Whittle Introductory Gold Tutorial

Copyright 2009 Gemcom Software International Inc. (Gemcom).

This software software and documentation is proprietary to Gemcom Gemcom and, except except where expressly provided otherwise otherwise,, does not form part part of any contract. contract. Changes may be made in products or services services at at any time without without notice. Gemcom Gemcom publishes publishes this documentation documentation for for the sole use of Gemcom Gemcom license licensees. es. Without Without written written permission permission you may not sell, sell, reproduce, reproduce, store in a retrie retrieval val system, or transmit any any part of the documentation. documentation. For such permission, permission, or to obtain extra extra copies copies please please contact your local local Gemcom Gemcom office office or visit www.ge www.gemcomsoftw mcomsoftware are.com. .com. While While eve every ry precauti precaution on has been been taken in in the preparation preparation of this manual, manual, we assume no responsibili responsibility ty for errors errors or omissions. Nei Neither ther is any liabil liability ity assumed for for damage resulting resulting from from the use of the information information contained contained herein. herein. Gemcom Gemcom Software Software International International Inc. Gemcom, Gemcom, the Gemcom Gemcom logo, combinations combinations thereof, thereof, and Whittle, Whittle, Surpac, GEMS, Minex, Minex, Gemcom InSite and PCBC are trademarks trademarks of Gemcom Gemcom Software Software International International Inc. or its wholly-ow wholly-owned ned subsidiaries. subsidiaries. Product Gemcom Gemcom Whittle Whittle 4.3

Table of Contents Introduction - Gold tutorial

P rerequisites Importing

4

4 5

Validation of Imported Model

11

Setting Pit Slopes for the Optimisation

15

Optimisation

19

M ining Tab

19

M ethod 1. Using range function alone

19

M ethod 2. Using line of of be best fit within a range fu function

20

Entering the equations into the M ining tab

20

Processing Tab

22

Selling Selling tab

23

Opti Opt imisation tab

24

Output tab

24

Operat Operational Scenario

28

Sensitivity analy anal ysis

30

Final pi pit and NPV Practical Practical Pushbacks

33

Create Create pushbacks pushbacks Congr Congratulations

35 40

Introduction Introduc tion - Gold Gold tutorial

Introductio Introdu ction n - Gold tutorial tutorial This tutorial tutorial is provided provided to introduce introduce various parts parts of software software through a worked worked exampl example. e. For more information information on any part of this tutorial: tutorial: l l l

see the relevant relevant information information in the hel help p file file view demonstration demonstration datasets and and read notes notes in the descripti description on tab on each node contact contact your loc local al Gemcom Gemcom offi office ce for module module informa informatio tion n or traini training ng options. options.

In this tutorial, tutorial, we we will will work work with with a validated validated block block model from a genera generall mine planning planning package such as Surpac, GEMS GEMS or other. This This block block model has been been created created in in the format .mod and also has a corresponding .par file.

Prerequisites You can find find these data files files in \tutorials\gold l l l

the block block model model training.mod . the parameter parameterss file file training.par. the block model validation validation report report training_rpt.txt.

(Undefined variable: gemcomVars.Product)™ comVars.Produ ct)™ (Undefined ( Undefined variable: gemcomVars.Version)

Page4 Pa ge4 of40

(Undefined variable: gemcomVa gemcomVars.Docu rs.DocumentTitle) mentTitle)

Importing

Importing 1. Open Whittle from the desktop icon or Start > All Programs > Gemcom Software > Whittle [ver] 2. From the project selection dialog, choose Create a new project. This will start the Project Wizard which will guide you through the import process.

3. In the Project Name field, type a name for the project. You do not need to enter any other information as all other fields on this page of the Project Wizard will fill in automatically. Note: If you would like to save the project in a different folder, rename the project directory and the working directory will be automatically updated.

4. Click Next.

5. Now select Whittle block model, and specify the location of the .mod and .par files. The .mod and .par files can be anywhere on your network.

