fxmansin

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Four-XStrategic Planning Software for Open Pit

Mines

Getting Started Manualfor the Single Element version of Four-X

As for print of November, 1998

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Copyright 1996, 1997, 1999 Whittle Programming Pty Ltd. All rights reserved.

Apart from any use as permitted under the Berne Convention and the relevant Copyright Act of eachcountry, no part of this publication may be reproduced by any process without prior written permissionfrom Whittle Programming Proprietary Limited, Melbourne, Australia, A.C.N. 065 377 004.

This version of the Getting Started Manual for the Single Element version of Four-Xwas released with revision 1.10 of Four-X.

Whittle Programming Pty LtdLevel 41013 Whitehorse RoadBox HillVictoria 3128AUSTRALIATelephone: +61 3 9899 3799Facsimile: +61 3 9899 3755

email: [email protected]: www.whittle.com.au

Table of Contents5 July, 1999

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Table of Contents

USING THIS MANUAL ________________________________________ 6Overview____________________________________________________________________6Conventions Used in this Manual _________________________________________________7Terminology and Abbreviations __________________________________________________8

GETTING STARTED__________________________________________ 9Overview____________________________________________________________________9Hardware and Software Requirements ____________________________________________10Installation__________________________________________________________________11Preparation _________________________________________________________________14Using the Four-X Menu _______________________________________________________15Using the Command Line ______________________________________________________18At the Terminal ______________________________________________________________20

TUTORIAL 1 - THE BASICS___________________________________ 23Overview___________________________________________________________________23Step 1: Examining Data with the Utilities Program __________________________________24Step 2: Producing the Structure Arcs with the Structure Arcs Program ___________________30Step 3: Doing the Pit Optimization with the Optimization Program______________________35Step 4: Using the Pit Visualisation Program to Produce Diagrams of the Pits ______________40Step 5: Analysing the Results File with the Analysis Program __________________________44File Summary _______________________________________________________________61What you have Learnt _________________________________________________________62

EXERCISE 1 - USING DIFFERENT PIT SIZES ____________________ 63Overview___________________________________________________________________63Step 1: Procedure ____________________________________________________________64Step 2: Examining the Print File _________________________________________________67Step 3: Using Value Ranges to Enter a Series of Pit Numbers __________________________69

TUTORIAL 2 - FURTHER ANALYSIS OF THE RESULTS FILE _______ 70Overview___________________________________________________________________70Step 1: Running the Analysis Program with a Log File and Spreadsheet Output ____________72Step 2: Examining the Log File and Spreadsheet Output ______________________________75File Summary and What you have Learnt __________________________________________79

Continued on next page


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Table of Contents, Continued

EXERCISE 2 - DEALING WITH THE LARGE PIT-SIZE DIFFERENCES 80Overview___________________________________________________________________80Step 1: Procedure ____________________________________________________________81Step 2: Analysing the Output ___________________________________________________84

TUTORIAL 3 - USING CONTRACT MINING ______________________ 85Overview___________________________________________________________________85Tutorial 3a: Adding One Million Tonnes of Contract Mining in the First Period____________87Tutorial 3b: Using a Range of Capacities in the First Period ___________________________89What you have Learnt _________________________________________________________93

EXERCISE 3 - USING THREE PUSH-BACKS_____________________ 94Overview___________________________________________________________________94Step 1: Determining the Preliminary Push-backs ____________________________________95Step 2: Examining the Spreadsheet Definition File___________________________________96Step 3: Using the Analysis Program with Specified Schedules__________________________97Examining the Spreadsheet Output _______________________________________________99

TUTORIAL 4 - RE-ARRANGING A MODEL______________________ 100Overview__________________________________________________________________100Step 1: Extending the Model___________________________________________________102Step 2: Running the Other Programs with the New Model ____________________________103What you have Learnt ________________________________________________________105

EXERCISE 4 - ADDING POSITIONAL MINING CAFS______________ 106Overview__________________________________________________________________106Running the Re-blocking Program ______________________________________________107

TUTORIAL 5 - DEALING WITH AN OBSTRUCTION_______________ 108Overview__________________________________________________________________108Step 1: Preparing the Special Model File _________________________________________109Step 2: Running the Re-blocking, Optimization and Pit Visualisation Programs ___________110What you have Learnt ________________________________________________________112

EXERCISE 5 - SHOULD THE MILL BE MOVED? _________________ 113



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Table of Contents, Continued

TUTORIAL 6 - THE BASICS OF MINING WIDTH CONTROL ________ 114Overview__________________________________________________________________114Step 1: Running the Mining Width Program_______________________________________115Step 2: Examining the Print File ________________________________________________116Step 3: Running the Analysis Program using the Modified Results File__________________120For More Information ________________________________________________________121

EXERCISE 6 - FURTHER TIDYING UP _________________________ 122Overview__________________________________________________________________122Step 1: Using the Mining Width Program with a Log File ____________________________123Step 2: Doing Analyses with the Analysis Program _________________________________126Step 3: Examining the Results__________________________________________________127

TUTORIAL 7 - IMPROVING THE SCHEDULING WITH MILAWA _____ 128Overview__________________________________________________________________128Step 1: Creating the Spreadsheet Definition File ___________________________________130Step 2: Scheduling using Milawa in improving NPV mode ___________________________131What you have Learnt ________________________________________________________137

EXERCISE 7 - EXPLORING FURTHER OPTIONS ________________ 138Overview__________________________________________________________________138Step 1: Checking the earlier push-back___________________________________________139Step 2: Using Milawa in improving throughput balance mode _________________________140Step 3: Extending the ultimate pit _______________________________________________142

INDEX ___________________________________________________ 143

Using this Manual5 July, 1999

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Using this Manual

Overview

Introduction This part provides information about how to use this Manual.

In this part This part contains the following topics.

Topic See Page

Conventions Used in this Manual 7

Terminology and Abbreviations 8


7

Conventions Used in this Manual

Introduction There are a number of conventions that are used in this Manual and theseconventions are detailed below.

Enter symbol “↵↵” In this Manual, the symbol “↵” is used to indicate that you need to press the“Enter” (or Return) key.

Here is an example.

In response to the question, “Please enter a name for the print file”, type tut1↵↵

In the preceding example, the “↵” indicates that you need to press the Enter keyafter typing “tut1”.

Italics Italics are used to highlight references to related topics or documentation.

Here is an example.

For more information, see Using this Manual, starting on page 6.

Bold type Bold type is used:

• To show the user’s response to a question asked by Four-X

Here is an example.

Print file name Call the print file tut1.pra

• To emphasise important words or to highlight filenames

Here is an example.

The initialization file is called fs.ini.


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Terminology and Abbreviations

Terminology There are a number of terms that have meanings that are peculiar to Four-X.For more information, refer to the Glossary in the Four-X Reference Manual.

Abbreviations The following abbreviations are used in this Manual.

Abbreviation Term

CAF Cost Adjustment Factor

IRR Internal Rate of Return

k Thousand(s)

m Million(s)

NPV Net Present Value

PC Personal Computer

Getting Started5 July, 1999

9

Getting Started

Overview

Introduction Four-X is a large package with a wide range of facilities. You may not need touse all of these facilities, but you need to know what options exist and whatthey can do for you in order to be able to choose the appropriate facilities foryour project. These tutorials and exercises have been created with this in mind.

In this Manual This Manual contains 7 tutorials and 7 related exercises that are of increasingcomplexity and difficulty, each building on what has been learnt before.

Because of this, we recommend that you work through the tutorials andexercises sequentially.

Four-X ReferenceManual

This Manual is designed to be used in conjunction with the Four-X ReferenceManual.

We advise therefore, that you read through the Four-X Reference Manualbefore attempting Tutorials and Exercises 2 to 7. If you do not, you may findthem hard to follow.

Note: These tutorials and exercises use ore selection by cut-off. You can alsouse ore selection by cash flow, but this is much less common. For moreinformation, Refer to the Four-X Reference Manual.

In this part This part contains the following topics.

Topic See Page

0 10

0 11

Preparation 14

0 15

0 18

0 20


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Hardware and Software Requirements

Introduction This section lists the hardware and software requirements for running Four-Xon a:

• PC• UNIX workstation

PCs Minimum requirements

• IBM compatible PC version 386• 4MB of memory• Maths co-processor• 100MB of free disk space

Preferred

• IBM compatible Pentium PC• 32MB of memory• 300MB of free disk space

Platforms

Four-X will run:

• Under DOS• In a DOS window under Windows 3.x, Windows 95, Windows NT and OS/2

Note: When used in a multi-tasking environment, Four-X can be run as either aforeground or background task.

UNIX workstations Minimum requirements

• 16MB of memory• 100MB of free disk space

Preferred

• 32MB or more of memory• 300 MB or more of free disk space

Four-X is ported to all of the major UNIX platforms (DEC, HP, SGI and SUN).Check with Whittle Programming for a current list of manufacturers.


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Installation

Installing Four-Xon your PC

PCs This section details the procedure for installing Four-X on your PC.

Other computersIf you are installing Four-X on a computer that is not a PC, then you will begiven separate instructions about installing it.

The diskettes This release consists of:

• Three program diskettes:

- Four-X, Disk 1 of 3, PC Version



• One installation diskette for Windows icons:

- Four-X, Disk 1 of 1, Whittle Icons

If this is your first copy of Four-X, you will also receive a separate diskettecontaining the Four-X initialization file (fs.ini). Note that the Four-XReference Manual refers to the initialization file as fx.ini throughout. That isthe name used for the Multi-Element version of Four-X.

Existing users will have received their initialization file on a separate diskettewhen they received their first copy of Four-X.

Installing Four-X Follow these steps to install Four-X on your PC.

Step Action

1. Make sure you are in MS-DOS mode or you have a DOS windowopen.

2. Select your hard drive as the default drive.

Example

Type “C:” at the DOS prompt, then press the Enter key (↵↵)to change your default drive to the C drive.

3. Insert the disk labelled Four-X, Disk 1 of 3, PC Version into adiskette drive.



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Installation, Continued

Installing Four-X (continued)

Step Action

4. At the DOS prompt, run the program, INSTALL, by typing:

x:INSTALL (then press the Enter key “↵”),

where x is the letter name of the diskette drive.

Example

C:> a:INSTALL ↵

In this example, Four-X would be installed from the A drive.

5. Follow the instructions on the screen carefully. The Four-X packagewill be installed onto your computer.

By default, the installation will install the programs into C:\4X andthe tutorial information into C:\4X\TUTOR. You can change thesedefaults and also control what to load.

Installing Whittleicons

If you are running under Windows 3.1, 95 or NT, you can also install theWhittle icons. To do this follow the instructions below.

Step Action

1. Insert the disk labelled Four-X, Disk 1 of 1, Whittle Icons into adiskette drive.

2. At the DOS prompt, run the program, INSTALL, by typing:

x:INSTALL (then press the Enter key “↵”)

Where x is the letter name of the diskette drive.

Example

C:> a:INSTALL ↵

In this example, the Four-X icons would be installed from theA drive.

Follow the instructions on the screen carefully.

The Whittle icons will be installed onto your computer.



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Installation, Continued

Location of theinitialization file

On a separate diskette, you will have been provided with an fs.ini file. In orderto use Four-X, copy fs.ini:

• Into the tutorial directory (e.g. \4x\tutor)

• Into any directory where you intend to do work with Four-X

We also suggest that you store it in a directory \4x\ini for safekeeping.

For moreinformation

For more information, refer to the instructions:

• Provided with the program

• In the readme.txt file included with the programs


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Preparation

Introduction This topic contains information that you need to know in order to run thetutorials and exercises.

Disk space You will need about 50 megabytes of disk space.

Directory and files The tutorials and exercises make use of a small set of demonstration files thatare supplied with your software.

The instructions assume that you are working in the directory containing thetutorial data files. On a PC, this is usually directory C:\4X\TUTOR.

Please check this by using the “DIR” command on a PC under DOS, the “ls”command under UNIX, or the appropriate action in one of the graphicaloperating environments (e.g. Windows).

You should find at least the following files.

File Description

fstut.mod A Model File for a single element model. It contains details ofthe contents of the blocks. The model represents a small golddeposit.

fstut.par A Parameters File that gives information about the model as awhole and about the slope and economic requirements.

tut2.ssd A Spreadsheet Definition File that is used in Tutorial 2.

exer3.ssd A Spreadsheet Definition File that is used in Tutorial 3.

tut5.mil A small portion of a Model File that is used in Tutorial 5.

Other files In addition, you must have an initialization file, called fs.ini in your current, ordefault, directory. This file is usually supplied to you separately from theprograms and tutorial data.

Important to keepfiles

It is important to keep the all of the files that you generate in the tutorials andexercises. This is because some of them are used again in the tutorials andexercises that follow.


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Using the Four-X Menu

Introduction The Four-X package includes a Menu from which you can access the programs.

Note: You can also access the programs from the Command Line. For moreinformation, see page 18.

Accessing theMenu

The Menu can be accessed in two ways.

If you are using… then access the Menu…

The Command Line By typing FXMENU and pressing the Enter key (↵)

Windows® Via the Whittle Four-X icon which looks like this.

Once the Menu is accessed, all programs will return to the Menu oncompletion, after the message: Press any key to continue…

The Four-X Menu looks like this.

Main Menu bar Working directory

Selection submenu

Note: The Menu looks slightly different under UNIX.



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Using the Four-X Menu, Continued

Main Menu Bar The Main Menu Bar has 3 “drop down” submenus:

• Files• Options• Selections

Selection submenu By default, the Four-X Menu opens with the Selection submenu displayed,ready for you to select a program. The Selection submenu appears on the right-hand side of the screen.

The Selection submenu lists the Four-X programs, generally in order of use.

It also allows you to:

• View output• Invoke a text editor• Exit from the program

When another submenu has been selected, the Selection submenu is still visible,but it is greyed out, and you will be unable to select any of the items from it.

Files submenu The Files submenu sets the locations, or “paths”, of:

• The working directory The path for the working directory is displayed above the Selection submenu.

The working directory should be set to where your data and fs.ini files arelocated.

• The Four-X programs The program path is automatically set up during the installation process. If

you change the location of the programs, then the program path must beupdated. The system will check to ensure that the programs exist in thedirectory you specify.

• The viewer This allows you to specify the path for a file viewer. PC users might like to use LIST (shareware†). UNIX users might like to use

more, emacs, jove or vi.


† LIST is readily available but if you have difficulty in locating a copy, contact Whittle Programming.


17

Using the Four-X Menu, Continued

Files submenu (continued)

• The editor This allows you to specify the path for a text editor. Note: You only need a

text-based editor.

PC users might like to use: EDIT (provided with MS-DOS 5.0 and above) orLIST (shareware†). UNIX users might like to use emacs, jove or vi.

The system will check to ensure that the program exists.

The Files submenu also allows you to exit from the program.

Options submenu The Options submenu sets the Menu colour.

The colour of the Menu can be changed to monochrome, or to a variety ofcolour schemes.

Selecting items You can select an item from the Menu or a submenu by:

• Moving the highlighted bar with the arrow keys on the keyboard and thenpressing the Enter key (↵↵)

• Typing one of the letters or numbers highlighted in the Menu items

For example, if you type the letter “O” when the Selection submenu isdisplayed, the Optimization Program would start.

• Using the point and click method, with a mouse

Exiting The Menu can be exited by:

• Choosing eXit from the Selection submenu or from the Files submenu

• Pressing the Escape key (Esc) twice and then pressing the Enter key (↵)

† LIST is readily available but if you have difficulty in locating a copy, contact Whittle Programming.


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Using the Command Line

Introduction This topic describes how to access the programs using the Command Line.

Note: You can also access the programs via the Four-X Menu. For moreinformation, see 0 on page 15.

The CommandLine

The programs can be accessed from the Command Line, by typing in theCommand Line name and pressing Enter (↵).

Command Linenames

Here is a table of Command line names, and corresponding Program names.

Program name Command Line name

Edit Parameters FXED

Re-blocking FXRE

Structure Arcs FXST

Optimization FXOP

Pit Visualisation FXPI

Mining Width FXMI

Analysis FXAN

Utilities FXUT

Note: The Command Line name is made up of four letters:

• The first two letters of the Command Line name are always FX, for “Four-X”

• The last two letters of the Command Line name relate to the name of theparticular program (underlined above)

Example By typing: FXAN↵↵ at the Command Line, you would start the AnalysisProgram.

Note: Make sure that you are in the appropriate data directory, that a copy offs.ini is also in that directory, and that the Four-X program directory is in yourPATH.

PC users can refer to the readme.txt file located on Four-X, Disk 1 of 3, PCVersion for more information.



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Using the Command Line, Continued

Viewing andprinting print files

You can view or print out a print file by loading it into a word processor or texteditor or from the Command Line.

The following table shows how you can view or print out a print file from theCommand Line.

On a PC On UNIX

To view a print file, try:EDIT <filename andextension>↵

- or -TYPE <filename andextension> | MORE↵

To view a print file, try:more <filename andextension>↵

- or -pg <filename andextension>↵

To print a print file try:print <filename andextension>↵

To print a print file, try:lp <filename andextension>↵


20

At the Terminal

Introduction This topic contains information about user interaction with the Four-Xprograms.

In particular, it discusses:

• Prompts and answers• Selecting from a list of items• Default answers• Editing default answers and text• Overwriting files• Exiting a program

Prompts andanswers

All user interaction with Four-X takes the form of prompts for information, towhich you respond by typing an answer.

The prompts request:

• Decisions• Values• Filenames

Below is an example of a prompt.

Please enter the name of the print file :

Selecting from alist of items

Sometimes Four-X will display a list of options or items from which you canchoose.

Generally, items can be selected by typing one of the highlighted letters ornumbered options in the list.



