fields. There is also a string 2 in this filewhich contains the thickness of all other material (in this case this represents interburdenthickness) and the average diluted_grade. String 2must be deleted from this file beforeyou can create a DTM of ore thicknesses and grades, or the values from string 1 and 2willbe averaged when creating the DTM - giving you meaningless results.

5. Open ore_thickness12.strin Graphics.6. Choose Edit > String > Delete range and delete string 2 from ore_thickness12.str.7. Choose Surfaces > DTM file functions > Create DTM from string file.




Contours can now be extracted of the ore thickness.

9. Choose Surfaces > Contouring > Contour DTM file.




11. Drag and drop the file contour_thickness.str into graphics.The contours are displayed.

Note: To see all of the steps performed in this task run _14_thicknesses.tcl. You will need to clickApply on any forms presented.


Documents

6-Block Modelling 106p