(Undefined variable: gemcomVars.Product)™ (Undefined variable: gemcomVars.Version)

Page5 of40

(Undefined variable: gemcomVars.DocumentTitle)

Importing

6. On Model File to import click browse, and select your .mod file. By default, these files will be installed in the \projects directory of your Whittle installation. The Project Wizard will assume the corresponding .par file is in the same directory and has the same name as the .mod file. 7. If required, on Parameters File to import click browse button and select your .par file. 8. Click Next.

9. Continue clicking Next without entering any values until you come to the Processes page (not the Process Description page). 10. Click the Add button, to add a process. 11. Edit the row renaming it to MILL. Note: Renaming the row to MILL is important for a later stage of this tutorial.


Page6 of40


Importing

No more information will be added until we have validated the model. You could finish here and create the project but in this tutorial we will continue clicking through the pages of the Project Wizard to identify the features of the wizard and their functions. 12. Click Next to display more pages of the wizard until the Next button becomes unavailable.


Page7 of40


Importing

The next few pages of the Project Wizard show summary information for the grade element and allow editing of element names. You do not have to enter any information in these pages. 13. Click Finish. The Define Element Type Codes page is displayed.


Page8 of40


Importing

14. Click Next to display the Define Model Dimensions page. This page allows editing of the model summary information. You do not need to enter any information in this page.


Page9 of40


Importing

15. Click Finish. You have now imported the model into the Whittle interface. A range of standard analysis nodes have been created to guide you through the mine planning process.


Page10 of40



Validation of Imported Model First, we will rename the block model node so we can identify the block model – in this case, we will use the model dimensions. 1. In the Description field on the Description tab of the Block Model node, enter “10 x 20 x 10”. There are already notes filled out specifying the location of the original .mod and .par files. You can add more notes here if required. 2. Click Accept to save the changes.

3. Click on the Dimensions tab to visually check the block size and model origin. 4. Click the Report tab of the Block Model node to check the totals against the validation report from the GMP. A sample validation report from Surpac is provided in the same folder as the training.mod file. Its file name is training_rpt.txt.


Page11 of40



5. Further down the report, check the Summary by bench by rocktype. 6. Next we will use the 3D Viewer as a visual check. a. Click on the Block Model node in the project tree. b. Select Start Three-D Viewer from the icon on the toolbar. c. On the Select data to display dialog box, click OK. Tip: By clicking the Block Model node in the project tree, you bring the block model into the 3D viewer. Later we will visualise different things by clicking on different nodes in the project tree.

d. In the 3D Visualiser, select the Show Topography box and the Show XZ Plane box. e. Rotate the view by clicking and dragging the mouse. f. Zoom the view by holding down the wheel button of the mouse and moving the mouse forward or backward. g. Click Invert (in the lower left of the window) to give the 3D Viewer a white background. (Undefined variable: gemcomVars.Product)™ (Undefined variable: gemcomVars.Version)

Page12 of40



Note: We have used an inverted view for many screen captures in this document so that you will save ink if you print.

Your view should look like the following. We will explore the 3D viewer later. For now, it is enough to visually check the model.

Once this is done, your model is validated! 7. Close the 3D Viewer. One final thing to do on the Block Model node is to set the units of the project to grams, because that is the unit of measure of our gold element. 8. On the Formats tab, in the Element data table, choose gram from the drop down menu as shown:


Page13 of40



9. To save your changes, click Accept.


Page14 of40



Setting Pit Slopes for the Optimisation 1. Click the New Slope Set node in the project tree. 2. In the data pane, edit the description on the Description tab to display Slope Case 1 - 60 degrees below level 16. 3. On the Slope Type tab, select Rectangular slope regions to define the slopes. Tip: Rock types are commonly used to specify slope angles. Alternatively, an attribute can be created in the block model and filled with integers specifying different zones based on any data.