21

At the Terminal, Continued

Default answers Four-X will often provide a default answer in a prompt. The default answer isalways enclosed in square brackets: [ ]

If the default answer is the answer you want to give, press the Enter (↵) key.

Example

Here is an example of a default answer.

How many Model Files do you want to input [1]?

In this example, if you press Enter, 1 Model File will be used.

Editing defaultanswers and text

Editing default answers

On PCs and some other systems, it is possible to edit default answers.

If a default is given and the first key you press is either the “backspace” key orthe “left arrow” key, then the default answer will appear on the screen as thoughyou had typed it. You will then be able to edit it.

Editing text

The following table lists the effects of the various keys on text.

Key Function

End Moves the cursor to the end of the text.

Home Moves the cursor to the start of the text.

Left arrow Moves the cursor one character to the left.

Right arrow Moves the cursor one character to the right.

DEL Deletes the character at the cursor position.

Backspace Deletes the character to the left of the cursor.

INS Toggles between insert and overtype mode.

Ctrl + Y Deletes all the text.

Esc Restores the text to the original default answer (seeDefault answers, above).



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At the Terminal, Continued

Overwriting files If you want to overwrite an existing file with a new file, you will need to type a# in front of the filename. Four-X will not allow you overwrite an existing fileunless you do this.

Example

By typing: #myrun1↵↵ you would be telling Four-X to overwrite the file,myrun1.

If Four-X suggests a default filename that you want to re-use, you merely haveto type the # character.

The # character does not form part of the filename.

Note: On some UNIX systems # is set up as the erase key. If this is the case onyour system, please redirect erase to another key.

Exiting from aprogram

PC

To exit from a program on a PC, hold down the Control key (Ctrl) and type theletter C. If you have not yet typed a response, you will then need to press theEnter key (↵).

UNIX

Under UNIX, the command for exiting a program varies as it is usually set upby the user. However, as a starting point we suggest that you try Ctrl C orCtrl Y.

Tutorial 1 - The Basics5 July, 1999

23

Tutorial 1 - The Basics

Overview

Introduction The object of this tutorial is for you to become familiar with the generaloperation of the programs. It makes use of a small gold deposit.

In working through this tutorial, you will:

• Examine your data with the Utilities Program.

• Convert your slope requirements into a form that is suitable for pitoptimization, using the Structure Arcs Program.

• Carry out a straightforward pit optimization using the Optimization Program.

• Examine the resulting outlines using the Pit Visualisation Program.

• Use the Analysis Program to do a preliminary analysis of the Results File.

In this tutorial This tutorial contains the following topics.

Topic See Page

Step 1: Examining Data with the Utilities Program 24

Step 2: Producing the Structure Arcs with the Structure ArcsProgram

30

Step 3: Doing the Pit Optimization with the OptimizationProgram

35

Step 4: Using the Pit Visualisation Program to ProduceDiagrams of the Pits

40

Step 5: Analysing the Results File with the Analysis Program 44


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Step 1: Examining Data with the Utilities Program

Introduction You will use the Utilities Program to examine the data contained in thefollowing files:

• The Parameters File, fstut.par (provided)

• The Model File, fstut.mod (provided)

You will use the Utilities Program in its “summarise a data file” mode.

Procedure Start the Utilities Program.

If you are using… then…

The Menu Select the Utilities Program from the Menu

The Command Line Type FXUT and then press the Enter key (↵↵).

It will display a heading similar to the one shown below, and will then ask forcertain information.

Whittle Four-X UTILITIES Single element Rev 1.10 Licensed for use by -Your Company name will appear here- ------------------------------------------------------------------------------

Please enter a name for the print file :

Do the following in response to the prompts.

Prompt Action

Print file name Call the print file tut1.pru† .

Select main option Type 1 to choose the “summarise a data file” mode.

Do you want to use aParameters File?

Accept the default [Y] offered by the program bypressing the Enter key.

Parameters File name Use the Parameters File provided, fstut.par.

Note: Four-X stores a list of default file extensions in fs.ini and will add theappropriate file extension when you do not provide one.


† If an output file already exists, as a result of a previous run, the program will display a message to thiseffect and will ask for the file name again. Enter the name again, but put a cross hatch (#) in front of it toindicate that you want to overwrite the existing file. Alternatively you can just enter the cross hatch, whichwill have the same effect.


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Step 1: Examining Data with the Utilities Program, Continued

Procedure (continued)

What you see on the screen looks like the following.

Note: We have added the Enter symbol “↵” to the following example screen tomake it clear where you press the Enter key. You will not actually see the ↵symbol on the screen when you press the Enter key.

Please enter a name for the print file : #tut1.pru ↵↵

SELECT MAIN OPTION

1. Summarise a data file 2. Show block value calculations 3. Show cut-off variation with processing CAF 4. Show Four-X system limits

Your choice : 1 ↵↵

Do you want to use a Parameters File (Y/N) [Y] ? y ↵↵

Please enter the name of the input Parameters File : fstut.par ↵↵

A new screen is displayed. Do the following in response to the prompts.

Prompt Action

Select file type Type 1 to summarise a Model File.

Model File Use the Model File provided, fstut.mod.



26




SELECT FILE TYPE

1. Use Model File 2. Use Results File 3. Use Mining Sequence File

Your choice : 1

Please enter the name of the input Model File : fstut.mod

A new screen is then displayed. Do the following in response to the prompts.

Prompt Action

Select type of summary Type 1 to choose “counts only”.

Rock-types excluded Press Enter to leave this blank.

Exclude any ore? Accept the default [N].

Output data for spreadsheet use? Type N.

What you see on the screen looks like this.

SELECT TYPE OF SUMMARY

1. Counts only 2. Distribution graphs only 3. Both counts and graphs

Your choice : 1

Rock types may be excluded from the summary.

Enter a list of rock type codes to exclude (separated by a space) or leave blank for no exclusions :

Do you want to exclude any ore (Y/N) [N] ?

Do you want to output data for spreadsheet use (Y/N) [Y] ? n

The program then starts its run.



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Examining theprint file

Now examine the print file (tut1.pru) in detail by printing it out, or by viewingit on the screen with a system utility, text editor or word processor. Forguidelines on how to do this, see Viewing and printing print files on page 19.

Apart from page headings, the print file contains:

• A listing of the contents of the Parameters File Note: This information appears at the start of every Four-X print file.

Input Parameters File - fstut.par

Contents of the Parameters File -

1 10.00 10.00 8.00 2 33 64 23 3 1 2 0 0 1 2.00 4 1 33 1 64 19 23 5 1 5 6 0.00 37.00 4 1 33 1 64 1 18 5 2 10 6 0.00 50.00 6 180.00 55.00 12 0 0 7 2 0 $ 13 2160 2 3 1.250 1

14 0.25 0.025 2.5

18 GOLD 1 2 0 3 20 GOLD 500.00 21 WTHR 1.000 0 1.000 21 OXID 1.000 0 1.000 21 SULF 25 MILL OXID 21.250 26 GOLD C 0.950 25 MILL SULF 18.750 26 GOLD C 0.900

• File count information

File count information -

12840 Blocks were read: 2587 were air (no rock) 10253 contained parcels: 10253 parcels might be processed



28


Examining the print file (continued)

• Active model dimensions

X Y Z Minimum block 1 1 1 ore 1 1 1 Maximum block 33 64 23 ore 33 64 23

• Total tonnage and element content

Total ROCK in file 18762480 tonnes Total GOLD in file 530487 units

WASTE is calculated from ROCK minus total parcel tonnage

• A summary by rock-type

Summary by rock type -

Rock No of Mine Proc Total Total ---------- Grade ---------- Type Parcels CAF CAF Tonnes Element Minimum Average Maximum

-------------- ------ ------ --------- --------- -------- -------- --------

OXID 348 1.000 1.000 640320 64675 0.037 0.101 0.229 SULF 3087 1.000 1.000 6667920 465812 0.018 0.070 0.220 -------------- ------ ------ --------- --------- -------- -------- --------

TOT 3435 1.000 1.000 7308240 530487 0.018 0.073 0.229 WASTE 1.000 1.000 11454240

This shows that there are 18,762,480 tonnes of rock and 7,308,240 tonnes ofore, with average oxide and sulphide gold grades of .101 and .070 oz pertonne, respectively.



29



• A summary by bench

Summary by bench by rock type -

Bench Mine Proc Total Total ---------- Grade ---------- Rock CAF CAF Tonnes Element Minimum Average Maximum

-------------- ------ ------ --------- --------- -------- -------- --------

23 WASTE 1.000 1.000 697200 22 WASTE 1.000 1.000 2002560 OXID 1.000 1.000 55200 6094 0.047 0.110 0.210 21 WASTE 1.000 1.000 3393600 OXID 1.000 1.000 169280 17557 0.037 0.104 0.229 20 WASTE 1.000 1.000 3281040 OXID 1.000 1.000 224480 22228 0.040 0.099 0.197

. . . and so on.


30

Step 2: Producing the Structure Arcs with the Structure ArcsProgram

Introduction In this step you will convert your slope requirements into a form that is suitablefor pit optimization, using the Structure Arcs Program.

Procedure Start up Structure Arcs Program (FXST).


The Menu Select the Structure Arcs Program from the Menu

The Command Line Type FXST and then press the Enter key (↵).

It will display a heading similar to the one shown below, and will then ask forcertain information.

Whittle Four-X STRUCTURE ARCS Single element Rev 1.10 Licensed for use by -Your Company name will appear here- ------------------------------------------------------------------------------

Please enter a name for the print file : _


Prompt Action

Print file name Call the print file tut1.prs†.

Parameters File Use the Parameters File suggested, [fstut.par].

Use an AdditionalArcs File?

Accept the default [N] by pressing the Enter key.

Structure Arcs Filename

Call the Structure Arcs File tut1.stu†

.




31

Step 2: Producing the Structure Arcs with the Structure ArcsProgram, Continued



Please enter a name for the print file : #tut1.prs

Please enter the name of the input Parameters File [fstut.par] :

Slope profiles appeared in the Parameters File.

Do you have a file of additional arcs to add (Y/N) [N] ?

Please enter a name for the Structure File : #tut1.stu


Output The Structure Arcs Program reports on the screen the slope accuracy for eachof the two slope profiles.

The report looks like this:

====================================================================== Preparing the possible arcs list for slope profile 1

With 5 levels, there are 21 possible arcs per block.

This gives an average slope error of 1.1 degrees.

Preparing the possible arcs list for slope profile 2


This gives an average slope error of 1.1 degrees. ======================================================================

A more detailed report on slope accuracy appears in the print file (tut1.prs).

The Structure Arcs Program gives progress reports as it generates the structurearcs and writes them out in the Structure Arcs File.

In this tutorial example, it should report that 1,698,317 arcs are output.



32



Now examine the print file (tut1.prs) in detail by printing it out or viewing iton the screen (see page 19 for guidelines).

The print file should look like this.

Whittle Four-X STRUCTURE ARCS Page 1 Single element 14:39 Rev 1.10 27-OCT-98 Licensed for use by -Your Company name will appear here- ------------------------------------------------------------------------------

Input Parameters File - fstut.par


1 10.00 10.00 8.00 2 33 64 23 3 1 2 0 0 1 2.00 4 1 33 1 64 19 23 5 1 5 6 0.00 37.00 4 1 33 1 64 1 18 5 2 10 6 0.00 50.00 6 180.00 55.00 12 0 0 7 2 0 $ 13 2160 2 3 1.250 1

14 0.25 0.025 2.5


-----------------------------------------------------------------------------

The parameters as understood by the program -

* XYZ block dimensions - 10.00 by 10.00 by 8.00

* XYZ model dimensions in blocks - 33 by 64 by 23

* Total blocks - 48576

Sub-region 1 -

* Extends from block 1 to 33 in the X direction * Extends from block 1 to 64 in the Y direction * Extends from block 19 to 23 in the Z direction

* Number of benches to consider when generating the structure vectors - 5

* No default block tonnage was defined for this sub-region

* The slopes for this sub-region -

Bearing - 0.0 Slope - 37.0



33


Sub-region 2 -





Bearing - 0.0 Slope - 50.0 Bearing - 180.0 Slope - 55.0

-----------------------------------------------------------------------------

Structure File - tut1.stu



If these are applied repeatedly from a block mined at level 1, then the blocks shown below must be mined at level 5.

***************** * * * * * * * +++ * * +++++++ * * +++++++ * +++++++++ * Y ++++O++++ * +++++++++ * * +++++++ * * +++++++ * * +++ * * * * * * * ******* X *******

If sampled all round at one-degree intervals:-

the minimum slope error is 0.0 degrees, the average slope error is 1.1 degrees, and the maximum slope error is 1.7 degrees.



34




If these are applied repeatedly from a block mined at level 1, then the blocks shown below must be mined at level 10.

******************* * * * * * + * * +++++++ * * +++++++++ * * +++++++++ * * +++++++++++ * +++++++++++ * Y +++++O+++++ * +++++++++++ * * +++++++++++ * * +++++++++ * * +++++++ * * +++ * * * * * ******** X ********

At the specified bearing of 0.0 the slope error is 0.2 degrees. At the specified bearing of 180.0 the slope error is 0.2 degrees.

If sampled all round at one-degree intervals:-

the minimum slope error is 0.0 degrees, the average slope error is 1.1 degrees, and the maximum slope error is 2.1 degrees.

1698317 arcs output to the Structure File.

The run time was 0 hrs 0 mins 9 secs

The print file contains:

• A listing of the contents of the Parameters File, and a detailed explanation ofthe parameters pertaining to structure arcs

• The name of the output file

• For each slope profile:

- Detailed information on the slope accuracy

- Diagrams showing the blocks influenced by the slopes


35

Step 3: Doing the Pit Optimization with the Optimization Program

Introduction In this step, you will carry out a straightforward pit optimization using theOptimization Program.

Procedure Start up the Optimization Program (FXOP).


The Menu Select the Optimization Program from the Menu

The Command Line Type FXOP and then press the Enter key (↵↵)

It will display a heading similar to the one shown below.

Whittle Four-X OPTIMIZATION Single element Rev 1.10 Licensed for use by -Your Company name will appear here- ------------------------------------------------------------------------------



Prompt Action

Print file name Call the print file tut1.pro†.

Restart run? Use the default [N] offered by the program.

Parameters File Use [fstut.par].

Model File Use [fstut.mod].

Structure Arcs File Use the Structure Arcs File created in Step 2,above, [tut1.stu].

Work File name Call the Work File tut1.wrk† .

Results File name Call the Results File tut1.res†.




36

Step 3: Doing the Pit Optimization with the OptimizationProgram, Continued



Please enter a name for the print file : #tut1.pro

Is this a restart run (Y/N) [N] ?


Please enter the name of the input Model File [fstut.mod] :

Please enter the name of the Structure File [tut1.stu] :

Please enter a name for the Work File : #tut1.wrk

Please enter a name for the output Results File : #tut1.res

Note that the package has remembered three of the filenames from previousruns (namely fstut.par, fstut.mod, tut1.stu). This information is stored in thefile fs.ini which is re-written after the user has entered all of the filenames anddata at the keyboard.

Output As the program does the optimizations required to produce a set of nested pits,you will see various messages on the screen telling you what is happening† .

The time taken for the optimizations depends on your computer, but will bemeasured in minutes rather than hours.

The last message on the screen (apart from the run-time message) should tellyou that it is printing pit 62.

You may find it surprising that, after 90 optimizations, there are only 62 pitoutlines. This is because, in some cases, the economic change between twooptimizations was too small to change the outline by even one block.


† Do not be concerned by the fact that the first optimization is number 2. This is because optimization 1 iscompleted during the preliminary scan.


37



Now examine the print file (tut1.pro). As this file is quite big, we suggest thatyou look at it on the screen rather than printing it out.

The print file contains:

• A listing of the contents of the Parameters File, and a detailed explanation ofthe parameters pertaining to optimization

• Details of the files used

• Counts of the blocks read from tut1.mod (12,840)

• Details of the progress of each of the 90 optimizations

• Counts of the blocks written to tut1.res (14,955)

• For each of the 62 pit outlines starting with the smallest:

- The pit number, and a letter if the number is greater than 9 (this is usedwhen printing plans and sections of the pits)

- The Revenue Factor value(s) for which it is optimal

- The applicable cut-offs

- For each bench:

The tonnes mined (“Rock”) with the stripping ratio

The tonnes, element content and grade of the material processed for gold.

The tonnes, element content and grade of unprocessed mineralised material(Reject)

- Grand totals of the tonnages and grades



38


Example Pit 1 Pit 1 is an example of a pit which is optimal for a specific Revenue Factor.

Pit 1 which is optimal for ======= a Revenue Factor of 0.2500000

--------------------------------- Rock Process Cut-off Type Method Element /over OXID MILL GOLD 0.179 SULF MILL GOLD 0.167 ---------------------------------

Strip Bench Method Product Tonnes /Element Grade

22 Rock 3680 0.00 MILL GOLD 3680 738 0.201

21 Rock 3680 0.00 MILL GOLD 3680 737 0.200 --------- --------- --------- Totals Rock 7360 0.00 MILL GOLD 7360 1475 0.200 --------- --------- ---------



39


Example pit 48 Pit 48 is an example of a pit which is optimal for a range of Revenue Factors.

