COMPUTEWSED OPEN PR PLANNiNG AND THE DEVELOPMENT AND

APPLICATION OF A SOFTWARE OPEN PIT PLANNER

BY

Kenneth Albert Ronson

A thesis submitted to the

Department of Mining Engineering

in conformity with the requirernent for

the degree of Master of Science (Engineering)

Queen's University

Kingston, Ontario, Canada

January, 200 1

Copyright O Kenneth Albert Ronson, 200 1

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Abstnct

K.A. Ronson: Development and Application of a Software Open Pit Plamer,

MSc. Thesis, Department of Mining Engineering, Queen's University at Kingston,

January 200 1.

Cornputer aided methods have become mandatory in the design of open-pit

rnining projects. Planning and extraction sequence software has lagged behind in ternis of

developrnent, as these were o f t a modules of existing mine design software and were not

given hl1 attention when designing newer versions and upgrades to the full package.

An open-pit mine planning utility has been developed in Visual Basic for

Applications for Autodesk's Autocad software package (Release 14). This utility alIows

the mining engineer to plan days, weeks and years in advance, through selection of

mining blocks using the mouse. The utility provides data for each block, mining period

selected or plan, including tonnes mined, the average grade of the materiai rnined, tomes

above cut-off as well as other information. The utility will ailow short and long term

plans, with any number of planning periods being acceptai, and will allow the engineer

to quickly produce these plans.

included in this thesis is a review of computerized mine planning practices, an

oveniiew of the software development process and it's application to an actuai mine, and

finally conclusions and recommendations based on the research.

iii

I would like to express my th& and appreciation to:

Professor Gar Blackwell for his assistance throughout the development of this software

and in this research, and for putting up with me for the last 6 years.

The Mining Engineering Department at Queen's University for al1 the help given to me,

especially Departmental Assistants Beverly McCallum and W a d a Badger.

Barrick Gold Ltd., Battle Mountain Ltd., Homestake Inc., and Cameco Ltd. for their

assistance and support of this research.

The many people that frquent various Autodesk and Visual Basic newsgroups

throughout the Internet for collectively solving many problems and adding to my

knowledge of Visual Basic and AutoCAD.

Dave MacDonald & Dr. Kim Dow for their hospitality.

My girlfiiend Alison for al1 of her motivational skills and support.

My parents Sue & Jirn for aii their support, and particularly to my Dad for his painstaking

pro0 freading of this thesis.

TABLE OF CONTENTS

Abstract

Acknowledgements

Vita

Table of Contents

List of Tables

List of Figures

Chapter 1

Introduction

1 . 1 Open Pit Planning

1.2 Computerized Open-Pit Planning

1.3 Description of Open-Pit Planner

1.4 Software and Hardware Selection and Requirements

1.5 Outline and Scope of the Thesis

Chapter 2

Computerised Open Pit Planning

2.1 History

2.2 Examples of Computerized Mine Planning

2.3 Review of Mining Software

2.3.1 Minex

. . ll

... 111

iv

vi

xi

xii

1

1

1

3

7

9

11

14

14

14

20

25

25

vii

2.3.2 Maptek Vulcan

2.3.3 Surpac

2.3.4 Gemçom

2.3.5 Mintec Minesight

2.3.6 Q'Pit

2.3.7 DataMine

2.3.8 Runge Mining

2.4 Summary

Chapter 3

Introduction, Objectives and Software Choices

3.0 VBA and AutoCAD

3.1 Cornparisons Between M a m Languages

3.2 Fundamentals of Visual Basic for AutoCAD

3.2.1 Projects, Foms, ModuIes and Controls

3.2.2 Events, Objects, Methods and Properties

3.2.3 Variables

3.24 Procedures and Events

3.3 Visual Basic Techniques

3 -3.1 Cycling Through Layers

3.3.2 Creating a Polyiine

3.3.3 Pulling information into Selection Sets

3.3.4 ManipulaMg Selection Sets

Chapter 4

Open Pit Planner

4.0 Introduction & Practical Objectives

4.0.1 Drawing and Database Construction

4.0.2 Software Design

4.3 DrawPolygon

4.4 LoadPolygon

4.4.1 Drawing Database

4.4.2 Polygon Files

4.5 Calculate

4.6 RemovdMine

4.7 Unrnine

4.8 Data Storage

4.8.1 Drawing Database

4.8.2 Text Files

4.9 Summary

Chapter 5

Case Study

5.0 Brenda M i e

5.1 Setting Up the Data

5.2 initiai Resewe Caicuiation

5.3 Currently Available 'Source Code' Mine Planning and

Scheduling Software

5.4 Problems to Avoid in Open Pit Mine Planning

5.4.1 Blast-Hole and Grade Control Layout

5.4.2 Ensuring Drill Access

5.4.3 Development o f Sinking Cuts

5.4.4 Maintaining Efficient Haul Road Access

5.4.5 Rarnp Layouts for Multiple Adjoining Pits

5.5 Applications o f the Open Pit Planner (OPPR)

5.5.1 A Typicd Short Term Weekiy Mine Plan

5.5.2 A Sample Plan using OPPR

5.6 Summary

Chapter 6 186

Conclusions and Recommendations

6.1 Conclusions

6.2 Recommendations for Further Work

6.3 A Final Footnote

Chapter 7

References

Appendix A

List of Prograrns and Sample Files

A. 1 List of Program Files

A.2 Sample Polygon File (48 10 1 C 1 Aug00 1 .p l )

A.3 Sample Reserve File (reserve 44 10 1 B 1 JAN0 1 .dat)

List of Tables

Table 3.1 - Cusiomization Languages

Table 3.2 - Variable Types

Table 4.1 - OPP Sub-Program

Table 5.1 - Reserve Tonnages

Table 5.2 - Tonnages above Cut-ws

Table 5.3 - Pit A Grade/Tonnage Data

Table 5.4 - E- ample of OreMiaste Scheduling Spreahkeet

Table 5.5 - Planning T a t File

Table 5.6 - Sample Mine Plan, Periods 1-4

Table 5.7 - Polygon Summary for Monrh 1

Table 5.8 - Polygon Summary for Month 2

Table 5.9 - Poiygon Summaryfbr Month 3

xii

List of Figures

Figure 1.1 - Planning Hierarchy Figure 1.2 - Brenda Interactive Planner 1 Figure 1.3 - Brenda Interactive Planner 2 Figure 1.4 - Copper Prices - 1979- 1999 Figure 2.1 - Brenda Interactive Planner Figure 2.2 - Miner Orion Figure 2.3 - WLCAN (Drilling and Pit) Figure 2.4 - WLCAN (Pit and ûretypes) Figure 2.5 - WLCAN (Virtual Mining) Figure 2.6 - VUL CAN (Overview) Figure 2.7 - Surpac2OOO / Grade Placement Figure 2.8 - Surpac2000 / Textured Mode1 Figure 2.9 - Gemcom Figure 2. I O - Mintec Minesighr #I Figure 2.11 - Mintec Minesight #2 Figure 3.1 - Visual Basic IDE Figure 3.2 - Sample Controls Figure 3.3 - Control Toolbar Figure 3.4 - Project Box Figure 3.5 - Properties Diaiog Bo.r Figure 3.6 - Calling a Module Figure 3.7 - Two Modules, Two Form Erampie Figure 4.1 - Splash Introdtrctory Screen Figure 4.2 - ChangeParamerers Figtire 4.3 - DrawPolygon Figure 4.4 - LoadPolygan Figure 4.5 - Calculate Main Window Figure 4.6 - Unmine Warning Screen Figure 4.7 - Unmnine Main Rndow Figure 4.8 - Mineralized Entity fiample Figure 4.9 - Wmte Entity ExampIe Figure 4.10 - 1 7452b3julOO.pol Polygon File Figure 4.1 1 - Temporary Polygon File Figure 4.12 - 17452b3julOO.dat Polygon Reserve File Figure 5.1 - Pit Expansion. Ramps & Pifs A, B and C Figure 5.2 - Switchback Eiample Figure 5.3 - SMU Layout Figure 5.4 - Ksmerg Figure 5.5 - Mifû-f Figure 5.6 - Cash Flow and Revenue us. Cut-WGradefir Pif A Figure 5.7 - Mining Costs vs. Cur-ûf Grade for Pit A Figure 5.8 - GraddTonnuge CurveJIor Pit A Figure 5.9 - GradelKonnage Curve fur Pit B

Figure 5.1 O - Grade/Tonnage Cunte for Pif C Figure 5. I I - Grade Tonnage Curvefor al1 Pits Figure 5.12 - Truck Hours, Unsmoothed Figure 5- 13 - Truck Hours, Smoothed Figure 5.14 - Blast Layout Cfiom Nahan, 1988) Figure 5.15 - Drill Cab Showing GPS Antenna Figure 5.16 - GPS Display Inside Drill Cab Figure 5.17 - Three Examples of Mixed Blasts Figure 5.18 - Blasting Adjacent Benches Figure 5.19 - Typical Narrow Pushback Figure 5.20 - Moving Ramps Figure 5.2 1 - 'Temporary ' Sinking Cut Figure 5.22 - Loader Location, Truck Eflciency Figure 5.23 - Catchment Berm Cleanup Figure 5.24 - Shovel GPS Antenna Figure 5.25 - Shovel GPS Display in Cab Figure 5.26 - Mine Plan (ajer Nahan, 1988) Figure 5.2 7 - Weekly Mine Plan, Isomenic View Figure 5.28 - Plan View on Completion of Mine Plan Figure 5.29 - lsometric Viav Showing Ore Stockpile & Wmte Figure 5.30 - Example Gantt Chart Weekly Plan Figure 5.3 1 - Outlined Polygon and 'Calculate' Figure 5.32 - Month 1 Figure 5.33 - Month 2 Figure 5.34 - Month 3

Cbapter 1

Introduction

This first chapter will discuss mine planning as it relates to open pit rnining. Section 1.2

describes how computerized open pit planning has overtaken the pen-and-papa

approach. A description of the author's software follows in Section 1.3. Software and

hardware requirernents are covered in Section 1.4. The objectives and scope of this

research are in Section 1 S.

1.1 Open Pit Planning

Mine planning is the scheduliig of ore and waste mining within a pit boundary such that

ore is continuously supplied to the mil1 and waste is removed in a timely manner to reach

ore. This is conducted such that there is enough material designated as botb ore and waste

(as well as any intermediately graded mateaials) to satisfy the mill, leach pad, stockpiles

or dumps on a continuous basis. There should be some flexibility in the plan to overcome

any unforeseen equipment failures or other problems such as wall slope instabilities.

Mine planning follows a general cycle in open pit rnining. Che designation can be based

on exploration and/or blast hole data. Assaying of drill cuttings must be timely in order

to keep an up to date record of ore and waste Iocations, as weU as to support or disprove

previous mine plans. Once ore and waste has been designatd, the mine plmer must

decide when and where ore and waste will be mined.

Since mine planning is essentially a tirne-based process, it is usually broken up into four

different types: immediate, short, medium and long term plans. This is anaiogous to a

daily, weekly, monthly and annual plan set-up. Figure 1 shows how each plan relates to

the Ievel of information available to the mine planner.

Mnc Plan

Mnt Plan

Blast OrdVasti contact Layout

Figure 1.1 - Planning Hierarchy showing the input inforuution (wide spieed exploraîhn venus close

spacd production drill simpiing) and tbe degree of dcWl of ibe mhie p h

Each of these tirnefiames has its own objectives and associated diffi.culties. For example,

with a long-term mine plan the conceni is with the number of tonnes and average grade

of the material to be mined, as well as general locations of ore and waste such that

Company goals and requirernents are met. Long term planning also allows the

development of different mine plans based on ranges of metal prices and operating costs.

Therefore, different scenarios based on specific metal prices and operating costs can be

generated years before mining will actually take place. These multiple plans minimize

risk, and provide options for the mine if, once in production, metal prices a d o r

operating costs fluctuate.

in the short-term mine plan the need to know exact locations of ore and waste such that

material is properly classified and being hauled to the correct place is paramount. Short-

term plans also have the further problem of dealing with day-today events such as

cmsher shutdowns or scheduled mechanical maintenance. The objective of short terni

planning is to optimize the grade and tonnage of the ore extracted, without running out of

ore grade material, while maintaining the stripping ratio and allocating mining resources

to benches. The plan should also be able to be changed quickly in case unforeseen

circurnstances should occur.

1.2 Computerized Open-Pit Planning

In the past, al1 plaruiing was accomplished on paper, using Mylar drawings and ledgers

for record keeping. Producing mine plans was tedious and required the work of many

people to get the plan completed. Cornputer aided design had been used successfully in

architecture and automotive design but had not made the transfer over to mining.

However in the early 1980's mining engineers began to use mini and personal

cornputers to augment their plans or even produce them outright. In this early tirne, there

was no professional soha re available; mining engineers such as Paul D.D. Chick and

Garston Blackwell of Brenda Mines wrote their own software that would dow the user

to input many of the mining variables such as cost and metal price and develop long and

short-term plans. Using the Limiteci equiprnent of the time, they wrote professional quaiity

software that allowed them to produce plans quickIy and easily (Figure 1.2 and Figure

1.3). Throughout the 1980's cornputer use became much more widespread in both open-

pit and underground mining operations.

Figure 1.2 - Brenda Miw Planner hoaetrir (Chiek, 1984). Uppcr Mt iad rigbt are the pit

topographies at the start and end of tk plnn period mpecthdy wi ih c r h ckvrtioa r scpurte

colour. Bottom left is the materid minai, rcd ore to b l ~ c wos(c Bottom rigbt is the 'birds eye view' of

grade at the end of the present pbn iag period rudy fitr planning tbc next bench.

Figure 1.3 - Brenda Planner (Click, 1984). T& topognpby is sboni ia plan centre rigbt. Upper left

arc the planner controis to be picked wiih tbc niaist, aad ieft am the produclion strtistics by

polygon, bench and overail The cdour code lfgend is placd rt lbe bottom,

Cornputers have greatly improved since the eariy 1980's. They are less expensive and

more powerful in terms of processing speed, have larger memory in tems of hard disk

and RAM and vastly improved graphic capabilhies. Since that time, cornputeriseci mine

planning has corne into its own. Today, there are many professional grade stand-alone

mine planning cornputer sohvare systems, and mine planning software packages as part

of a larger mine design system.

Computerisation of mine planning tends speed and ease to ali stages of mine planning.

For example, a computer wuld eady generate numerous manumatic (user aided) long-

term mine plans based on multiple metal prices and mining costs in mere hours, while

on papa it might take months. This increase in productivity has helped mine plannas

minimise risk, study sensitivity to various parameters, and allow their operations to run

more smoothly, having more mine plans ready in case of emergency. This scenario

generation is especially important in the Brenda case study exmple (Chapter 5). The

Brenda mine was an extrmely low grade copper/molybdenum deposit and needed to be

planned around continually fluctuating metal prices. Multiple scenarios based on

changing copper and molybdenum prices rninirnised loss and maximised cash fl ows. For

the purposes of this thesis the molybdenum grades were converted to 'copper equivalent'

and Figure 1.4 shows the copper prices from the last 2 1 years.

1979 1 984 1 989 1 994 1993

Year

Figure 1.4 - Copper Frices 1980-1999 - Consta~~t prices are in 1999 doUm. W, 1999)

Management objectives were to have a mine in place in 1968 to take advantage of any

'high metal price windows' in both copper and molybdenum. The molybdenum window

of 1980 saw the price rise fiom $3Ab to $30/lb, and the mine become part of the 'Fortune

500'. With two products the windows might occur more oflen, and it was feIt that the

location close to the Okanagan Valley in the BC interior would enable the best personnel

to be hired. In turn, technology would be developed to reduce costs and increase

throughput. The mine was designed to operate for 12 years at 24,000 short tons of ore per

day, and lasted 23 years, eventuaily reaching 35,000 metric tons per day. (Brenda

Company Reports, 1966 to 1993). There were periods of low metal prices, which came

close to closing the operation several times, and the computerised open pit mine planning

was important in providing management with alternatives for continued production.

1.3 Description of Open-Pit Planner

With the almost universal use of computers in mining has come large mining-specitic

software packages that provide solutions for mine design and mine planning. Most of

these professional packages deal with al1 aspects of mining, fiom ore estimation and

database management to undergroundlopen-pit mine design to truck dispatch to planning

and scheduling.

Each package has its own strengths and weaknesses, stemming fiom the fact that it rnust

cover al1 bases of mining engineering and cannot focus on one aspect of mining. As well,

most professional mining software packages tend to be quite expensive compared to more

mainstream CAD packages like AutoCAD. AutoCAD is a general cornputer-aided

drafüng systern available since 1982. It is the most widely used CAD computer package

in the world. One advantage to using AutoCAD is that it is easily customized using

various computer and scripting languages and has a cheaper total cost of ownership than

many other cirafting packages. This is why many companies opt to stay with AutoCAD

rather than switch to a mining-specific CAD package. Oae of AutoCAD's newest

custornization languages is Visual Basic for Applications, developed by Microsafi.

Visual Basic for Applications (VBA), a subset of Microsoft's Visual Basic, was chosen

as the language to program Open Pit Plannet (OPPR). It is quite powerfiil, it can interface

with Microsofi Windows, it allows for full manipulation of entities and blocks in an

AutoCAD drawing, and can lin! to external databases and other Widows prograrns.

The inspiration for writing this particular stand-alone mine planner came h m a version

w-ritten in Fortran by Mr. Paul Chick on a Texas Instruments 990/10 multi-user

microcomputer at Brenda Mines. The original version utilised a text screen with two

brightnesses @lus black), and mined text characters using blxking arrangements similar

to those for selecting big areas of text in a modern word processor. What was mined was

then output, and material beneath made visiile on the screen. The successfuI application

of the planner to consuiting work for Brenda's parent company, Noranda, provided the

funding to purchase a 256 colour 640x480 pixel graphic screen costing $10,000 in 1983.

The untirnely death of Paul in a flying accident that same year meant that Blackweii,

assisted by Norman Nomsh and later Gil Clausen and Tom Johnson had to complete the

second TI 9901 10 and later PC versions, again in Foriran, of what becarne BrenPLAN.

These later versions will be looked at in Chapter 2.

The curent version by the author, renamed OPPR (Open Pit Planner), is written in VBA,

an addition to AutoCAD version 14.0 1. This version perfomu the same tasks as preMous

versions but adds some enhancements including the familiar look and ease of the

Windows environment. It is modular and the source code is editable, making it highty

customisable. The planner ernbeds itself in the AutoCAD toolbar and can be run by

clicking on the corresponding icons on the bar.

The original BrenPLAN Fortran code and complex graphic interfaces were not

refetenced in the writing of OPPR by this author, but some programs and sub programs

modelled the display of the original BrenPLAN.

1.4 Software and Hardware Selection and Requirements

As this research was directed at mining companies looking to reduce theu computer and

training costs by using familiar software and average hardware, an ordinary PC

compatible computer is required. PC's have corne d o m in pnce to where a good

computer system can cost l a s than $1500 (www.~ricewatch.com). Better systems from

reputable vendors will cost between 5 1700 and $3000.

The minimum recommended hardware configuration is a PC compati'ble computer with

at least an Intel Pentium 200MHz chip (or equivalent), an ultra DMA (direct memory

access) hard drive, a 4 megabyte or more video c d , a mouse, and at least 64

megabytes of RAM. However, newer system based on htel Pentium iü or AMD

Athalon processors, as well as faster peripherals (ATA 66 hard drives) will of course

improve the execution speed of most software.

As most PC's come installed with a version of Mimso£t Windows, this was the

operating system chosen. AutoCAD version 14.01 will nui on Windows 95,98, NT and

2000. Newer computm will corne pre-instrtlled with eittier Widows 98 Second Editioa

or Windows NTl2000. Mining companies will have to balance price with stability.

Windows 98 is much cheaper than Windows 2000 but is much more unstable. To reduce

any problems the recommendation would be to use Windows NT or Windows 2000.

VBA was chosen as the focal programming language as it is the easiest high-level

language to l e m that is directiy embedded in AutoCAD. Because of this, mining

engineers with rudimentary knowleâge of programming can modiQ the software as

required.

A surnmary of hardware and software requirements can be fomd below.

IBM compatible PC running Widows ~(SP3+)/2000

AutoCAD Rl4.O 1 and above

VBA for AutoCAD installed

1.5 Outline and Scope of the Thesis

As mentioned in the previous sections, professional open-pit planning software usuaily

cornes as a module attachrd to a much larger mine design software package. This

software cm be difficult to operate because of its usually steep leaming curve and

because of its higher cost of ownership.

Many mines and mining companies stiU use AutoCAD for their draftïng requirements

due to its relatively low cost and to the fact that it is easy to lem. As well, most mining

engineers have been exposed to AutoCAD at some point in th& education and require

minimal retraining. Open pit planning software for AutoCAD was developed to fil1 the

requirements of companies unwilling or unable to purchase larger mining software

packages.

Software developed by the author integrates directly with AutoCAD. It ailows the

selection of various mining periods so that multiple planning scenarios can be nui.

information generated for each user selected area includes: mining period selected,

tonnes mined, the average grade of the material mined, tonnes above cut-off as well as

other information. The software aiiows for long and short-term plans, with up to 99

planning periods per session king accepted.

it is important to note that mine planning includes rnany variable and factors such as,

Blast Design Blending Climate

Cut Off Grade Dewatering

Dump Design Equipment Selection

Grade Control

Grade Estimation HauI Road Design

Head Grade Loading

Maintenaace Metal Pnce

Mineral Econornics ûperating Cost

Ore Production Produc tivity

Rock Mechanics Slope Stability

Smelter Contracts Stockpile Strategies

Timely Mining Waste Production

Chapter 2 will discuss the history of computenzed mine planning and how it is being

used to improve efficiency within the miniag industry. As well, Chapter 2 will desçribe

some of the better commercial systerns availabte to the minhg engineer. Chapter 3

describes Visual Basic for AutoCAû, how it is used to customize A u t o 0 and

compares Visual Basic for Applications with other AutoCAD customizing languages.

