Introductory Gold Tutorial

8/18/2019 Introductory Gold Tutorial

1/39


2/39

Copyright 2009 Gemcom Software International Inc. (Gemcom).

This software and documentation is proprietary to Gemcom and, except where expressly provided

otherwise, does not form part of any contract. Changes may be made in products or services at

any time without notice.

Gemcom publishes this documentation for the sole use of Gemcom licensees. Without written per-mission you may not sell, reproduce, store in a retrieval system, or transmit any part of the doc-

umentation. For such permission, or to obtain extra copies please contact your local Gemcom

office or visit www.gemcomsoftware.com.

While every precaution has been taken in the preparation of this manual, we assume no respon-

sibility for errors or omissions. Neither is any liability assumed for damage resulting from the use of

the information contained herein.

Gemcom Software International Inc. Gemcom, the Gemcom logo, combinations thereof, and Whit-

tle, Surpac, GEMS, Minex, Gemcom InSite and PCBC are trademarks of Gemcom Software Inter-

national Inc. or its wholly-owned subsidiaries.

Product

Gemcom Whittle 4.3


3/39

Table of Contents

Introduction - Gold tutorial 4

Prerequisites 4

Importing 5

Validation of Imported Model 11

Setting Pit Slopes f or the Optimisation 14

Optimisation 18

Mining Tab 18

Method 1. Using range function alone 18

Method 2. Using line of best fit within a range function 19

Entering the equations into the Mining tab 19

Processing Tab 21

Selling tab 22

Optimisation tab 23

Output tab 23

Operational Scenario 27

Sensitivity analysis 29

Final pit and NPV Practical Pushbacks 32

Create pushbacks 34

Congratulations 39


4/39

Introduction - Gold tutorial

Introduction - Gold tutorial

This tutorial is provided to introduce various parts of software through a worked example. For more

information on any part of this tutorial,

l see the relevant information in the help file

l view demonstration datasets and read notes in the description tab on each nodel contact your local Gemcom office for module information or training options

In this tutorial, we will work with a validated block model from a general mine planning package such

as Surpac, GEMS or other. This block model has been created in the format .mod and also has a cor-

responding .par file.

Prerequisites

You can find these data files in your projects folder \tutorials\gold

l the block modeltraining.mod.

l the parameters filetraining.par.

l the block model validation report training_rpt.txt.

Page4 of39


5/39

Importing

Importing

1. Open Whittle from the desktop icon or Start > All Programs > Gemcom Software > Whit-

tle [ver]

From the project selection dialog, choose Create a new project.

2. This will start the Project Wizard which will guide you through the import process.

3. Enter a name for the project in Project Name.

All the other entry boxes will be filled in, you do not need to do anything more. If you

would like to save the project in a different folder, just rename the Project Directory and

the working directory will be automatically updated.

4. After you have named the project, click Next.

5. Nowselect Whittle block model, and specify the location of the .mod and .par files.

The .mod and .par files can be anywhere on your network.

Page5 of39


6/39

Importing

6. Click the browse button on Model File to import and browse to the location of your

.mod file.

By default, these files will be installed in the \projects directory of your Whittle instal-

lation. 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, click the browse button and browse to the location of the .par file.

8. Click Next.

9. Continue clicking Next without entering any values until you come to the Processes

screen.10. Add a process by clicking the Add button, then edit the row to rename it to MILL (this will

save us time later on).

Page6 of39


7/39

Importing

You can finish at this screen or the next. We will not do anything more until we have val-

idated the model.

Page7 of39


8/39


9/39

Importing

12. Click Next.

This screen allows editing of the model summary information. You do not have to do any-

thing in this screen.

Page9 of39


10/39

Importing

13. Click Finish.

You have now imported the model into the Whittle interface. A range of standard analysis has been

created to guide you through the mine planning process.

Page10 of39


11/39

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. Enter “10 x 20 x 10” in the Description field on the Description tab of theBlock Model

node.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. Nowclick on the Report tab of the Block Model node to check our totals against the val-

idation report from the GMP.

Page11 of39


12/39


5. Further down the report, check the Summary by bench by rocktype.

6. Finally, use the 3D Viewer as a visual check.

7. Click on the block model node in the project tree.

8. Then select Start Three-D Viewer from the icon on the toolbar.

9. Click OK on theSelect data to display dialog box.

Tip: Clicking the block model node in the project tree will bring the block model into

the 3D viewer, later we will visualise different things by clicking on different nodes in the

project tree.

10. In the 3D Visualiser, select the Show Topography box and theShow XZ Plane box.

11. Rotate the view by left clicking and dragging the mouse.

12. Zoom the view by holding down the wheel button of the mouse and moving the mouse

forward or backward.

13. Click Invert to give the 3D Viewer a white background.

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

Page12 of39


13/39


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

One final thing to do on the Block Model node is to set the units of the project to grams,

since that is what our gold element is measured in.

14. On the Formats tab, in theElement data table, choose gram from the drop down menu

as shown:

15. Click Accept to save your changes.

Page13 of39


14/39

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. Then on the Slope Type tab, ensure Rectangular slope regions is selected to define the

slopes.

Tip: Rocktypes 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. Add two new profiles by clicking the Add Profile button and specifying the slope angles

as:

l Profile 1 - Slope 45 degrees

l Profile 2 - Slope 60 degrees

Page14 of39


15/39


Now we want to split the model into two ‘slope regions’ and assign each of our two pro-

files to a different region.

5. First add a second slope region using the Add button in the Slope Regions section.

6. Then split the regions up using the Z value of the model. Change the values so the fol-

lowing regions are defined, then assign the slope profile using the drop down box in the

Slope Profile column:

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. Click the Slope node if it is not highlighted and then click Run To to run all the analysis

down to the selected node (slopes).