Pit 48 (m) which is optimal for ======= a Revenue Factor range 1.4250000 to 1.5000000

--------------------------------- ----------------------------- Rock Process Cut-off Cut-off Type Method Element /over /over OXID MILL GOLD 0.031 0.030 SULF MILL GOLD 0.029 0.028 --------------------------------- -----------------------------

Strip Strip Bench Method Product Tonnes /Element Grade Tonnes /Element Grade

23 Rock 275520 999.99 999.99

22 Rock 1321920 22.95 22.95 MILL GOLD 55200 6094 0.110 55200 6094 0.110

21 Rock 2148320 11.69 11.69 MILL GOLD 169280 17557 0.104 169280 17557 0.104

… and so on …

--------- --------- --------- --------- --------- --------- Totals Rock 22491120 2.14 2.14 MILL GOLD 7163520 523754 0.073 7170000 523937 0.073 Reject GOLD 45360 1180 0.026 38880 997 0.026 --------- --------- --------- --------- --------- ---------

Note: Although the pit outline, and hence the total tonnage, is the same for thetwo Revenue Factors, the cut-offs, and hence the tonnes and grades processed,are different.


40

Step 4: Using the Pit Visualisation Program to Produce Diagramsof the Pits

Introduction In order to get some idea of the shape of the nested pits, you will now use thePit Visualisation Program to create plans and sections of the pits.

Procedure Start up the Pit Visualisation Program (FXPI).


The Menu Select the Pit Visualisation Program from the Menu

The Command Line Type FXPI and then press the Enter key (↵↵).


Whittle Four-X PIT VISUALISATION Single element Rev 1.10 Licensed for use by -Your Company name will appear here- ------------------------------------------------------------------------------



Prompt Action

Print file name Call the print file tut1.prp.

Parameters File Use [fstut.par].

Type of file that can be read Accept the default [1] to use the ResultsFile.

Results File Accept the default [tut1.res] offered bythe program.

Way of displaying blockscontaining rock

Accept the default [1] to use pit numbers.

Emphasise a pit number Type N.

Planes to display Accept the default [1 2 3].



41

Step 4: Using the Pit Visualisation Program to Produce Diagramsof the Pits, Continued



Please enter a name for the print file : tut1.prp


Three types of file can be read:

1. Results File (with defined pits) 2. Model File (with optional zones) 3. Mining Sequence File (with periods) Your choice [1] :

Please enter the name of the input Results File [tut1.res] :

There are two ways of displaying blocks containing rock:

1. Using pit numbers (1-9,A-Z,a-z) 2. Using value signs (+mineral,-waste) Your choice [1] :

Do you want to emphasise a particular pit number (Y/N) [Y] ? n

Which planes do you want to display (1=XY, 2=XZ, 3=YZ) [1 2 3] ?

The program then starts its run, reads in the Results File and creates plans andsections of the model.


The plans and sections can be found in the print file (tut1.prp). As this file isvery long, we suggest you view it on the screen.

You will find plans and sections laid out like the following sample plans. Notethat the proportions are incorrect because the characters used to represent eachblock are not the same shape as a block.



42


Example plan -top bench

The plan below shows the top bench of the model.

XY plane for Z = 23 facing in the direction of -ve Z

Symbols: "." is air, "1-9,A-Z,a-z" denote pits

**********|*********|*********|**** *............................... * *............................... * *............................... * *............................... * -...............................R - *..............................CP * *..............................AIR* *..............................ACK* *..............................9EI* *..............................9DE* *..............................9DG* *..............................BDG* *..............................BGJ* *..............................BGI* -.............................BFGJ- *.............................EFIJ* *.............................EFIK* *.............................EFHJ* *.............................EGIJ* *.............................FHJJ* *.............................GHJJ* *.............................HHJJ* *.............................HIJJ* *.............................HJJJ* -.............................HJJJ- *.............................HJJK* *.............................HJJK* *............................HHJJL* *............................HJJKL* *............................HJJLL* *............................JJLLR* ............................JLLLR* Y............................KLLPT* ...........................KKLMRV* -...........................KKMRTk- *...........................KLQTi * *..........................KKMTV * *..........................KMOVu * *..........................KMOk * *..........................KOk * *.........................KKO * *.........................KOO * *.........................LOR * *.........................LOz * -.........................OOz - *.........................OO * *........................OOj * *........................Oj * *........................Wx * *........................jx * *........................px * *.......................pv * *.......................vx * *......................vxx * -......................xxx - *.....................vxx * *.....................xx * *....................xx * *....................xx * *.................... * *.................... * *.................... * *.................... * *.................... * **********|***** X *|*********|****

As explained in the header of the plan, the dots represent air blocks and theletters represent pit numbers. You can see from this that the topography slopesupwards to the right.



43


Example plan -third bench fromtop

The plan below shows the third bench from the top, and the full extent of thepits can now be seen.



**********|*********|*********|**** * * * * * * * KP * - PKAAPP - * HHAAAAACP * * rGBAAA5AACIR * * rGGCAAA888AAERb * * KGGGBAAAAA588AEKLb* * GFEEEAAAAA28889EIKL* * GFEEEBAAAA88387DDGKL* * KGFEEEDBAA959798ADEJKL* * yNKKGEEEEDBA975A77ABBGJKL* * ZNKHHGFEEEEA897777BABBFGJKN* - ZNJHGGFEEEEA86777367CDDFGJKN- * ZJJHGGFFEEDCA77573667AEEFIJKR* * fJJHGGGFDD999777777678EEEFIKKR* * fQJHGGFFD9999467777778EEEEGIKKR* * fJIGGGFDD99976167877AEEEEGGIJKR* * fQJGGGFDDB9771667799CCEEEGGHJJKR* * fJJGGGDDBA7766647779CEEEGGHHJJKR* *ffJGGGGDDD77666444779CEEEGGHIJJKR* *fKJGGGGDDDC664664779CCEEEGHHJJJKR* *fKJGGGGDDDCC66669799DDEEEGHHJJJKR* -fJGGGGGDDDDCA66999CCDEEEGGHHJJJKR- *KJGGGGGDDDDCAA999CCCEEEEGGHHJJKLR* *KJGGGGGGDDDDCAA9CCDEEEEGGGHHJJKLR* *KIGGGGGGGDDDDCACCCEEEGGGGGHHJKLRR* *JIGGGGGGGGDDDEDEEEGGGGGGGHHJJLLRT* *JIGGGGGGGGEEEEEGGGGGGGGGGHHJLLQRj* *IIGGGGGGGGGGGGGGGGGGGGGGHHJKLLRTu* IIGGGGGGGGGGGGGGGGGGGGGHHIKLLPTi * YIIHGGGGGGGGGGGGGGGGGGGHHHKKLMRVu * IIHGGGGGGGGGGGGGGGGGGGHHKKKMRVk * -IIHHGGGGGGGGGGGGGGGGGHHKKKMRTj - *JIIHHHGGGGGGGGGGGGGHHHJKKKMTV * *JIIIHHHGGGGGGGGGGGHHHIKKKKMV * *JJIIHHHHHGGGGGGGHHHHIJKKKMO * *LJJIIHHHHHHHHHHHHHHIJKKKKOk * *MLJJIIIHHHHHHHHHHIIJJKKKKO * *MLKJJIIIIHHHHHHIIIJJKKKKNO * *MMLKJJJIIIIIIIIIIJJKKKKLOO * *QMMLKJJJJIIIIIIJJKKKKKKLOj * *ZQMMLKJJJJJJJJJJKKKKKKLOOz * -nVNMLLKKKJJJJKKKKKKKKLNOO - * ZQNMMLKKKKKKKKKKKKKLNOOj * * VQNMMLKKKKKKKKKKKLNOOj * * ZUQNMMLLKKKKKKKLNNOOWv * * xZUONNMMLLLLLMMNOOOWjx * * xpZUQONNNNNNNNOOOOWjpx * * xvpZUQOOOOOOOOOOQWhpvx * * AxvmZUUUQOOOQQUUZhpvx * * xxvmZZUUUUUUUZhhmvxx * * xxxvmhhZZZZZhhmpvxxx * - Axxvvpmmhhhmmppvxxx - * Axxxvvvppppvvvxxx * * Axxxxvvvvvxxxxx * * Axxxxxxxxxxxx * * Axxxxxxxxxx * * AAxxxxA * * * * * * * * * **********|***** X *|*********|****

Adding blocks If you examine the print carefully, you will see that pits 1, 2, 3, and 4 add 2, 1,3 and 7 blocks respectively. Thus the inner pit shells each add only a fewblocks, whereas you can clearly see that pit shells “D” to “K” (representing pitshell numbers 13 to 20) each add a significant number of blocks. It is normalfor some steps in Revenue Factor to produce much larger effects than others.


44

Step 5: Analysing the Results File with the Analysis Program

Introduction In this step you will do a preliminary analysis of the Results File and its nestedpits by using the Analysis Program.

Procedure Start up the Analysis Program (FXAN).


The Menu Select the Analysis Program from the Menu

The Command Line Type FXAN and then press the Enter key (↵↵)


Whittle Four-X ANALYSIS Single element Rev 1.10

Licensed for use by -Your Company name will appear here- ------------------------------------------------------------------------------


Use the following information in response to the prompts.

Note: If you make a mistake, after the spreadsheet question (below) you cancorrect the mistake by either:

• Typing in the ^ symbol to go back to the previous question†

- or -

• Continuing to enter values and responding with “n” when the program asks ifthe “above values are correct”It will then repeat all the questions with your previous responses as defaults,and you can correct your error when you get to it.


† This is a feature specific to the Analysis Program. The ^ symbol cannot be used by any of the otherprograms to go back to the previous question.


45

Step 5: Analysing the Results File with the Analysis Program,Continued

Preliminaryinformation


Prompt Action

Print file name Call the print file tut1.pra.

Parameters File Accept the default [fstut.par].

Results File Accept the default [tut1.res].

Spreadsheet output Type N.


Please enter a name for the print file : tut1.pra


Please enter the name of the input Results File [tut1.res] :

Do you want to output data for spreadsheet use (Y/N) [Y] ? n

Run description Call the run Single element tutorial 1

Enter time/replacementcosts explicitly

Accept the default [N]


RUN DESCRIPTION : Single element tutorial 1

Do you wish to enter time/replacement costs explicitly (Y/N) [N] ?



46


Economic variables Do the following in response to the prompts.

Prompt Action

Initial capital expenditure Accept the default [0].

Reference mining cost Type 1.

Price of GOLD Type 370.

Pit number Type 22.

Discount percentage per period Type 10.

Maximum TONNES of rock per period Type 4m††.

Maximum TONNES per period for method MILL Type 1m.

Maximum units of GOLD per period Accept the default [0].


ECONOMIC VARIABLES

Initial capital expenditure [0] : 0

Reference mining cost [1.25] : 1.00

Price to be obtained for the GOLD [500.00] : 370

Select a pit number ( 1 to 62) : 22

Discount percentage per period [0] : 10

Maximum TONNES of rock per period [0] : 4m

Maximum TONNES per period for method MILL [0] : 1m


† Remember that “m” or “M” can be used to denote millions. Similarly “k” or “K” can denote thousands.


47


Economic variables (continued)

The program then offers to modify the other Parameters File values.


OTHER VALUES (* indicates a modified value)

Mining dilution: 1.000 recovery: 1.000

Elements: GOLD Selling cost: 0

Rock types: WTHR OXID SULF Mining CAF: 1.000 1.000 1.000 Rehabilitation cost: 0 0 0 Throughput factor: 1.000 1.000

Processes: MILL.OXID MILL.SULF

Enter N if you do not wish to change any of these values Y if you wish to modify any of these values Your choice (N/Y) [N] ? _

Prompt Action

Modify these values? Accept the default [N].

Schedule variables Do the following in response to the prompts.

Prompt Action

Specified schedule Accept the default [N].

Worst case schedule Accept the default [Y].

Best case schedule Accept the default [Y].


SCHEDULE VARIABLES

Do you want to produce a specified schedule (Y/N) [N] ?

Do you want to produce the worst case schedule (Y/N) [Y] ?

Do you want to produce the best case schedule (Y/N) [Y] ?



48


Other information Finally you tell it what you want to do next. Do the following in response tothe prompts.

Prompt Action

Values correct? Type Y.

Another analysis request? Type N.

Full print? Type Y.


Are the values for that request correct (Y/N) ? y

1 scenarios have been defined so far

Enter another analysis request (Y/N) ? n

Do you want a full print (Y/N) ? y




49



The information is output to the print file, tut1.pra. If possible, print this fileout as it contains a wide range of information that we will now discuss.

Preliminaryinformation

The print file contains the following preliminary information:

• A listing of the Parameters File and the expanded details of the relevant partsof this file


1 10.00 10.00 8.00 2 33 64 23 3 1 2 0 0 1 2.00 4 1 33 1 64 19 23 5 1 5 6 0.00 37.00 4 1 33 1 64 1 18 5 2 10 6 0.00 50.00 6 180.00 55.00 12 0 0 7 2 0 $ 13 2160 2 3 1.250 1

14 0.25 0.025 2.5




50


Preliminary information (continued)

• The parameters as understood by the program

The parameters as understood by the program -

* XYZ block dimensions - 10.00 by 10.00 by 8.00

* XYZ model dimensions in blocks - 33 by 64 by 23

* Total blocks - 48576

* Active blocks indicator - 1

* Positional mining CAFs will not be used * Positional processing CAFs will not be used

Global values -

* Decimal places for -

Block tonnes of rock - 0 Total tonnes of rock - 0 Revenue Factor values - 7 Small dollar amounts - 2 Large dollar amounts - 0

* Restart dumps occur every - 2.000 hours

* Mining dilution factor - 1.000 * Mining recovery factor - 1.000

* General default block tonnage - 2160

* Air blocks are not considered in the optimization * All air blocks are included in the Results File

* Rejected tonnages and elements will be reported

Revenue Factor values -

0.2500000 0.7250000 1.2000000 1.6750000 2.1500001 0.2750000 0.7500000 1.2250000 1.7000000 2.1750000 0.3000000 0.7750000 1.2500000 1.7250000 2.2000000 0.3250000 0.8000000 1.2750000 1.7500000 2.2249999 0.3500000 0.8250000 1.3000000 1.7750000 2.2500000 0.3750000 0.8500000 1.3250000 1.8000000 2.2750001 0.4000000 0.8750000 1.3500000 1.8250000 2.3000000 0.4250000 0.9000000 1.3750000 1.8500000 2.3250000 0.4500000 0.9250000 1.4000000 1.8750000 2.3499999 0.4750000 0.9500000 1.4250000 1.9000000 2.3750000 0.5000000 0.9750000 1.4500000 1.9250000 2.4000001 0.5250000 1.0000000 1.4750000 1.9500000 2.4250000 0.5500000 1.0250000 1.5000000 1.9750000 2.4500000 0.5750000 1.0500000 1.5250000 2.0000000 2.4749999 0.6000000 1.0750000 1.5500000 2.0250001 2.5000000 0.6250000 1.1000000 1.5750000 2.0500000 0.6500000 1.1250000 1.6000000 2.0750000 0.6750000 1.1500000 1.6250000 2.0999999 0.7000000 1.1750000 1.6500000 2.1250000



51



Sub-region 1 -





Bearing - 0.0 Slope - 37.0

Sub-region 2 -





Bearing - 0.0 Slope - 50.0 Bearing - 180.0 Slope - 55.0

Element details -

-Decimal places- File Selling Base Element Block Total Grade Posn Cost Price

GOLD 2 0 3 1 0 500.00

Rock type details -

Rock Mining Rehab Throughput Type CAF Cost Adj factor

WTHR 1.000 0 1.000 OXID 1.000 0 1.000 SULF 1.000 0 1.000

Ore selection by cut-off

Processing data for open pit mining -

Proc. Rock Process Recovery Threshold Minimum Maximum Method Type Cost Element Fraction Linearity Cut-off Cut-off

MILL OXID 21.25 0 GOLD C 0.950 MILL SULF 18.75 0 GOLD C 0.900



52



• The name of the input Results File used, and the counts obtained in readingthrough the Results File.The program should have read 14,955 blocks, of which 2,587 were air.

Input Results File - tut1.res

14955 Blocks were read: 2587 were air (no rock) 7603 contained parcels: 3431 parcels might be processed 4172 parcels were defined waste 4765 were entirely undefined waste

Scheduleinformation

The remainder of the print file consists of details of the consequences ofsequencing and scheduling Pit 22 in two different ways:

• A “worst case schedule”, with each bench mined completely before the nextbench is startedThis is almost always practicable, but generally produces the worst possibleNet Present Value (NPV).

• A “best case schedule” in which Pit 22 is mined out in a series of 22push-backs!This is, of course, almost never practicable, but, if it were, it would give thebest possible NPV. It is very useful as a target to aim for when devising aworking schedule.



53


Examining thescheduleinformation

Each schedule starts with a heading setting out the economic scenario for whichthe schedule is developed. The heading is the same for both schedules.

Single element tutorial 1

Reference mining cost ($/TONNE) : 1.00 GOLD price ($/UNIT) : 370.00 Pit number : 22 (M) Discount rate (MethodA) (% per period) : 10.00 Calculation based on selection by : Cut-off Maximum mining per period (TONNES) : 4000000 Maximum MILL per period (TONNES) : 1000000 Results File : tut1.res

Rock Proc Meth Proc T/R Recov Threshold Minimum Maximum Cut-off Type Element Cost adj Ratio Grade cut-off cut-off /over

OXID MILL 21.25 GOLD 0.950 0.060 SULF MILL 18.75 GOLD 0.900 0.056

It includes all of the figures that you entered when running the AnalysisProgram, plus some figures from the Parameters File and cut-offs worked outby the program.

The letter “M” (highlighted) next to the pit number is the character used toidentify the pit in the plans and sections output by the Pit VisualisationProgram.



54


Detailedinformation

Each schedule then provides details of what will happen in each time period.

We will use the fourth period, worst case schedule, as an example.