Chapter 3 will provide some insight into how the planner software was written by

providing code 'tips and trickst. Chapter 4 provides a description of the pit planner's

modules and intemal programs. It describes each procedure's interface and what is

needed at run tirne, and describes the background algorithm of each procedure. Chapter 4

also describes how Open Pit Planna stores its data in the drawing database and in text

files with examples.

Chapter 5 shows how the p l m e r can be applied to rd-world ore bodies. in this case, the

planna was run using data h m the Brenda Mine, a Iow grade copperlmolybdenum open

pit mine in south-central British Columbia. Chapter 6 wiii provide conclusions and

recornmendations towards fùture research into a public open pit planner based on

AutoCAD.

It is aIso important to defhe what was outside the scope of the thesis. In the case study,

recoverable reserves (grade estimates) were made with a mixture of big block kriging,

recovery functions and simulation for SMU (Selective Minùig Unit) location. Pit limits

and pushbacks were defined usiag available muving cone software. Diswunted cash flow

@CF-ROR) and net present value (NPV) techniques were replaced by a gamble that if

the mine could survive the average metal price scenario, any window of opportunity in

rising commodity prices could be exploited to advantage. No cut-off grade optimisation

based on Lane's work (1988) was attempted.

Such a case study is a good test of mine planning software. It is far easier to schedule

mining at an operation with a built in 20% DCF-ROR and inflated cut-off grade than at

an operation based on marginal economics. With the available source code sobare

developed as part of this thesis, it will be possible to research the effects of al1 of the

above in t m s of a practical mine plan. It is the author's opinion that practicality will

demand diversions fiom the 'optimal' to create an orderly mine plan. The case study

demonstrateci that there is much the mine planning engineer can do to mitigate the effects

of low wmmodity prices on cash flows, and to enhance cash flows in 'good times'.

The independence to create and modifi programs and not await commercial upgrades

(that may affect software than ran perfectly in earlier versions) makes it essential that in-

house software be developed and used for research purposes in mining. To use a broad

cornparison, we will otherwise be reduced to testing the acceleration of sports cars, not

designing them.

Chapter 2

Computerised Open Pit Planning

The use of computers in the design and planning stages of mine engineering has become

routine. Integrated and stand-alone mining software packages have allowed the mine

engineer to perforrn short, mid- and long-range plans easily, while minimizing the time

needed and maximizing the eficiency of the work. This is not the case if software and

hardware do not perform as intended. Software modifications required as users find

errors, program re-writing to perform a task not envisaged during the planning of the

software, or poor instructions for using the software lead to a total breakdown of the mine

planning iünction for periods of hours to weeks. The advantage of having immediately

available source code which can be modified and re-compiled, and the engineering and

programrning staff available to accomplish such modifications, are part of the direction of

this thesis.

2.1 History

Before affordable personai computers and mining sothvare existed, mine engineers

designed and planned mines by using hand drawings, and estimated volumes of ore and

waste using planimeters. M e r the initiai design, plans were usually limited to the short

tenn because of the amount of time required to wmplete hand drawn plans (Gibbs,

1940). Plans and designs were drawn on Mylar, a plastic-paper with a semi-transparent

base. Many mines still have their original plans and designs archived on large rolls of

Mylar. In the late 1970's and early 19807s, mine sites purchased mini and small

mainfiame computers to handle daily processing requirements such as ore estimation, pit

optimisation and mil1 reagent optimisation. This avoided the large computers located at

'head office', cutting costs and obtaining better pnority Cor mine site tasks. It was at this

time that mining specific software packages began io evoIve.

Smaller mine sites could not afford the high costs of mini and mainframe computers and

the software and human resources to operate them unless actively encuuraged by forward

thinking management. It was the development of the personal computer by both [BM and

Apple that has led to the Ievel of computensation found in most workplaces, including

mines. The micro or personal computer market remained, throughout the 1980's, a user-

developed market. Users and programmers recognised work that could be performed

better with, or with the aid oc relatively inexpensive computers, and developed the

applications for personal computers which have advanced to the commercial software

and hardware products presently available.

OIder personal computer systems as well as mini and mainfiame computer systems

consisted of the computer with some form of storage device (i-e. tape, diskette or hard

drive), a display or monitor, a keyboard, and quite often an extra input device such as a

graphics tablet or mouse. More ofien than not, the visual display was black and white,

and the availabIe rnemory was a few hundrd kilobytes, with disk storage of the order of

tens of megabytes. Mining software developed on these pIatforms was relatively simple

as it was constrained by the limitations of the computer hardware, but it was effective in

starting the evolutionary process. Text based software was popular for orebody

database management until colour displays became cost effective, and simple mine

planning and design software could be developed. Mining engineers at the mine site or in

smaIl consulting companies wrote most of the early mining software catering to a mine's

special needs, and the BRENplan software package of 1984 is typical (Chick, 1984).

Chick and Blackwell developed the software at the Brenda open pit mine in south-central

British Columbia in the early 1980's.

it was onginally run on a text screen using the 'arrow' keys to locate ore and waste and

'mine it' using the delete key to show the exposed block on the bench beneath. Although

efficient in producing the required mine plan and grade and tonnage statistics, it was not

user friendly. Once management recognised the potential of the mine planner, the mines'

Texas Instruments 990110 mini-computer was equipped with a 'Ramtek 621 1' colour

graphics terminal and digitising tablet. Figure 2.1 shows a typicaf coiour display. The

menu options (upper lefi) are used to select planning tasks, the production thus far is

shown iower left, and the right side shows the bench being mined in plan view with the

varying grades shown coloured.

Fipyre 2.1 - The Brenda Mines lntcrrtive Mine Plrnncr (Cbiek, 1%). T& cria k srlectcd from

the upper Ieft, production ta date is s b n a h r left, nad d o h g ireas are ailliiied on î k plm d

grades stiown on the rigûî. A digiîising Wkt w u uscd w t k ~ekt ing device.

The re-written sohare package had the abiIity to crate short and long-term plans for

Brenda, and was able to create multipie scenarios at a period of severely depressed meta1

prices starting in the fa11 of 1981. This was very important to the operators of Brenda, as

the mine revenues came equally fiom copper and molybdenum. When molybdenum

prices collapsed, and copper prices began to fluctuate widely, the multiple plans producsd

helped management and the board of directors deal with these fluctuations.

Many mining companies have charged their own e@eers with designing a company-

wide mining ç o h e package. Placer Dome Ltd., and Nomda (Gibbs, 1990) have both

developed their own in-house mining software including AutoLISP customisation of

AutoCAD.

As personal computers became more p o w M in the late 1980's, sofhvare that had once

ody run on mini and rn-e cornputers began to be transferred to the microcornputer.

This included al1 of the major integrated mining packages as well as al1 of the public

domain and 'shareware' mining software. By 1990, there existed ova 700 rnining related

software programs for micro, mini and m a i n h e computers (Gibbs & Krajewski, 1990).

Personal cornputers based on processors such as the htel 80286 and htel 80386, as well

as Motorola based computers (e.g. Apple Macintosh) begm to rival the power of mini

and mainfiame computer systems. A typid workstation in 199 1 consisted of an 80386

personal computer with 640k of main memory and 2 megabytes of extended memory, a

hard disk drive of 100 megabytes, a hi&-resolution colour monitot and VGA

(64Ox480x8b) video card as well as math coprocessor chips (Gibbs, 1991).

The early nineties had two main types of mining software available to the minhg

engineer, public-domain software and integrated software. Publicdomain software

consisted of software written by universities or government agacies and was available at

tow cost or no cost at al1 (Gibbs, 1990). This made it a very attractive aquisition for

companies not wilhg to invest heavily in large inining packages and the computers

needed to nin them. A h , publicdomain software was (and is) v q spBcialised software

in that each program was written to pedom a specific mining ta&. Multiple programs

must be nrn in order to provide the same kvel of software coverage as that of larger,

integrated packages. With source code available for modification, the user an

integrate programs if necessary, but less computer proficient mining personnel were often

lefi to fend for themselves when learning how to use the software or when they

encountered an error. Authors of the software provided little or no support for their

product, which was, after dl, tieely given. In some cases, employing the software writer

for a short period to customise the source code would have been prudent.

By 1990, integrated mining packages were taking advantage of the personal computer's

power as well as still supporting the more powerful U N E based mini-computers

manuractured by companies such as Sun and Silicon Graphies. Integrated packages at

that time offered ore body modelling, mine planning, and reserve estimation. Ail of the

packaged subsystems became linked so that data manipulated in the orebody mode1

would be represented by a change in the mine drawing. ûther integrated packages ran in

the DOS environment and used multiple files to store user data

Integrated software was much more expensive than public-domain software but offered

customer support and in some cases, initial set-up of the software at the mine site.

Integrated software costing, for example, US$l0,000-US$25,000 in 1990 (Gibbs, 1990),

was generally easier to use than public-domain software, offering pull-down menus and

graphical displays. However, wen with integrated packages, the mine engineer would

still have to match the package to his or her needs at the actual mine site.

By 1994 with the release of the intel Pentium processor, desktop cornputers had reached

workstation status, and every mine with a PC could nin either integrated mining software

packages, AutoCAD, sharewarelfieeware, or in-house software without having to

purchase expensive UNIX workstations.

2.2 Examples of Computerised Mine Planning

Mining cornpanies have always embraced new technology because of the very nature of

the industry. Fluctuating metal prices, the rising cost of labour and the need to develop

lower grade ore bodies have spurred the search for more efficient mining and processing

methods. Computers are fast and can cany out multiple tasks at once, thereby increasing

throughput, reducing the number of personnel needed for the same task, and providing

multiple answers for rnining problems.

A review of the literature suggests that most mining companies have embraced

computerised mine planning and design. Jerez and Andersen (1991) showed how

computerising ore control procedures at the Cypnis Copperstone Gold Mine increased

performance and productivity as well as producing more accurate assay results. As part

of this total package, Copperstone employed Mintec's Blast Hole Module and

InterGraphics Planner Average program, taking drawings produced fiom blast hole

assays, and created rnining zones for their shovels to follow. The program allowed for an

infinite number of cuts (polygonal outlines to be mined) to be created on the drawing,

thus enabling the mine engineer to mate different scenarios based on varying geology or

gold prices. The final choice of cut was analysed by taking the average grade of al1 the

bfast holes contained within the cut. These cuts were t h printed out and given to the

surveyors in order to stake out (outtine in the field) the broken muck.

Coai mines have also benefited from cornputerid mine planning. The Leigh Creek

CoalfieId near Adetaide in South Australia has been in production for over 100 years. It

has a very cornplex geology with three phases of deposition on top of four sedimentary

basins containing the coal. With the adoption of a new mining method, terrace mining in

July 199 1, computer consulting assistance in the selection and installation of a new

computerised mine planning software was required (KRJA Systems, 1991).

Leigh Creek has large amounts of data that must be accessibIe to the mine planner. Over

it's 100-year history it has drilled over 4500 holes throughout its ore zone. The software

used by the mine planner would have to be very robust and timely in assimilating and

presenting information. KRJA Systems chose a UMX based workstation, manufactured

by Silicon Graphics as the hardware platform as PCs were still relatively slow. An

integrated mining package, W C AN, was chosen as it was thought that it had a user-

ffiendly interface, and would be the easiest to install and operate. The integrated systern

at Leigh Creek created al1 the mine plans and produced al1 monthly v o h e cdculations.

The strength of VüLCAN is its three-dimensional orebody modelling capability. With

the most ment survey data available as well as up to date geologic models created by

VULCAN, mining engineers were abIe to plan the design of ramps, haulage roads and

push backs in timely fashion. During bis time period (1991), VULCAN also induded an

experimentd mine schedding software module called SCHUTE. The mine pIanner codd

input various grade ranges, coal price ranges, equipment availabilities, various production

scenarios and other cost variables and the software would graphically show how the pit

shouid be mined, with overburden removal as well as cod extraction. It showed potential

probIems that might have been encountered if a particular piece of mining equipment

broke down, and scheduled operating and maintenance labour including overtime

requirements.

Another computensed mine planning system for a strip coal mine in South Afica is

described by Marshall and Francis (1994). Unfortunately, the work Marshall and Francis

conducted excluded the mine's name fiom the report. Initial in-house development using

UNIX based software started in the mid-seventies. In the 1980's and 1990's as persond

computers became commonplace in their engineering offices, the mine integrated its

mini-cornputer resources with those contained on the PC' S. AutoCAD emerged as the

program of choice for use on PCYs, and the mining personnel wrote their own LISP

routines to rnodify AutoCAD for their own uses. AutoLISP is a customisation language

of AutoCAD, and specific routines cm be run fiom within AutoCAD much likc Visual

Basic for Applications. These routines were used for calculating topography, boundary

pillars, and other physical factors. As of 1994, the mine's t.JIJIX based computers were

ninning Mincom's MineStar; an integrated mine planning and scheduling software

package. The software allowed the mine to input their dragline mining information, and

MineStar would set up the scheduling of the dragline based on various operational

parameters such as mining cost and coal grade. Surveying data collected during the

mining process was input into AutoCAD, and LISP routines calculated volumes for

stockpiles, overburden stripping and coal mined. This mine therefore relied on two

specific systems for their mine planning: AutoCAD for initial topography and volume

calculation and Minestar for scheduling. Modern integrated packages and shared and

publicly available software can accomplish these tasks fiom within a single program if

required.

Koski (1994) described the mine planning sofiware at the Empire Mine near Palmer,

Michigan. The Empire Mine was a large iron ore deposit that as of 1994 had been worked

for 30 years. Since mining s o h e was unavailable in 1979, the mine decided to develop

an in-house computerised mine planning system to be used for al! mine planning, as well

as for creating blast patterns, merging blast hole assay data, ordwaste scheduting and for

volume calculations. This system was used until the late 1980's when increased

availability of commercial software, and the need for a more efficient and cost-effective

system, was indicated. The mine personnel investigated 15 different integrated mine

planning and scheduhg systems in 1988, and chose a mine software package suitable to

their needs. The name of the software was not releaseâ, and it was installed on various

SunSparc M X cornputers in 1989, and peripherals purchased included a plotter,

digitising tablets, and pnnters.

An orebody block mode1 using diarnond drill data was set up, and as the information

became available, blast hole assay data was incorporated into the model. The s o b a r e

also merged geological, structural and metallurgical data into the database, and each

resulting geological zone was assigned a specific number. The mine planning portion of

the software ailowed the mine engineer to d i n e a specific region corresponding to a

mine cut or blast pattern Selecting that outline would provide data such as grade and

tonnage of the cut dong with material type and metallurgy details. Using the

geological zones, the mine engineer pIanned the mining of three different ore types and

adjacent waste pockets. The software was re-run using multiple scenarios based on

equipment availability, and different ore blending needs. The software aiso created blast

maps for the surveyors and the blasting technicians. Atter blasting, contact maps were

created containing metallurgical information, ore, waste and overburden tonnages as well

as mineral ownership of each blast. The surveyors then used these maps to locate contact

points on the blasted rock.

The software also included mine design components that would create 'optimal' pit

outlines using the floating cone method, incorporating designs for haul roads and ramps.

Up to 100 designs and plans could be stored in the software database and these multiple

scenarios could be used to plan around equipment faiiures or metailurgical problerns. The

mine planner could outline cuts on the plan and the software could describe how the cut

would affect pit outlines, and update ihem accordingly. Once a particular cut had been

approved, the mine engineer could determine a haulage profile fiom the selected cut to

the crusher or waste dump. The software checked the selected route against known truck

haulage profiles and suggested alternate haulage routes based on that data. The ability to

create multiple cuts along with the resulting haulage routes enabled the mine engineer to

choose the most efficient method of mining. The planning software was aiso used to

design and schedule the building of waste and stockpile dumps. The volume of mataial

contained within these dumps could be calculated and integrated into the mine plan.

2.3 Review of Mining Software

The following section will look at a selection of integrated software packages available to

the mining industry for use in mine planning and design. The list is up to date as of the

tirne of writing and includes the most popular software and features. It should not be

viewed as an endorsement or recommendation for any of these software packages.

Further information on the products can be obtained fiom the manufacturer, and their

locations are provided in the bibliography section (Chapter 7) of the thesis. It should be

noted that the majority of the soîbvare is Australian based, and this should be a concem

to a country such as Canada, which is equally proficient at mining.

Minex develops integrated mining packages for underground, open pit mines, and

quames. The Company installed its first package in the early 1980's for Broken Hill

Proprietry (BHP) in Australia, and has continued to wnsult and provide software

solutions to mining problems.

The Minex software consists of a core program into which various modules can be added.

The core prograrn is called Vista, which runs in various versions of UNlX including PC

based Linux. Vista provides a graphical interface using X-Windows, the window

manager incorporated in Sun, SGI, Linux and other üNiX operating systems. It is aiso

employed for three dimensional (3D) modelling, viewing, and the drawing of surfices,

lines and objectq and as a hll-fledged drawing editor containing most of the features of a

standard CADD package. Vista's 3D capabilities include such features as multiple output

windows, solid rendering with various lighting effects, texture mapping and rotation in

real-time. Vista interfaces with databases using Stmctured Query Language (SQL).

Two different mine planning modules supplied by Minex can be added to Vista, a

package for short-term mine planning called Orion, and a long-term planning package

called Apollo. Orion can be used by the mining engineer in the course of a day to set

production schedules, design blasts, haul roads, ramps, pits and dumps, and to provide

haulage truck cycle time simulations. Orion allows the direct input of survey data in

various forms such as delimited ASCK

Orion itself can have various modules added to castornise the software for each mine site.

These include modules for:

blast pattern design

i scheduling of short and medium term mine plans

haulage road design

surveying

dump design

truck and dragline simulations

interfaces accessing other commercial software such as blast hole and diarnond

drill hole databases.

Of particular interest is the Face Advance Scheduling package. This allows the mining

engineer to plan equipment moves and production for the different blasts that make up

the loading equipment working face based on the orebody mode1 and the final pit design.

The Face Advance Scheduler interfaces with the Short and Medium Term Pit Scheduler

which uses the face advance schedules and other material such as truck haulage data,

orebody models, topography and the uitimate pit limit to provide mining sequences that

will meet production goals and maximize equipment availability and eficiency. An

exarnple of Orion's use can be found in Figure 2.2. This is a s u ~ e y e d pick-up fiom the

Drayton Coal Company Ltd., and shows how the face scheduler is used, and the

triangulated and rendered polygons produced by Vista. The various strips can be seen in

different colours.

Figure 2.2 - Mines Oriw sbowing we ot the frc rheduiet, Uc iiiia@rtcd and makred pdysws,

and tbc variau minhg diip i i dinemut colaira

Apollo, Minex's long-tm planning module, is used mainly for stnp mines or benched

mines with stratified deposits. Apollo dows various mine scheduhg, mine reserves,

mine design and pit optimisation options. Using Vista's 3D interactive visualisation and

manipulation software system (Vista), Apollo dows the mine engineer to design benches

using offsets and slopes or by attaching (snapping) a pre-fond bench mode1 to an

imported surveyed line. Apollo calculates volumes by using the measured pit angles and

height of each face within the block model and cm also calculate re-handle volumes for

dragline strip mines, storing data and tracking which pit, bench, block or layer the

material came fiom.

Since Apollo is aimed at the strip coal mining market, its short and long term planning

tools reflect that objective. Such targets as tons of overburden per day, or tons of coal per

month can be set up in the scheauler. The availability and eficiency of equipment can

also be input in the program. This data is used to provide time schedules for multiple

pieces of equipment such as draglines and scrapers, and for various operations such as

drilling, blasting and coal removal. These schedules are presented in 3D, similar to that

shown in Figure 2.2, Mining equipment cm be 'dragged' to altemate locations on the

computer screen using the mouse, and the schedule will be revised based on the new

position of the equipment. Optimum equipment usage can be calculated automatically

using linear programming methods and with interactive input from the mine engineer. As

in the case of Orion, Apollo can be tailored to the mine site by purchasing and using only

the modules that are necessary for that operation. Examples of modules are;

dragline and truck simulators

haul road and dump design

cost model development

blast hole database interface

For strip coal mines, Minex provides an integrated system that can also be tailored to the

needs of the individual mine. The ability to add modules to a common core allows the

software to be updated should the need arise. Scheduling and simulation modules can

map and plan for different cost, equipment availability and efficiency data.

2.3.2 Maptek WLCAN

VULCAN is an integrated s o b a r e package developed in Australia by Maptek Ltd., and

is a 3D modelling and design program that allows for spatial anaiysis, rendering and

visualisation. The core graphics engine is used in a range of industries, including mining,

geological, surveying, defence and urban planning. Modules are available that customise

VüLCAN for a specific industry or application, and can be run on UNiX based

computers or on PC's using the Windows NT operating system.

Although it does have a scheduling and planning module, W C A N is more of a mine

design and visualisation tool for the mining industry than a scheduler or planner. A

separate module named Chronos can be run to perfom detailed mine scheduling and

planning. Four modules can be added to WJLCAN to customise it for the mining sector:

Modeller, GeoModeller, MineModeller, and SurveyModeller.

Modeler is the core program of WLCAN, which contains the 3D 'engine', and Envisage,

the graphical user interface. ModelIer contains al1 of the commands needed 3 r computer-

aided design. One of the most useful aspects of Modeler is the ability to create virtual

'fly-bys' and 'fly-throughs' of an existing or potential mine site. Examples include 'driving'

down the mine haul road to discover problems such as blind corners or narrow traflk

lanes.

GeoModeller is the geostatistics and block modelling module of VULCAN. Block

models are plotted and rendered to show enhanced views of fault structures, grade and

geological trends as well as location. Geostatisticai analysis is included, ailowing the

mine and geological engineers to estimate ore reserves. For environmental and tailings

pond design, GeoModeller can trace and mode1 groundwater and geological layers.