In the Profiles tab, we will create two new slope profiles in addition to the default slope profile. 4. Us the Add Profile button to create two new profiles specifying the slope angles as: Profile 1 - Slope 45 degrees. Profile 2 - Slope 60 degrees. l l


Page15 of40



Now we want to split the model into two ‘slope regions’ and assign each of our two profiles to a different region. 5. Use the Add button in the Slope Regions section, to add a second slope region. 6. Split the regions up using the Z value of the model. Change the values so the following regions are defined, then use the drop down box in the Slope Profile column to assign the slope profile. Region

Min X

Max X

Min Y

Max Y

Min Z

Max Z

Slope Profile

1

1

90

1

40

16

35

Profile 1 (45.0)

2

1

90

1

40

1

15

Profile 2 (60.0)

7. Click Accept to save your work. Now we have entered all of the relevant information, we need to generate the slope file for use in the optimisation. To do this, we need to “run” the analysis. We will use the Run To icon. 8. If it is not highlighted, click the Slope node and then click Run To to run all the analysis down to the selected node (slopes).

9. Click the Report tab of the Slopes node to briefly check the slope errors. Tip: Slopes are created between blocks in the block model and therefore cannot exactly define the entered slope angle. However, normally the difference is small.


Page16 of40



We have defined two different regions for applying our slopes, so we should see the two profiles listed for those regions in the Messages tab.


Page17 of40



These slope errors are acceptable, so we will proceed.


Page18 of40


Optimisation

Method 2. Using line of best fit within a range function

For more examples using the Range function, see the Expression Button help topic in the Whittle help.

Method 2. Using line of best fit within a range function 1. 2. 3. 4.

In Excel create the table shown in method 1. Create line of best fit with the linear part of the table, below 230RL. Highlight IZ and MCAF columns (below 230RL), and insert a scattergraph. Right click on plotted line, choose show line equation on graph.

In other words, the line should read MCAF = -0.0333 *IZ + 1.9667 and your graph should look like the one below:

We can then use the range function and nest the line of best fit within the range function. What we want to represent can be described as the following: Up to the 230RL (level 29) use the equation MCAF = -0.0333 *IZ + 1.9667, for level 29 and thereafter use a value of 1 (up to the top of the model).

As an equation, we can express this as:R(IZ,-0.0333*IZ+1.9667,29,1)

Entering the equations into the Mining tab 1. On the Mining tab, enter 1.5 for the Reference Mining Cost. 2. Select Calculate under Block mining cost adjustment factors then press the function button at the right hand side of the entry box. This will expose the expression builder.

The expression builder can be used to build expressions using a range of standard functions, variable, and special functions.


Page20 of40


Optimisation

Entering the equations into the Mining tab

3. Type or copy the preferred expression, for example R(IZ,0.0333*IZ+1.97,29,1), into the expression builder dialog, then click the Check Expression button. 4. If there are no errors, click OK in the expression builder to complete the Mining tab.

Your formula should now be shown in the Block mining cost adjustment factors section of the Mining tab.

Or


Page21 of40


Optimisation


5. If the Rock-type mining CAFs are not set to 1 then set them each to 1.

6. Click Accept to accept the changes on the Mining tab. When you click Accept, the Data Synchronization form is shown.

7. Click Yes . This dialog box confirms that you would like to copy the mining information down the project tree to the economic analysis node. Because we want to analyse our pitshells using the same criteria as was used to create them, we will always answer yes to this question in this tutorial.

Processing Tab 1. Click on the Processing tab and enter the information as shown below. The Processing Paths have used the rock types in the model file and have been assigned to the process MILL that we specified in the import wizard.


Page22 of40


Optimisation


Tip: You can use the Up and Down buttons to the right of the screen to order the processing paths in a logical order.

2. If you see a blank table, manually create processing paths, assigning each rocktype to the available process ‘MILL’ by clicking the Add button on the right hand side and entering the information in that dialog box.

3. Click Accept on the processing tab to save.

Selling tab 1. On the Selling tab, enter the Price to be obtained for the gold, in this case $800/oz or $25.72/gram. You can enter either value, just make sure that: 1. The units are correct for the entered price and 2. You have set the element units as grams on the Formats tab of the Block Model node.