WORST CASE SCHEDULE: with each bench mined completely before proceeding

Category Element Process Strip Costs and Costs and Method/rock Units Tonnes /Feed Income Income Period Element Limit Input Input Grade Cash Flow Discounted ==============================================================================

4 Rock MILL 2625347 1.63 -2625347 -1722490 MILL SULF 1000000 -18750000 -12301875 GOLD 81345 0.081 27087729 17772259 Rejected 494776 GOLD 22434 0.045 ---------- ---------- Bench 14 to bench 11 ( 26%) 5712382 3747894

First line

The first line for a typical period is explained below.



4 Rock MILL 2625347 1.63 -2625347 -1722490

Item Description

� The period number. In this case, the period number is 4.

� The category “Rock” indicates that this line gives figures for all thematerial mined.

� The “MILL” throughput sets the limit on material handled in theperiod.

� The amount of material (ore and waste) mined in the period. Inthis case 2,625,347 tonnes.

� The stripping ratio (material not processed/material processed). Inthis case, the stripping ratio is 1.63.

� The cost of mining all of the material as waste. In this case,$2,625,347.

� The discounted cost of mining all of the material as waste. In thiscase, $1,722,490.


� � ��


55


Detailed information (continued)

Second (and subsequent) processing-method/rock-type line(s)

These line(s) contain processing-method/rock-type information.

If more than one processing-method/rock-type is used, then more than one ofthese lines will be displayed. In this case, there is only one. It is explainedbelow.



4 Rock MILL 2625347 1.63 -2625347 -1722490 MILL SULF 1000000 -18750000 -12301875

Item Description

� The processing method to which the figures apply. In this case, thefigures for the processing method, “MILL”, will follow.

� The rock-type to which the figures apply. In this case, this line willgive figures for rock-type “SULF”.

� The amount of material that was fed to this processing method. Inthis case, 1,000,000 tonnes.

� The cost of processing associated with this processing method. Inthis case, $18,750,000.

“Processing cost” includes any extra mining cost for ore.

� The discounted cost. In this case, $12,301,875.


��


56



Third (and subsequent) line(s) detailing products being extracted

The next line provides details of the product being extracted.


Category Element Process Strip Costs and Costs and Method/rock Units Tonnes /Feed Income Income Period Element Limit Input Input Grade Cash Flow Discounted ============================================================================== 4 Rock MILL 2625347 1.63 -2625347 -1722490 MILL SULF 1000000 -18750000 -12301875 GOLD 81345 0.081 27087729 17772259

Item Description

� The product to which the figures apply. In this case, the product isGOLD.

� The amount of the product contained in the material processed. Inthis case, the material processed contains 81,345 units of GOLD.

� The average grade of the material processed. In this case, theaverage grade of the material processed is 0.081 for GOLD.

� The revenue associated with the particular product. In this case,the revenue associated with GOLD is $27,087,729.

� The discounted revenue cash flow. In this case the discountedrevenue cash flow is $17,772,259 for GOLD.


��


57



Other lines

The processing method lines are followed by (optional) lines giving details ofmaterial that was associated with a processing method, but which was rejectedbecause the grade was below cut-off.



4 Rock MILL 2625347 1.63 -2625347 -1722490 MILL SULF 1000000 -18750000 -12301875 GOLD 81345 0.081 27087729 17772259 Rejected 494776 GOLD 22434 0.045

Item Description

� The amount of product in the rejected material. As in this case, ifmore than one element is present, this line is repeated as required.

In this case, the rejected material contains 22,434 units of GOLD.

� The rejected tonnage. In this case it is 494,776.

� The average grade of the rejected material. In this case, theaverage grade of the rejected GOLD is 0.045.


� ��


58



Totals line

The printout for each period ends with a totals line.



4 Rock MILL 2625347 1.63 -2625347 -1722490 MILL SULF 1000000 -18750000 -12301875 GOLD 81345 0.081 27087729 17772259 Rejected 494776 GOLD 22434 0.045 ---------- ---------- Bench 14 to bench 11 ( 26%) 5712382 3747894

Item Description

� This tells you that during this period, mining started somewhere onbench A and ended somewhere on bench B. In this case, miningstarted on bench 14 and ended after mining 26% of bench 11.

Note: The layout of the information given here depends on themining sequence.

� The total cash flow for the period. In this case, $5,712,382.

� The total discounted cash flow for the period. In this case,$3,747,894.


��


59



Grand totals

At the end of each schedule, the grand total figures appear, together with themine life, in periods.

The grand totals information for the worst case schedule is shown below.


Category Element Process Strip Costs and NPV Method\rock Units Tonnes /Feed Income Discounted Period Element Limit Input Input Grade Cash Flow Cash Flow------------------------------------------------------------------------------ Totals Rock 17372640 2.77 -17372640 -13052777 MILL OXID 564880 -12003700 -10308388 GOLD 60799 0.108 21370848 18375258 MILL SULF 4045680 -75856500 -49191733 GOLD 331211 0.082 110293260 71482913 Rejected 1792640 GOLD 82178 0.046 Internal rate of return % N/A ---------- ---------- Total number of periods 5.77 26431268 17305273

Item Description

� Internal rate of return. In this case, no internal rate of return islisted as no initial capital expenditure was specified.

� The life of the mine, in periods. In this case, 5.77.

Note: A period is whatever length you wish, and you define it bythe discount rate and throughputs that you supply.

The mine life is worked out on the assumption that all periods,except the last, are of equal length. However, periods can be ofdifferent lengths if you wish.

� The grand total of the cash flows.

� The grand total of the discounted cash flows. This is the NetPresent Value of the operating cash flows (if the up-front capitalcosts are subtracted, we obtain the NPV of the mine).


� � ��


60



The grand totals information for the best case schedule is shown below.

BEST CASE SCHEDULE : with inner pits always mined out first

Category Element Process Strip Costs and NPV Method\rock Units Tonnes /Feed Income Discounted Period Element Limit Input Input Grade Cash Flow Cash Flow ------------------------------------------------------------------------------ Totals Rock 17372640 2.77 -17372640 -12568983 MILL OXID 564880 -12003700 -10799811 GOLD 60799 0.108 21370848 19229303 MILL SULF 4045680 -75856500 -54927451 GOLD 331211 0.082 110293260 80143979 Rejected 1792640 GOLD 82178 0.046 Internal rate of return % N/A ---------- ---------- Total number of periods 5.08 26431268 21077036

You will notice that the grand total of the discounted cash flows are verydifferent in the two schedules.

Clearly, the order in which this pit is mined can have a profound effect on NPV.

Comparing the schedule information

Look at the tonnages mined and milled in each period in relation to bothschedules. Although the grand totals of the tonnages mined and milled are thesame in both cases, the period tonnages follow quite different patterns.

You will notice that the rock tonnage in the first period of the worst caseschedule is exactly the limit of 4,000,000 tonnes, but the mill does not receiveits desired input of 1,000,000 tonnes. This also occurs in periods 2 and 3, butin periods 4 and 5 the stripping rate falls off and the mill is fully supplied.Period 6 just uses up the remaining tonnages. If this deposit is to be mined inthe worst case sequence, then something will have to be done about the highstripping in the earlier years. We will look at how this could be overcome inTutorial 3 - Using Contract Mining, on page 85.

In contrast, in the best case schedule, the mill is fully supplied in periods 1 and2, but under-utilised for the rest of the mine life. In other words, in worst casemining, stripping ratio starts high and ends low, whereas in best case mining thereverse is true. This is, of course, exactly what you would expect.


61

File Summary

Introduction The following diagrams give a summary of the files used by each of theprograms in this tutorial.

Input Program Output

fstut.parfstut.mod

Utilities Program(FXUT)

“summarising a data file”

tut1.pru

fstut.par Structure Arcs Program(FXST)

tut1.prstut1.stu

fstut.parfstut.modtut1.stu

Optimization Program(FXOP)

tut1.protut1.restut1.wrk

fstut.partut1.res

Pit VisualisationProgram(FXPI)

tut1.prp

fstut.partut1.res

Analysis Program(FXAN)

tut1.pra


62

What you have Learnt

What you havelearnt

In working through this tutorial, you have:

• Learnt how to run five of the programs

• Learnt what files are required by the programs

• Seen how Four-X takes note of the filenames that you use, and provides themas defaults, to save you re-typing them repeatedly

• Seen how you can look at the pit outlines and how you can start to simulatethe operation of the mine, with all its tonnages, grades and cash flows

Important to keepfiles

Although you have now completed this tutorial, it is important to keep thefiles that you generated, including the print files, because some of them areused again in the tutorials and exercises that follow.

For moreinformation

For further information about any of the following topics, see the pageindicated in the Reference Manual.

Topic See Page

Analysis Program 119

Error messages 404

Filenames and extensions 19

Model Files 214

Optimization Program 90

Parameters File information 178

Pit Visualisation Program 96

Print files 24

Results Files 223

Structure Arcs Files 23

Structure Arcs Program 83

The Utilities Program 149

Using the Four-X package 15

Work Files 24

Exercise 1 - Using Different Pit Sizes5 July, 1999

63

Exercise 1 - Using Different Pit Sizes

Overview

In this exercise This exercise contains the following topics.

Topic See Page

Step 1: Procedure 64

Step 2: Examining the Print File 67

Step 3: Using Value Ranges to Enter a Series of Pit Numbers 69


64

Step 1: Procedure

Introduction In the analysis done in Tutorial 1, you examined the consequences of mining Pit22 in two different sequences.

You will now do the same analysis for a range of different pit numbers, from 17to 24, so as to find the pit with the best NPV under the same economicconditions.

Procedure Start the Analysis Program.


Preliminary information

Prompt Action

Print file name Call the print file exer1.pra.

Parameters File Accept the default [fstut.par].

Results File Accept the default [tut1.res].

Spreadsheet output Type N.

Run description Call the run Single element exercise 1.

Enter time/replacementcosts explicitly

Accept the default [N].



65

Step 1: Procedure, Continued


Economic information

Prompt Action

Initial capital expenditure Accept the default [0].

Reference mining cost Type 1.

Price of GOLD Type 370.

Pit number Type 17.

Discount percentage per period Type 10.

Maximum TONNES of rock per period Type 4m.

Maximum TONNES per period for method MILL Type 1m.

Maximum units of GOLD per period Accept the default [0].

Modify these values? Accept the default [N].

Schedule variables

Prompt Action

Specified schedule Accept the default [N].

Worst case schedule Accept the default [Y].

Best case schedule Accept the default [Y].



66



Other information

Prompt Action

Values correct? Type Y.

Another analysis request? Type Y.

The Analysis Program will loop back to the question about the referencemining cost, above, and will ask the rest of the questions again. Follow thesteps in the table below.

Step Action

1. Press Enter in response to each of the prompts, except for the pitnumber prompt where you need to type in pit number “18”.

Note: You only need to press Enter in response to all of the otherquestions because the default responses will be what you typed inthe first time through.

2. Continue looping around the questions, typing in a new pit numbereach time (i.e. 19, 20, 21, 22, 23, 24). Then answer: N to thequestion about whether you want to enter an analysis request.

3. Answer: N to the question about whether you want a full print (weonly require the totals from this printout).

The Analysis Program will then complete its run which will take a minute ortwo.


67

Step 2: Examining the Print File

Introduction The results of the analysis are printed in exer1.pra. Take the time toexamine this report in detail.

Note: Because you responded “N” to the question about a full print, the periodinformation is missing, but the grand total information remains.


Look at the grand total of the discounted cash flows, that is, the Net PresentValue.

Questions

1. Which pit has the highest NPV for worst case scheduling?

2. Which pit has the highest NPV for best case scheduling?

Look at the difference in total rock and ore tonnage for these two pits.

You should find that, if the pit is to be mined in the worst case sequence,mining Pit 19 rather than Pit 22 will increase the NPV of the cash flows by 4%,while mining 29% less and processing 19% less. Indeed, if Pit 17 is mined, westill get an increase in NPV of 2%, and the pit is 46% smaller! Thesepercentage changes of NPV become much greater when we subtract the initialcapital expenditure.

Conversely, for the best case sequence, Pit 23 has the highest NPV.



68

Step 2: Examining the Print File, Continued


The following graph shows the relevant values.

0

5

10

15

20

25

17 18 19 20 21 22 23 24

Pit number

NP

V a

nd

To

nn

es (

mill

ion

s)

Tonnage

Worst casemaximum NPV

Best casemaximum NPV


69

Step 3: Using Value Ranges to Enter a Series of Pit Numbers

Introduction In this exercise, we got you to enter each scenario separately. There is, in fact,a much easier way. Follow the procedure set out below.

Procedure Start the Analysis Program and type in the responses, as above, except:

• Type # for the print file name. This will overwrite the existing print file,exer1.pra.

• Type 17-1-24 in response to the pit number prompt. This tells theAnalysis Program to use 17 as the first pit number, 17+1 as the second etc.until 24 is reached. This is the equivalent of entering 8 scenarios in one hit.

• Type N in response to whether you want to enter another analysis request.

The results will be exactly the same as if you had entered each scenarioseparately.

Tutorial 2 - Further Analysis of the Results File5 July, 1999

70

Tutorial 2 - Further Analysis of the Results File

Overview

We strongly suggest that you read through the Four-X Reference Manualbefore working through the remainder of these tutorials and exercises. Ifyou do not, you may find them hard to follow.

Introduction In this tutorial you are going to find the best pit sizes for a range of gold prices,under the assumption of worst case scheduling.

Logging responses When studying a Results File, it is very common to want to re-run the AnalysisProgram with small variations in the scenario values.

The easiest way to do this is to “log” your keyboard responses to a log filewhich you can then edit and re-play, as required. In this tutorial, you will uselog files and also use ranges as a means of entering a series of values.

Using thespreadsheet outputfacility

When you do a lot of simulations, you generate a large print file even if you optnot to have a full print, and the task of extracting the figures that you areinterested in can become quite onerous.

Four-X includes a facility to output selected values to a separate file, and,because users often want to do further manipulations of the figures, these areoutput in a format that is suitable for input to a spreadsheet program.

There are two files involved in this:

• The Spreadsheet Definition File

The Spreadsheet Definition File is a small text file that lists the particularitems that you want to output. It can easily be prepared with a text editor.

• Spreadsheet Output File

The Spreadsheet Output File contains the output itself that can be viewed onthe screen, printed out, or input to a spreadsheet program.



71

Overview, Continued

SpreadsheetDefinition File

The Spreadsheet Definition File used in this tutorial is called tut2.ssd. Itcontains the following single line of text.

Gra GOLD/Price Pit/FI Rock/tpw Mill/tiw OPVALUE/DTW

• Gra indicates that the information will relate to grand total amounts.

• Gold/Price indicates that the gold price will be output.

• Pit/FI indicates that the final pit number will be output.

• Rock/tpw indicates that the total rock (ore and waste) in-place tonnage forthe worst case schedule will be output.

• Mill/tiw indicates that the total tonnage input to the mill for the worstcase schedule will be output.

• OPVALUE/DTW indicates that the total open pit value for discounted worstcase, that is the NPV of the cash flows will be output.

As you can see, the text in the Spreadsheet Definition File can be in upper caseand/or lower case, or a mixture of both.


Topic See Page

Step 1: Running the Analysis Program with a Log File andSpreadsheet Output

72

Step 2: Examining the Log File and Spreadsheet Output 75

File Summary and What you have Learnt 79


72

Step 1: Running the Analysis Program with a Log File andSpreadsheet Output

Procedure Start the Analysis Program. As you are going to use a log file, enter a loggingcommand instead of a print file name as the first response.

Prompt Use

Print file name !L tut2.loa

This can be shortened to !L tut2.

This tells the program to start logging your responses and to ask for the name ofthe print file again.

Use the following information in response to the prompts (items in squarebrackets are defaults and only require you to press enter).

Prompt Use

Print file name #tut2

Parameters File [fstut.par]

Results File [tut1.res]

Spreadsheet output [Y]

Spreadsheet Definition File tut2

Spreadsheet Output File #tut2

Run description Single element tutorial 2

Enter time/replacement costsexplicitly

[N]

As mentioned in Tutorial 1, Four-X has a list of default file extensions stored infs.ini and will add the appropriate extension when you do not provide one.

The # symbol is used to automatically overwrite an existing file.

This is good practice for output files if you wish to re-run the log files.



73

Step 1: Running the Analysis Program with a Log File andSpreadsheet Output, Continued


Economic information

Prompt Use

Initial capital expenditure [0]

Reference mining cost 1

Price of GOLD 300-50-450

Pit number 13-1-23

Discount percentage per period 10

Maximum TONNES of rock per period 4m

Maximum TONNES per period for method MILL 1m

Maximum units of GOLD per period [0]

Modify these values? [N]

Schedule variables

Prompt Use

Specified schedule [N]

Worst case schedule [Y]

Best case schedule [Y]



74

Step 1: Running the Analysis Program with a Log File andSpreadsheet Output, Continued


Other information

Prompt Use

Values correct? Y

Another analysis request? N

Full print? Y

The program will start its run.

We will now examine the log file tut2.loa, and the Spreadsheet Output Filetut2.sso.


75

Step 2: Examining the Log File and Spreadsheet Output

Examining the logfile

The log file, tut2.loa, should look like this.

Print_File #tut2Parameters_File fstutResults_File tut1Output_spreadsheet_data? ySS_Definition_File tut2SS_Output_File #tut2Run_descn Single element tutorial 2Timecost_ovr? nCAPEXINI 0UNDEF/UNIT_CM 1.00GOLD/PRICE 300-50-450PIT/FI 13-1-23DISCOUNT 10ROCK/LIMIT 4mMILL/LIMIT 1mGOLD/LIMIT 0Modify_params? nSpecified_schedule? nWorst_case? yBest_case? NOK? yAnother_request? nFull_print? N

The log file contains a list of abbreviated prompts and your responses.