MineModeller can be used in both underground and open-pit mining applications for

mine design, planning and scheduling. It is perhaps better adapted to underground rather

than open pit, as it bas built in tools for long-hole and ring blast design, as well as stope

sequencing and ventilation design. Open pit mine planning and schedu!ing can still be

performed, with the mine plan automatically restncted by the final pit limits.

Representations of equipment can be placed manually on the drawings.

SurveyModelIer is the interface used to transfer surveying data to and fiom hand held

computers and cornputerised surveying equipment inciuding Global Positioning Systems

(GPS). Surveying database fields can be customised to the mine site, and SurveyModeller

will load, track and manipuIate surveying data directly fiom a nurnber of different survey

and data stonng instruments.

Chronos, the mine planning and scheduiing software, stores production, equipment

eficiency, and cost data in a spreadsheet form that can be manipulated to investigate

fluctuating metai prices, mining costs, or equipment availability. Plans and schedules are

recalculated when changes to pnces and costs are input, and the different scenarios can

be examined. Chronos is linked to VCnCAN and the other mining specific modules, and

graphical representations of schedules can be displayed on screen. For exarnple,

animations can show shovels digging, trucks traversing hau1 roads and trucks on dumps

or at the crusher. Processing speed can be increased such that a month of mining may

be viewed in minutes.

Chronos consists of four different systems. The base scheduler is the core software of

Chronos and generates the graphical user interface, permits graphical manipulation,

creates the spreadsheet, and provides al1 the reporting hnctions. 'Optimiser' is a linear

programming module that optimises solutions based on various constraints and

production requirements. Equipment scheduling incorporates equipment calendars

showing equipment availability and utilisation predictions, and haulage and haul road use

profiles at any interval of the schedule. Short term scheduling allows the mine engineer to

select a region with a polygon and obtain the information about the schedule, equipment

and production outputs contained within that polygon instantly.

In summary, VULCAN is a good 3D modelling tool with strong scheduling capabilities

and is particularly useful for visualising underground mining rather than mine planning.

The ability to undertake 'virtud mining' can show the mine engineer where problems

might occur, and provides a visual component to what would otherwise be numbers, as

shown in the pictorial examples of VüLCAN in Figures 2.3 through 2.6.

Figure 2.3 is a 3D view showing diamond drill holes intersecting an orebody, and a

resulting open pit mine design shown grey. Yellow, green and red show the different

types of mineralisation in the orebody. Figure 2.4 shows a typical VüLCAN display with

the pit wall (brown), with red and yellow differentiating two different mineral matenais.

Figure 2.5 shows Vulcan's virtud mining dispIay and Figure 2.6 shows Vulcan's main

interface screen. On the left hand side of Figure 2.6 is a List of layers contained within

the database. Various drawing and database tmls are contained in toolbars attached to the

layer list. The bottom window is the command window, which shows the current

command being implemented, and it's resulting messages. The main window contains the

actuai drawing. in this case, the ground level surface is coloured green, and the various

rnineralized zones are r d , yeiiow, orange and blue.

Figure 2.5 - Vulcpa hwing a 31) vinr aC d a Loka imteractiag ia a d w l y , rn apca pit aniac d d g i

shown grey, and dirent typcs of mintirlisrika &ma yellow, green aad red.

Figure 2.1 - VULCAN sbowimg an opea pit modd with tuo typa of o n abmm ydloff .nd rrd, rad

tbe pit wllls as brown.

2.3.3 Surpac

Surpac Software international of Australia produces Surpac2000, dong with a number of

other programs suitable for mining industry applications such as open pit and

underground design, planning and çcheduling, resewe estimation and geostatistics, grade

control and blast hole assay database -puIation. As with the other integrated packages

described previously, oniy the modules required by the mine engin- aeed be purchad

and installeci. Surpac can be nin on PC's with Microsofl Windows 9x and NT, as welt

as various UNiX based cornputers. The graphical user interface was developed in the

Java programming language, which allows it to be ported easily between different

operating systems and cornputers.

S o m important mining modules include: Drilling and Blasting, Surveying, Pit Design,

Geostatistics, and Grade Control. Dnlling and Blasting allows the mine engineer to

automatical1y create blast patterns, with line holes following pit wall contours. Drill holes

are merged with the block rnodel database so future assay data c m be entered easily.

Suntey ing is used to input, merge and manipulate surveying data fiom a number of

sources. The su~ey ing module can also create layout plans for surveyors to foIlow.

Pit Design allows berm creation with changeable bench heights and angles, and seamIess

merging of pit outlines from other commercial sofiware products such as the Whittle

open pit optimisation programs. The pit design module can autornatically generate up to

nine ramps. Geostatistics contains histogram anaIysis as well as fùll variogram analysis

including directional continuity and grade estimation by kriging. Grade control uses the

polygonal rnethod as well as kriging to create block models. These block models are

compared to raw data from the miIl and mine assays to better interpolate ore location and

grade.

Surpac bas two scheduling and planning modules applicable to open pit mining, The first

module, Surpac Scheduler is very similar to the author's Open Pit Planner. Scheduler

allows the mine engineer to select blocks contained in polygons on the cornputer graphie

screen. Grade and tonnage of ore and tonnage of waste are then calculated by the

program and compared to a production target as the graphical block data on the screen is

linked to the orebody block model. Multiple mining periods can be run simultaneously,

but, as in the case of Open Pit Planner, only 'visible' blocks (blocks open to the sky) may

be mined. This allows rnany scenarios, or what Surpac calls "What-Ifs?" to be examined.

The second module, ALPS, is currently under developrnent. ALPS will use a graphical

interface and will create mining schedules for both underground and open-pit mines. It is

designed to optimise equipment usage while meeting production quotas. Trucks and

shovels will be displayed graphicaily in order to visualise the schedule. Reporting will

include graddtonnage data for the mined areas, dump and stockpile data, and equipment

avaiiabi lity reports.

Surpac has good open pit mine design and planninghcheduling software. It has the full

range of tools for open pit design, and a separate scheduler and planner. The planner

allows for rapid testing of various scenarios and the scheduler makes sure the plan fits the

design and production requirements. Figures 2.7 and 2.8 are examples of Surpac2000.

Figure 2.7 is an example of the dual screen capabilities of Surpac2000. On the lefi is a 3D

view of a specific production area to visualise the adjacent working faces while the right-

hand window is a plan view showing coloured grade data. Figure 2.8 shows a pit that has

been coloured with respect to its incline. Blue areas are horizontai, while red areas are

closer to vertical.

Gemcom is an inîegrated software package fiom Gemcom Software Internatid of

British Columbia, Canada. Gemcom software can be used 6om the expioration stage,

through mine design and planning and on to mine operation. Like the prwiously

described products, it is modular in nature and the user need onIy p h a s e and run those

modules necessary fix their specific purposes. In addition to versions of Gemwm that

focus on expioration and ore r e m estimation, Gemcom provides moduies that fiiciiitate

mine design and productioa/scheduling. Gemcom is a fiil1 CAD package that contains

al1 the necessary drawing tools and 3D commands for building drawings.

The mine design module interfaces with Whittle (a mine design package) to mate

optimised pit outlines. The software d l automatically mate camps, benns and benches

based on user input bench heights and pit wall and b m angles. ln 3D design, most

objects are represented in wire h e by joined polygons. When lines and vertices of

these polygons cross each other, instead of linking together, they mate an error in the

drawing. The software will draw the pit in 3D and will automatically find mon with the

design such as crossed triangles, and intersecting bul roads. The pit design links to the

orebody block model, and the planner built into this module aiiows the mine engineer to

select different blocks to be mined and the sequence in which îhey will be rnined. Similar

to the author's Open Pit Plamer, various blocks can be selected by choosing a polygon.

Full reporting of the data pertaining to blocks inside the polygon is given, and the

software makes sure that unexposed materid is not mined.

The Gerncom scheduler produces simulations based on the proposed mine plan, and

incorporates equipment data for haulage andysis. The fÙll schedule can be animated in

the graphic window, and can indicate where enors such as ineficient haulage routes

rnight exist in contrast to spreadsheet ody schedulers such as Vulcan's. Scheduling can

take place with any type of mining quipment and simulations created based on

capacities, production rates, haul speeds, tmcklshovel matching and various cost factors.

The open pit production madule manages and merges blast hole assays and

immediately updates the drawing database. It links to various surveying systems

including GPS su that the newast surveying data is incorporated. It dso links to the

planner and scheduler so that grade and tonnage controt is maintained. Figure 2.9 is an

illustration of the capabilities of Gemcom. The 'undisturbed' surface is shown green. The

open pit walls are shown in grey and blue to depict different waste rock types. Ore is

shown red.

Figure 2.9 - Gemcom 3D M d ahorring the 'undisluMt sprîacc in green, ihe opca ph wllls arr

grey,oreh sbcnm is &,and b l h c h u d toâepict dlllemtwmtemktrpg

2.3.5 Mintec Minesight

MineSight is an integrated modular software package developed by Mintec Ltd., of

Tucson, Arizona. Its modules are geared towards exploration, orebody modeling,

geustatistics, pit optimisation, pit design and scheduling. It also has a planning module

incorporated into its ore control systern module.

The scheduling program comes as part of the mining engineering module, which includes

pit optimisation and pit design. Both the pit optimisation and pit design programs have

the same features as the previously described software packages. The pit optimisation

prograrn will provide overall pit volumes and uses its own intemal Lerchs-Grossman (as

described by Lizotte, 1988) and rnoving cone methods for pit generation. The long-range

planning portion of the mining engineering module has an application that will

automatically or interactively create schedules that optimise mining sequences. It will

evaluate every possible mine plan based on user provided information and the

information in the various databases. The variables that can be analysed include variable

pit angles, equipment restrictions and haulage times, mil1 requirements, mining rates of

both ore and waste, and blending requirements. Also, the software can minimize and

maximize plans for individual variables such as stripping ratio, grade, haulage and shovel

cost, haulage times, exposed ore and net cash value. It has many different reporting

hnctions, with its mine planning report containing grade and tonnage by mining periods

or benches. It does not have a separate mine planner like the author's Open Pit Planner as

that Function is incorporated into the scheduling prograrn.

MineSightYs main strength lies in the reporthg features of the scheduler portion of the

mine engineering module. The other w g t h of the software Lies in its automatic

determination of mine schedules, finding the best plan possible given the available data.

Figures 2.10 and 2.1 1 show typical graphic output fiom MineSight. Figure 2.10 is a

section through an open pit showing three mining phases: an initial pit and pushbacks one

and two. The colours represent the annual mhhg to be canid out starting with magenta

in centre screen then blue, cyan, dark magenta, green, yellow, mustard yeiiow and r d .

There is a possible error on the l& of the picture in pushback one where material at the

bottom of an inner pit has been inadvertently shown as yellow. It is obviously ore and

should have been mined in the dark magenta penod. Figure 2.1 1 is a rendered graphic

From Mintec MineSight showing equipment location and truck haulage routes in 'real

time'.

Figure 2.10 - M i t a MincSight - C m Scrtion of Worlting Pits b i o g tbret mining phases: an

initial pit and pushbacks ont and two. A n n d mùi.g is mpfwenîcd by cdoun stuting with

magenta in centre rreen tben b l ~ c , cyan, dulr magenta, green, y e h , mastord y e b and rd.

Figure 2.11 - Mintec MinzSigbt - DrilVSbovel Simulation: A mademi graphk fnw sbmviag

equipment location md tniek bdage mutes in 'rcd tinte',

Q' Pit is an open pit mine design and planning package from Q'Pit Ltd., based in

Kingston, Ontario, Canada. it integrates the various steps invoived in mine planning,

including economic pit limit analysis, production planning, haulage road design, and

waste dump design. Like OPPR, Q'Pit has a wmprehensive 'undo' command that dows

the mine planner to undo various planning events and restore originai plans. In addition

ta JIowing the mine engineer to develop mine plans, Q'Pit also contains sub-programs

that dow ramp and haul road design, the reporting of data on the bais of any number of

geological and planning variabIes, road network administration and hdage route

profiiing, as weli as fidl graphical display ofgeology. A short term planning module

extension allows for added planning functionality, including daily shovel and

equipment placing and scheduling.

Datamine of London, U.K., is a software package designed to assist the mine engineer in

mine design, planning, scheduling and ore control. Their scheduling package allows plans

to be developed based on production rates needed, equipment tirnetables, ore blending

requirements, mil1 and dump requirements, as well as a number of economic constraints

such as metal pnces and mining costs.

Scheduling the extraction of ore using the software is controlled by uxr-dehed limits.

For example, a mine plan can be generated tiiat is limited by equipment availability.

Also, with multiple benches contributing to the mine's overall ore and waste needs, the

software will automatically determine whether or not a plan is able to satis@ al1 mil1 and

dump requirements.

2.3.8 Runge Mining

Runge Mining of Australia has developed a number of software programs designed to be

customized to individual mine sites. Their main scheduiing program, called XPAC,

creates a mining database and peïfiorms mine scheduiing. Scheduling c m be canied out

either manually or automatically througfi their Autoscheduler program built into XPAC.

The scheduler can generate reports on a specific mining area based on rock classification,

depth or otha userde6ned characteristic. The software provides plans based on the

economic factors, equipment availabilities and efliciencies, and can provide plans

showing production quantities and quaiities over tirne.

Runge's Autoscheduler automaticaily creates mine plans and schedules to meet any user-

defined tonnage or grade requirement. Up to ten variables can be added to the mode1 in

order to create more detailed plans. These variables can include various cut-off grades,

haul times, and mining costs. Plans can be generated by period. Choosing a large period

cm generate long-tem schedules, while selective grade control can be achieved by using

a short time period and regulating the different variables specifically for that period.

2.4 Summary

In the author's selection of commercial open pit mining software, not al1 companies have

been described, nor al1 the products of those that have. Al1 the software companies appear

to want total integration of their product to the exclusion of others with the notable

exception of the Whittle pit optimiser, which has been interfaced to many of the packages

described.

Total integration will not be acceptable to many mining companies who will prefer to

pick and choose between various products to obtain the best solutions to their problems.

This has not led to CO-operation beîween software companies, and the minhg indusûy

has need of well trained and educated rnining and geological engineers capable of making

working interfaces between software products and th& data bases.

It would appear that software companies obtain a large amount of their revenue fiom

support services and upgrades. Thae is a need for skilled mine engineering personnel to

act as consultants in training and operating the software, and in providing solutions to

problems found at one particular mine and not common within the mining industry.

Whether al1 the products supported by the sofrware developers are needed is doubtful, for

example m i n g simulations of truck haulage while working on a mine plan would

indicate a lack of experience on the part of the planner.

Niche products continue to appear and find uses, for example NPV tiom Earthworks

Corp. in Australia (Earthworks, 2000) has provided some long sought cornpetition for the

Whittle optimiser. The continued improvement in computer performance and graphics

coupled with the low cost of such hardware wiIl enable commercial software dwelopers

to innovate and survive in an extremely cornpetitive environment.

Cbrpter 3

Introduction, Objectives and Software Chokes

The objective of the thesis was the creation of a 'fùlly available source code' open pit

mine planning software system called 'Open Pit Planner' or OPPR (with 'R' standing for

'Ronson', the author's last name). The s o h a r e would be similar to 'BrenPLAN',

developed at Brenda Mines by Chick and BIackwell in the early 19801s, but utilizing the

more powefil computers, software languages and graphics available today. This would

provide the necessary starting point for continued research into open pit mining

economics, design, planning, operation, scheduling and many other associated topics.

The advantage of having source code software that cm be revised and added to without

restriction cannot be overstated. Vendors and owners of commercial software must keep

their source code secret, or demand c ~ ~ d e n t i a l i t y agreements that would limit

expetimentation and dissemination of techniques, algoriths and results.

The choice of AutoCAD as the cornputer aided design (CAD) software was made based

on the popularity of the product, especially in mining applications. Although mining is

not a major user of AutoCAD in cornparison to other applications, within the mining

industry, AutoCAD is the dominant CAD product.

The choice of a software language and database to be used in conjunction with AutoCAD

was simplified by the introduction of an interface to Visual Basic for Applications (VBA)

being provided by Autodesk, AutoCAD's publisher. Basic is a simple, easily leanied

and powertùl language, and typical DOS versions include Power Basic. The language has

been improved to work within Microsotl Windows environments as stand-alone Visual

Basic (VB), allowing the user hl1 controt of a high level object oriented programming

language directly integrated with AutoCAD's drawing model. Further integration with

Microsoft Excel and Access, stnictured query language (SQL), and Oracle databases

made the choice of VBA for software development most appropriate.

This section of the thesis employs AutoCAD and VBA technical and compter software

terminology not commonly used. It is assumed that the reader has some grasp of such

terms and some knowledge of the two products. Suitable reference material includes the

AutoCAD manuals and tutorial and help CDROMs (Autodesk, 1997), and similar

material for VBA, VB and PB (Roe, 1999, Microsofl, 1994, PowerBasic, 1993). It is not

the intent of the thesis to re-write such material.

3.0 VBA and AutoCAD

AutoCAD, developed by AutoDesk, is a generic, di-purpose CAD software package with

open architecture. This means that the user can modify twlbars and buttons and can

create rnacro commands and executable commands to acwmplish any drawing or

drawing modification task. The ability to nistomize AutoCAD and tailor it to any

industrial task has made AutoCAD a most popular software package for cornputer-aided

design.

Visual Basic is an object-oriented programrning language. This means that the

program mns based on which object is being manipulated, rather than as a line to Iine

procedure. For example, in a Visual Basic program, code is executed when the user clicks

on a button or selects an item fiom a list. In older, linear versions of BASIC, the prograrn

runs the code fiom the out set, prompts the user for information and continues running

code after the user input. Code must be re-run in order to re-input information.

Visual Basic is powerfiil and easily leamed. In older versions of BASIC, the programmer

had to code al1 display functions. Visual Basic already uses the graphical interface of its

host Microsofl Windows, and automaticdly creates windows without any code

knowledge. Objects such as command buttons and text boxes are ready made and can be

inserted into a prograrn without creating additional code.

VBA first appeared as a macro command language for Microsofl Office products in 1994

(Roe, 1999). It allowed the user to modifjr the software in order to simplify repetitive

tasks. Autodesk saw how popular this customisation language was and licensed VBA for

AutoCAD.

AutoCAD7s version of VBA has full application scripting, hl1 Visual Basic language

syntax, error location and identification (the 'debugger'), and a fully Integrated

Development Environment (IDE, an editor). A display of the IDE can be found in Figure

3.1. One item missing fiom the VBA environment that &sts in stand alone Visual Basic

is a compiler. A VBA application written in AutoCAD cannot be compiled into native

code. VBA for AutoCAD is an interpretive language and programs written in

AutoCAD's IDE must be nin in AutoCAD, but submuîines may be tesied in V8.

The older macro language of AutoCAD, AutoLiSP and its later Windows version,

VisualLISP, had a very çryptic and unhelpfui 'debugger' and was text based.

Cornparisons between VSA, AutoLISP and other macro languages for AutoCAD are

presented in the following Section 3.1.

Figure 3.1 - Visuai Basic IDE. On the top b tbe current cvtat being proenmnstd, ia this case

CommandButtonl~Click Oa the upper kft & the %t of formi and d d s mnkuieà wiîhi~~ the

project, and on the lower lrft the properdes of tht curttnt objcct. The prognm code covers the rigbt

sWe of the display.

3.1 Cornparisons of the Macm Laaguages

There are many macro languages for AutoCAD other than VBA. They include: ADS,

ARX, Diesel and SQL. Each is respectively different, and each has its own advantages

and disadvantages. A chart comparing the languages can be found in Table 3.1.

AutoLISP is the oldest customization language for AutoCAD, being incorporated into

AutoCAD 2.1 in 1985. It is now completely homogenous with AutoCAD, interpreting

LISP commands directly without the need for compilation. Although fast in execution, it

does not have a user-fï-iendly interface, is hampered by a cryptic syntax, and locating and

resolving errors ('debugging') can be very tedious. These disadvantages are more than

compensated for by the speed of execution and direct interpretation within the AutoCAD

environment. It has a relatively simple command set (albeit with difficult syntax), and is

well supported by AutoDESK and the AutoCAD community worldwide.

Name

Visual Basic for Applications

Command Customization

Diesel

ARX

Base Lanma~e 1 Comoiler? 1 AutoCAD Version

Visual Basic

Evaluated String Expression

1 N/a

Existing AutoCAD Commands / New

Commands

C

Direct hterpretively

No

Stnictured Query Language Extensions

Release 14.01 and above

N/a

Unknown

Language

AutoCAD nintirne extensions, ADS (ADSRX) AutoCAü

Al l

<= RI3

Table 3.1- Customization Lmguagn. 'R' rclcrs to the AutoCAD rekiuc number, and NI8 indicaiu

'not applicable'.

Yes

LISP

ADS stands for the 'AutoCAD Development System'. An oIder customization language,

ADS was discontinued with the release of AutoCAD 14. It is based on the "C"

programming language, a very fast and very poputar language.

>=RI4

ARX has replaced ADS and contains the ADS library within its programming shell

(renamed ADSRX). It is a compiled language and melds itself into AutoCAD's memory

and process space, resulting in very strong performance.

No AutoCAD with AD€-3, >= R2.1

SQL (Structured Query Language) is a database query language used to extract data

Rom different databases. In AutoCAD's case, SQL can link data in Access, dBASE I l i or

Oracle databases to drawing objects in AutoCAD's drawing editor. This means that as

changes are made to databases, the drawing is automatically updated. Consequently

drawing sizes (in terms of disk space and memory) are reduced and there can be one

source (the database) for multiple drawings.

DIESEL (Direct Interpretivel y Evaluated String Expression Language) uses on1 y strings

for input and output. As there is no need for variables, this is a purely fùnction based

language. Introduced in AutoCAD R12, it can act like a macro language and could

therefore displace AutoLISP were it not for the fact that the usual use of DESEL is to be

called as a function by an AutoLlSP routine.