9. Now, briefly check the slope errors by clicking the Report tab of the Slopes node.

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.

Page15 of39


16/39


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.

Page16 of39


17/39


These slope errors are acceptable, so we will proceed.

Page17 of39


18/39


19/39

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. Create table as above in Excel.

2. Create line of best fit with linear part of table, below 230RL.

3. Highlight IZ and MCAF columns (below 230RL), Insert scattergraph.

4. 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 theReference Mining Cost and change the radio button

to Calculate 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 func-

tions, variable, and special function.

Page19 of39

http://localhost/var/www/apps/Content/datapanes/common/expressionButton.htmhttp://localhost/var/www/apps/Content/datapanes/common/expressionButton.htmhttp://localhost/var/www/apps/Content/datapanes/common/expressionButton.htm


20/39

Optimisation Entering the equations into the Mining tab

2. 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.

3. If there are no errors, click OK in the expression builder to complete theMining tab.

Your formula should now be shown in the Block mining cost adjustment factors section

of the Mining tab.

Or

Page20 of39


21/39


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

5. Accept the changes on the Mining tab.

When you click Accept, the Data Synchronization form is shown.

6. 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

dialog in this tutorial.

Processing Tab

1. Click on the Processing tab and enter the information as shown below.

The Processing Paths have used the rocktypes in the model file and have been auto-

matically filled out and assigned to the process MILL that we specified in the import wiz-

ard.

2. Use t he Up and Down buttons to the right of the screen to order the Processing Paths in

logical order.

Page21 of39


22/39


3. If you see a blank table, you will have to 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.

4. Click Accept on the processing tab to save.

Selling tab

1. On the Selling tab, enter thePrice to be obtained for the gold, in this case $800/oz or

$25.72/gram.

You can enter either value, just make sure that:

2. The units are correct for the entered price and

3. You have set the element units as grams on the Formats tab of theBlock 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.

Page22 of39


23/39


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.

Page23 of39


24/39


Then we will examine the output pitshells visually. Click on the Pitshells node and start the3D

Viewer

To visually validate the MCAFs, do the following:

1. Snap to View XZ.

2. Show Data – MCAF.

3. Show XZ Plane.

4. Click Info tab.

5. Click Show to float the information window, position it in the top right of the viewer.

Page24 of39


25/39


As you hover over the blocks in the visualiser, the information will be shown in the infor-

mation 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 must 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 Reblocking or contact your local Gemcom office for training options.

9. Click the red X in the top right to exit out of the viewer.10. Go to the Output tab of the Pitshells node and view the range of pits created.

Page25 of39

http://localhost/var/www/apps/Content/datapanes/reblockedBlockModel/advancedReblocking.htm


26/39


We now need to determine the final pit and create some pushbacks for the deposit, but before going

to that stage, we will quickly examine the sensitivities of the deposit.

Page26 of39


27/39

Operational Scenario Entering the equations into the Mining tab

Operational Scenario

The next step is to enter financial information into the New Operational Scenario node.

1. Go to the Operational Scenario node.

Notice that the Mining, Processing and Selling tabs are identical to those on thePit

Shells node.2. On the Time Costs tab, enter the following:

l Capital cost for project $10 million.

l Discount rate 8%.

3. On the Limits tab, enter the mining limit as 5 000 000 (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).

Page27 of39


28/39

Operational Scenario Entering the equations into the Mining tab

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 Sce-

nario node.

5. Ifyou don’t see the Pit by Pit graph, right-click and Adda Pit by Pit graph.

Page28 of39


29/39

Sensitivity analysis Entering the equations into the Mining tab

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 and enter the following information:

2. In the Values to vary section of theDefinition tab, click theAdd 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 S 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 browse to the Discounted

open pit value (NPV). Click OK twice.

Page29 of39


30/39


5. Click Accept.

6. Run theSpider Graph node and examine the graph:

Page30 of39


31/39


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.

Page31 of39


32/39

Final pit and NPV Practical Pushbacks Entering the equations into the Mining tab

Final pit and NPV Practical Pushbacks

Steps we will followto 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.4. Go to the Pit by Pit Graph node under theNew Operational Scenario node.

5. 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.

6. 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 push-

backs.

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).

Page32 of39


33/39


For this tutorial, we will use the middle of each section - 3, 18, 32 - then use these push-

backs to determine a likely final pit.

7. Copy the Pit by Pit Graph node using CTRL-C, CTRL-V (make sure the navigation tree is

highlighted in blue) or use the toolbar icons or use the right-click copy node, paste.

8. 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.

9. 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.

10. Accept the changes and run to the Pit by Pit Graph.

11. Now we can examine the pit by pit graph, paying attention to the green line – the spec-

ified 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.

12. Again, we will select the middle shell, pit shell 38 as our final pit.

Page33 of39


34/39


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. Renamethe New Schedule Graph node to NPV Practical Pushbacks.

2. Enter the following information on the Schedule and Mining Width tabs of theNPV Prac-tical 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 tol-

erance of 1

Page34 of39


35/39


3. Now, run the NVP Practical Pushbacks node using theRun 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:

Page35 of39


36/39


Finally, the Summary tab will display the key indicators for the schedule including

expected NPV, and Internal Rate of Return.

Page36 of39


37/39


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 the3D Viewer icon.

5. Choose to visualise the pitshells by clicking the RES button.

Page37 of39


38/39


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

backs.

Page38 of39


39/39

Date post:	07-Jul-2018
Category:	Documents
Upload:	johnnyrondanricaldi
View:	226 times
Download:	1 times

Introductory Gold Tutorial

Documents