The run can be repeated exactly by starting up the Analysis Program and thenentering “!use tut2.loa”. This can be shortened to “!u tut2”. Indeed, if youwant to re-run the same log file that you ran with a program the last time, evenif you have edited it in between, “!u” is sufficient, because Four-X rememberslog file names as well.

This makes it very easy to re-run complicated analyses.



76

Step 2: Examining the Log File and Spreadsheet Output, Continued

Examiningspreadsheet output

The Spreadsheet Output File, tut2.sso, should look like this.

Single element tutorial 2

Grand totals:

GOLD Pit Rock Mill OPVALUE /Price /FI /tpw /tiw /DTW

300.00 13 1853840 676320 5304549 300.00 14 2853680 901840 5677210 300.00 15 3151280 979600 5725568 300.00 16 7209600 1756880 5907284 300.00 17 9345120 2150000 5673354 300.00 18 10449360 2312000 5220741 300.00 19 12388320 2560400 4498953 300.00 20 15522960 2912480 3249105 300.00 21 16580160 3020480 2762941 300.00 22 17372640 3091760 2375865 300.00 23 17836800 3117680 2133859 350.00 13 1853840 777760 8696480 350.00 14 2853680 1082560 9959499 350.00 15 3151280 1179760 10341751 350.00 16 7209600 2248640 13236896 350.00 17 9345120 2797280 14068768 350.00 18 10449360 3043520 14181785 350.00 19 12388320 3386960 13894872 350.00 20 15522960 3890240 13357014 350.00 21 16580160 4054400 13027856 350.00 22 17372640 4168880 12743916 350.00 23 17836800 4216400 12509010 400.00 13 1853840 876800 12292107 400.00 14 2853680 1254720 14691659 400.00 15 3151280 1377840 15381333 400.00 16 7209600 2690800 21341678 400.00 17 9345120 3351760 23427633 400.00 18 10449360 3654160 23981286 400.00 19 12388320 4060240 24541111 400.00 20 15522960 4708240 24631269 400.00 21 16580160 4896160 24547350 400.00 22 17372640 5043040 24464849 400.00 23 17836800 5107840 24322703 450.00 13 1853840 937120 16041963 450.00 14 2853680 1355760 19683684 450.00 15 3151280 1498320 20721780 450.00 16 7209600 2966800 30105846 450.00 17 9345120 3705520 33394766 450.00 18 10449360 4048960 34569147 450.00 19 12388320 4498240 35641743 450.00 20 15522960 5208880 36658518 450.00 21 16580160 5416240 36861915 450.00 22 17372640 5584720 36948744 450.00 23 17836800 5662480 36855091



77


Examining spreadsheet output (continued)

You will notice that the Spreadsheet Output File contains five columns ofnumbers, each headed by one of the codes from the Spreadsheet Definition File.

You will find that the range of pit numbers has been dealt with for each goldprice in turn. A great deal can be learnt about the economics of the projectfrom this output.

If NPV is your criterion, and you know that the gold price is going to be$450/oz, then clearly you should use Pit 22 as your starting point for design.Similarly, if the price is to be $300/oz, you should use Pit 16. Pit 16 is only58% the size of Pit 22, so you probably would not use the same infrastructureand mill size in the two cases. However, let us ignore this for the moment.

If management has specified that you should design so as to have an NPV of atleast $2.00 per tonne mined, a calculator will quickly show you that the bestpits for the different prices are 13, 15, 18, and 23. You will also find that thepits are rather too far apart for this criterion. For example, at $350/oz, pit 15gives $3.28 of NPV per tonne and pit 16 gives $1.83, with nothing in between.You will learn how to deal with this in the next exercise.

If you do not know what the gold price is going to be, but you are convincedthat it will be somewhere between $300 and $450, can you find the bestcompromise? What you do will depend on your interpretation of “best”, but letus assume that you want the pit that will deviate as little as possible from thehighest possible NPV for each price in the range.



78


Examining spreadsheet output (continued)

The following graph is created from the information in the Spreadsheet OutputFile, tut2.sso, using a spreadsheet program.

NPV for Different Gold Prices

0

10

20

30

4013 14 15 16 17 18 19 20 21 22 23

Pit Number

NP

V -

mill

ion

s

350

400

450

300

From the information given in the Spreadsheet Output File it is easy to work outthat Pit 17 guarantees a deviation of no more than 9.6% from the highestpossible NPV.

Other strategies forpit evaluation

So far we have looked at maximum NPV as the sole criterion for pit evaluation,however, there are many other corporate strategies that can be considered.

In general, these other objectives will be met at a lower NPV. They can all beevaluated with the aid of a spreadsheet and plotted for ease of display.

Other objectives can include:

• Keeping production costs below a certain $ per oz or $ per gm• Maximizing mine life• Providing a certain rate of return on investment• Balancing mining and production rates• Keeping the mill fully supplied• Minimizing risk• Starting with a small scale operation, followed by upgrade when finances

allow


79

File Summary and What you have Learnt

Introduction The following diagram gives a summary of the files used by the AnalysisProgram in this tutorial.

Input Program Output

fstut.partut1.restut2.ssd

The Analysis Program(FXAN)

tut2.loatut2.pratut2.sso

What you havelearnt

In working through this tutorial, you have learnt how log files and spreadsheetoutput can greatly facilitate work with Four-X, and how Four-X willautomatically add appropriate extensions to the filenames you use.

You have also seen how you can further analyse the data to select appropriatepit outlines according to almost any criterion.

For moreinformation

For more information, refer to following the page references in the Four-XReference Manual.

Topic See Page


Error messages 404


Model Files 214


Print files 24

Results Files 223

Spreadsheet Definition Files 241

Spreadsheet Output Files 263


Exercise 2 - Dealing with the large pit-size differences5 July, 1999

80

Exercise 2 - Dealing with the large pit-size differences

Overview

Introduction In Tutorial 2 you found that the interesting pits were from about 13 to 23, andthat this covered pit sizes which differed by a factor of six. Consequently thedifference in size between successive pits was considerable, which made itdifficult to refine the design.

The size of an individual pit is determined by the Revenue Factor value used inthe optimization. When the Results File tut1.res was produced in Tutorial 1,an equally spaced sequence of Revenue Factor values was used.

In this exercise, we would like you to try optimizing with a different RevenueFactor sequence, which uses smaller steps where required.


Topic See Page

Step 1: Procedure 81

Step 2: Analysing the Output 84


81

Step 1: Procedure

Introduction We will need to produce a new Parameters File, change some Revenue Factorsand re-run an optimization and analysis.

Follow the procedures set out below.

Find the oldRevenue Factorsfor pits 13 and 23

The Revenue Factor values used for pits 13 and 23 can be found in the print filetut1.pro, produced during the optimization. You will find that these are 0.55and 0.80 respectively. (Do not make the mistake of calculating the values fromthe original sequence. This does not always work because, occasionally,adjacent Revenue Factor values may produce the same optimal outline.)

Change theParameters File

Follow the steps in the table below to produce the new Parameters File,exer2.par.

Step Action

1. Start the Editor Program (FXED) and press “enter” key to continue.

2. Enter “O” to open an old file for editing and accept the defaultresponse of fstut.par.

3. Enter “H” to change to a new file name and enter exer2.par.

4. Enter “E” to edit the data.

Enter “G” to edit the global values.

Enter “R” to edit the Revenue Factors.

5. Change the existing range:Enter “E” to edit a value/range.Accept the defaults for start range and step size.- and -Change the range ending value to 0.55.

6. Add a new range:Enter “A” to add a value/range.Enter start range 0.555.Enter step size 0.005.- and -Enter range ending value 0.7.



82


Change the Parameters File (continued)

Step Action

7. Add a new range:Enter “A” to add a value/range.Enter start range 0.75.Enter step size 0.05.- and -Enter range ending value 2.0.

8. Press “enter” three times to return to the main Menu.

Enter “S” to save the new Parameters File.

Press “enter” to exit the editor.

Perform theoptimization

Start up the Optimization Program (FXOP) and enter the following in responseto the prompts.

Prompt Action

Print file name Call the print file exer2.

Restart run? Use the default [N] offered by the program.

Parameters File Use the default [exer2.par].

Model File Use the default [fstut.mod].

Structure Arcs File Use the Structure Arcs File created previously[tut1.stu].

Work File name Call the Work File exer2.wrk.

Results File name Call the Results File exer2.res.



83


Producing the logfile

Follow the steps in the table below to produce the log file, exer2.loa.

Step Action

1. Open and view tut2.loa using a text editor or word processor inpure text mode.

2. Save the file as exer2.loa.

3. Edit exer2.loa as follows:

Change the… to…

Print file #exer2

Results File exer2

Spreadsheet OutputFile

#exer2

Run description Single element exercise 2

Pit range 13-1-44

4. Save exer2.loa again and exit from the text editor or wordprocessor.

Running theAnalysis Program

Start the Analysis Program and type !u exer2 at the print file name prompt.


84

Step 2: Analysing the Output

Introduction Study the Spreadsheet Output File exer2.sso in the same way as you did inTutorial 2.

Best pit The refined Revenue Factors have provided a finer gradation in pit tonnage forpits 14 to 40. You should find that you can refine the concepts of best pit whichhas at least $2.00 of NPV per tonne mined etc. quite considerably.

For example, for a gold price of $ 300 TUT2 gave a pit with 1.85m tonnes @$2.86 per tonne where as EXER2 shows a pit with 2.47m tonnes @ $ 2.24 pertonne.

Tutorial 3 - Using Contract Mining5 July, 1999

85

Tutorial 3 - Using Contract Mining

Overview

Introduction Up to this point we have concentrated on the over-all value of the pit withoutconcerning ourselves about what happens in the individual periods.

Let us assume that you want to mine Pit 19 in the worst case mining sequencewith the economic values and constraints used in the first tutorial.

These are:

• Reference mining cost $1.00/T• Price of gold $370• Discount rate 10%• Rock throughput 4,000,000 tonnes per period• Mill throughput 1,000,000 tonnes per period

In Exercise 1, if you had done a full print, in relation to Pit 19 for period 1 youwould have seen the following.


Category Element Process Strip Costs and Costs and Method/rock Units Tonnes /Feed Income IncomePeriod Element Limit Input Input Grade Cash Flow Discounted==============================================================================

1 Rock Rock 4000000 8.07 -4000000 -3600000 MILL OXID 429191 -9120302 -8208272 GOLD 46550 0.108 16362382 14726144 MILL SULF 11878 -222714 -200442 GOLD 1021 0.086 339846 305861 Rejected 59742 GOLD 3071 0.051 ---------- ---------- Bench 23 to bench 19 ( 19%) 3359212 3023291



86

Overview, Continued

Introduction (continued)

You will notice that:

• In the first period, there is 429,191 tonnes of OXID and 11,878 tonnes ofSULF input to the mill. This means that the mill runs at only 44.1% ofcapacity.

This may cause operational problems, but it is also an economic problembecause of the wasted mill capacity.

If you could organise some contract mining to increase the mining capacityduring the first period, you might be able to alleviate the problem, and increasethe NPV of the pit. The question, of course, is how much contract mining, andat what price?

In this tutorial In this tutorial, you will:

• Run the Analysis Program using expressions to vary the mining capacityduring the first period.

• Create a Spreadsheet Definition File to control the output to the SpreadsheetOutput File.

• See how the spreadsheet data can be used to calculate the adjusted NPVs fora range of contract mining premiums.

• Analyse the effects of varying the mining capacity during the first period.

This tutorial contains the following topics.

Topic See Page

Tutorial 3a: Adding One Million Tonnes of Contract Miningin the First Period

87

Tutorial 3b: Using a Range of Capacities in the First Period 89

What you have Learnt 93


87

Tutorial 3a: Adding One Million Tonnes of Contract Mining in theFirst Period

Introduction The effect that contract mining would have on the rock mining capacity in thefirst period can easily be handled in the Analysis Program by increasing thecapacity for the first period only.

You can use the following expression to add one million tonnes of contractmining in the first period, when the Analysis Program asks for the maximumtonnes of rock per period:

5m p2/4m

This sets the maximum tonnes of rock per period to 5,000,000 tonnes for thefirst period, and then to 4,000,000 tonnes thereafter.

Procedure Start the Analysis Program and use the following information in response to theprompts.

Prompt Use

Print file name tut3a



Spreadsheet output N

Run description Single elementtutorial 3a

Enter time/replacement costs explicitly [N]



Price of GOLD 370

Pit number 19


Maximum TONNES of rock per period 5m p2/4m

Maximum TONNES per period formethod MILL

1m





88

Tutorial 3a: Adding One Million Tonnes of Contract Mining in theFirst Period, Continued


Prompt Use




Values correct? Y


Full print? Y


Analysing theoutput

Print out or view the print file, tut3a.pra. Look at the worst case scheduleinformation for periods 1 and 2.

Note that the maximum of rock per period is 5,000,000 tonnes for the firstperiod, and then changes to 4,000,000 tonnes thereafter.

Compare the figures with those shown on page 85, above.

Questions How has increasing the maximum tonnes of rock in the first period affected:

1. The total tonnes input to the mill in the first period? At what capacity(percentage) is the mill now running?

2. The use of the OXID in both periods?

3. The cash flow in both periods?


89

Tutorial 3b: Using a Range of Capacities in the First Period

Introduction In this part of the tutorial, you will evaluate the effects of a range of capacitiesin the first period, using the following expression:

4m-0.5m-8m p2/4m

This expression sets the maximum tonnes of rock at the start of the first periodat 4,000,000 tonnes. It then increases in steps of 500,000 to 8,000,000 tonnesduring the first period. Then, from the second period onwards, the maximumtonnes of rock is set at 4,000,000.

Since contract mining is usually more expensive than in-house mining, we willlook at how this can be taken into account. This could be done by putting theadjustment in as an initial capital expenditure, but in this case we will look athow it can be handled outside of the Analysis Program, using the data from aSpreadsheet Output File.

Procedure Follow the steps set out below.

Creating aSpreadsheetDefinition File

Create a small Spreadsheet Definition File, using a text editor or wordprocessor in pure text mode, which contains the following line of text.

Gra ROCK/LIMIT OPVALUE/DTW

• Gra indicates that the information will relate grand total amounts.

• ROCK/LIMIT indicates that the throughput limit will be output.

• OPVALUE/DTW indicates that the total open pit value for discounted worstcase, that is the NPV of cash flows, will be output.

Call this file tut3.ssd.

If you are unsure about how to do this, follow the steps in the table below.

Step Action

1. Open a text editor or word processor.

2. At the prompt, type Gra ROCK/LIMIT OPVALUE/DTW.

3. Save the file in the directory where your Four-X tutorial files arekept (usually C:\4X\TUTOR). Call it tut3.ssd.

4. Exit from the text editor or word processor.



90

Tutorial 3b: Using a Range of Capacities in the First Period,Continued


Start the Analysis Program and use the following information in response to theprompts.

Prompt Use

Print file name tut3b





Spreadsheet Output File tut3b

Run description Single elementtutorial 3b




Price of GOLD 370

Pit number 19


Maximum TONNES of rock per period 4m-0.5m-8m p2/4m


1m






Values correct? Y


Full print? Y

The Analysis Program will then complete its run.



91


Examining thespreadsheet output

The Spreadsheet Output File produced by the Analysis Program should looklike this.

Single element tutorial 3b

Grand totals:

ROCK OPVALUE /LIMIT /DTW

4000000 18021213 4500000 18311353 5000000 18545868 5500000 18667367 6000000 18837479 6500000 19040025 7000000 19154792 7500000 19154792 8000000 19154792

Calculatingadjusted NPVs fora range of contractmining premiums

If you load this data into a spreadsheet program and calculate the adjustedNPVs for a range of contract mining cost premiums (from 20 cents to 40 centsper tonne) you should get the figures in the following table.

Raw Contract Premiums for contract mining

NPV mining +20c +25c +30c +35c +40c

tonnes Additional profit

18021213 0 0 0 0 0 0

18311353 500000 190140 165140 140140 115140 90140

18545868 1000000 324655 274655 224655 174655 124655

18667367 1500000 346154 271154 196154 121154 46154

18837479 2000000 416266 316266 216266 116266 16266

19040025 2500000 518812 393812 268812 143812 18812

19154792 3000000 533579 383579 233579 83579 -66421

19154792 3500000 433579 258579 83579 -91421 -266421

19154792 4000000 333579 133579 -66421 -266421 -466421



92


Plotting theinformation

If you plot the additional profit versus contract mining rate for the differentpremiums and add an overlay showing the mill input in period one, then youwill get a graph like the following (scaling is in millions).

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

0.0 1.0 2.0 3.0 4.0

Contract mining

Mill

in p

erio

d 1

0.0

0.1

0.2

0.3

0.4

0.5

0.6

Ext

ra p

rofi

t Mill

+20c

+25c

+30c

+35c

+40c

This shows that there can be considerable profit gained by the use of contractmining (depending on the rate). Additional capacity of up to 3.0m tonnes canbe utilised.


93


What you havelearnt


• Learnt how to create a Spreadsheet Definition File to control the output to theSpreadsheet Output File.

• Seen how spreadsheet data can be used to calculate adjusted NPVs for arange of contract mining premiums.

• Learnt how to vary constraints with time.

For moreinformation


Topic See Page


Error messages 404

Expressions 282


Print files 24




Exercise 3 - Using Three Push-backs5 July, 1999

94

Exercise 3 - Using Three Push-backs

Overview

Introduction The basic problem with mining Pit 19 a bench at a time is that initially thestripping ratio is very high. This makes it impossible to maintain millproduction at the full rate without spending an amount on contract mining andthis eats severely into the profit.

One way around this is to mine Pit 19 in a series of push-backs, or miningphases.