The advantages of VBA have been described, but some disadvantages were found as the

depth of knowledge of the product improved during the completion of this thesis. The

main disadvantage is that, unlike AutoLISP, VBA is separate fiom the AutoCAD users'

working environment and VBA cannot cal1 AutoCAD commands directly. This problem

will be examined in depth in Chapter 4, as it was found that in some cases a page of VBA

code was needed for a task that takes 2 lines in LISP code.

Since it is non-compiled, VBA relies on an extema1 interpreter to execute code, which

makes it slower than a compiled language like ARX or a natively imerpreted language

like AutoLISP. However, unlike the stand-atone versions of Visual Basic, VBA for

AutoCAD saves al1 of its forms and modules in a single file, making transportation of

software rnuch easier. VBA programs can be executed fiom toolbars, drap down

menus or fiom the command line. They can also be called h m AutoLISP routines. VBA

programs can be automatically loaded when AutoCAD is executed either through

inclusion in AutoCAD menus (.MNü and . M N tiles) or by naming the program

'project.dvb' and placing it in any of AutoCAD's support folders, or in user folders

inciuded in the AutoCAD drawings support path.

3.2 Fundamentals of Visual Basic for AutoCAD

3.2. I Projects, Fornts, Modules and Conhols

A typical VBA project consirtr of several user-generated f m s and moduler. Forms are

empty (blank) windows on to which controls are placed. Controls can include command

buttons, text boxes and picture boxes. Figure 3.2 shows examples ofdifferent controls

pIaced on a user form.

Figure 3.2 - Sample Controls. Shown are: the text box informing the user; comboldropdown to select

options with the mouse; check box and option button to select options; command button to execute a

command; various sliding and scrolling controls and a picture box.

Controls are placed on the form from the Control Toolbar (Figure 3.3). Additional

controls can be added to the toolbar.

Figure 3.3 - Control Toolbar. Tbe programmer dects tools sueh as A for test here.

Controls include labels, text boxes, combollist dropdown boxes, check boxes, option and

push button choice controls, scroll lists and picture boxes.

Modules are purely code based and can contain standard subroutines that are used oflen

in many programs. They can be used to coordinate the execution of multiple fonns. The

user, through the 'Macro' menu choice, can see every module in a project. Within each

module, the user can choose to execute any of the subroutines contained within that

module. Therefore, one module should be used to cal1 upon ail 0 t h fonns and

subroutines. OPPR (Open Pit Plamer) was set up in this way with a centrai module

calling al1 of the different programs.

VBA programs are termed 'projects'. A VBA project consists of a number of AutoCAD

objects, user forms, and modules. When projects are saved, ail forms, modules and

AutoCAD drawing objects are saved in a singie file with the extension '.dvb'. This

differs tiom standalone versions of Visual Basic (e.g. Microsofi VB 5), which Save

their forms, modules and code individuaily. This fundamental difference makes VBA

projects incompatible with curent standalone Visual Basic (Versions 5 or 6). Figure 3.4

shows how a typical project contains AutoCAD drawing objects, user forms and user

modules.

- ThînDrawing El 3 Farms

g Frmûfplash --a FrmlChangeParameters I

h2DrawPolygon I

..- frm3LoadPoiygon Frm4Cdcuiate frm5Cddatel

... hm5Cdcdate2 .-.Q frm6Fkmove I

- a frm7ümiine - frm8Uminel

1

Q-& Modules 4 Module1 -.-a OpenPitPlanner

Figure 3.4 - Project Box showing the AutoCm drawing, the forms (Wiidows contoiniiig controls)

and the modules (subroutines wbich complete a specirc tuk such as a caiculation of grade)

Projects c m be executed in a number of different ways. They can be automaticalIy

loaded when AutoCAD is nin or when specitic events such as loading a drawing occur.

Project macros cm be executed fiom the drop down menu bars. Macro commands can be

found in 'Tool [ Macro' (the '1' indicates that the top menu button 'tools' is chosen which

then displays a pull down selection which includes the choice 'macro' and when selected

a fbrther side menu is displayed). These commands include 'Run', 'Load', 'Unload' and

'VBiDE'. Choosing the 'Run' command will bnng up a dialog box containing a Iist of al1

modules contained in the project. Clicking on a module name will show al1 the

subroutines available within that macro. Choosing a subroutine fiom this second Iist will

execute the code contained within it. The 'Load' command loads a project into memory

whiIe 'Unload' removes the project fiom memory. 'VBIDE' loads the VBA Integrated

Design Environment, more simply referred to as 'the editor'

Al1 of these cornmands can also be run from the command line, using 'vbamn', 'vbload',

'vbunload' and 'vbaide'. It is important to note that these are the commands that can be

used within AutoLISP routines to mn VBA rnacros.

3.2.2 Events, Objects, Methods and Roperfies

The code of VBA is organized around four main concepts: events, objects, ntethods and

properties. An EVENT is when an action occurs, such as clicking on a command button,

or loading a drawing. Events trigger the execution of code. For example, in OPPR, when

the user opens a drawing, the 'Load Drawing' event automatically shows the OPPR

introductory screen display (the 'Splash'). Many events may exist in a project. Some other

examples inchde moving the mouse pointer over a certain area, or selecting an item

Frorn a list box.

An OBJECT called upon in VBA is usually a drawing object such as a block, a polyline

or a layer. METHODS include copying, drawing, changing properties, or setting

variables. To manipulate drawing objects, they must first be assigned a variable name

that will represent them in VBA commands. A standard command in VBA might look

like this:

Set circleobj = blockObj.AddCircle(centre,radius)

In the above line, circleobj is a variable representing a specific circle object in the

AutoCAD drawing. AddCircle is a method that is modifying blockobj, by adding a circle

object at the coordinates designated by the variable center, with a radius of 'radius' to the

blockobj. In plain language, this line adds a circle with a center point of 'centre' and

radius 'radius' to the block represented by blockobj. It then assigns this circle object to

the variable circleobj.

Properties and methods are not limited to AutoCAD drawing objects, but can be extendeci

to VBA controls. VBA controls are items such as command buttons and text boxes that

are placed on user forms. A sample line of code could be:

In this case the command button called 'CmdOK' is having its '.font7 changed to 'Arial'.

Each object in the drawing as well as each form, module and controt has

PROP ERTiES. Objects in the drawing have PROPERTES such as colour, layer, scale

or thickness. Many of these properties c m be changed through simple commands such

as:

This line changes the colour of a circle assigned to circleObj to the colour rd. Properties

of the various controls added to user forms are changed using the property window built

into VBA's IDE. Each control has different properties, though some properties are

comrnon to al1 controls. Such cornmon properties include whether or not the contrai is

enabled and whether or not the control is visible. Other properties include text cotour,

font and font size and whether the control has a 'flat', 'sunken' or '3-D' look on the form.

Figure 3.5 shows an exarnple properties box for the main user form. From this dialog

box, any property of the form can be changed.

Figure 3 5 - Properties Diaiog BOL In this display the programmer hm chwen to modüy the

'Caption' or the test that the user sees w M e sektlag various options. Programmer contra1 of the

propertieJ of 'objectr' Is masr extensive.

3.2.3 Variables

The definitions of variables in VBA remains the same as those found in standalone

versions of Visual Basic and the older versions of BASIC. Variables have four different

permission States: public in module, public in form, variable in form, or constant.

'Public in module' means that a variable has been dirnensioned as public in the general

declarations area of a module. As a result, this variable can be used and its value changed

by any subroutine in any module or form. The variable's value does not change or

become reset frorn its last value when it is used by another subroutine.

'Public in form' indicates a variable that has been declared 'public' in the general

declaration area of a form. As a result, this variable can be seen and modified by any

subroutine contained within that fonn. It keeps its value between subroutines.

'Variable-in-form' is a variable defined within a subroutine. This variable will only be

used within that subroutine and will be reset the next time that subroutine is executed.

This variable cannot be shared, so the variable will be regarded by other subroutines as if

it had a different name, and its value will not be changed.

A 'constant variable' is one whose value cannot be modified once a value is assigned.

These constants can be made public to dl subroutines or they may be restricted to only

certain subroutines.

Variables themselves may be divided into types such as floating point, string, integer,

currency and date. Each variable type has its own memory requirements and has to be

defined in its own way. Table 3.2 is a summary of the different variable types used in

VBA (frorn Roe, 1999).

Data Type

Intcger 7 Long Intcgcr r floating-point

integer)

Description

Space-saving way 10 SIOIE smaii inlegen; also used 10 handle binary files.

Uscd for variables that are either truc or falsc.

Holds numcric intcger values.

Hold numetic integer values over an expanded range.

Holds real m m k r wiih accuracy of 7 significant digits

Holds rcal m b e t s with accuracy of 16 signifiant digits.

Holds futed-decird numbers wiîh up to 4 digits to righl of decimal point.

Used within a Variant to hold numeric values as unsigned itilegers scaled by a variable power of IO.

Storw &te and rime values as ffoating-pint numbers.

Addresses thai refer specifïcaiiy 10 objecîs.

Storage Size (bytes)

Range

-3.10 x l d y o -1.40 x loJ5 br neg. values; 1 .JO x 10''~ 10 1.80 x 10- for pos. dues

Same as Single Precision I l % P g l 6 U I J f 64337593,543JMJ35

wiih no decimal point; -7 E21116u14264337593W395~35

with 28 places to the right of the decimal

3 1,9999

String (variable- mm String (fixed-length)

Variant (w/ chanctcrs)

Variant (w/ numbers)

Userdefined (using Type)

Holds text values.

Holds text values.

Used for text variables not explicitiy declared as some o h type.

Used for numeric variables not explicitly declared as some other type

Used Io contain one or more elements of a data type, anay, or another uscrdefïned type.

10 + string lengrh

range of a Double

O to appmx. 2 biiiion

22 + string lengih Same range as for variable- length String

Table 3.2- Variable Types with their description, di& mdlor memo y storage ~quirements and the

Number required by elements

maximum/minimum value that CM be stored, eg. a vdue of 32770 cannot be stomd u an integer.

Range of each elerneni is the same as the range of its data

Variables should be declared in the 'General Declarations' area of the form or module, or

at the beginning of each event in order to keep memory usage down and maintain

program organization. However, variables that are not declared will be assigned the

'Variant' type. The 'Dim' command is used to dimension string, number and array

variables as in the standalone versions of Visual Basic. For example, to declare a string

variable known as 'SampleText', the declaration line would be:

Dim SampleText As String

VBA for AutoCAD adds a number of new object variables related to objects present in

drawings. Each AutoCAD drawing object has its own corresponding variable type.

These variables must be dimensioned at the start of each event or in the 'General

Declarations' area of forms and modules. Variable types usualiy corne in the form of

' Acad[Object]'. Sample declarations could be:

Dim Layer l as AcadLayer

Dim Pline 1 as AcadPolyLine

In this example, variables with the names of 'Layerl ' and 'Plinel ' are being dimensioned

as a layer object and a polyline object respectively. Drawing objects cannot be

manipulated unless they have been assigned to a variable. In tum, a drawing variable

cannot be used until it has been dimensioned.

3.2.4 Procedures and Events

As mentioned in Section 3.2.2, an event occurs when an action such as clicking on a

cornmand button or loading a drawing happens. in VBA, these events can be broken

down into two specific categories: application events and VBA events. When an

'application event' occurs, it will execute any code contained within any subroutine (event

handler) found in that designated event. There are seven specific application events for

AutoCAD, 'BeginCommiuid', 'Beginûpen', 'BeginQuitl, 'BeginSave', 'EndComrnand',

' Endopen', and ' EndSave'.

Events with 'Begin' as their prefk are triggered irnmediately before the suffix occurs.

For exarnple, the 'BeginCommand' event occurs immediately after a command is issued,

but before it completes. This event couid be used to intercept commands that should not

be run. The events 'Beginûpen', 'BeguiQuitl, or 'BeginSave' are triggered immediately

before AutoCAD loads a drawing, quits an AutoCAD session, or saves a drawing

respectively.

Events with 'End' as their prefix naturally refer to when the events with the suffix

occur. 'EndCornmand', 'Endûpen', and 'EndSave' are triggered when a command

completes, AutoCAD finishes opening a drawing, or after AutoCAD finishes saving a

drawing respectively.

VBA events revolve around the manipulation of controis by the user. There are many

different VBA events, ranging fiom selecting an item from a drop dowu list, to changing

the text in a text box. However, dl events, including application events, have a common

feature. When the event is triggered, VBA looks at the subroutine contained within the

event. The subroutine or 'event handler' contains the code to be executed.

Code within form subroutines can then 'cdl' on subroutines contained in modules. This

allows for tasks such as repetitive calculations to be perfomed repeatedly and easily.

Calls of module subroutines tiom f o m subroutines allow the passing of variables to and

From the module subroutine. Variables can be sent to the module, changed, and sent back

to the form code From the modde as shown in Figure 3.6.

1 Subroutine 1 Subroutine s

Figure 3.6 - Calling a Module. Data c m be pasmi to the module so that it can be worked on. For

example, if a variable 'vbl' W passed to, and chaoged in the module and 'vbl' is a globaiiy defmed

variable, then 'vbl' wüi remain cbangd once the code in the module has finished executing. if 'vbl' is

not globaiiy defmed, theo 'vbl' wüi retain it's initiai value when the module fmishes executing.

Module subroutine code can perform the sarne tasks as form code but is not linked to an

event. Module code can open fonns, run subroutines contained in foms and pass variable

data back to the form routine that called it. Module subroutines also play a very

important part in VBA for AutoCAD in the execution of maçros (Le. running individual

macro programs within the VBA for AutoCAD project). The command 'vbarun', or

through choosing 'run' from the M a m menu will bring up a dialog box listing modules

contained within the project.

Selecting a module shows dl the subroutines contained within that module. Clicking on a

subroutine and choosing 'Run' or double-clicking it will execute the code in that module

subroutine. Therefore, one method of organizing a project is to have a module that

controls the execution of different portions of code and the showing of foms within the

project. If the main code to be executed is contained within form subroutines linked to

controls, then the procedure in the module visible to the user when the 'Run ...' menu is

activated would only have to contain a 'Forrn.Show' command.

For example, a project could contain two foms and two modules. The first form ailows

some data to be input, the second fom takcs the input data tiom the first form, calls a

subroutine within the second module that manipulates the data and sentis it back to the

second form for some action, e.g. to be printed out. Al1 the while, the first module

organizes the project. The following flowchart shows the flow of information (Figure

3.7).

Show Foml '-4

Subroutine

Figure 3.7 - Two ~Modules, Two Forms Example. Only if the user requires the updating of

F o r d wiii control pass to that form.

OPPR was written using one module as an organizer. This ailows the user to run each of

the constituent parts of the planner individually fiom the 'Macro 1 Run' pull-down menu,

or by typing 'vbanin' or by clicking an icon on the button bar.

3.3 Visual Basic Techniques

VBA is not a command level language like AutoLISP and the user cannot use direct

native AutoCAD command calls to perform actions. For example, in AutoLISP the user

cm, from within the LISP routine, tell AutoCAD to draw a polytine simply by using the

cornmand 'Pline'. In VB A however, algorithms must be devised to provide the same

results as a simple one-word command such as 'Pline'. This is comparable to creating an

algonthm that will draw a circle by drawing 360 line segments each 1 degree of arc round

a centre point, rather than using a simple 'Circle' command found in the language itself

The following sections show examples of coding techniques used to draw polylines,

extract information and place the objects in selection sets. It will also present other

rnethods used to simplify activities in VBA for AutoCAD. Sections 3.3.2 and 3.3.3 are

included to demonstrate solutions for two specific problems the author encountered while

developing the OPPR.

Prior to starting the OPPR project, organization and file planning were canied out in

order to decide what would be the most efficient method of storing mine planning data. In

the older versions of the planner (1984 on), planning data was stored in multiple files on

the host computer's hard drive. This included al1 drill and blast hole data, mining period

data and polygonal data representing the different areas mined during the particular

mining period. This led to rnany files being used with rigid file name procedures as a

result of the limit of eight-characters per filename required by older versions of DOS.

AutoC AD itself also had strict naming restrictions on layers, script and other filenames

in earlier versions.

AutoCAD R14.0 1 and later versions altow for very lengthy layer (groups ofdrawn

entities) names, as well as having the long-filename support of 32-bit Windows

environrnents. It was decided that planner data would be stored in both AutoCAD,

through its use of layers, and as named files on the local or network hard drive. Long

layer names allowed for the creation of a layer for each polygon in a mining period. Each

polygonal layer name would store representative data such as the polygon's number, its

color, its mining period, and whether or not it had been mined out. Files on the hard

drive would include the actuai drill hole database, files allowing the ore cut-off grade to

be changed in order to investigate changes in ore grade, ore tonnage and stripping ratio,

and most importantly, backup data on each polygon and mining period.

The method of storing information in Iayer names was chosen because of one simple

programming technique found in VBA for AutoCAD. VBA allowed for scrolling through

al1 layer names in a drawing or through a list of layer names filtered fiom the full list of

drawing layers, by using a simple FOR-NEXT loop. The layer name could be taken fiom

each layer as it passed through the loop and wuld be analyzed for pertinent data For

example, if the user wanted al1 polygons that were blue, the program would cycle through

al1 of the drawing's layers, look at the layer's names and 8ag layer narnes containing a

code designating the colour blue.

The following example shows how a FOR-NEXT loop cari be used to find and extract

the pertinent data fiom AutoCAD layers for tùrther analysis or entity modification:

Dim la As AcadLayer

1 = Len ("SampleName* )

Foc Each la In ThisDrawing.Layers

layernamel = la-name

midtemp = Mid$ (layernamel, 1, 1)

If midtemp = "SampleName* Then

act ive = ThisDrawing.ActiveLayer.name

If active = layernamel Then

If ThisDrawing.Layers.Item("0").Freeze = True Then

ThisDrawing. Layers. 1 tem("O1') .Freeze = False

End If

ThisDrawing-ActiveLayer = ThisDrawing. Layers. Item("0")

End If

1a.Freeze = True

End i f

Next l a

In this example, the code is searching for the layer with the name 'SampleName'. First,

'la' is defined as a layer object. The FOR-NEXT loop begins cycling through al1 the

layers in the drawing, designated by 'ThisDrawing.Layers'. The name of each layer as it

passes through the loop is assigned to a temporary variable ('layernarnel = la.nameY).

This variable is checked against the desired name 'SampleNameY. If the layer has the

required name, the default layer ('0') is thawed if it is &zen and made the active layer.

The layer named 'SampleName' is fiozen and replaced as the active layer (if applicable)

by the default layer ('Oî).

[n surnmary, the exampte code finds a layer by using a layer name flag, and fieezes

that Iayer once found. Layer names can be andyzed for individual components, such as

mining period, colour or polygon number. This is done using the 'mid$' function, as

shown in the code example in the line:

midtemp = Mid$ (layernamel, 5 , 3 )

'Midtemp' is being assigned a portion of the layer's name, fiom the fifth character to the

eighth c haracter inclusive (3 characters).

AutoCAû uses three types of lines. Simple lines are defined by joining two vertices with

threc-dimensional coordinates making a single entity. Polylines are a series of lines

joined in a continuous string making a single entity with no 'T' junctions. Polylines are of

two types, LWPOLYLiNES that have a cornmon elevation, and 3DPOLYLlNES, which

need not share the same elevation. The LWPOLYLINE, termed pline or poiyline

throughout this thesis, is important because it can be used to define entities cuntained

within it provided it does not cross over itself.

VBA cannot use AutoCADrs direct command line structure. This limitation was

indicated in Section 3.1. In order to create objects in AutoCAD using WA, new VBA

comrnands were created. Nearly ail AutoCAD commands have equivalent VBA

comrnands, for example, the circle is created the sarne way in both the manual user or

AutoLISP run command, and in VBA, by issuing a circle command and augmenting it

with (x,y,z) coordinates for center location and a radius value. Most VBA commands

act in a similar manner to their AutoCAD counterparts. However, there are some

differences. For example, in AutoCAD (or AutoLISP) the 'pline' command, plus a series

of coordinates, will draw a polyline from a designated vertex to another designated

vertex. Issuing a single 'pline' command without coordinates will cause AutoCAD to ask

the user to select vertices fiom which to create the polyline. Therefore, a free hand, user-

created polyline can be created quickly and easily, with automatic closure. There is no

VBA equivalent to this action.

A polyline command exists in VBA through the creation of a polygon object. First, a

variable is declared as type AcadPolyline:

D i m polyûbj As AcadPolyline

Only by providing a series of known wordinates can a 'polyobj' object be created.

Therefore, if a series of three-dimensional coordinates are stored in an array with an

example name of 'PolyPoint', a polyline can be created using the following command:

Set polyObj = ThisDrawing.ModelSpace.Add~olyline(~oly~oint)

This is a simple rnethod of creating polylines, albeit a little lengthy. Unfortunately, the

ability to let a user choose the vertices of polylines during polygon creation does not

exist. This is a serious problem for OPPR as users define their own polygons to describe

areas. Al1 searches of the Iiterature on VB A for AutoCAD, on various AutoDesk

newsgroups and of other resource areas for a solution to this problem proved fiuitless.

The author developed the following complex aigorithm that ailows the user to m a t e a

pdygon by choosing vertices on s m . A simple 'pline' command in the AutoCAD

command shell is replace. by 3 1 lines of code in VBA.