This selling price does not include royalties. If royalties are payable, reduce the selling price or add a selling cost. Note: Selling prices are scaled by the revenue factor. Selling costs are not. (Undefined variable: gemcomVars.Product)™ (Undefined variable: gemcomVars.Version)

Page23 of40


Optimisation


Optimisation tab 1. Click Default on the Optimization tab. We will produce approximately 50 nested pitshells at varying prices depending on the revenue factors specified here. The revenue factors scale the entered selling price to produce different pits that are optimal for different prices.

2. Click Accept. 3. Run the optimisation using the Run To command from the toolbar icons.

Output tab Before analysing the results, we need to check the MCAFs were applied correctly.


Page24 of40


Optimisation


Then we will examine the output pitshells visually. Click on the New Pit Shells node and start the 3D Viewer.

To visually validate the MCAFs, do the following: 1. 2. 3. 4. 5.

Snap to View XZ. Show Data – MCAF. Show XZ Plane. Click the Info tab. Click Show to float the information window, position it in the top right of the viewer.


Page25 of40


Optimisation


As you hover over the blocks in the visualiser, the information will be shown in the information window. 6. Check the MCAFs have been applied correctly. 7. Examine the pitshells visually by using the check box Show Pit and scrolling up and down using the spinner directly to the right of the pit number or using the up and down arrows on your keyboard. You might also like to view the gold grades in an XY plane whilst viewing the pitshells. 8. Change the options as shown and use the left mouse button to orbit the view. Tip: Left click to orbit, right click to pan, hold mouse wheel button down and move the mouse forward or backward to zoom.

Note: The edge of the pit is right to the edge of the model. In this tutorial, we will accept this. In reality, you would either extend the model in the GMP or use the reblocking functionality in Whittle to do the extension. For more information, see the Whittle help on Advanced Reblocking or contact your local Gemcom office for training options.

9. Click the red X in the top right to close the viewer. (Undefined variable: gemcomVars.Product)™ (Undefined variable: gemcomVars.Version)

Page26 of40


Optimisation


10. In the Pitshells node select the Output tab and view the range of pits created. We now need to determine the final pit and create some pushbacks for the deposit. Before going to that stage, we will quickly examine the sensitivities of the deposit.


Page27 of40


Operational Scenario


Operational Scenario The next step is to enter financial information into the New Operational Scenario node. 1. Select the New Operational Scenario node. Notice that the Mining, Processing and Selling tabs are identical to those on the Pit Shells node. 2. On the Time Costs tab, enter the following: Capital cost for project $50 million. Discount rate 8%. l l

3. On the Limits tab, enter the mining limit as 10,000,000 (tpa), the milling limit as 1,000,000 (tpa) and change the element limit units to the project units of grams. We must do this even though we are not using this limit in this scenario. We also need to set the throughput factors to 1 (the zeros are caused from the .par file which has been exported from a GMP package).


Page28 of40


Operational Scenario


4. Accept the changes on the Operational Scenario node. You should see a Pit by Pit graph already in the project tree under the Operational Scenario node. 5. If you don’t see the Pit by Pit graph, right-click and Add a Pit by Pit graph.


Page29 of40


Sensitivity analysis


Sensitivity analysis Note: You need to have the Advanced Analysis module to complete sensitivity analysis. If you do not have this module, you cannot perform automatic sensitivity analysis.

We will examine the sensitivities of the deposit, using the revenue factor 1 pitshell – Pit # 41, to give a broad understanding of sensitivities. Later, we can examine sensitivities of specific schedules once we have created them. 1. Add a Spider Graph node under the Operational Scenario using the right click – Add menu. 2. In the Values to vary section of the Definition tab, click the Add button and browse the data selector for the following information:

3. Examine the Mining, Processing, and Output Groupings from the top left hand panel of the Data Selector then choose the secondary grouping from the right. For example, to select the mining capacity, you would select:

4. In the Values to display in output section, click Add/Edit and, in the Output section, browse to the Discounted open pit value for Specified Case. 5. Click OK twice.


Page30 of40




6. Click Accept. 7. Run the Spider Graph node and examine the graph:


Page31 of40




You can see that for this project, the RF 1 pit is most sensitive to the following: 1. Price of gold. 2. Mining recovery. 3. Metallurgical recovery for FRESH material.