As you saw in the first tutorial, best case mining suffers from the oppositeproblem in that initially the stripping ratio is low, but so high later that the millcannot be fully supplied. This is better than the worst case mining we havebeen looking at, because it allows you to use the spare mining capacity that youhave in the early periods to do some preparatory stripping. However, best casemining involves 19 push-backs, which is obviously not feasible, and rememberthat, when you mine waste early, you reduce the NPV because the cost of thismining is not discounted as much as it would otherwise be.


Topic See Page

Step 1: Determining the Preliminary Push-backs 95

Step 2: Examining the Spreadsheet Definition File 96

Step 3: Using the Analysis Program with Specified Schedules 97

Examining the Spreadsheet Output 99


95

Step 1: Determining the Preliminary Push-backs

Introduction Would it be feasible to do two preliminary push-backs to pits 11 and 13 beforecompleting Pit 19? Check to see whether this is feasible by examiningbench 21 of the plan that you produced using the Pit Visualisation Program inthe first tutorial (reproduced below).

Bench 21 Bench 21 is the first which is entirely below the surface. Pits 15, 16 and 19 arerepresented by the letters F, G and J respectively.



**********|*********|*********|**** * * * * * * * KP * - PKAAPP - * HHAAAAACP * * rGBAAA5AACIR * * rGGCAAA888AAERb * * KGGGBAAAAA588AEKLb* * GFEEEAAAAA28889EIKL* * GFEEEBAAAA88387DDGKL* * KGFEEEDBAA959798ADEJKL* * yNKKGEEEEDBA975A77ABBGJKL* * ZNKHHGFEEEEA897777BABBFGJKN* - ZNJHGGFEEEEA86777367CDDFGJKN- * ZJJHGGFFEEDCA77573667AEEFIJKR* * fJJHGGGFDD999777777678EEEFIKKR* * fQJHGGFFD9999467777778EEEEGIKKR* * fJIGGGFDD99976167877AEEEEGGIJKR* * fQJGGGFDDB9771667799CCEEEGGHJJKR* * fJJGGGDDBA7766647779CEEEGGHHJJKR* *ffJGGGGDDD77666444779CEEEGGHIJJKR* *fKJGGGGDDDC664664779CCEEEGHHJJJKR* *fKJGGGGDDDCC66669799DDEEEGHHJJJKR* -fJGGGGGDDDDCA66999CCDEEEGGHHJJJKR- *KJGGGGGDDDDCAA999CCCEEEEGGHHJJKLR* *KJGGGGGGDDDDCAA9CCDEEEEGGGHHJJKLR* *KIGGGGGGGDDDDCACCCEEEGGGGGHHJKLRR* *JIGGGGGGGGDDDEDEEEGGGGGGGHHJJLLRT* *JIGGGGGGGGEEEEEGGGGGGGGGGHHJLLQRj* *IIGGGGGGGGGGGGGGGGGGGGGGHHJKLLRTu* IIGGGGGGGGGGGGGGGGGGGGGHHIKLLPTi * YIIHGGGGGGGGGGGGGGGGGGGHHHKKLMRVu * IIHGGGGGGGGGGGGGGGGGGGHHKKKMRVk * -IIHHGGGGGGGGGGGGGGGGGHHKKKMRTj - *JIIHHHGGGGGGGGGGGGGHHHJKKKMTV * *JIIIHHHGGGGGGGGGGGHHHIKKKKMV * *JJIIHHHHHGGGGGGGHHHHIJKKKMO * *LJJIIHHHHHHHHHHHHHHIJKKKKOk * *MLJJIIIHHHHHHHHHHIIJJKKKKO * *MLKJJIIIIHHHHHHIIIJJKKKKNO * *MMLKJJJIIIIIIIIIIJJKKKKLOO * *QMMLKJJJJIIIIIIJJKKKKKKLOj * *ZQMMLKJJJJJJJJJJKKKKKKLOOz * -nVNMLLKKKJJJJKKKKKKKKLNOO - * ZQNMMLKKKKKKKKKKKKKLNOOj * * VQNMMLKKKKKKKKKKKLNOOj * * ZUQNMMLLKKKKKKKLNNOOWv * * xZUONNMMLLLLLMMNOOOWjx * * xpZUQONNNNNNNNOOOOWjpx * * xvpZUQOOOOOOOOOOQWhpvx * * AxvmZUUUQOOOQQUUZhpvx * * xxvmZZUUUUUUUZhhmvxx * * xxxvmhhZZZZZhhmpvxxx * - Axxvvpmmhhhmmppvxxx - * Axxxvvvppppvvvxxx * * Axxxxvvvvvxxxxx * * Axxxxxxxxxxxx * * Axxxxxxxxxx * * AAxxxxA * * * * * * * * * **********|***** X *|*********|****

From the plan above, you can see that it is feasible to do two preliminarypush-backs to Pits 15 and 16 before completing Pit 19.Note: You could also run the Utilities Program in the “summarise a data file”mode and look at the shell and pit volumes in the Results File to give you anidea of the best push-backs.


96

Step 2: Examining the Spreadsheet Definition File

Introduction In this exercise, you will use a Spreadsheet Definition File, exer3.ssd, whichwill provide you with output for both period and grand total values.

In particular, it will provide:

• The lag, period, total rock and tonnes input to the mill for each period

• The lag and discounted open pit cash flow for the specific push-back case foreach grand total

Examining theSpreadsheetDefinition File

The Spreadsheet Definition File, exer3.ssd, contains the following lines of text.

PER PERIOD ROCK/LIMIT ROCK/TP MILL/TI OPVALUE/DTGra BLANK ROCK/LIMIT ROCK/TPS MILL/TIS OPVALUE/DTS

Questions

Refer to the section on the Spreadsheet Definition File in the Four-X ReferenceManual.

Explain the meaning of following items contained in the Spreadsheet DefinitionFile, exer3.ssd, above:

1. PER

2. PERIOD

3. ROCK/LIMIT

4. ROCK/TP

5. MILL/TI

6. OPVALUE/DT

7. Gra

8. BLANK

9. ROCK/TPS

10. MILL/TIS

11. OPVALUE/DTS


97

Step 3: Using the Analysis Program with Specified Schedules

Introduction In this step you will do an analysis run with the Tutorial 3 figures, but with arock throughput limit fixed at 4,000,000T/period. The schedule will be forspecified push-backs of 15, 16 and 19 and you will investigate the use aconstant lag range of 1-1-10.

Exercise 3 Specified Push-back Schedule with a Specified Lag

In this exercise you will produce a schedule with specified push-backs of 15, 16and 19 and you will use a constant lag range of 1-1-10.

Procedure

Start the Analysis Program and use the following information in response to theprompts.

Prompt Use

Print file name exer3




Spreadsheet Definition File exer3

Spreadsheet Output File exer3

Run description Single element exercise 3

Enter time/replacement costsexplicitly

[N]



98

Step 3: Using the Analysis Program with Specified Schedules,Continued

Exercise 3 (continued)

Prompt Use



Price of GOLD 370

Pit number 19


Maximum TONNES of rock perperiod

4m


1m

Maximum units of GOLD perperiod

[0]


Specified schedule Y

Pit numbers to push back to 15 16 19

The way push-backs scheduled [1] (for constant lag)

Number of benches by which eachpush-back must lead to the next(lag)

1-1-10

Worst case schedule N

Best case schedule N

Values correct? Y


Full print? Y


99

Examining the Spreadsheet Output

Introduction Print out or view the Spreadsheet Output File for Exercises 3.

Examining thespreadsheet output

In the Spreadsheet Output File, exer3.sso, you should be able to find a casewhere the NPV is $19.9m, which is a great improvement on the $18.0m forworst case mining and almost as good as the best case value of $20.1m.

The added complication of the extra push-backs will cost something, howevermining a small pit to start with allows you to redesign the outer pit if economicconditions change.

Tutorial 4 - Re-arranging a Model5 July, 1999

100

Tutorial 4 - Re-arranging a Model

Overview

Introduction In all the preceding tutorials and exercises we have turned a blind eye to aproblem with the original optimization in Tutorial 1.

The problem is that some of the pits, including the pit used in much of thiswork (22), hit the side of the model. That is, they do not continue their correctslope to the surface.

In effect, they have a vertical wall at the side of the model, and, consequently,they are not really optimal. See the diagram below.

Verticalwall

Air

EarthPit

Since it can be difficult to judge in advance how far the pits will extend, it isnot unusual for models to be too narrow.

When this problem is discovered, the correct solution is to re-create the modelwith the extended topography accurately represented. However, Four-Xprovides a shortcut that allows you to extend the model with the topographycontinuing horizontally from its height at the edge of the existing model. Thisapproximation may be sufficient in many cases.



101

Overview, Continued

Tutorialdescription

In this tutorial you will extend fstut.mod and fstut.par by five blocks to theeast and by three blocks to the west to produce tut4.mod and tut4.par. Thefollowing diagram shows the relationship between the two model frameworks.

fxtut.mod (33 blocks)

tut4.mod (41 blocks)

X offset (3)

You will then optimize the new model and check how much difference theseextensions make.


Topic See Page

Step 1: Extending the Model 102

Step 2: Running the Other Programs with the New Model 103



102

Step 1: Extending the Model

Procedure Start the Re-blocking Program.


The Menu Select the Re-blocking Program from the Menu

The Command Line Type FXRE and then press the Enter key (↵↵).


Prompt Action

Print file name Type tut4.

Type(s) of file(s) to be read Accept the default [1] to read ModelFile(s).

Number of Model Files Accept the default [1].

Primary Parameters File name Accept the default [fstut.par].

Change size/position ofmodel?

Type Y.

Framework size X direction, type 41.

Y direction, accept the default [64].

Z direction, accept the default [23].

Primary Model File name Accept the default [fstut.mod].

Position in the inputframework of the origin blockof the model to be loaded

X direction, type 3.

Y direction, accept the default [0].

Z direction, accept the default [0].

Combine/split blocks? Accept the default [N].

Maximum number of parcels Accept the default [5].

Calculate mining CAFs Accept the default [N].

Calculate processing CAFs Accept the default [N].

Trim output with polygon Accept the default [N].

New Model File name Type tut4.

Write a new Parameters File? Accept the default [Y].

New Parameters File name Type tut4.

The Re-blocking Program will now complete its run.


103

Step 2: Running the Other Programs with the New Model

Running theStructure ArcsProgram

• Run the Structure Arcs Program.• Call the print file and the Structure Arcs File tut4.• Accept the defaults offered by the program at the other prompts.

Running theOptimizationProgram

• Run the Optimization Program.• Call the print file, Work File and Results File tut4.• Accept the defaults offered by the program at the other prompts.

Running the PitVisualisationProgram

• Run the Pit Visualisation Program.• Call the print file tut4.• Type N to choose not to emphasise a pit number.• Accept the defaults offered by the program at the other prompts.

Examining the print file

View the print file for the Pit Visualisation Program, tut4.prp. You will findthat now, none of the pits hit the sides of the model framework.

If you compare the pit details in tut4.pro with those in tut1.pro, you will findthat pits 1 to 18 are unchanged, but that the remaining pits are different. Inmost cases the amount of ore processed has decreased.


Run the Analysis Program and use the following information in response to theprompts.

Prompt Use

Print file name tut4

Parameters File [tut4.par]


Spreadsheet output N

Run description Single elementtutorial 4




104

Step 2: Running the Other Programs with the New Model,Continued

Running the Analysis Program (continued)

Prompt Use



Price of GOLD 370

Pit number 22



Maximum TONNES per period for method MILL 1m






Values correct? Y


Full print? Y

Comparing the Analysis Program print files from Tutorials 1 and 4

Print out or view the print files tut4.pra and tut1.pra.

You will find that the worst case total discounted cash flow in Tutorial 4 hasdecreased by $80, 428. This is a very small reduction, but then Pit 22 only justhits the side of the model framework.

Pits that extend substantially beyond the framework can be affected much more.To avoid any such problems, it is always a good idea to make sure that none ofthe pits in a Results File hit the side.


105


What you havelearnt

In working through this tutorial, you have learnt that pits that hit the side of themodel have incorrect values, and you have learnt how to extend a model usingthe Re-blocking Program.

For moreinformation


Topic See Page


Error messages 404





Pits that hit the side of the framework 316

Print files 24

Re-blocking Program 45

Structure Arcs Program 83


Exercise 4 - Adding Positional Mining CAFs5 July, 1999

106

Exercise 4 - Adding Positional Mining CAFs

Overview

Introduction Tutorial 4 used only one of the many facilities offered by the Re-blockingProgram. The Re-blocking Program can also insert positional mining and/orprocessing CAFs into a Model or Results File.

In this exercise you will be adding positional mining CAFs to the Model File.

Mining CAFs Assume that the following table represents the expected mining cost variation,with depth, in the model.

Benches Cost of mining Positional mining CAF

18 to 23 1.25 1.000

12 to 17 1.47 1.176

7 to 11 1.63 1.304

1 to 6 1.97 1.576

The Ranges function, using the bench number IZ as the controlling variable, isthe simplest way of representing this variation. The above positional costadjustment factors can be represented as follows.

Range IZ( , . , . , . , . , . , . , . )1576 65 1304 115 1176 17 5 10 ....)

This means that when IZ, the bench number, is:

• Less than 6.5, the positional cost adjustment factor is 1.576.



• Equal to or greater than 17.5, the positional cost adjustment factor is 1.0.

In this exercise This exercise contains the following topic.

Topic See Page

Running the Re-blocking Program 107

Exercise 4 - Adding Positional Mining CAFs5 July, 1999

107

Running the Re-blocking Program

Procedure Start the Re-blocking Program and use the following information in response tothe prompts.

Prompt Use

Print file name exer4

Type(s) of file(s) to be read [1]

Number of Model Files [1]

Primary Parameters File name fstut

Change size/position ofmodel?

[N]

Primary Model File name fstut

Combine/split blocks? [N]

Maximum number of parcels [5]

Calculate mining CAFs Y

Adjustment formula range (iz, 1.576, 6.5, 1.304,11.5, 1.176, 17.5, 1.0)

Calculate processing CAFs [N]

Trim output with polygon [N]

New Model File name exer4

Write a new Parameters File? [Y]

New Parameters File name exer4

You will notice that the program warns you that if it calculates positionalmining CAFs it will write out every block in the framework. The reason that allthe blocks have to be output is that there has to be a block in each position tocarry the mining CAF. This is also why the file is much bigger.

This does not apply to a positional processing CAF, which is only required forblocks containing material that might be processed. These blocks are, ofcourse, in the Model File already.

Examining theoutput Model File

View the Model File produced by the Re-blocking Program.

Check that the positional mining CAFs have been added, and that the valuechanges at the required bench levels.

Tutorial 5 - Dealing with an Obstruction5 July, 1999

108

Tutorial 5 - Dealing with an Obstruction

Overview

Introduction It is not uncommon to have obstructions, such as roads, rivers or leaseboundaries, that limit the sideways spread of a pit. “Immovable” objects, suchas processing mills, pose similar problems.

This tutorial looks at how you can handle obstructions and immovable objectswith Four-X.

Dealing withobstructions andimmovable objects

You can deal with obstructions and immovable objects with Four-X by addingblocks to the model that have a very high rock tonnage and that will be soexpensive to mine that they are not included in any optimal pit.

Tutorialbackground

For this tutorial, assume that there is already a processing mill at X/Y blockco-ordinates 29/61, in the north-east corner of the model.

If you are to continue using the mill, you will need some working space aroundit, so in this tutorial you will exclude an area covering X = 20 to 33 andY = 59 to 64 from optimization.


Topic See Page

Step 1: Preparing the Special Model File 109

Step 2: Running the Re-blocking, Optimization and PitVisualisation Programs

110



109

Step 1: Preparing the Special Model File

Introduction Normally, you would first have to create a small Model File containing blockswith very high rock tonnages that cover the area you wish to exclude fromoptimization.

This is easily done with a text editor or word processor, by typing in one block,making copies of it, and editing the co-ordinates as required.

However, to save you this effort, we have supplied you with the necessary filefor this tutorial.

The Model File you will be using in this tutorial is called tut5.mil. It looks likethis.

! File used in Tutorial 5 to exclude the area of! the mill from optimization

! Each block contains 100,000,000 tonnes of! waste.

! The blocks cover a range of 20 to 33 in the X! direction and 59 to 64 in the Y direction.

20 ,59,22,0,1,1,10000000021 ,59,22,0,1,1,10000000022 ,59,22,0,1,1,10000000023 ,59,22,0,1,1,10000000024 ,59,22,0,1,1,10000000025 ,59,22,0,1,1,10000000026 ,59,22,0,1,1,10000000027 ,59,22,0,1,1,10000000028 ,59,22,0,1,1,10000000029 ,59,22,0,1,1,10000000030 ,59,22,0,1,1,10000000031 ,59,22,0,1,1,10000000032 ,59,22,0,1,1,10000000033 ,59,22,0,1,1,100000000

20 ,60,22,0,1,1,10000000021 ,60,22,0,1,1,10000000022 ,60,22,0,1,1,10000000023 ,60,22,0,1,1,10000000024 ,60,22,0,1,1,10000000025 ,60,22,0,1,1,10000000026 ,60,22,0,1,1,10000000027 ,60,22,0,1,1,10000000028 ,60,22,0,1,1,10000000029 ,60,22,0,1,1,10000000030 ,60,22,0,1,1,10000000031 ,60,22,0,1,1,10000000032 ,60,22,0,1,1,100000000

…and so on.

Strictly, these blocks should all lie on the surface, which slopes upwards to theright in this area, but, for simplicity, we have put the blocks all on one level.

You will use the Re-blocking Program to paste this small Model File over thecorresponding blocks in the original Model File, fstut.mod, and then to outputa new Model File called tut5.mod.