The user is Id to believe that by selecting points on the graphic screeu, a polyüne is

being created. in reality this is an operation in which the user merely creates simple lines

on the screen. VBA reads the vertex data for each line çreated and stores them in an

array that wiIl be sent to the polyhne creation comrnand once the user has 6nishôd

choosing vertices:

D O B v e n t s

on Error GoTo nullinput:

returnhrt = ThisDrawing.Utility.GetPoint[, "Get Point of ~olyline:")

points (Count) = returnPnt ( 0 )

points(Count + 1) = returnPnt tl)

points(Count + 21 2 returnPnt(2)

If Count > O Then

startPoint (01 = points(Count - 3 )

startPoint(1l = points(Count - 2)

startpoint (2) = pointe (Count - 1)

endpoint IO) = pointe tcountl

endPoint (1) = points (Count + 11

end~oint(2) = points(Count + 2)

Set lineobj = ~his~rawing.~&el~pace.AddLfne~start~oiut, end~oint)

End If

Count = Count + 3

Loop Until Counr: = 90

nuilinput:

ken = Count - 1 ReDirn PolyPoint(0 Tg ken + 3) Aa Double

kount = O

For kount = O To (Count - 1) PolyPoint (kount) = points (kount

kkount = kaunt + 1

Next kount

PolyPoint (kkount) = points (0)

PolyPoint (kkount + 1) = points (1)

PolyPoint(kkount + 2) = points (2)

set polyObj = ThisDrawing.ModelSpace.AddPolyline(PolyPoint~

poly0bj.Closed = T N ~

First, 'nullinput' is defined as an error trap. When a user right-clicks during an AutoCAD

command or hits return without choosing a vertex, AutoCAû retums a 'nullinput' to

VBA. This is treated by VBA as an error, and will normally stop the execution of code

unless there is an error trap. With the trap, the error is ignored and software processing

will go to the label 'nullinput:'. The code then asks the user to select a point, under the

guise that the user is creating a polyline. This vertex is stored in the variable 'retumPnt'.

In order to make it appear that a polyline is behg drawn, individual lines are drawn

between the starting and ending points 'picked' by the user, and the vertices stored in the

variable 'points' as an array of six numbers. The first three positions in the array contain

the start point (x 1, yl, zl) and the last three positions contain the end point (x2, y2,22).

Line drawing is simpler than polyline drawing in that the 'line' command is given an

individual start point and end point, not just an array containing the two points plus

others. Therefore, in line 8 of the code above; ' If Count > 0 ', the array 'points'

containing the 6 values representing 3 lines with 2 vertices each, is broken up into a start

point and endpoint, and the code then draws the line.

The user continues to pick points, with the old end point becoming the new start point for

the next Iine in the sequence. The user can pick up to ninety vertices to make up the

eventual polyline. This is an arbitrary number and can be increased if the normal 10 or so

vertices is exceeded. When the user completes se1ecting points, and cancels the action,

the code jumps to the 'nullinput:' label. Al1 the points chosm by the user are now stored

in the array 'points' in triplets of x, y, and z. These CO-ordinates are mapped into the new

array, 'PolyPoints'. In order to close the polygon, the original start point of the polyline

must be added to the end of the 'PolyPoiots' array if required, so the a m y will start and

end with the sarne point. The array is then used to draw the polygon as a 'pline', and the

individual 'line' entities used to guide the u s a in drawing the polygon are erased. The

erasure is not s h o w in the code example above.

3.3.3 Combining Information into Selecrion Seîs

A selection set is useful programming feature from AutoLISP that ailows the

combining of data with a particular feature h m all or part of an AutoCAD drawing. A

selection set rnight be used to store ail r d items in a drawing, or contain al1 objects

within a certain boundary. It is the thai impurtant application applied to the designing the

OPPR. Using selection sets, the software can isolate specific information containeci

within a defined polygon or within other boundaries.

Selection sets were easily gathaed in AutoLISP using various filters in the command

'ssget'. The process is slightly different in VBA for AutoCAD as a selection set must first

be defined as a variable and given a comment name:

Set entselect = ThisDravhg.SelectionSets.AddIaB~THOLBS~)

In this case the selection variable name is 'entselect' and the comment name is

'BLASTHOLES'. For tbis code example, the software will ask the user to choose a

polygon in order to extract al1 the entities from within that polygon.

ThisDrawing.Utility.GetEntity plineobj, Pt, "Select the ~ o l y l i n e to qet vertices Erom"

The first line asks the user to select a polygon. This object is stored in the variable

'plineobj'. The coordinates of the selected polygon are then transferred to the array

'retcoord'. The third line shown actualIy does the work of adding entities to the seIection

set. The first portion of the command tells AutoCAD to add entities to 'entselect' by

using a 'selection by poIygon method'. However, there are multiple ways of selecting

entities by polygon including not-crossing, crossing or extemal to the polygon. in this

case the software filters the 'SelectByPolygon' method by asking for any entities crossing

or inside the polygon. The coordinates stored in 'retcoord' define the polygon used to

describe the crossing poiygon.

ln this manner, the user cm select a polygon, and dl the entities and information stored

within and crossing it will be added to a selection set for latw anatysis and modification.

3.3.4 Manipulating Seleetion Sets

Once the entities have been stored in a selection set, software must be created to analyze

the contents and report the desired information back to the user. For example, if

AutoCAD blocks (combinations of entities) within a polygon are stored in a selection

set, it would be interesting to know how many of them are waste and how many are ore.

A grade below which material is deemed to be waste (because it will not rnake sufficient

profit when processed) is required to accomplish this, and the tonnage of waste and grade

and tonnage of ore calculateci. In the following code example, block information has been

stored in the setection set 'entselect'. Each block has a data tag associated with it relating

back to a record number in a mining block mode1 (srnall volumes of material on a regular

grid) database of block assays and the block location.

The code extracts the data tag from each block ('AutoCAD' or 'mining' refer to the same

object) and writes it to a file. Blocks without tags are assumed to be waste blocks (Le.

their grade was not interpolated because of insuficient close drill information), and the

number of these are counted and added to the data file at the end. Blocks outside the pit

limit or already mined in a previous mine plan are not visible within the poiygon and are

ignored when the selection set is built. Note that AutoCAD uses the term 'block' to define

a colIection of entities such as the faces on a cube, and mining engineers use the term

'block' to define that cube at a specific location in the ground.

ind = O

For Each ent In entselect

'Get Block object from H a n d t t

Handle = ThisDrawing.HandleToOb j ect [entselect . Itemlindl . Handle)

Set AcadBlock = ThisDrawing. HandieTaOb ject (entselect . Itern(ind) .Handie)

'Retrieve block attributes

BlockAttribs = AcaàI3lock.GetAttributes

For 1 = O To üBound(BlockRttribs}

textstr = BlockAttribs (1 1 .TextString

P r i n t #1, textstr

ore = ore + 1

flag = 1

Next 1

If f l a g = O Then

vaste = waste + 1

Else

flag = O

End If

End If

ind = ind + 1

Next

wdste = waste -1

P r i n t U1, waste

Close # L

The code starts by creating a FOR-NEXT loop that will look at each 'ent' (entity) in the

selection set 'entselect'. The next Iine transfers the entity type to the variable 'typel'.

The selection set contains al1 the data contained by and crossing the polygon, including

the polygon itself Therefore, the program must ignore entities in the selection set of type

'pline', and this is accomplished using the IF THEN - ELSE statement in line 3.

The next two Iines assign ail the data tag information fkom the entities to a bIock. The

handle and 'AcadBlock' are assigneci per entity representing a mining block. The

attributes of the handle are then extracted into a variabte called 'BlockAttribsY.

'BlockAttribs' is very similas to an array. An entity can have any number of attributes,

and they would di be stored in this one variable. However, the entities being dealt with

here contain onty a singie handle or data tag attribute. The variable 'BlockAtûibs' must

still be treated as an array in extracting the actual value of the attriiute. A FOR-NEXT

loop is used to cycle through the number of attributes the array could hold (in this case,

there is only a single attriiute contained within 'BlockAttribs'). This attribute has its

own characteristics (e.g. colour, width or a text string). In this case the text string

attribute holding the record number of the block in the mining block database is requùed.

This information is stored in the variable 'txtstr' and, in a mining context, wouid typically

be grade(s), density, percent extracted, and financiai value.

The loop continues through al1 the entities in the selection set. When a block is

encountered that does not have a text string attribute, it is deemed to be waste and the

waste counter is increased by one. When the loop is finished, the text string characteristic

of each ore block has been written to a file dong with the number of blocks without text

string attributes (waste blocks). This file c m then be used to extract the block's records

fiom the mining block database in ordw to calcuiate grade and tonnage for the drawn

polygon.

3.3.5 Summary

Finding the waste and ore statistics within user drawn polygons is the most important

action of the Open Pit Planning sottware. The process m u t be completed many times

during a mine planning session, and mut operate smoothly without enor. The cut-off

grade applied to any polygon must also be a user dehed variable to be redenned at any

tirne der selecting a polygon or group of polygons.

Chapter 4

Open Pit Planner

Research into computerised open pit mine planning demands that source code software

be made available. As commercial source code cannot be obtained for proprietary

reasons, the sofiware was developed by the author based on the BrenPLAN package

(Chick, 1984), as described earlier in Section 2.1. The software will be made available to

the mining companies who fùnded the research to help their mining engineers produce

multiple plans for open pit mines, and as a teaching aid in open pit mine engineering

courses for students in the Queen's program as well as visiting industrial course

participants.

4.0 Introduction & Practical Objectives

The Open Pit Planner (OPPR) must interactively create multiple scenarios for different

mining penods and allow the development of an orderly mining sequence of waste and

ore mining. This sequence must satisfy profitability expectations, ore processing

requirements, the longer terni stripping ratio, and fully utilise the equipment. The mine

plan must allow the circumventing of problerns created by varying met4 prices or

changing grades. In doing so it must ensure that mining sequences are practical. For

example, it is not possible to mine material on any bench that is not open to the sky, and

which does not conform to the waü dope and to pit and push back boundaries. The

cornputer software must ensure that such s d o s w u i ~ t happa, even when the

prograrn user later decides not to mine materiai already selected for mining. The software

must also ensure that material is not mined hvice, because, for example, pulygons

outlining rnining areas ovdap. Further, sequençes must be in tirne order, but the length

of periud may be variable, e.g. weeics to years, and revisions of an earlier period must

r@re later periods to be updated.

In the ongoing work of mine planning for a particular mining period using the OPPR

software, many polygonal outlines are drawn, often overlapping, and the contents noted

in terms of tonnes of ore and waste and ore grade. The experienced planner will then

delete some poiygons and mine others to ensure objectives are met.

4. O. I Drawing and Dotabase Construction

Mine design mates pits based on mining costs and metal prices. An 'ultimate' pit is

created first, with artiticially low mining crists and high metal prices. This pit represents

the best-case scenario of the mine, and is usai to define the outennost boundaries of the

mine. Other pits are then designeci based on more reaiistic mine cost and metai price

figures. These pits wilI Vary in size with the smaiiest pit usually containhg the most

profitable material and the largest with more marginal material. DiRecent pits are

designated by letter or number in order to keep them separate. For example, a mine with

three planned pits might have Pit a, Pit b, Pit c etc. hrshbacks occur when a mder pit is

mined before a larger one and the w d s are 'pushed back' to incorporate the larger pits.

in the case study (Chapter 5), the Brenda mine was selected and au ultimate pit was

created, Three smaller pits were then designal based on realistic cost figures. These

pits were designateci as Pits a, b and c. Since mining can take place on al1 three pits

simultaneously, ail the pits must be incorporated into the drawing model used in OPPR.

in Brenda's case, Pit a, the smallest of the pits, is mined out first, with Pit b created as a

pushback during the mining of 'a'. Pit c is a pushback of b. Al1 three pits, as well as the

ultimate pit (for limit control) have to be included in the model that OPPR will work on.

The AutoCAD drawing format contains al1 the information needed to produce a drawing

in AutoCAD. It is a binary file that is created h m drawing objects contained within the

current drawing. To create the initial drawing to be used in OPPR, the pits created during

the mine design phase must be imported into AutoCAD. The pit outlines, and ore and

waste data are converted to DXF format using Visual Basic programs (Ksmerg, and

Mifdxf) designed to convert text databases into DXF. These programs will be d e s m i

in Chapter 5.1. DXF is a text file representation of AutoCAD drawing objects. Each

object has text references to position, colour and other attniutes represented as crosses

showing ore and waste blocks. Various files created by the mine design prognuns contain

data on block size, the origin of the drawing and costing data. Each block is referenced

fiom a single block model database record, calculated h m the origh of the drawing,

block size and coordinates. This is accûmptished such that any block number will

produce the block's coordinates, and any coordinates will produce the block number. A

block model is created fiom drill hole data based on these parameters. Only ore and waste

blocks that lie within the confines of the various pits will be included. This is carried out

by checking the block model against the pit outlines created by the PowerBASIC mine

design program (Mvngcone.bas, BIackwell, 1996, MINE 445). Ore and waste falîing

within the various outlines are converted to DXF that can then be imported into

AutoCAD and saved in an AutoCAD drawing format. OPPR can handle any type of data

included in a block model. However, the pit/pushback drawings and haulage ramp

locations needed for OPPR are very specitic and mua be created very carehlly by

trained mine engineers. The creation of the mine design, and the conversion of pit

outlines and block data to DXF c m take several hours. Therefore, the planning and

execution of the mine design and subsequent conversion to a form usable by OPPR is of

paramount importance.

Different layers represent dl pit and grade data once it is imported into AutoCAD. Layer

cames designate pit outlines based on elevation and pit number, and whether or not the

nit is mineabIe. Layèrs also contain the block rnodel based on elevation. Objects within

each layer can aIso contain information necessary to OPPR For example, each block

model object contains information on grade and a link to a record in a database. This is

stored as a text 'tagY within the drawing object. The exact organization of data within the

drawing database as it relates to OPPR is desctibed in Sections 4.8,4,8.1 and 4.8.2. AI

the layer and object information must be mateci and imported as designed into AutoCAD

in order for OPPR to nin conectly.

4. O. 2 Software Design

Open Pit Planner COPPR') is a single project file that can be pIaced and loaded fiom any

directory. It cm be loaded automatically by renaming it 'Project.dvb' and placing it in a

support directory of AutoCAD 14. This single project file is controlied by one module,

which executes each fonn or sub-program of OPPR as quired. Each ~ub-propm b

its own function, and an individual entry in the main module, and by using 'vbarun', the

pull-dom m a m menu, or a tmlbar, each sub-program within the project wiU be m.

There are seven diffetent sub-programs containecl within the plannefs main module.

With the exception of the introductory screen ('splash meen'), each i s designed to be run

independently by clicking on the toolbar, using the 'vbarun' commaad, or using the

dropdown macro menu. The sub-program do not have to be run in orda, and have been

arrangeci to provide a natural progression to the mine plan. The following Table 4.1 lists

the seven different sub-programs with a short description of each.

Pro~ram Name

Splash

1 LoadPol ygon 1 AlIowstheloadingand/orhidingof 1

Deseri~tion

Splash (introductory) screen for the OPPR

Changeparameters

DrawPolygon

Changes rnining period, pit number and ' elevation

Selects polygon number, colour and dmws a polygon

Calculate ~olygons

Calculates puidtonnage data

RemoveAtfine

Table 4.1 - The Scven OPPR Sub-Progrunr and theh functiou

Removes polygons and 'mines' the data wntained withùi them

I

Each sub-program is descn'bed in the sections below, and it is assumed tbat the reader has

a good working knowledge of AutoCAD and Visual Basic.

Unmine Restores polygons and mined data

4.1 'Splash'

When a drawing is loaded and OPPR is present in AutoCAD's memory, OPPR will

automatically display an introductory 'splash' screen containing the planner's version

number and copyright information (Figure 4.1).

This 'splash' screen uses the ' AcadDocument-Endopen' event in order to run

automatically when a suitably constructed drawing finishes loading. Remarking the

source code that enables this fbnction will prevent this automatic feature fiom occurring

should the user demand this.

Figure 1.1 - The introductory 'Splrrh' sripen indicating verniou numkr and copyright idormation

superimposed at start up on an AutoCAD dnwing set up for tbc OPPR Note tbe smlll OPPR

toolbar located rbove and to the ngbt hmd side a h mperimpoacd aa the drawing . This todbu

Y l h s the user to select wks in the OPPR

4.2 Changeparameters

'ChangePararneters' is invoked by clicking on the red 'C' on the OPPR toolbar o r by

choosing 'a-ChangeParameters7 fiom the macro window afler using the pull-dom

macro menu, or 'vbanin'. The characters 'a-' in fiont of 'ChangeParamaers' (and

subsequent Ietters) are used to sort the individual sub-programs within the main module.

This gives the user a visual order of execution of the OPPR. Changeparameters sets up

the planner by allowing the choice of a mining period, pit number and elevation.

The mining period is selected fiom the first dropdown combo box. When

Changeparameters is first loaded it checks the user's hard drive for a parameter file. This

parameter file contains the last working mining period, pit number and elevation. The

sub-program shows the last worked mining period in the text window of the mining

period's combo box. The drop down list therefore contains the last known working

mining period, and al1 mining periods that have been worked on in the drawing.

Ciiçking on the text window of the mining period combo box allows the user to type in a

new mining penod. In the second combo box the uqr must select a pit or pushback to

work on. The current version of the planner allows for up to three pits to be worked on

simultaneously. These three pits can be separate entities or, for example, an initial pit

with two pushbacks. Mining more than three adjacent working areas at different

elevations wouId probabiy be impractical, but changing a simple variable in the source

code can increase the number of pits that can be worked on.

When a pit number has been selected, the sub-program searches through the drawing

database for visible drawing layers that have the corresponding pit number attached to

them. Visible layers are those that are open to the slcy and are able to be mined. Visible

layers are designated as those beginning with a 'K', and Chapter 5 describes this

designation system in detail. For each K layer, the sub-program records it's elevation, and

if that elevation is not in the cornbo box list, adds it. Thus only those elevations

containing material available for mining are shown for selection by the user.

The text box below the elevation cornbo box contains the path to the current parameter

file containing detail on the pits being worked and elevations available for rnining. This

box allows the user to type in the path of an existing parameter file, or where a new

parameter file should be saved. When al1 parameters are selected, the user can either exit

out of ChangeParameters or select 'OK'.

If 'OK' is selected, ChangeParameters checks to see whether each of the parameters has

been set. If the parameters are correct, the sub-program checks that the K layer is 'thawed'

(visible) for the selected pit number and elevation, thaws it if required, and makes it the

'active' Iayer. The sub-program then cycles through al1 the other layers in the drawing and

makes them invisible by fieezing them.

ChangeParameters saves the selected rnining period, pit number and elevation to the

parameter file given by the path in the configuration file text box. Finaily, the sub-

program 'regenerates' the drawing and 'zooms' to the drawing 'extents', making ready the

material to be 'mined' by the OPPR program user. Figure 4.2 shows the computer display

of ChangeParameters mnning in AutoCAD.

Figure 4.2 - The ChangeParPmeien windorr which ~ k c t s tbe mining period, pit, and bencb. The File

containing configuration informaha is listai, aiad there is an optioa ta ' F m ' (hide firw view)

aider pdyggms airerdy dm-

'DrawPotygon' can be run by choosing 'b-DrawPolygon' Eom the macro whdow that

appears der using the macro dropdown menu, by 'vbamn', or by clicking on the yeiiow

'D' in the OPPR too1ba.r. DrawPolygon aüows the user to draw a polygon around a

desired area, with characteristics such as colour, ahhg period, and the nurnber of the

polygon in that mining period.

The DrawPolygon window contains a number of attributes of the polygon to be drawn.

The mining period and elevation of the polygon are locked, as those characteristics were

set in the ChangeParameters sub-program. The tirst attniute is stored in the 'Polygon

Number' list box. Each polygon must have a number associated with it. This allows for

multiple polygons within a specific mining period. The colour of the polygon is chosen in

the second list box. In its simplest form, colour can be used to discern between individual

polygons. However, polygon colour can also used to describe specific mining actions.

For example, blue polygons could represent blasts occurring in waste, while red polygons

could represent blasts in ore. In this way colour wuld represent almost any type of

rnining action.

At the bottom of the page is a text box in which the user can type a description of the

polygon being drawn to allow for the distinction between polygons by means other than

the simple use of a polygon number. For example, the tag wuld be a blast number, a date,

a physical description of the area, digging qudity, equipment to be used, reason for a

planned action that appears illogical, and etc. The polygon description tags provide a

means for precise identification of polygons, especially when the OPPR user is reviewing

plans afier a length of time, or the plan is under review.

On the left side of the DrawPolygon window are a number of labels that show the

currently selected mining period, pit number and elevation. These are variables chosen in

ChangeParameters. The layer king mined is dso shown, as well as the selected polygon

number and polygon colour.

Figure 4.3 shows a graphic display of DrawPolygon superimposed on a sample

drawing containing multiple polygons. In this case, each polygon represents a different

blast on this bench.

When DrawPolygons is first run, it checks for a parameters file generated by

ChangeParameters. It uses this file to set the mining penod, pit number and elevation. If

the parameter file cannot be found, it gives an error message stating that

ChangeParameters must be run. When the polygon number and polygon colour have been

chosen, the 'Draw Polygon' button in the lower lefl corner of the window becomes

active. Clicking on this button runs the polygon drawing routine. The code asks the user

io d r ~ w the polygon on screen. The user clicks on a series of points that the sofhvare uses

to draw the polygon as descnbed in depth in Chapter 3.3.2. The sub-program then colours

the polygon and gives it a specific layer name based on its mining period, pit number,

elevation, polygon number and colour.

t... - *

Figure 1.3 - DrawPolygon d o w s the user to seiecî a polygon number rad rolour, and p m * k a

description. The full information qarding pit number, kneh etc,, is diyilayeâ in the upptr rigbt oi

the window. The user can d n w or crase a poiypn fmm thW whdon.

After drawing the polygon, the sub-program saves the vertex data for the polygon to a

text file in case the polygon in the drawing is erased by accident. This 6le contains only

the vertex data for that specific polygon and has the form of Clayer name>.pol. The sub-

program also saves the vertex data to a file that contains aii polygon data for the worbg

mining period. This file has the fom of <minhg period>.per. Both of these mes are used

later in other sub-programs, and al relevant information such as mining period, pit and

bench number is stored in the layer name.