Page32 of40


Final pit and NPV Practical Pushbacks


Final pit and NPV Practical Pushbacks Steps we will follow to determine the final pit and the set of NPV Practical Pushbacks are: 1. Run pit by pit graph to determine likely pushbacks. 2. Run pit by pit graph again to determine final pit. 3. Run NPV Practical Pushbacks to determine mineable pushbacks. 1. Go to the Pit by Pit Graph node under the New Operational Scenario node. 2. Run the pit by pit graph. You don’t need to change anything. This graph will run an NPV analysis for each pitshell using benchmark schedules – worst case and best case. Tip: Best and Worst Case are benchmark schedules and are not designed to be used as realistic mine schedules. Best case schedule is ‘onion skin’ type scheduling where each successive pitshell is mined out before moving to the next. Worst case scheduling is simply starting at the top bench of each pitshell and mining down. These two benchmark schedules will give an upper and lower bound to the NPV for each pitshell.

3. Analyse the graph of the pit by pit graph output.

You can see the upper and lower NPV expectations, and the different pitshells that they occur at. From this graph, we will choose a number of likely pushbacks. This will enable us to plot a specified schedule and base a final pit decision on some more realistic pushbacks. To get a more accurate NPV, we will choose a set of pushbacks to work with. The first will come from the first section of the graph (pits 1-5) then a pushback from the next section (6 – 29) then a pushback from the next tonnage jump (30-35).


Page33 of40




For this tutorial, we will use the middle of each section, 3, 18, 32, then use these pushbacks to determine a likely final pit. 4. Copy the Pit by Pit Graph node by right clicking and selecting Copy Node, then paste. You could also use CTRL-C, CTRL-V (making sure the navigation tree is highlighted in blue) or the toolbar icons. 5. On the Schedule tab, enter the manual pushback definitions as below and use a fixed lead of 7 as an approximation to the final mining schedule. 6. Click the Add button on the right hand side of the Specified Case Pushback Definitions and enter the three pushbacks, separated by commas or spaces.

7. Click Accept to accept the changes and run the Pit by Pit Graph. 8. Examine the pit by pit graph, paying attention to the green line – the specified case – which is the schedule we have defined, pushbacks 3, 18, 32 with a fixed lead of 7 benches between pushbacks. From this graph, we can see that pitshells 35 – 41 will all deliver a similar NPV with our three pushbacks. 9. Again, we will select the middle shell, pit shell 38, as our final pit.


Page34 of40




Create pushbacks Note: You need to have the NPV Practical Pushbacks module to perform this step. If you do not have this module, please continue using pitshells 3,18,32 and 38.

We now want to ensure that we have a practical, but high value set of pushbacks selected for our given final pit, pit #38. To do this, we will use the NPV Practical Pushbacks module to generate pit shells that satisfy mining width constraints but also target maximum NPV for the given pitshell. 1. Rename the New Schedule Graph node to NPV Practical Pushbacks. 2. Enter the following information on the Schedule and Mining Width tabs of the NPV Practical Pushbacks node: Final pit – 38, Scheduling Algorithm – Fixed Lead 7, Pushback Definition – Auto, Number Pushbacks = 4 (3 pushbacks + final pit). Mining Width = 40m, Override default template to allow 4 x 2 block template with a tolerance of 1.


Page35 of40




3. Now, run the NVP Practical Pushbacks node using the Run To icon and examine the results. Note: It might take several minutes for the system to finish processing the pushbacks. The Output tab will show the schedule output information for each period. The Graph tab will show the same information graphically as follows:


Page36 of40




Finally, the Summary tab will display the key indicators for the schedule including expected NPV, and Internal Rate of Return.


Page37 of40




Now, we can use the 3D viewer to examine the shape of our pushbacks. 4. Click on the NPV Practical Pushbacks node and then click the 3D Viewer icon.

5. Click the Revised pit shells button to visualise the pit shells.


Page38 of40




Pushbacks 2 and 3 are very small and might be combined at design time, leaving three practical pushbacks.


Page39 of40


Whittle Introductory Gold Tutorial

Recommend Documents