110

Step 2: Running the Re-blocking, Optimization and PitVisualisation Programs

Running theRe-blockingProgram

Start the Re-blocking Program and use the following information in response tothe prompts.

Prompt Use


Type(s) of file(s) to be read [1]

Number of Model Files 2

Merge element data? [N]

Primary Parameters File name fstut

Change size/position of model? [N]

Primary Model File name fstut.mod

Secondary Parameters File name [fstut.par]

Secondary Model File name tut5.mil

Combine/split blocks? [N]

Maximum number of parcels [5]

Calculate mining CAFs [N]

Calculate processing CAFs [N]

Trim output with polygon [N]

New Model File name tut5

Write a new Parameters File? N

Running theOptimizationProgram

Run the Optimization Program and use the following information in response tothe prompts.

Prompt Use


Restart run? [N]


Model File [tut5.mod]

Structure Arcs File tut1.stu

Work File name tut5

Results File name tut5



111

Step 2: Running the Re-blocking, Optimization and PitVisualisation Programs, Continued

Running the PitVisualisationProgram

• Run the Pit Visualisation Program.• Call the print file tut5.• Emphasise Pit 19.• Accept the defaults offered by the program at the other prompts.

Examining the print file

Look at the print file, tut5.prp.

If you look at the XY plane for bench 22, you will see that Pit 19 sits againstthe excluded area.


112


What you havelearnt

In working through this tutorial, you have learnt how to paste one model overanother and how to exclude the pits from a specific area.

For moreinformation


Topic See Page

Error messages 404


Model Files 214




Print files 24

Re-blocking Program 45


Exercise 5 - Should the Mill be Moved?5 July, 1999

113

Exercise 5 - Should the Mill be Moved?

Introduction In Tutorial 5, we regarded the mill as fixed, but it could always be moved, for aprice. The question is, does the increase in the value of the pit caused bymoving the mill exceed the cost of moving it?

How to determinewhether the millshould be moved

This is very easily answered by running the same analysis on Results Fileswhich were produced with and without the exclusion area.

If the difference in NPVs for the two cases is more than sufficient to pay formoving the mill, then you will gain by doing so.

Procedure Run the original analysis that you did in Tutorial 1 using tut5.res and comparethe NPV for, say, worst case mining with the NPV that you got in Tutorial 1.

Call the print file exer5.

Question What is the maximum amount that it would be reasonable to spend on movingthe mill?

Tutorial 6 - The Basics of Mining Width Control5 July, 1999

114

Tutorial 6 - The Basics of Mining Width Control

Overview

Introduction In working through this tutorial, you will carry out a straightforward applicationof mining width to a selected series of push-backs in a Results File. You willstart with the Tutorial 1 data.

Establishing thepush-backs andfinal pit

To apply the mining width concept, you first have to specify a set of initialpush-backs.

For the purpose of this tutorial, you will use the initial push-backs used inExercise 3, namely Pits 15 and 16, with 19 as the final pit (represented by theletters F, G and J respectively in the Pit Visualisation print file output).

For more information, refer to Step 1: Determining the Preliminary Push-backson page 95.


Topic See Page

Step 1: Running the Mining Width Program 115

Step 2: Examining the Print File 116

Step 3: Running the Analysis Program using the ModifiedResults File

120

For More Information 121


115

Step 1: Running the Mining Width Program

Procedure Start the Mining Width Program.


The Menu Select the Mining Width Program from the Menu

The Command Line Type FXMI and then press the Enter key (↵↵).


Prompt Use



Use a Results File or a Pit List File? [1]

Results File tut1

Structure Arcs File [tut1.stu]

Output Results File name tut6

Pit number for the final pit 19

Intermediate push-backs and finalpit

15 16 19

Push-backs correct? Y

Mining width 20

The program will display the current push-back control values. You will notethat the template size is 2 × 2 and that the mining tolerance has defaulted to 1.

Prompt Use

Modify any of these values? N

The program will now complete its run. It will process each bench, from thebottom up, and will then write a new Results File.


116

Step 2: Examining the Print File

Introduction The print file (tut6.prm) will list the following preliminary information:

• The contents of the Parameters File• The names of all of the input and output files used• The push-back numbers

It will also contain the following.

Block information The print file contains the number of blocks read, accepted, rejected andwritten.

14955 Blocks were read: 2587 were air (no rock) 7603 contained parcels: 3431 parcels might be processed 4172 parcels were defined waste 4765 were entirely undefined waste

8913 Blocks were accepted: 2587 were air (no rock) 4865 contained parcels: 2439 parcels might be processed 2426 parcels were defined waste 1461 were entirely undefined waste

6042 Blocks were rejected: 2738 contained parcels: 992 parcels might be processed 1746 parcels were defined waste 3304 were entirely undefined waste

Writing the revised Results File -

9012 Blocks were written: 2587 were air (no rock) 4919 contained parcels: 2475 parcels might be processed 2444 parcels were defined waste 1506 were entirely undefined waste

Adjustments to the final pit -

99 Blocks were added to the final pit 89 Blocks were from larger pit shells 10 Blocks were not in the Results File and were added as waste blocks. These blocks are:

IX IY IZ 15 37 4 15 38 4 12 40 6 23 55 17 23 56 17 23 56 18 22 57 19 22 58 20 21 59 21 21 60 22

The total material added is: Rock 205200 GOLD 3983



117


Block information (continued)

You will note that extra blocks have been added to the pit. These are caused bypit expansion to provide mining width. 99 extra blocks have been added, whichinclude 10 for which records did not exist in the Results File. These 10 blockshave been written out as pure undefined waste using the default block tonnagevalue(s) in the Parameters File.

Summary report A summary report is produced that shows the changes in tonnage for each ofthe push-backs.

Push-back tonnage summary report

Push Original Revised Back Tonnage Tonnage Variation Percentage

1 3151280 3811920 660640 21.0 2 4058320 4024560 -33760 -0.8 3 5178720 4757040 -421680 -8.1 ---- ---------- ---------- Total 12388320 12593520 205200 1.7

You will notice that tonnage of the first push-back has increased, and thetonnage of the other push-backs has decreased.

The total pit tonnage has increased because of the pit expansion.



118


Modifiedpush-backdiagrams

The modified push-back plans are then displayed. The push-back numbers arestored as numbers in the Results File but are displayed as alphabetic charactersin the diagrams. The results for bench 21, before and after, are shown on thenext page.

In these diagrams, the original push-backs are shown as lower-case letters, andreassigned blocks are shown in upper-case letters, so that you can see what hashappened to the push-back and the effects that various user controls have on thefinal shape. The reassigned blocks are also shown in highlight to make themeasier to see, but that is not normal. Note: Some changes will be the result ofchanges to lower benches.

The four other symbols used in the diagrams are explained below.

Symbol This symbol…

. Denotes an air block, as in the Pit Visualisation Program.

+ Shows expansion beyond the ultimate pit into higher numbered pit shellsin the Results File.

The push-back number can normally be deduced from its neighbours.

* Shows expansion beyond the last pit shell in the Results File.

Since there are no block details available, a block of undefined waste isused. The push-back number can be deduced from its neighbours.

# Shows a block which has been removed from the floor of the final pit.



119


Modified push-back diagrams (continued)

Before After **********|*********|*********|**** * * * * * * * * - aa - * ccaaaaaa * * baaaaaaaac * * bbaaaaaaaaaa * * bbbaaaaaaaaaaa * * baaaaaaaaaaaaaaac * * baaaaaaaaaaaaaaaab * * baaaaaaaaaaaaaaaaac * * baaaaaaaaaaaaaaaabc * * ccbaaaaaaaaaaaaaaaaabc * - ccbbaaaaaaaaaaaaaaaaaabc - * cccbbaaaaaaaaaaaaaaaaaaacc * * cccbbbaaaaaaaaaaaaaaaaaaac * * ccbbaaaaaaaaaaaaaaaaaaaabc * * ccbbbaaaaaaaaaaaaaaaaaaabbcc * * cbbbaaaaaaaaaaaaaaaaaaabbccc * * ccbbbaaaaaaaaaaaaaaaaaabbcccc * * cbbbbaaaaaaaaaaaaaaaaaabbcccc * * cbbbbaaaaaaaaaaaaaaaaaabccccc * * cbbbbaaaaaaaaaaaaaaaaaabccccc * - cbbbbbaaaaaaaaaaaaaaaaabbccccc - * cbbbbbaaaaaaaaaaaaaaaaabbcccc * * cbbbbbbaaaaaaaaaaaaaaabbbcccc * * cbbbbbbbaaaaaaaaaaaabbbbbccc * *ccbbbbbbbbaaaaaaaabbbbbbbcccc * *ccbbbbbbbbaaaaabbbbbbbbbbccc * *ccbbbbbbbbbbbbbbbbbbbbbbccc * ccbbbbbbbbbbbbbbbbbbbbbccc * Ycccbbbbbbbbbbbbbbbbbbbccc * cccbbbbbbbbbbbbbbbbbbbcc * -ccccbbbbbbbbbbbbbbbbbcc - *ccccccbbbbbbbbbbbbbcccc * *cccccccbbbbbbbbbbbcccc * *cccccccccbbbbbbbcccccc * * cccccccccccccccccccc * * ccccccccccccccccccc * * ccccccccccccccccc * * ccccccccccccccc * * cccccccccccc * * cccccccccc * - cccc - * * * * * * * * * * * * * * * * * * - - * * * * * * * * * * * * * * * * * * **********|***** X *|*********|****

**********|*********|*********|**** * * * * * * * * - aa - * *AAaaaaaa * * +AaaaaaaaaA * * AAaaaaaaaaaa * * AAAaaaaaaaaaaa * * AaaaaaaaaaaaaaaaA * * AaaaaaaaaaaaaaaaaA * * AaaaaaaaaaaaaaaaaaA * * AaaaaaaaaaaaaaaaaAA * * AAAaaaaaaaaaaaaaaaaaAA * - BBAAaaaaaaaaaaaaaaaaaaAA - * cBBbAaaaaaaaaaaaaaaaaaaaAA * * ccBbbAaaaaaaaaaaaaaaaaaaaA * * ccbbaaaaaaaaaaaaaaaaaaaaAc * * ccbbbaaaaaaaaaaaaaaaaaaaAAcc * * BbbbaaaaaaaaaaaaaaaaaaaAAccc * * BBbbbaaaaaaaaaaaaaaaaaaAAcccc * * BbbbbaaaaaaaaaaaaaaaaaaAAcccc * * BbbbbaaaaaaaaaaaaaaaaaaAccccc * * +BbbbbaaaaaaaaaaaaaaaaaaAccccc * - BbbbbbaaaaaaaaaaaaaaaaaAbccccc - * Bbbbbbaaaaaaaaaaaaaaaaabbcccc * * Bbbbbbbaaaaaaaaaaaaaaabbbcccc * * Bbbbbbbbaaaaaaaaaaaabbbbbccc+ * *BBbbbbbbbbaaaaaaaabbbbbbbcccc * *BBbbbbbbbbaaaaaAbbbbbbbbbccc * *cBbbbbbbbbbbbbbbbbbbbbbbccc * ccbbbbbbbbbbbbbbbbbbbbbccc * Ycccbbbbbbbbbbbbbbbbbbbccc * cccbbbbbbbbbbbbbbbbbbbcc+ * -ccccbbbbbbbbbbbbbbbbbcc+ - *ccccccbbbbbbbbbbbbbcccc * *cccccccbbbbbbbbbbbcccc * *cccccccccbbbbbbbcccccc * * cccccccccccccccccccc * * ccccccccccccccccccc * * ccccccccccccccccc * * ccccccccccccccc * * cccccccccccc * * cccccccccc * - cccc - * * * * * * * * * * * * * * * * * * - - * * * * * * * * * * * * * * * * * * **********|***** X *|*********|****

In the diagrams above, most of the very narrow areas have been removed.

If you look at lower benches, you will see that there are several areas that couldbe cleaned up. These matters will be explored in Exercise 6.


120

Step 3: Running the Analysis Program using the ModifiedResults File

Introduction Results File produced by the Mining Width Program can be used by theAnalysis Program to generate new period cash flow and tonnage reports.

Procedure Do two runs of the Analysis Program using the prices, costs and throughputsfrom Tutorial 1.

These are:

• Reference mining cost $1.00 per tonne

• Price of gold $370

• Discount rate 10%

• Rock throughput 4,000,000 tonnes per period

• Mill throughput 1,000,000 tonnes per period

First run Call the print file tut6a.pra.

Use tut1.res as input, and analyse Pit 19.

Do a specified schedule with push-backs to pits 15, 16 and 19, with a userspecified constant lag of 0.

What is the total discounted cash flow produced?†

Second run Call the print file tut6b.pra.

Use tut6.res as input, and analyse Pit 3.

Do a specified schedule with push-backs to pits 1, 2 and 3, and again use aconstant lag of 0.

What is the total discounted cash flow produced?‡

The difference inNPV

The difference in NPV, $170,457 or -0.8%, indicates the cost of making themining more feasible.

† This should produce a total discounted cash flow (NPV) of $19,660,895.‡ This should produce a total discounted cash flow (NPV) of $19,490,438.


121

For More Information

For moreinformation


Topic See Page


Error messages 404

Mining Width Program 104

Minimum Mining Width 313




Print files 24


Exercise 6 - Further Tidying Up5 July, 1999

122

Exercise 6 - Further Tidying Up

Overview

Introduction It was noted in Tutorial 6 that, on many of the benches, there were small areasthat could be improved.

In general there is little cost in removing the small stumps, small holes andsharp corners. The cost of removing drop cuts and small walls can be greater,as ore bearing rock can be omitted from the final pit, the processing of ore maybe delayed due to blocks being reassigned to a later push-back, or waste may bemined earlier.

Obviously these are areas that need to be investigated by trial and error for anyResults File.


Topic See Page

Step 1: Using the Mining Width Program with a Log File 123

Step 2: Doing Analyses with the Analysis Program 126

Step 3: Examining the Results 127


123

Step 1: Using the Mining Width Program with a Log File

Introduction As you are going to make three improvements in total to the benches, you willlog your responses the first time through to save repeatedly typing in theresponses.

Cleaning up thesmall walls andcreating a log file

Start the Mining Width Program. Use the following information in response tothe prompts.

Prompt Use

Print file name !l exer6 (the program will now start loggingyour responses)

Print file name !ask (this command enables to program to askyou for a response the next time this log file is used)

Print file name #exer6a


Use a Results File or aPit List File?

[1]

Results File tut1

Structure Arcs File [tut1.stu]

Output Results Filename

!ask

Output Results Filename

#exer6a

Pit number for thefinal pit

19

Intermediatepush-backs and finalpit

15 16 19

Push-backs correct? Y

Mining width 20



124

Step 1: Using the Mining Width Program with a Log File, Continued

Cleaning up the small walls and creating a log file (continued)

The program will display the current push-back control values.

PUSH-BACK CONTROL VALUES

Mining width 20.0 Mining width in X (in blocks) 2 Mining width in Y (in blocks) 2 Mining tolerance (in blocks) 1

Minimum Additional smoothing options: Blocks Remove small drop cuts No 0 floor 0 elsewhere Remove small walls No 0 Remove small stumps Yes Remove small holes Yes Remove sharp corners Yes Allow expansion of outer pit Yes

Do you want to modify any of these values (Y/N) [Y] ?

Prompt Use

Modify any of these values? [Y]

The control values will be re-displayed with a Menu.

PUSH-BACK CONTROL VALUES

1. Mining width 20.0 2. Mining width in X (in blocks) 2 3. Mining width in Y (in blocks) 2 4. Mining tolerance (in blocks) 1

Minimum Additional smoothing options: Blocks 5. Remove small drop cuts No 0 floor 0 elsewhere 6. Remove small walls No 0 7. Remove small stumps Yes 8. Remove small holes Yes 9. Remove sharp corners Yes 10. Allow expansion of outer pit Yes

99. Exit

Your choice [99] : _



125

Step 1: Using the Mining Width Program with a Log File, Continued

Cleaning up the small walls and creating a log file (continued)

Prompt Use

Your choice 6 (to access the small walls control value)

Minimum blocksin an isolated wall

10 (so that small walls of 9 blocks or less will beremoved)

Your choice !end (this command will tell the program to stoplogging responses)

Your choice [99]

The program will now start its run. It will produce a revised Results Filecontaining the modified push-backs. Note that push-backs will appear as pits 1,2 and 3 in the revised Results File, rather than as 1-15, 16 and 17-19.

Adding a minimuminternal drop cut

• Start the Mining Width Program.

• Type !use exer6 in response to the print file prompt to use the log fileexer6.lom.

• Call the print file and the Results File #exer6b.

• The program will stop to request further input. Type 5 edit the “removesmall drop cuts” control values. Change the minimum blocks in a drop cutelsewhere to 10. Type 99 to exit.

Removing singleisolated blocksusing a floor dropcut

If you look at the push-backs from the previous examples, you will note thatthere are many cases of single isolated blocks. These could be removed byusing a floor drop cut minimum of 2.

• Start the Mining Width Program.

• Type !use exer6 in response to the print file prompt to use the log fileexer6.lom.

• Call the print file and the Results File #exer6c.

• Type 5 edit the “remove small drop cuts” control values. Change theminimum blocks in a floor drop cut to 2 and the minimum blocks in a dropcut elsewhere to 10. Type 99 to exit.

The next step is to do some analyses to determine the cost of these decisions.


126

Step 2: Doing Analyses with the Analysis Program

Procedure Do three runs of the Analysis Program using the prices, costs and throughputsfrom Tutorial 1

These are:

• Reference mining cost $1.00 per tonne

• Price of gold $370

• Discount rate 10%

• Rock throughput 4,000,000 tonnes per period

• Mill throughput 1,000,000 tonnes per period

Analyse Pit 3 with push-backs to pits 1, 2 and 3, and use a lag of 0. (These arethe pit numbers output by the Mining Width Program.)