Finally, the sub-program closes the polygon and retums control of AutoCAD to the

user, leaving the polygon visible on screen while erasing al1 temporary lines and polygon

building objects.

4.4 LoadPolygon

'LoadPolygon' can be run by clicking on the 'L' on the Open Pit Planner toolbar or by

choosing 'c - LoadPolygon' off the macro pulldown menu or through invoking 'vbanin'.

LoadPolygon allows the user to load polygons back ont0 the drawing in the event they

have become hidden. This could be caused by changing layers or by coming back to old

working areas.

The LoadPolygon window has a number of different options for bringing back hidden

polygons. The user m u s first enter a mining penod for the sub-program to use in

searching for old polygons. h performs the search through the drawing database itself or

through back-up polygon files created by DrawPolygon depending on the users

preference. M e r clicking the 'Check for Polygons' button, the sub-program will display

the pit number of any hidden or backed up polygons it finds. Clicking on a pit number

will display al1 elevations associated with hidden polygons in that pit. Clicking on an

elevation will display al1 the polygon numbers associated with that elevation.

There are a number of options to filter the polygons to be reloaded. The first level of

filters is on the pit, elevation or polygon number boxes, Mer clicking on the pit number

and selecting the 'Draw Al1 Polygons in this Pit' option, the sub-program will load d l the

hidden polygons contained within that pit. M e r ciicking on an elevation, the user can

select 'Draw All Polygons on this Elevation' and the sub-program will load al1 hidden

polygons contained on that elevation for the selected pit. A sub-filter allows al1 polygons

on an elevation, regardless of which pit number, to be drawn. The third filter is the

default option, 'Draw this Polygon ûnly'. There is a polygon number filter under the

polygon number list box that links the polygon number to elevation. If this filter is

unchecked, al1 polygons with the chosen polygon number will be loaded. This can be

helpful if, for example, each sinking nit blast was labelled polygon number 1.

Figure 4.4 shows a typical graphic display of LoadPolygon with the different filter check

boxes and radio buttons at the bottom of the window.

Figure 4.4 - LOPdPolygon ensum tbat the umer is inormcd of whkb pi& bcnch, etc in rtivc, and

Iillows al1 the poiygons already dram to be visudiscd by piî, by efevatioa, or by indihiduai pdygoa.

The 'Draw this Polygon Only' option enables the FoUowing selections to be chosen by

the user:

Poiygon numbw filter check box checkeâ, and the eievation tilter check box checked

loads a single polygon with the given polygon number, elevation and pit nurnber.

Cleating the polygon number check box but leaving the devation check box enab1ed

draws aii polygons in that pit and selected elevation regardles of polygon number.

Clearing both check boxes under elevation and pit number will load al1 polygons

with the chosen polygon number that exist regardless of elevation or pit number.

If the OPPR parameter file is not found on loading the sub-program, the user is informed

that ChangeParameters must be mn before continuing. If the parameter file is found, it

prints the last known mining period in the upper lefl of the window created by VBA, as

weil as entering it in the mining period text box. The user can change the mining period

contained within the text box at any time. New periods can be mined, but the user must

be careful in going back to previous periods. Changing polygons drawn in earIier periods

might necessitate changes to polygons created in subsequent periods. When the 'Check

for Polygons' button is clicked the sub-program checks to see whether the Drawing

Database or Polygon File checkbox is selected. If the Drawing Database button is

checked, the sub-program cycles through the layers contained within the drawing

database and extracts those layer names that represent polygons in the entered mining

period. If the Polygon File checkbox is checked, the sub-program will search the default

parameter directory as determined by ChangeParameters and search for polygon files

containing the entered mining period in the file name.

4.4.1 Drmving Database

AAer searching through the drawings' table of layer names (easily accomplished in the

open architecture of AutoCAD), the sub-program now has a list that represents polygons

contained within the selected mining period. It extracts the pit numbers fiom the layer

names and enters them in the pit number list box, eliminating redundant entries.

NormalIy, al1 filter boxes are checked, and the 'Draw Single Polygon Only' radio

button is selected followed by the selection of a particular pit. The sub-program then

searches through the list of layer names for names chat contain that pit number and

extracts al1 the associated elevations tiom the layer names, entering them in the elevation

list box. Clicking on an elevation will search through al1 the layer names that contain the

selected pit number, and the selected elevation. Each layer that fits these criteria

represents a polygon, and the pit number ofeach is read fmm the polygon's layer name

and entered in the polygon list box. Clicking on a polygon number will enter its number

and colour into the parameter list in the upper leil of the window.

The search for, and extraction of data fiom layers and their layer names is similar for

each scenario created by the selection or de-selection of the various filter check boxes.

After a poIygon is chosen, the 'Load Polygon(s)' button cm be clicked, the layer(s)

associated with the selected polygons will be turned on ('thawed') and the drawing will be

'redrawn' to show the pits, elevations, polygons and other material selected by the user.

4.4.2 Polygon Files

If the Polygon File check box is enableâ, and the 'Check for Polygons' button is cIicked

the sub-program will search the default parameter directory for any polygon files that

have a filename containing the emered mining period. If no polygon files are found, the

user is informed and the sub-program ends.

The polygon filenarne also contains the elevation, cobur and pit number of the polygon.

Therefore, al1 pit numbers contained within the found polygon fite names are entered into

the pit number list box. Clicking on a pit number will search through the list of

filenames containing the selected pit number, and their respective elevations will be

entered into the elevation list box. Selecting an elevation will search for filenames

containing the selected pit number and elevation, and will enter al1 the polygon numbers

into the polygon number list box. Selecting a polygon number will extract the colour

from the polygon file name and al1 parameter data will be entered into the parameter area

in the upper left of the window. The results of searching the polygon file names will

differ depending on which filter check box or radio button is selected.

Clicking on the 'Load Polygon(s)' button will load and draw the selected polygon(s) by

obtaining the vertex data from the individual polygon files and plotting them in

AutoCAD. The polygons will have layer names assigned to them based on their

characteristics.

'Calculate' can be run by selecting 'e-Calculate' fiom the macro menu afier using

'vbarun' or the Run Macro option in the Twls dropdown menu. Alternatively, clicking

on the 'GR' (grade and tonnage) button on the Open Pit Planner twlbar can run the sub

program. 'Caiculate' will calculate the number of ore and waste blocks contained within a

specified poIygon and give various average grades of the selected area based on a number

of cut-off grades. These various cutsff grades are shown as exarnples only, Usually a

single nit-off grade will be used throughout a plan. Average grades of ore are calculated

fiom material that is above the cutsff grade. Dollar values are in current dollars and

are not discounted to the mine start up date, as such financial calculations were outside

the scope of the thesis.

AAer Calculate has been started, the user must select a polygon fiom the screen window.

The contents of this polygon are then collected by Calculate for analysis. Calculates'

main window (Figure 4.5) consists of three main areas. At the bottom of the window the

sub-program gathers data about the block model representing the orebody, and the user-

selected polygon. Included is the elevation of the polygon and a correction factor. This

correction factor may be used if the elevations in the drawing do not match the elevations

in the block model exactly, for example because part benches are being mined for grade

control reasons. The actual polygon layer name is displayed as well as the paths to two

files: the block model file, and to a working (temporary) file. The block model file is one

that contains al1 of the grade and location data upon which the drawing is built. The

working file is used by 'Calculate' to store the data relevant to the polygon for timely

processing of the gradehomage data for al1 the individual cut-off grades. Each file must

have a correct path on the disk drive. If the block modei file cannot be found, an error is

generated and the user is asked to try again. The middle command button in the bottom-

right of the window ('Check Field Length') is used when a block model file is being

inputted for the first time. It is a small utility that checks the field length of one record in

the model file. This number is needed by Calculate in order to be able to read in a record

by direct access to the line in the file rather than by a sequential access method starting at

the beginning of the file. The field length must be included in the general dechrations

area of the Open Pit Planner module for Caiculate to work correctly. Once the

number has been entered, it does not bave to be re-entered unless the field length of the

data file is altered, a most unlikely event in the middle of a mine planning session.

Figure 4.5 - Calculate/Analyze Miin Window sboning tbt produrtioa JtrtWties of tbc OPPR tbus

far. The gradeltonnage cume data fur the lrecst mining pdygw is displaycd for the uacr to sckrt a

particular at4 grade for tbis pdygam.

The Calculate window has a secondary area at the top. When the 'Go' button is clicked,

this area wii show the number of interpolated 'mineralid' blocks, the number of

uninterpolated 'waste' blocks, and the total number of blocks contained within the

selected polygon that are available for minùig (Le. open to the sky) within the pit or

pushback. This output includes total tonnes, waste tonnage and mineralised tonnage

based on the specific gravity of the block. This may be a constant in the set-up

parameters file, or a variable listed for each block in the block model database.

The third area is the text box in the middle of the window. The desired output is

dispIayed in this area comprising the average grade of the material, mineralised tonnes

and waste tonnes when a cut-off grade is applied. To the lefl of the text box is an area

where the user can enter a cut-off The application of a cut-off here may convert some

niineralised blocks to waste iftheir grade is less than the cut-ofF. Clicking on the 'Show

Data' button will add the input cut-off and resulting grade-tonnage data to the main

grade-tonnage window. This allows the user to create grade-tonnage data for any cut-off

in addition to the default grades.

When Calculate is first run, a small window appears asking the user to select a polygon

on screen. Data fiom the polygon, such as layer narne, and elevation are stored in

variables. The CO-ordinates of the polygon are read. Each entity contained within the

polygon is collected into a selection set using the polygon-crossing filter and the co-

ordinates gathered from the polygon itself. The selection set is filtered such that only the

specific block types representing visible mineralised and waste blocks are retained. The

text 'handle' (defined as Textstr, or text string by AutoCAD) of each entity is read and

sent to a working (temporary) file. When the drawing was constmcted, ore blocks were

assigned this text string handle, in the entity's ATTRIBUTE area. Waste blocks do not

have a text string handle. The mineralized blocks therefore have an AutoCAD

ATTRIBUTE with a text string handle, and this tag is the record in the block model to

which the entity is linked. Therefore, al1 mineralised entities will have their tag values

also output to the working file, while each waste entity will simply be counted. The

number of waste blocks is printed to the same working file as the mineralised block text

handles d e r al1 mineralised blocks have been written. The first portion of Calculate then

mns the main window.

The elevation and layer names are printed in their respective labels at the bottom of the

main Calculate window. When the 'Go!' button is clicked, the sub-program checks to see

whether the paths leading to the model file and working file are correct. lf the model file

cannot be found, a message box is generated letting the user know that the file does not

exist. It then checks for the temporary working file where al1 of the mineralised block

record labels are stored, as well as the number of waste blocks. If the temporary file

cannot be found an error message box is generated.

The sub-prograrn then takes each record number found in the temporary working file and

loads the record fiom the block model file, saving the grade data in arrays. When each

record is loaded, total tonnes and the average grade and tonnes of ore for the area

contained within the polygon (der applying the cut-off grade) are caiculated. Clicking

on the 'Show Data' button d e r input of aiternative cut-off grades will result in

recalculation of the statistics, which are pnnted below the previous information in the

main grade-tonnage text box for cornparison.

'Remove' can be run by clicking on the red 'R' on the Open Pit Planner toolbar or by

selecting 'e-Remove' fiom the macro pull-down menu that appears atler typing 'vbamn'

or through ToolslMacro on the AutoCAD main menu bar. Remove 'removes' material

contained within a polygon and designates it as mined.

Remove consists of a smail form that asks the user to select the polygon to be 'mined'.

Once selected, the polygon co-ordinates are found and al1 the ore and waste block entities

contained within and touching it are read into a selection set using the polygon-crossing

method. Remove then cycles through al1 the entities in the selection set, designating each

entity as 'mined'. This is accomplished by assigning each entity a new layer name, and

erasing the old layer name. The new layers are then 'frozen' and disappear From the

screen, in effect 'mining' them. In this way, waste and ore blocks cm never be

'Calculated' or 'Mined' twice,

The sub-program now has to make the matenal immediately below that mined 'visible

and available for mining'. Having mined one elevation, the sub-program fieezes ail the

material still visible on that current elevation and thaws the elevation directly below it,

superimposing the removed polygon. The material inside this polygon is now exposed

(since the material on the elevation directly above it has been mined), and the Iayer name

of the entities enclosed by the superimposeci polygon changes to those of the new bench.

Changeparameters will now see the newly exposed areas on this lower elevation. The

sub-program then Freezes everything on the lower elevation (because the user is not

currentjy mining on that elevation) and restores the upper elevation minus the mined

portions outlined by the polygon mined. nie removed polygon is designated as mined,

and 'frozen', and the mining statistics updated.

'Unmine' can be mn by clicking on the 'U' on the Open Pit Planner toolbar or by

choosing ' f - Unmine' h m the macro menu that appears afier typing 'vbarun' or

choosing TaolslMacro[Run from AutoCAD's menu. Unmine allows the user to undo the

remove command and return mined material to the orebody.

When Unmine is run. the user is presented with a warning window (Figure 4.6) as actions

perf'ormed by Unmine cannot be reversed (undone) if the polygon unmined has matenal

mined below it. Unmining on a higher bench means that nothing c m be mined beneath it.

Clicking 'OK' will bnng up the main Unmine window (Figure 4.7).

Figure 4.6 - Unmine Warning Screea to enmm the ploaoing ~~ un&rsttads tért carcksr use

of the option cwld result in biving to mpeat aot only the mining oi the snmiacd pdygm, but maoy

polylps on many comecuth bencbes klorr.

Figure 4.7 - Unmine Main Wiadow iIlowiag the user to select a pdygoa such tbit tbc mimi b k k s

are placed back in the ore body. Full âetaüs regadmg bench and pit as weil u the k t desctiptioa

and coiour for the pdygoa slketed are proviâed to the user.

The top of the window has some pull down Iists that must be completed by the user. The

first text box points to the location of any backup polygon files in case the user wants to

use them instead of mined polygons stored in the drawing database. These backup

polygon files are descnied in Section 4.8.2, The next pu1 down list is the pit number.

Clicking on this wiil show al1 pit numbers that contain mined polygons. After choosing a

pit number, the bench selection list box will show the elevations of the mined polygons

stored within the chosen pit number. W1th the selection of an elevation, the mined

polygons are drawn on the selected elevation and pit number is displayed in the

'Mined Polygons in this Bench' drop down list.

Clicking on a polygon provides information about it. The polygon number and colour

will be show in the text box and label below the 'Mined Polygons in this Bench' drop

down Iist. The polygon's description tag will be shown, and finally its rnining period will

be displayed.

Unrnine will also show the difference in elevation between the current working bench

and the polygon that will be unmined. This is extrernely important as shown in Chapter

4.8. If a polygon is unmined above the current bench, al1 blocks that exist between the

current working bench and the upper bench that contains the polygon to be unmined will

nn longer be mineabIe. These blocks rnust be removed from the production for the

periods affected. Further, the working wall dope will detemine which blocks will be

involved as they will not be venically below the unmined blocks but increase in number

with depth.

This algorithm used is not perfect as it does not take into account precise pit angles or

angIes of repose between benches. In the majority of cases the algorithm is overly

prudent, as it unmines any polygon, not just individual blocks, below the sekcted

polygon. By cycling d o m to each elevation in tuni, the sub-program uses not only the

original polygon selected for the unmine procedure, but dl of the other polygons found

on the Iower benches in the process, unmining them al1 in tum until the cwrent working

elevation is reacbed.

This ensures that more than the affected areas below the selected unmine polygon are

retumed to a mineable state, Le. a conservative approach. It must be understood that

unmining polygons well above the curent working bench indicates the users lack of mine

planning experience, or a serious error in planning which should have been addressed by

restarting the mine plan several mining periods pnor to the active plan.

In the case of long term planning (1 year or more), Unmine is very effective because the

large polygons used cover whole benches, effectively unmining the whole pit below. In

this case, the Unmine procedure can be 'undone' (Le. state retumed to that before the

command was issued) almost instantaneously and for al1 the benches below the unmined

bench.

The button at the bottom lefi of the main Unmine window allows the user to move the

chosen polygon into the centre of the computer display. Using this button, dong with the

description tag of the mined polygon, the user can make sure that the chosen polygon is

the correct one to be unmined. Clicking on the 'Unmine' button will unmine the chosen

polygon.

When Unmine is first activated, it loads the default parameter directory ftom

Changeparameters and adds the pit number to the pit number List box. Selecting a pit

number will search through the drawing database for mined polygons that exist in that

pit. As described above, this filters down to the specific polygons coatained within a

given elevation and pit number.

Clicking on the 'Show Polygon Location and FUN Bench' button fieezes the current

layer being worked on. It then thaws the mined polygon, and then thaws both the

mineable and unminable portions of the selected elevation, as well as the mined material

contained within the mined polygon. Regenerating the drawing shows where the polygon

exists on the fùl l bench. Clicking 'OK' on the message box that pops up returns the user

to Unmine.

4.8 Data Storage

Data is stored by the planner in two different locations, in the drawing database itself and

in files stored on the hard drive.

Data is stored in the drawing database in two different ways, through layer names and

through text handles. In AutoCAD R14 and above, layer names can be up to 255

characters in length, and can be defined as string variables for manipulation in VBA,

using such command as MID$, LEFT$ and RIGIiT$, The planner uses the layer name of

objects to store various amounts of information such as colour, pit number, polygon

number, elevation, mined or not mined, visible or mineable, or hidden and unminable.

Block mode1 entity data is stored with five different layer forms:

M layers.

E layers are non-visible, mineable layers. They cannot be mined until the material above

them has been mined. N layers are pit outlines. T layers are topography layers. K layers

are mineable layers. M layers are entity data that bas been mined. All material designated

by a K can be mined by the planner. Each drawing can have dif'ferent layer set-ups as

long as there is unmineable and mineable material available. These two layers mua also

include the pit number and elevation in their layer name. A sample E layer would be

Eb1750, and a sample N layer might be N4960.

M layers have complicated file names. K layers represent Block entities only when

blocks are visible. When they are mined using the Remove command, the layer narne

changes. First, an M replaces the K in the layer name. Then, the narne of the polygon that

mined the block is placed after the M<elevation>. This ensures the 'unmining' procedure

can see which polygon mined which block entity should it have to return it to the

'mineable' database at a later time. A before and after example would have the original

entity, represented by KB 1745, and being mined by polygon 17452b3jun00, becoming an

entity with the layer name MB1745mI7452b3jun00 after mining. The smali 'm' between

the original layer name and that of the polygon is used as a separator.

The polygons that represent the are- (volume on one bench) mined are stored in two

different ways. Polygons that have not been mined (through Remove) have this layer

format:

A sample polygon layer name (as used above) would be 17452b3jun00, indicating an

elevation of 1745, colour 2 (green), pit number b, polygon number 3, and mining period

Jun00.

Polygons that have been mined have the same layer name as before, but with an M placed

at the front. The above example would be changed to M 17452b3jun00.

Each block entity has a number of text handles attached to it. Figure 4.8 shows an

exarnple of an ore entity. Its handle is L7A3 with a text value of ORE. in the second half

of the figure is an attrr'bute with a 'value' with the number 039733 applied to it. This is

the record in the block model database to which this entity corresponds. The tag

underneath the record number is a cemark designating the values needed fiom the record

as being GRADE. Figure 4.9 shows an example of a waste entity. The handle of the

waste entity is 238A with a text handle of WASTE. Since the entity has been declareci as

waste, there is no second half attniute to the entity Iist and it does not have a

corresponding record in the block model database.

Fiprc 4.8 - An example minerdised Entity of two parts Tbe fint is the AutoCAD BLOCK, whkh

contains the lines making up the enb'ty and the second is the ~ssociated ATTRLBUTE contaiaing the

tag GRADE with the value of the record numbcr in the orebody block modcl.

Figure 4.9 - An example wutc BLOCK cntity not refcrenced to the mlncrrW bloek modei. Note

that the entity bis an iodividuai idtntifyhg 'Hande'.

4.8.2 Texî Files

Polygons, reserve output and temporary working files are also stored as text files on disk

in case the drawing database should fail. Each polygon when created by DrawPolygon is

exported to a text file with the fonn <Layer Name>.pol, with the Iayer name being that of

the polygon in the drawing database. A typical polygon file (mch as that of

17452b3jun00) would take the fonn show in Figure 4.10.

Figure 4.10 - The 17J52b3juIOO.pol Polygon File. The vertices are in triplets of X, Y and 2, the

elevation being constant.

The file describes the vertices of the polygon and an example of a few lines is shown in

Figure 4.1 1. The second type of text file is the temporary working file that 'Calculate'

uses. This temporary file contains al1 of the record numbers of ore entities, and the

nuniber of waste blocks within the selected polygon. The number of waste blocks is made

negative so that it cannot be conhsed with a record number. Figure 4.12 shows an

example of a temporary polygon file.

Figure 4.11 - Temporary Polygon File showing record number (line number) in the mioer.lised

material data base. The last value Û tbe number of waste blocks mined precedd by a negative sign.

The third type of text file is the reserve file. When 'Calculate' Ends the grade and tonnage

for various cut-ORS, in addition to p ~ t i n g the data on screen, it p ~ t s it to a text file.

This file can be printed by a normal text editor or imported by Word or Excel for

manipulation. The file example Figure 4.12 shows the diffaent cut-offs, tomes of ore,

average grade and tonnes of waste.

Figure 1.12 - 17452b3juIOO.dat Polygoa Resenr Fite graddtonnage data shoning cutsff, tons above

cut off, grade o f ore at that eut off and tous of wastc

4.9 Summary

Chapter 4 has explained the working on the Open Pit Planner in detail such that fiture

modifications can be completed with a minimum of effort. The mine planning engineer is

now equipped with software and a graphic interface enabling open pit mine plans to be

developed on a commonly available cornputer. The software also provides production

data by mining sequence and period. Such plans cm be analysed, iniproved by re-mnning

the program, and used for tinancial analysis and product price and cost simulation to

examine the long-tem effects of product price predictions and bestlworst case scenarios.

As each block mined is identified by time of mining, haulage simulations can determine

the truck hours and truck fleet required to nin the mine at any time period. Other

simulations including equipment availability can help determine the exposure of the mine

plan to malhnction of particular pieces of equiprnent, and provide input to appropriation

requests for capital for essential new equipment. Al1 these simulation examples are

beyond the scope of this thesis, but are typical of the research work possible when source

code such as that for the Open Pit Planner (OPPR) is readily available.

Chapter 5

Case S tudy

The Open Pit Planner (OPPR) was designed to develop plans for mines producing several

products contributing to revenue. This is important because several grades in various

types of units and orders of magnitude have to be displayed to the user. Software design

and testing was canied out using an erratically mineraliseci gold bearing orebody located

in South Arnerica (Anderson 1999). Grade and tonnage calculations were based on gram

per ton of gold, and al1 cut-off caIculations were based on gold grades.

In order to ensure that the start-up parameters (cosrdinate origins, block sizes, units,

etc.) were being interpreted correctly, and to test the planner's speed, the rnining of

another larger orebody was planned. The Department of Mining Engineering at Queen's

University at Kingston has permission to use and publish any work on the Brenda

orebody, which was used for the case study. Source code prograrns made available to

students in the fourth year open pit design course were usai in building the mine mode1

on the computer, and two case studies (Sorensen, Shepherd, Sattler, and Mompati, 1998)

and (VanDusen, Ward, Wilson and Cronkwnght, 2000) were used for comparative

purposes.

5.0 Brenda Mine

The Brenda Mine was a copper-molybdenum open pit operation in south central British

Columbia. It is located 235 kilornetres east of Vancouver, at an elevation of 1550 metres.

The mine operated from 1968 to 199 1. Ney (1 957) and Carr (1967) describeci the

regional geology, and the geology of the mine is descnied by Soregeroli (1974) and by

Oriel (1 972). The mine was a low-grade porphyry copper deposit, with multiple fractures

caused by regional stresses in the host rock, a quartz diode and granodionte fiom the

Jurassic age that intnided into Upper Triassic sedimentary and volcanic materiai. into this

host rock, veins of chalcopyrite and molybdenite, as well as other sulphides, intruded.

The orebody has a main core that is of higher grade than the surrounding material. As

distance from the centre of the orebody increases, the grade diminishes, except for where

stringers of ore are found. Average grades for the mine were h m 0.216% Copper and

0.064% Molybdenurn in 1970, to 0.128% Coppet, and 0.033% Molybdenum in 1980,

(Chick, 1984). in 1984, the minerai inventory was cdculated at 100 million tons of

0.147% Copper and 0.032% Molybdenum. For revenue purposes, the grade of

molybdenum was converteci to 'copper equivalent' and added to the copper grade.

The Brenda orebody was rnined in four different phases, consisting of an initiai pit (pit A)

and three push backs bits B, C and D). The push back expanded to the north and

east. The second took material fiom ail round, and the final push back took materiai from

the south. This arrangement was easiiy mmaged by the OPPR, as it was designed for

multiple pits.

5.1 Setting Up The Data

Like al1 Canadian rnining operations started pior to the mid 1970ts, the irnperial units of

measurement were used. As the mine Iife was not expected to extend much beyond the

1 990fs, the mine continu4 to use imperial units for production and surveying until

closure, and this case study uses imperial units to avoid confusion when discussing CO-

ordinate locations and bench names (elevations).

The Brenda orebody database was knged (Joumel and Huij%regts, 1978) using large 200-

foot side square blocks. The grades of 50-foot side square small selective mining units

(SMU's) within the large blocks were then estimated using a 'recovery fiinction' and

simulation. The recovery function in this case was based on the grade of the large block

and the grade distribution of contained SMUts. The SMU grades produced were Iocated

within the block using simulation and had the expected dispersion variance of grade

found in practice From mindmill grade comparisons. Estimating SMU's directly results in

a lower dispersion variance such that hi& and low grades are not represented and the

grade distribution is smoathed towards the average grade of the deposit. Details of the

methodology are outside the s a p e of this thesis and can be found in Anderson (1999).

The SMU's were then located in the large blocks such that the 16 SMü's fined perfecdy

in a 4x4 pattern.

For pit optimisation purposes, IOO-foot side blocks were chosen to define the wall

curvature and to ensure timely completion of the many pit outlines generated. in brief, the

optimisation procedure consisted of ninning a series of 'moving cone' pit limits (Lizotte,

l988), with an allowance for haulage rarnps included in the wall slope, using the

program 'Mvngcone' available to staff and students in the Mining Engineering

Department at Queen's University. An initial pit (A) and pushbacks (B, C, etc.) are

seiected fiom this series of cones, and later rarnps are inserted using AutoCAD, The

pushbacks are often mined concunently with previous pits and pushbacks, but at a higher

devation, and are not usually simple rings around the initial pit. Such a ring would

seldom be wide enough for productive mine operation, and would cause serious safety

concerns and accessibility problerns for the haulage ramp of any earlier pit (Btackwell

1993). Each push-back is made up of parts of several of the senes of cones, expanding in

a particular direction, for example north and east for the first push-back, Pit B, as shown

in Figure 5.1 after Blackwell(1993).

Figure 5.1 - The initial Pit A ia expanded to the nortbcast by pu& back B and al1 rwnd by pit C.

The r m p in Pit A stam in tbe mtû and aiovcs clackwk amad tbt pit. Tbc drubed ü r is Pit B's

ramp that starts in tbe soutb west and mwes ~materc~kwise arwad t k pit. Pit C's nmp wwes

dong the east woll and sriritcks back tnice in ùotb the mrrb and -th end of the pit

Most important is the placement of haulage ramps. These usudy start at the pit crest

where the surface topography is lowest, and as close to the processing plant crusher as

possible. From the crest they may spiral dom ctockwise or counter clockwise, or even

switch back several tirnes. Figure 5.2 illustrates a switch back moving down a pit wall.

Figum 5.2 - Switchback - This pboto shows a srritcbback moving donn Ihe w d l of a pi t

It is essential that haulage rarnps in earlier pits and push backs that are still in use are not

be affected by later pushbacks. Common problems uiclude safety issues resulting fiom

rock falling on the ramp d e r catchment berms are fiiled h m blasting above, and

disruptions to production caused by mining out the earher ramp.

Having selected a senes of pits as in Figure 5.1, and suitable hauiage ramp placements,

the pit and ramps are designed in AutoCAD, starting at the crest and ~oing d o m bench

by bench, moving the ramp dong in the desired direction. This can be accomplished

using automatic or manual procedures. For the pits designed for this thesis, the AutoLISP

routines MIDER and NEWMIDER (Blackweii, 1993) compIeted the drawing,

automaticaiiy moving each new mid-beoch line to its correct location and setting its

elevation, layer and colour. A fiuther AutoLISP routine COORDS3 exported the mid

bench vertices to files for the building of micromaps for each pit and pushback (Basic

programs PTLOC3A and MAPMAKEI) and DXF files to re-import the pits and surface

topographies into AutoCAD (Basic prograrn CONTOR22).

Coordinates for the (1 00ft) block centres were estimated and located in the large 200 foot

BLOCKS. Note that a BLOCK (intentionally capitalised) refers to a 200x200~50 foot

volume with an individual kriging grade estimate, a block (lower case) refers to a

1 OOx 100x50 volume, and a SMU to a 50x50~50 volume, and the dimensions are in the

fom X,Y,Z with a bench height (2) of 50 feet. The SMU grades were estimated using a

recovery fùnction such that although the BLOCK grade may be above or below cut-off, it

will likely contain both ore and waste. The blocks were located such that the four 100

foot blocks fitted perfectly in a 2x2 pattern, and used the average grade of the four

contained SMU's. A line from a kriged and simulated 100-foot block file for Brenda is as

follows:

The data file is in the form easting, northing, elevation, SMU 1 grade, SMU 2 grade,

SMU 3 grade, SMU 4 grade, the number of diarnond drill intersections used in knging,

and the kriging variance fiom kriging the original 200 foot block. The last two values

allow the reliability of the grade estimate to be ascertained at any time during a planning

session. SMU 1 is located in the northeast, and the other SMU's are counted clockwise

From the first. Using the coordinates of the centre of the original 100 foot block, the co-

ordinates of the four SMU's can be found and a new data file can be generated

representing a 50 foot side SMU block model of the orebody as show in Figure 5.3.

SMU 3

Coordinate Centre

Figure 5.3 - S M ü Layout - tbe centres of the 50 foat ride SMU's (smaü blocks) are caieulated from

the coordinate centre o t the 100 foot sidt blocir, in turn esîimated from a 200 timt BLOCK.

This was accomplished using a purpose written Visual Basic program called 'KSMERG'.

This program would take each 1Wfoot block data file for each bench, and would

calculate co-ordinates and create block model files based on small 50-foot blocks. Note

that the t m SMU is used primarily in the mineral inventory (grade estimation) stage of

mine operations, and the terni 'bbck' in the block model sense of mine planning is

equivalent. The terms are interchangeable in feasïbility studies, at mining operations

and in this thesis. This 50x50~50 size whether descnied as SMU or block, would provide

a high resolution for the orebody of approximately 10,000 tons per srnail block,

equivalent to about one fifth of a day's production. Figure 5.4 shows the options available

when running program 'KSMERG'.

Micromaps of Brenda were created in 100-foot block sizes, showing the initial

topography, the outlines of the initial pit and the first two pushbacks. A modified version

of the PTLOC subroutine (Hall, 1975) was used to detennine which blocks are inside or

outside a complex topography or pit outline. A micromap is a simple 110 text file

showing a11 the blocks in plan, one file for each elevation. The mine co-ordinate origin is

represented as the bottom left (south-west) text character (block). The surface topography

is also represented in the micromap. Air or rock not included in the particular pit or push

back is coded as zero, as is material outside any map for a particular pit or pushback.

The final south push back (Pit D) was not planned by the author using the OPPR as it was

never completed due to the clomre of the Brenda mine in 1991. Appendix A contains

sarnple micromaps. The IOO-foot block rnicromaps were converted to 50 foot mine

planning block micromaps (grade estimation SMü's) using a purpose written program

such that the different micromap sizes and small block grade files would interface

correctly. Using these 50-foot micromaps and the 50 foot grade block model, an

AutoCAD drawing could be generated. This drawing represented the thtee different pits,

with each block designated as mineralised @as a grade attached and a 1 in the micromap)

or waste (has a 1 in the micromap but no grade has been interpolated due to the

scarcity of local drill data). Ore blocks would have an additional text tag attached

indicating the location of that particular ore block record in the 50-foot block mode1

database of grade and other features (rock type, density, metailurgical recovery, etc.) of

each particular mineralised block.

Figure 5.4 - Ksmerg - Converthg 100 faat bloek m d e l s to vanous new sizes, in this cwe, 50 bot.

The program 'MIFDXF' was written in Visuai Basic to match each of the SMU (50 foot

block) entries to their conesponding location given by the rnicrornap, and produce the

DXF (Drawing exchange File) to build the drawing in AutoCAD. Since grade data

existed for areas outside the designed pit or push back, the micromaps ailowed the

trirnrning of unnecessary data. Only grade data contained within the pit limits would

normally be included in the AutoCAD drawing, aithough al1 the material outside the

'ultimate' pit could be designated push-back N' if required. MIFDXF drew the pit outlines

based on the micromaps and overlaid the grade data for both the 200 and 50-fi t

micromaps and grade databases. As a result the drawing contains al1 ore and waste blocks

within the pit or pushback limits. Typical micromap and grade plans displayed for

confirmation purposes during the execution of 'MiFDXF' cm be seen in Figure 5.5.

Figure 5.5 - MIFDXF workiag display - the p- matches SMU block models to tbeir

correspoading micromap 110 (idout d boiiodiry) entry. In the right-band prw, tbe micromap of

Pits A, B, and C are d r a w ~ ~ UI the kft banâ pane, tbis miciamrp bas kcn coavertcd to a coordiiatc

system that matches tbat oî tbe block modcl di- Grpd# from îbc database am plotted in tbe

left hand pane where micromap pit data erWts (cuiaud points). Wsste is piotteâ within the

micromap if grade data for tbit ana does aoL d s t (wbite points).

5.2 Initial Reserve Calcuiatioa

An initiai ore reserve and average grade calculaiion was performed using the Open Pit

Planner and a 50-foot block size. Polygons were drawa mund entire pits for al1 benches.

This is not an arduous task and can be accomplished with a simple rectangle or polygon

as big as the mine area. The software and àatabase permit only material inside the pit or

push back in question to be used. Grade and tonnage caicuiations were perfonned usuig

'Calculate' (see Section 4.9, and a summary of the results can be found in Table S. 1. A

full printout of the reserve and grade calculations can be found in Appendix B. Table 5.1

shows the amount of mineralised and waste per pit at a cut off grade of 0.00% Cu. This

gives ore tonnages for al1 mineralised blocks and waste tonnages for al1 waste blocks. Pits

A and B are the main revenue producing pits, yielding more mineralised materiai than

waste. Lower grade ore fiom pit A is stockpilecl for later processing during periods of ore

shortage, usually when one pit is nearing completion and the next pit has not reached ore

in sufficient quantities. OPPR aiiows for stockpiles to be built and mined during the

planning procedure.

Total: 259000 119000

Table 5.1 - Tonnages of o n and wut t L acb pY (Pit A & push backr B and C) i t i eut off of

O.W%Cu (Sortmon et rl. 1998)

These values are similar to those found in a typical fourth year open pit mine design of

the Brenda projea (Sorensen et ai, 1998 or VanDusen et al, 2000)) in the Department of

Mining Engineering at Queen's University, Kingston. However, the mine will not be

operating at a cut-off of O.W!Cu. Most mines will work at higher cutsffs in smaller

earlier pits, and reduce the cutsff for larger, later pi&. in Brenda's case, Pit A might

work at 0.30% Cu, Pit B at 0.20 to 0.25% Cu, and Pit C at 0.20% Cu. Note that only on

completion of this thesis will it be possible for students to produce detaild extraction

sequences for open pit mines that recognise that mine sequences must be both profitable

and operationally practical using in-house source code software.

Table 5.2 shows each pit with its cutsff applied and gives ore tons, average grade above

cut-off, waste tons and total tons. Note that at such a low-graâe operation the cut-off for

pit A is 'economic at the time of rnining' and includes no 'cash flow discounting' or 'rate

of r e m ' . At CDN$1.25/lb copper, a grade of 0.3% will generate CDN$7SOlton. If 67%

of the metal price is retumed to the mine after tailings, smelter, and distribution charges,

covering milling, mining ore and waste, and plaut/services ($5.00,2+1+1+1 at a sûip

ratio of 111) will be possible. If the rock is hauled h m the pit anyway, marginal

economics for Pits B and C would suggest that the odwaste selection should be made

when the truck is dumped at either crusher, stockpile or waste. On this basis, stripping

cost is neglected, and the cut-off grade can be reduced to say 0.2%Cu, paying milling, ore

mining and a third of plant~services. Materid in Pit A between 0.2 and 0.3% cm also be

selectively dumped in stockpiles (waste dumps close to the crusher) for later re-mining

These were the parameters used to evaiuate the mine, recognising that peaks in metal

price of copper and molybdenum (included as copper equivalent) would occur basd on

metai price forecasting. Ifthe mine could swvive times of low and average metal

prices, large profits would r d t fiom having an operathg facility, with no start up costs

and delays, in periods of high demand and metai price. Detailed discussion of such

economic scenarios is outside tbe scope of this thesis, which is directed to the ongoing

planning of mines to suvive low meial pr ies and then take full advantage of higher

prices whenever they materialise. Such detailed discussion does not include how the mine

is planneci, or how cut-off grades must be adjusted to ensure practicality in any given

orebody shape and grade distriiution.

Table 5.2 - OreNaste Tonnage bosod on 'Openting' and 'Mrrgioai' Cut-Ofis (Van Dusen et al,

Stockpile material is dumped in stockpile dumps and is d l e d when ore is unavailable, at

the critical transition when completing one Pit and working to full production fiom the

next, or at the end of the mine life. Table 5.2 indicates that the mine can work at a 1 : 1

sûip ratio with the given cutsfi . For inarginai' operations, such cutsffs are detennined

by plotting the 'cash flow' (revenue-cost) agallist cut-off and finding the cut-off grade

producing the greatest cash flow as shown in Figure 5.6. Figure 5.7 shows the costs of

mining versus cut-off.

Cash Flow vs. Cut=ûff Grade

Figure 5.6 - Cash Flow and Revenue vs. Cut-ûfîGrade for Pit A - A peak occnn between 0.15 and

0.25 % Cu, inditating that the higbut positive cash iiow wüi oceur iuhg cutsfïs bctweea thest

values.

Figure 5.7 - Minhg Coslr M. Cpt-Oll lor Pit A

Table 53 - Pit A GradelTonnage Data. In applying increasing cut-off grades, tbe average grade of

ore is increased, but the tons of ore deerease.

An exarnple of grade and tonnage data for Pit A is presented in Table 5.3. Data for the

other two pits, and al1 pits combined is summatised graphically in Figures 5.8 through

Figure 5.8 shows the grade tonnage curve for Pit A. If the cut-off grade was 0.30 %

copper, then the mean copper grade would be 0.47%, and the number of ore tons mined

would be 37900 kT. The total tons mined would always be 84800, and 46900 tons would

be mined as waste for a sîrip ratio (wastdore) of 1.2411 (often stated as simply 1.24).

Figures 5.9 and 5 . IO show gradeltonnage curves for Pits B and C.

Figure 5.8 - Grade/Toonage Curve for Pit A. The ore grade is almost linear but the ore tons change

sharply when the cut off grade varies in the 0.1 to 03% copper range.

Figure 5.9 - Gradefïonnage curve for Pit B - Grade Changes are linear but Iess sensitive to cutsff

Figure 5.10 - GradelTonnage Curve for Pit C. The grade changes remairi linear, but the steep dope

of the line indicates the rate of change is much greater. The effect of eut-off grade on tonnage is alsa

more pronounced that in either Pit A or B, indicating the level of risk in attempting the mining of

thU pit.

ooa o.u 0.20 0.m a40 0.50 am o.m oso C U U f aiad. (%cil

Figure 5.1 1 - Gradefïonnage Curve for Ail Pits Combineci. Tbe linearity of the grade curve venus

the sensitivity of the tonnage curve to rut-offs between 0.1 and 03%Cu can be seen.

Al1 three pit gradehomage curves show sharp declines in mineralized tons between cut-

offs of 0.10 and 0.30 percent copper, while the mean copper grade increases gradually.

This is significant because the amount of ore and waste available to the operation is

particularly wnsitive to the choice of cutsff grade. However, by adjusting the cutsff

grade slightly, the average grade mined is barely affecteci, but the required ore tonnage

cm be made available, explaining the success of this very low-grade mine. This data,

created by the mine planner, can be used to assess the effect of changes in cut-off grade

caused by fluctuations in metal price and othet factors. Using these simple graphs,

general scenarios based on different metal prices can be created, and sensitivity to

metal pnce determined. Coupled with more in-depth anaiysis of specific benches this can

minimise the impact of a metal price deciine, since grade and tonnage prerequisites

would already have been planned for. Conversely, plans can be revised to maximise the

impact of increasing metal prices. Figure 5.1 1 shows the gradeltonnage curve for ail

three pits combined.

5.3 Currently Available 'Source Codet Mine Planning and Scheduiing Software

Over the past several years, the Brenda deposit has been used by fourth year and graduate

students enrolled in courses in open pit mine design in the Department of Mining

Engineering at Queen's University. No two plans are identical because metal prices,

smelter contract terrns, capital and operating costs, equipment used, wall slopes, ramp

designs, push-backs, stockpiling strategies and recoveries are al1 among the choices made

and justified by each particular group of students. For example, one group could a s m e

heavy demand for copper and molybdenum and an aggressive cost effective management

while another could have a more pessimistic outlook. Note that only on completion of

this thesis will it be possible for students to produce detailed extraction sequences for

open pit mines using in-house source code software recognising that mine sequences

must be both profitable and operationaily practical.

The scheduling of production is based on a 'spread shed type program, GT-TABLE 1

(Blackwell, 1996) with mining periods as the columns and bench elevation as the rows.

Ore is removed starting at the top bench of the initial pit such that each bench m u t be

depleted of ore before dropping down to the next. Each period must mine the ore

production required, and ore mining flows diagonally fiom top lefi to bottom right of

such a spread sheet, When pits are depleted, production moves to the top of the next pit

(bottom of initial pit A to top of push-back pit B etc). The user has the option of having a

percentage of production tiom each of the pits for penods when the move is made.

PracticaHy, the push back will require several periods of 'pre-stripping' and very low

grade ore mining before being capable of supplying the mill. For example, by having the

first penod of the move mine 67% fiom A and 33% fiom B and the following period

33% from A and 67% fiom B, an orderly transition tiom one pit to the other might avoid

periods requiring excessive waste production. This completes the ore schedule.

A similar waste schedule is now made based on three user choices:

The maximum waste production (stripping ratio).

The number of imrnediately adjacent benches that can be mined togethet, usually 3 or

4.

The multiple of tonnage rnined on an upper bench in order to mine tons on the bench

imrnediately below, usually 1.5 to 2.

This ensures that ore production will be maintained. It does not ensure that the waste

production and haulage (truck) hours will be smooth, and having one particular month

demand 6000 truck hours and the next 8000 is not acceptable. It must also be noted

that truck hours are substantially higher per ton hauled when mining in the bottom of a

pit, and truck hours hauling uphill loaded are costly (Blackwell, 1997).