For the:

• First run:- Call the print file #exer6a.- Use exer6a.res as input.- Call the run Single element exercise 6a.

• Second run:- Call the print file #exer6b.- Use exer6b.res as input.- Call the run Single element exercise 6b.

• Third run:- Call the print file #exer6c.- Use exer6c.res as input.- Call the run Single element exercise 6c.

Check your results against those on the next the page.


127

Step 3: Examining the Results

Comparison ofNPV

The results you should get are tabulated below. Ultimately it is a valuejudgement as to what is the “better” solution. The ease of mining cleanpush-backs may translate into cheaper mining costs or lower set-up costs.

Description NPV Change

Base case as for Exercise 3 $19,660,895

With mining width template 2×2 $19,490,438 -0.9%

plus minimum wall = 10 $19,530,286 0.2%

plus minimum internal drop cut = 10 $19,453,922 -0.2%

plus minimum pit floor drop cut = 2 $19,268,865 -1.1%

Examining theprint files from theMining WidthProgram runs

If you spend some time examining the print files output by the Mining WidthProgram from the various runs, you will see the sort of changes that are madeand you will see that many of the problems have been cleared up.

Even with all these changes, the outlines are not perfect, and will still requiresome manual adjustment when the final detailed design is done, but they are agreat deal better than those produced without the adjustments, and the resultantNPV gives a closer estimate of the true pit value.

Tutorial 7 - Improving the scheduling with Milawa5 July, 1999

128

Tutorial 7 - Improving the scheduling with Milawa

Overview

Introduction In previous tutorials we have analysed best, worst and specified schedules for aspecific ultimate pit and have worked out which pit shells might provide the“best” compromise. We have also looked at logging commands and spreadsheetfiles to make the analysis easier. Let us now re-visit the first tutorial exampleand see if we can do better in the light of our new skills.

If we plotted the best and worst case schedules against pit number andsuperimposed the rock and mill tonnage on the one combination graph for pits10 to 25 we would get the following graph:

NPV vs Pit number

0

5

10

15

20

25

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

Pit number

NP

V (

$m)

0

4

8

12

16

20

24

28

32

To

nn

es (

m)

Best case

Worst case

Rock tonnage

Mill input



129

Overview, Continued

In the above example Pit 19 gives a worst case NPV of $18.0m while mining12.3m tonnes and milling 3.7m tonnes of ore. Pit 23 gives a best case NPV of$21.1m while mining 17.8m tonnes and milling 4.7m tonnes of ore. The bestcase provides an upper bound to what may be achievable. The additional $3.0mwould represent a 17% improvement over the worst case and is worthconsidering. While other corporate objectives such as maximizing mine life,maximum cost of production, scale of operations, exposure to risk, utilisation ofresource could be considered we will use maximizing profit for the purposes ofthis example.

Pit 15 contains 3.2m tonnes of material and at an annual mining rate of 4mtonnes this represents approximately 0.8 years of mining before the first push-back. In exercise 3, Pit 15 was taken as the ‘best’ position for the first push-back.

When choosing the final pit there are, however, some decisions to take. Is itbetter to go for Pit 23 which has the maximum NPV or does Pit 20 provide abetter solution with a pit that is 2.3m tonnes or 6% smaller for a reduction of$178,000 or 0.7% in NPV.

This tutorial explores these possibilities.


Topic See Page

Step 1: Creating the Spreadsheet Definition File 130

Step 2: Scheduling using Milawa in improving NPV mode 131



130

Step 1: Creating the Spreadsheet Definition File

Introduction We can use the Spreadsheet Definition File, exer3.ssd, as it stands but it maybe appropriate to add some additional push-back specific fields to it to makefurther analysis easier. For example:

PUSH1/TP will give the tonnes mined for the first push-back andPUSH1/BM will show the number of benches mined.

Producing theSpreadsheetDefinition File

Follow the steps in the table below to produce the Spreadsheet Definition File,tut7.ssd.

Step Action

1. Open and view exer3.ssd using a text editor or word processor inpure text mode.

2. Save the file as tut7.ssd.

3. Add the following lines to the text.

Per push1/tp push2/tp push3/tpPer push1/bm push2/bm push3/bm

Gra push1/tps push2/tps push3/tpsGra push1/bm push2/bm push3/bm

The Spreadsheet Definition File should now read as follows. PER PERIOD ROCK/LIMIT ROCK/TP MILL/TI OPVALUE/DT

Per push1/tp push2/tp push3/tpPer push1/bm push2/bm push3/bm

Gra BLANK ROCK/LIMIT ROCK/TPS MILL/TIS OPVALUE/DTSGra push1/tps push2/tps push3/tpsGra push1/bm push2/bm push3/bm

4. Save tut7.ssd again and exit from the text editor or word processor.


131

Step 2: Scheduling using Milawa in improving NPV mode

IntroductionIf we decide to have the first push-back at Pit 15 and have Pit 20 as the ultimatepit what is the best intermediate push-back to use. Since we may wish toinvestigate other options in a later exercise it would be a good idea to log theanalysis program input.

Procedure Start the Analysis Program. As you are going to use a log file, enter a loggingcommand instead of a print file name as the first response.

Prompt Use

Print file name !L tut7

This tells the program to start logging your responses and to ask for the name ofthe print file again.




132

Step 2: Scheduling using Milawa in improving NPV mode,Continued

Prompt Use

Print file name #tut7


Results File tut1.res



Spreadsheet Output File #tut7

Run description Single element tutorial7




Price of GOLD 370

Pit number 20




1m



Specified schedule Y

Pit numbers to push back to 15 16 20

The way push-backs scheduled [2] (for Milawa in improving NPVmode)

Specify bench lead or maximum benchmining constraints ?

[N]

Worst case schedule N

Best case schedule N

Values correct? Y

Another analysis request? Y



133


The Analysis Program will loop back to the question about the referencemining cost, above, and will ask the rest of the questions again. Follow thesteps in the following table.

Step Action

1. Press Enter in response to each of the prompts, except for the ‘Pitnumbers to push back to’ prompt where you need to type

15 17 20

Note: You only need to press Enter in response to all of the otherquestions because the default responses will be what you typed inthe first time through.

2. Continue looping around the questions, typing in a new ‘pit numberto push back to’ each time (i.e. 15 18 20 & 15 19 20). Thenanswer: N to the question about whether you want to enter anotheranalysis request.

3. Answer: N to the question about whether you want a full print (weonly require the totals from this printout).




134


Best intermediatepit

Print out or view the Spreadsheet Output File, tut7.sso. You will see that anintermediate push-back at Pit 17 gives the highest overall NPV.

NPV vs Intermediate push-back

18.0

19.0

20.0

21.0

22.0

16 17 18 19

Push-back

NP

V (

$m)

Review schedules With intermediate push-backs to pits 15 and 17 the spreadsheet output showsthe following tonnages for each of the periods.

Period Push1 push2 push3 /tp /tp /tp

1 2766239 1051001 0 2 385041 3605491 0 3 0 1421000 1922189 4 0 116347 3882897 5 0 0 372754

In this case, two push-backs are mined simultaneously in all periods except thelast.

Period PUSH1 PUSH2 PUSH3 /BM /BM /BM

1 7.15 3.28 0 2 4.85 6.85 0 3 0 5.81 5.31 4 0 3.06 10.70 5 0 0 3.99



135


A review of the benches mined in each period shows that in the first period 7.15benches are mined in push-back one. You can specify minimum and maximumleads and maximum benches if you need to refine the mining schedule.

Specific miningrate

A plot of the period mining tonnage shows that the target rate of 4m tonnes perannum was used in almost all of the periods except the last one where there wasinsufficient material to mine.

Rock Tonnage Throughput

0

1

2

3

4

1 2 3 4 5

Period

To

nn

age

(m)

Specific millingrate

A plot of the period milling tonnage shows that the target rate of 1m tonnes perannum was used in all of the periods except the last one where there wasinsufficient material to process.

Mill Tonnage Throughput

0.0

0.5

1.0

1 2 3 4 5

Period

To

nn

age

(m)



136


Overall result The final NPV of $20.5m is very close to the best case value of $21.1m and is13.8% better than a worst case schedule of $17.8m.

NPV vs Schedule

16

17

18

19

20

21

22

Worst ImproveNPV

Best

NP

V (

$m)

2.7%

13.8%


137


What you havelearnt


• Learnt how to apply push-back specific codes in the Spreadsheet DefinitionFile.

• Seen how the analysis program can be used to help select the best practicalresult.

• Learnt how to use the Milawa in improving NPV mode for improvingschedules.

For moreinformation


Topic See Page


Error messages 404

Expressions 282


How the Milawa Algorithm works 381

Print files 24



User Specified mining schedules 124


Exercise 7 - Exploring further options5 July, 1999

138

Exercise 7 - Exploring further options

Overview

IntroductionIn the previous tutorial we carried out an analysis based on push-backs to pits15 and 17 with an ultimate pit at Pit 20. There are several obvious questionsthat come to mind:

a) Would it be better to have a smaller first push-back, say at Pit 10

b) What happens if we use the Milawa throughput option.

c) Would there be any value in extending the ultimate pit to pit 21 or 22


Topic See Page

Step 1: Checking the earlier push-back 139

Step 2: Using Milawa in improving throughput balance mode 140

Step 3: Extending the ultimate pit 142


139

Step 1: Checking the earlier push-back

ProcedureThe easiest way to check this is to repeat tutorial 7 changing the first pit from15 to 10 and using a different name for the Print and Spreadsheet Output Files.

• Produce a new version of tut7.loa and call it exer7a.loa.

- and -

• Re-run the Analysis Program.

Follow the procedure set out below.

Producing the logfile

Follow the steps in the table below to edit the log file, exer7a.loa.

Step Action

1. Open tut7.loa using a text editor or word processor in pure textmode.

2. Save the file as exer7a.loa.

3. Edit exer7a.loa as follows:

Change the… to…

Print file #exer7a

Spreadsheet OutputFile

#exer7a

Run description Single element exercise7a

Change all occurrences of 15 to 10 for the push-back specification.

4. Save exer7a.loa again and exit from the text editor or wordprocessor.


Start the Analysis Program and type !u exer7a at the print file name prompt.

Checking theoutput

When you compare the NPV values for the specified schedules in exer7a.ssowith those in tut7.sso you will see that they are lower.


140

Step 2: Using Milawa in improving throughput balance mode

Procedure The easiest way to check this is to repeat tutorial 7 changing the schedule lagoption from 2 to 3 and using a different name for the Print and SpreadsheetOutput Files.

• Copy the log file tut7.loa to exer7b.loa.

• Edit this file and change the print file and spreadsheet output to exer7b,change the lag option from 2 to 3.


Checking theoutput

In this case the Milawa improving throughput balance mode produces a verysimilar NPV value to the improving NPV mode, but this is not always so.

Specific miningrate

A plot of the period mining tonnage shows that the target rate of 4m tonnes perannum was used constantly for the first three periods. This can be comparedwith the improving NPV case in tutorial 7.

Rock Tonnage Throughput

0

1

2

3

4

1 2 3 4 5

Period

To

nn

age

(m)



141

Step 2: Using Milawa in improving throughput balance mode,Continued

Specific millingrate

A plot of the period milling tonnage shows that throughput close to the targetrate of 1m tonnes per annum was achieved in all of the periods except the lastone where there was insufficient material to process. This is also very similar tothe improving NPV case.

Mill Tonnage Throughput

0.0

0.5

1.0

1 2 3 4 5

Period

To

nn

age

(m)


142

Step 3: Extending the ultimate pit

ProcedureThe easiest way to check this is to repeat tutorial 7 changing the final pit from20 to 21 and using a different name for the Print and Spreadsheet Output Files.

• Copy the log file tut7.loa to exer7c.loa

• Edit this file and change the print file and spreadsheet output to exer7c,change all occurrences of 20 to 21


Checking theoutput

You should find that Pit 21 gives a slight advantage in NPV. If you were torepeat the procedure substituting 20 to 22 you would find that Pit 22 gives alower value.

Index5 July, 1999

143

Index

Special characters and keys# for a block removed...................................................................................................................................................... 118# for overwriting files ........................................................................................................................................................ 22↵ Enter symbol .................................................................................................................................................................... 7* for expansion beyond last pit shell ............................................................................................................................... 118. for an air block .............................................................................................................................................................. 118^ to go to previous question.............................................................................................................................................. 44+ for an expansion beyond the ultimate pit...................................................................................................................... 118

AAbbreviations used .............................................................................................................................................................. 8Air block.................................................................................................................................................................... 42, 118Analysis Program

mining schedulesbest case.............................................................................................................................................................. 52, 94user specified

constant lag........................................................................................................................................................... 97worst case ............................................................................................................................................... 52, 71, 85, 94

spreadsheet codes ................................................................................................................................................. 89reference........................................................................................ 44, 64, 69, 72, 81, 83, 87, 90, 97, 103, 120, 131, 139

BBackspace key ................................................................................................................................................................... 21Bold type, use of.................................................................................................................................................................. 7

CCost adjustment factor

positional mining ........................................................................................................................................................ 106positional processing................................................................................................................................................... 106reference...................................................................................................................................................................... 106

Cost of miningreference........................................................................................................................................................................ 54

Ctrl + Y ............................................................................................................................................................................. 21Cut-off ............................................................................................................................................................. 37, 39, 53, 57

DDefault answers ................................................................................................................................................................. 21

editing ........................................................................................................................................................................... 21DEL key ............................................................................................................................................................................ 21Discounting ....................................................................................................................................................................... 54

EEnd key.............................................................................................................................................................................. 21Esc key .............................................................................................................................................................................. 21Expression ............................................................................................................................................................. 86, 87, 89

Index5 July, 1999

144

FFour-X Menu..................................................................................................................................................................... 15fx.ini .................................................................................................................................................... See Initialization FileFXMENU..................................................................................................................................................See Four-X Menu

HHardware and software requirements ................................................................................................................................ 10Home key........................................................................................................................................................................... 21

IImmovable objects........................................................................................................................................................... 108Initial capital expenditure ............................................................................................................................................ 59, 89Initialization file

reference........................................................................................................................................................................ 11Initialization file ................................................................................................................................................................ 14INS key.............................................................................................................................................................................. 21Installation......................................................................................................................................................................... 11Internal rate of return......................................................................................................................................................... 59Italics, use of........................................................................................................................................................................ 7

LLeft arrow key ................................................................................................................................................................... 21Log file

editing ................................................................................................................................................................... 83, 139example ......................................................................................................................................................................... 75reference.......................................................................................................................................................... 70, 72, 131

MMCOSTM

reference........................................................................................................................................................................ 80Menu .........................................................................................................................................................See Four-X MenuMilawa

improving NPV........................................................................................................................................................... 131improving throughput balance .................................................................................................................................... 140

Mining capacity, variation of....................................................................................................................................... 87, 89Mining width ........................................................................................................................................................... 114, 117Mining Width Program............................................................................................................................................ 114, 115Model File, example........................................................................................................................................................ 109

NNPV..................................................................................................................................................................... 52, 59, 127

adjusting for a range of contract mining cost premiums................................................................................................ 91

OOptimization Program ....................................................................................................................................... 35, 103, 110Overwriting files................................................................................................................................................................ 22

PParameters File .......................................................................................................................... 34, 37, 47, 49, 53, 116, 117Period .................................................................................................................................................................... 54, 87, 89Pit

Index5 July, 1999

145

expansion ............................................................................................................................................................ 117, 118shell............................................................................................................................................................................. 118

Pit Visualisation Program............................................................................................................................ 40, 95, 103, 111Price............................................................................................................................................................................. 70, 81Print Files

Analysis Program, example........................................................................................................................................... 49Mining Width Program, example................................................................................................................................ 116Optimization Program, example.................................................................................................................................... 37Pit Visualisation Program, example .............................................................................................................................. 42Structure Arcs File, example ......................................................................................................................................... 32Utilities Program, example............................................................................................................................................ 27viewing and printing ..................................................................................................................................................... 19

Processing mill, moving .................................................................................................................................................. 113Programs

accessingvia the Command Line.............................................................................................................................................. 18via the Four-X Menu ................................................................................................................................................ 15

exiting ........................................................................................................................................................................... 22Prompts and answers ......................................................................................................................................................... 20Push-back .......................................................................................................................................................... 94, 118, 138

RRanges function, example................................................................................................................................................ 106Re-blocking Program....................................................................................................................................... 102, 106, 110Results File.............................................................................................................................................................. 118, 120

reference........................................................................................................................................................................ 80Revenue Factor............................................................................................................................................................ 37, 38Right arrow key ................................................................................................................................................................. 21

Index5 July, 1999

146

SSelecting from a list of items ............................................................................................................................................. 20Sharp corner .................................................................................................................................................................... 122Small drop cut

floor............................................................................................................................................................................. 125reference.............................................................................................................................................................. 122, 125

Small hole........................................................................................................................................................................ 122Small stump..................................................................................................................................................................... 122Small wall................................................................................................................................................................ 122, 123Spreadsheet Definition File

creating.......................................................................................................................................................................... 89editing ......................................................................................................................................................................... 130example ............................................................................................................................................................. 71, 89, 96reference.............................................................................................................................................. 70, 77, 81, 96, 130

Spreadsheet Output Fileexample ................................................................................................................................................................... 76, 91reference.................................................................................................................................................................. 70, 77

Stripping ratio.................................................................................................................................................. 37, 54, 60, 94Structure Arcs Program ............................................................................................................................................. 30, 103

TText

editing during program runs.......................................................................................................................................... 21

UUnprocessed mineralisation............................................................................................................................................... 37Utilities Program ............................................................................................................................................................... 24

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