The truck hours are now estimated based on the average plan (horizontal) component of

distance of the haul road between loader and destination (dump or msher), and on the

change in elevation component between loader and destination (Blackwell 1997). The

spreadsheet program now smoothes the truck hours by moving waste production back in

time to a higher elevation or previous pit or pushback. The 'spread s h e d now provides an

acceptable mining schedule, and necessary pre-stripping periods to reach ore are often

introduced. An exarnple of such a spreadsheet for the Brenda deposit is shown in Table

5.4.

Plt B Ore and Waate

Waste 896,172

4,545.374 3,619,290

939.165

- 5157.149 4,842,852

O. 348

Table 5.4 - Example of Ore/Waste Production Scheduling Spreadsheet - The mining periods are

each one year. Waste and ore are in columns for each period, whiie the benches are in rows

starting at the highest elevation. Note how the ore is systematicaliy removed in down then across

then down moves, but waste is l a predictable, foliowing the strip ratio and miaing production

rules input by the user. The better grade waste is re-clauified as 'stockpile', and sdectively

dumped for mining later in periods of ore shortages.

Truck hours based on a mine plan without regard for truck haulage times will be anything

but constant (Van Dusen et al., 1999)' will fluctuate as pits deepen (Le. more truck hours

are required) and are completed, and decrease when moving material close to surface.

Truck efficiency is maxirnized when the truck fleet is running close to it's maximum

scheduled time, usually in the range 5,500 to 7,000 operating hours per truck per year

(Blackwell, 1997). Figure 5.12 shows how tmck hours will increase and demase while

mining the various pits. This is because in some periods not ail trucks are required, and in

others, more trucks are required than availabIe. The mine plan can be improved by

mining more waste in periods of less truck hou demand, i.e. pre-stripping. This is

accomplished with the program MATRIX2, (Blackwell, 1996). Re-arranging the mine

plan so that a fleet of trucks is being used constantly, rather than using different numbers

of trucks in different mining periods will provide a smoothed truck hours graph,

rnaximizing equipment usage while maintaining the mine plan as shown in Figure 5.1 3.

Figure 5.12 - Truck Eours pet Period, pre-smootbing (from Van Dmsen, et.al. lm). The demand for

ore truck hours peaks in periods 5,10 and 14 for piCs A, B and C respectively. The demand for waste

truck hours is lowest in periods 4 and 12 as suffirient sm'pphg for ore production h u been achieved.

Figure 5.13 - Truck E o u n per Period, post smodbhg ( h m Van Dasen, 1999). The ore truck houn

have not changed, but t h waste mining bu k a movcd brck in time (pmtripping) and the pcrb

of ore truck hour dtmurd coineide ri& dnip in w u t t truck hour demrnd

The software described above is an aid for detaiIed mine planning, but does not guarantee

a practical mine plan. In certain 'ypes of orebody, the ore and waste pockets might not be

conveniently located and available when needed for example the erratically mineraliseci

gold deposit used in software dwelopment and testing. It cannot revise mining plans in

the event of instability of the pit walls such that mining cannot be camed out in certain

sectors of the pit in spring, and it cannot allow for scbeduled major overhaul or

breakdown of equipment. It cannot ensure haul road access, or avoid ramp closure

because of blast spiil rock raveiiing dowu. Adjusting the cut-off grade moderately up or

up or d o m as the availability of ore changes is an option the mine p l m e r would like

to have, but is not provided thus far.

The software developed during the research conducted into open pit mine planning by the

author provides the means to interactively plan mines using the cornputer graphics of

AutoCAD, and to address the shortcomings of currently available 'source code' software.

The next section will describe typical applications of the Open Pit Planner, followed by a

detailed example of mine planning output fiom the OPPR software as applied to the

Brenda deposit.

5.4 Problems to Avoid in Open Pit Mine Planning

Mine planners have to be aware that their work must lead to the continueci production of

ore at satisfactory rates and grades, and the timely removal of waste, al1 fitting within the

long term goals of the operation. The plan must provide a safe, productive and efficient

schedule incorporating decisions regarding maintenance, wall stability and seasonal

variations. Some examples of typical problems which should be recognised and deait

with are presented before working on an actual mine plan.

5.4.1 Blast-hole and Grade Conîrol Layour

Many mine operations practice 'choke blasting' such îhat the d a c e is the only 'fiee

face'. Blast holes are typically laid out in patterns several 10's of hoIes wide and about

half as many holes deep. The resulting pattern of 100 to 1000 holes will break fiom

fifieen thousand to five million tons of rock dependhg on the blast-hoIe diameter and

bench height.

The OPPR can quickly provide the drill o p t o r or survey crews with the layout of the

blast pattern by outlining the area to be blasted, and providing the burden and spacing

required. A VBA routine base on the work of Nahan (1988) then plots the b1ast-hole

locations in AutoCAD as shown in Figure 5.14 (after Nahan, 1988). The senior mine

enginter, mine general foreman and mine superintendent al1 review the drawing on their

cornputers, following which the bfast pattern is manuatIy edited if required.

Figure 5.14 - Blast Loyout (from Nahan, 1988)

Modern mines have GPS and graphic displays indicating the drill hole location instailed

on the drills as shown in the photographs, Figures S. 15 and 5.16. The blast-hole pattern is

transfared to the display, and the drill operator moves to each hole in tum to drill and

also to sampIe the cuttings for grade control. At other options, the individual blast-

hole CO-ordinates might be transferred electronically to the survey equipment to be laid

out in the field. Aternatively, the blast pattern can be plotted on paper and laid out

using manuai survey techniques.

Figure 5.15 - Blwî Eole Driil Cab sboniag tbe data rommunication radio acrld and the GPS

receiver more distant to the ri@. Sow sy- use gyro's to dctrmiae the m a c h i oricaîatioa, and

otbers hvo CPS uni& From machine orkntatioo and GPS wmy, the blmî bok lac~tioia is found.

Figure 5.16 - Operator display in tk bllathdt drül, Worlring clorkwise tram upper Mt, the drill

bolc number location mwp, th TV mwilor to view ekctrieal cables etc., tbe engiaecring map

showing the pattern oi holes to bt drilkd, rad tbt smdl keypad idarming tbc main cornputer data

base of the slmpk aamikr d tbe drill cutciag s u p k are ~bima.

The blast-holes are typically numbered by the bench elevation king drilied to (the

elevation where the foader will be located to remove the rock), the btast number on the

bench and the hole number within the particular blast. This number (e.g. 4860-33-1 for

bench 4860, blast 33 and hole number 1 ) will be included as a tag in the cuttings sample

and assayed in the on-site assay labocatory. The assay iaboratory will retum several blast-

hole assays fiom al1 working areas of the pit severai times per day, and eacb will be

transferred to the database me. The OPPR wi t h plot the holes and the grades for any

bIast using the mine blast hole database. hterpolaiion of the ordwaste boundary, based

on a smd size grid (e.g Im or 5 fl side) laid over the irregular blast area (Anderson,

1999), can be accomplished ushg kriging, simulation or other meaos outside the scope of

this thesis.

Figure 5.17 shows three exarnples of mixd blasts. In the first, the ore and waste c m

easily be differentiated by the loader operator, and mining on the odwaste interface (the

'çplit') is rnost helpful in vxying the feed rate to the ore cnisher when the crusber may

already be supplied fiom anotfier ore loader. The second example shows how difficult it

would be to differentiate between ore and waste if approached fiom a direction

perpendicuiar to the first @en the movement of rock during the 'throwf of the blast. The

third exarnple shows a 'dog leg' blast where dilution and loss of ore are predictable results

of such poor practice. Exarnples 2 and 3 above can be avoided as the digging direction is

under the controI of the mine planning engineer.

Figure 5.17 - Three Examples of Wied Blasts witb blut direction Co the free face showa. Upper left

is ideal for digging on a 'split' of ore and waste to viry crusber feed rates. Centre rigbt the blut

throw would make the layout of the ordwaste baundary diMcuit to locate, and boetom left is an

example of poor practice leadhg to excessive dilution of ore.

Another problem facing the mine plannet is the coordination of blasts when two or more

benches are being mined. Figure 5.18 shows two benches that are being worked

concurrently. If the upper bench is loaded and fired, material wilI spi11 down ont0 the

lower bench, possibly damaging blasting cords with major safety implications. If the

lower bench is loaded and îïred, it may be a safety bazard to material and people working

on the bench above.

Figure 5.18 - Blasting Adjacent Benches - Bluting material on 5360 wüi spill onto 5310. In the bat

case sceaario some holes wül bave to k re-drüled. In the wont case, explosive bluting cor& wüi be

severed, with severe saltty implications.

It would also be a safety hazard if work or blasting were to continue on 53 10 while 5360

is loaded with explosives. The key to solving this problem is to avoid mining benches

directly above other working benches. Removing fly rock material fiom the Iowa bench

once the upper bench has been blasted is hardly appropnate.

5.4.2 Ensuring Drill Access

One of the problems involved in short tenn mine planning is ensuring that drill access to

the bench above the loader is always possiôle. The bench on which the loader operates

and trucks haul is always open for drill moves and drilling, but o h the drill must travel

up temporary ramps to drill the blast-holes on higher benches, and then return dom. This

is especially important with narrow push-backs where the drill ramp removes even

more of the loaders' scant working space, and when the bench has been almost depleted.

The mine planner must always consider how the drill is to access the bench above, and

Figure 5.19 shows how this might be accomplished in a typicai narrow pushback. The

rarnps in this case are made with a bulldozer pushing already blasted rock. Co-ordination

of shovel digging in the weekIy mine plan is important as over digging removes the

material the bulldozer needs to build a sufficientIy wide and stable rarnp.

2 (eg 49SQeiev) € G) + Pit B -

Pushback 1

Figure 5.19 - Typical Narrow Pushbick made even narrower by the ncrcuary temporary ramp for

drill access. Pit A would probably be complete, so tbere wodd bt a steep drop down some hundred

or so of meters on the right. On the left tkre wodd be r pit w d i some hnadred or so meters hlgh.

5.4.3 Developrnent oJSinRJng Cu&

Sinking cuts enable the next lower bench to be opened for productive h g . The cut

itself is hardly productive. The loaâer operator is most concernecl with maintaining the

gradient of the rarnp and ensuring that the water table will remain below any electrical

connections on the loader. Truck drivm also have problems manoeuvring on the gradient

in the smdl working area. If the cut is dug immediately d e r blasting, ground water wilI

be absorbed into the cracks propagated by the blast. Eventually these cracks will be filled,

and the water table retumed ta the higher elevatioa; sinking should always commence

imediately after cut blasting.

The mine planner must allow for inefficiencies in sinking to the next bench, which must

then be opened up (increased in am) to allow several loaders to wu* without

interference by the others. With push backs it is possible to sink an initial ramp at a

location 0 t h than that of the 'permanent' ramp. Such 'intemal' ramps cm be sunk

quiciûy at the interface of the pushback and its preceding pit (against the outer edge of

the previous pit/push-back), avoid water and aüow hauiage to continue for the most part

unintempted elsewhere on the main producing bench. The 'permanent' ramp cm then be

mined iiphill' at a time convenient to the mine plmer.

The photograph Figure 5.20 shows a situation where a haul road is being moved out to

the edge of the pit. The shovel removing the material mined to move the road impedes

the trucks hauIing fiom the pit bottom. Mer blasting the pattern king drilled, the cable

shovel in the pit bottom will be inaccessible until road access has been restored, and

tmck haulage from this lower shovel will still be impeded as the blast is mineci.

Figure 5.20 - Moviag Ramps - Tbis pbotogrrpb sbcnrs the sbovel diggiag out a rimp m tbat it cm be

moved to the edge of the pit. The sbovel is sloniag t d c oa the main baulagc ro8d M e r planniag

would bave pmcaîed tbis

Figure 5.21 shows a typical scenario of a 'temporary' sinking cut opened at a location

other than the 'permanent ' ramp.

1 / Fit

i initial pit 1 \

l

i i rst ,' j

Figure 5.21- 'Temporary' Sinking Cut. The temporary ramp opens the bench below for minhg and

continues in use until the permanent ramp can be completcd, sometimes by digging uphU

5.4.4 Maintaining Efficient Haul Roud Access

M e n mining the initial pit, it is unlikely that the haul roads fiom the loaders are other

than almost straight lines to the base of the ramp. The haul roads will be specially

constnicted, maintaineci and re-constructed as the large haulage trucks 'pound out' soft

spots. Most of the bench will have a mu& surface with electrical cables and

dewatering lines laid out.

When pushbacks are mined, the planner must avoid laying out blasts that will afféct

active haui roads, or plan alternative routes that are efficient. The OPPR, coupled with

good prediction of the location of ore, can improve hauiage efficiency by placing semi-

permanent bench haul roads coxrectly and planuing mining to avoid disturbing the haui-

road surface with blasting.

Figure 5.22 shows a poorly planned operation, with haul roads moving rock al1 mund the

pit. In this example, mining occmed dong the bench starting in a counter-clockwise

direction fiom the ramp base. The availability and productivity of the loader was

insufficient to start mining of the waste in the south (bottom of the figure). To get to the

pockets of ore quickly, the smdler amount of waste in fiont of ore had to be mined,

forcing mining in a counter clockwise direction Erom the rarnp. When the loader reached

position 'X', the trucks had to haul back clock-wise around the bench to teach the ramp

base because the large pocket of waste remained in the southern end of the bench,

blocking more direct access to the rarnp.

, I ,, * a , , , 17 I . .

1 i

,,,,,,,,,, r r , , , , , , , , I l , , , , , , , ,

Figure 5.22 - A typical situation where the hader is workiag at point 0. Ifthe waste in the south

(bottom of the figure) is not mliied, t ruck make the longer clockwlse haul to the base of the rampe

A better plan wouid have been to initially mine the waste bIock in the south of the bench.

The loader couId then move back and forth between the clockwise and counter clockwise

faces, giving the mine planner more options, and providing the trucks with the shortest

route to the base of the ramp. However, the option of e n g the waste block in the south

end of the bench depends on ttte availability and productivity of the IoadeHs), and on ore

requirements. If the mil1 is lachg ore, waste mining is not always possiile, and the

result will be as shown in Figure 5.22. If the bench heights are reIatively small (i.e. < 5

metres), or in an mtically mineraliseci orebody, the waste pckets could be ramped over

in order to get to the ore pockets. The ûucks will be going up and dowu over the

waste, adding to their haul times but no waste will be mined. The downside to this

alternative is that the waste will have to be mined eventually in order to uncover the

bench below.

5.4.5 Ramp Layouts for Multiple Adjoining Pits

In Figure 5.1, the conceptual design of the pit is shown, and there are alternatives to this

design. The combined pits A and B are based on one output 'shell' from the moving cone

routine making up approximately 10 years mining (200 million tons) with a wall dope

including a spiral rarnp al1 round the pit (45 degrees before ramps, and about 40 a k ) . Pit

A can be fitted into either the north east, north west, south eq t ar south west, leaving a

wide and efficient Pit B adjoining Pit A on only two sides. Pit A was placed in the

southwest quadrant because of the better grades immediately available. Both Pit A and

Pit B rarnps must exit in the south or south east where the primary cmsher is located,

If the Pit A ramp is run counter clockwise, on commencing Pit B, blast spiil will

immediately cause problerns for the Pit A haul road, and the Pit A haul road itself would

be mined out as Pit B completed each bench below the pit crest, disrupting production.

Placed ciockwise, Pit A's rarnp would be unaffecteci by Pit B for some time (about Bench

4860,200 feet below crest) and where it was affêcted, sufficient catchment b m s would

exists to ease safety concerns. The Pit B camp would progress down in a counter

clockwise direction, breaking into Pit A and rnining underneath it in the northwest. Such

a ramp design is ideal.

The situation for Pit C is more difficult. The eventual ramp design was a switchback

on the east wall. The final decision was not made until the 'last minute' when a wail

stability assessment indicated that having a ramp adjoining the walls al1 round the pit

would certainly lead to a haul road Failure at some time in the future. It was ais0 intended

that Pit C would catch up with Pit B, avoiding any blasting spill problems. However, the

mine operated with only thee shovels in the early years, and waste mining productivity

was not adequate.

Pit A's production according to the spread sheet schedule was to last for 5 years. Pre-

stripping began on Pit B (Period 18) in the second year of Pit A's production. Full

production of Pit B lasted 7 years, starting in Period 23.

Pit C will take approximately 6 years to mine, and also requires pre-stripping as the upper

benches contain much more waste than ore. Pit C is of interest because its haul road

approaches From the southeast d o m a counter-clockwise section of the switchback dong

the east wall.

The solution to the problem of Pit C blast spill affecting the operation of Pit B was to

install a long catchrnent b m about 100 feet wide on the 5060 bench. This barn was

wide enough to be quickIy cleaned with a cable shovel at regular (6 month) intavais. The

cost of such cleanup is not hi& and the spill rock would have to be mined in any event.

The loss of a productive shovel for a few weeks to complete the clem up, and the

reduction of the bench area by t 5,000 square feet were not included in the earlier

conceptual plan. Projected to the bottom of Pit B, the area lost represents approximately 3

million tons of ore that wiii be rnined in Pit C some years later than planned. The

photograph Figure 5.23 shows the catchent berm beiig cleared. Such problems are . l

typical in the rnining industry as pits age and mine plamers are forced to adopt

unconventional mining methods.

Figure 5.23 - Catchment Bcnn Ckam~p - Tbt truck king hudcd, the sbmcl cab and m e r d i e

on the wtside edge awvy from mg spill. A shift boss watcbcs tbe spill for my large rocks fnw 1

pickup parked on the berm, and a bigh 'wiadrow' of bmkn rock b pliced oa tbe avtslde edge

prewnt tniclu bîrkiagmr the w r l l

5.5 Applications of the Open Pit Planner (OPPR)

The planner was designed to cover planning for p e r d s including daily, weekly,

monthly, annual and Iife of mine. The following examples broadly fit these respective

increasing time periods.

5.5.1 A Typical Short Term Weekljt Mine Plan

Al1 mines have regular planning meetings chaired by the mine planning engineer. These

may be daily for large operations, bi-weekly for operations with engineering coverage on

a weekend shift system, or weekly for mid- and small sized operations. The mine

planning engineer must determine the drilling locations for the coming week such that

ore and waste rock will become available as required, and be aware of how much broken

rock (ore and waste inventory), is immediately available. Note that the close production

drill cuttings are sampled to provide assurance of the location of ore and waste.

In order to complete a weekly mine pIan (or daily plan for a large operation), the current

state of the pit must be known. For drilling this is a simple matter of determining how

many holes remain to be drilled on al1 the blast patterns aiready approved for drîllîng. in

an emergency, incomplete patterns can be blasted provided the holes have been drilled in

the correct order such that the front holes ofeach blast, or a particular area with a fi=

face, are drilled first.

For loading, the amount of materid remaining to be dug must be known, and subdivided

into ore, waste and stockpile(s) where applicable. This is not a simple matter, as the

immediate mid bench contour has to be mapped, and the volume between this contour

and the contour describing the extents of the blast pattern after firing estimated. From

many such volumes, an inventory of blasted rock must be compiled.

Open pit mine loader face advance surveys, whether by GPS mounted on the loader, or

by total station survey, robotic total station, reflector-less survey or GPS swveys, produce

several series of CO-ordinates described by dots or lines representing the loader advance.

From picking and editing areas of dots or survey lines (in AutoCAD for example), the

latest face advance can be deterrnined, and the volume and tonnage rernaining estimated.

A typicaI electric cable shovel GPS installation is shown in Figures 5.24 and 5.25. in

Figure 5.24, the GPS antenna can be seen on the rear of die shovel upper body. When the

shovel rotates, the GPS transmits the CO-ordinates of the arc of crave1 of the rem end &d

the position of the centre journal can be determined, and fiom that the bucket location.

Figure 5.25 shows a typical graphic display mounted in the cab of the shovel indicating

the shovd location in plan, the grade lines for the materid being dug and the final wall,

etc.

Figure 534 - Shovel GPS - Tbc GPS anteaa is mwatd rt the back d tbc sbmel's upper body oa a

bluk pole. The bucket trip eabk tenabaimg ncebanism and motor rrr in front.

Figure 5.2s - GPS display in the sbovd cab. T k yccllon rretrngk feprrwnting tbe sbmd rad tbe mi

om grade iinea can bt s#n.

Often the planning engineer may have to 'pace off the area remaining if volumeûic

data cannot be cornpiled quickly ahead of the planning meeting. Typicaiiy, 2 long paces

equal about 1.5 meters, and for a 15 meter hench height, 'ara times 40' gïves tonnes.

After making notes and sketches, the engineer cm now input these to the OPPR and

visualise the state of the operation shouId more advanced technologies fail ot be

unavailable.

The OPPR contains the grade block mode1 (usually re-intetpolated on an on-going basis

with 'bench above' blast-hole assay grades, Norrish and Blackwell, 1987), and can be

used to outline the next periods' production by location for al1 benches to be mined.

Figure 5.26 (afier Nahan, 1988) shows a typical operation at the start of planning, and the

material to be mined in the coming production wod. Ore and waste tonnage and ore

grade are listed, as well as the approximate dates of mining.

Figure 5.26 - Mine Plan - Each are8 is designated as ore and waste aod bas tonnages, grades and

approximate mining times attached. (After Naban, 1988)

A typical starting plan for a mine planning meeting is shown in Figure 5.27, and requires

some explanation. The plan represents a period at Brenda mine approximately in mid

1974, with Pit A about a year fiom completion and providing good grade ore and

stockpile materiai tiom benches 4810,4860 and 4910. Pit B is in operation at the 5260

level, and some pre-stripping is in progress in Pit C.

Figure 5.27 - 'Weekly' Miw Man -The batched materiai mprescnu b&n rock (ore rnd waste)

coloured by bencb, and a drill pattern is show0 on 5310 drüling 5260 bench, Otbcr drill pattcrns cm

be secn in tbe b e r pit UTL

In the north (top of the plan) and east, 5260 mid bench (5285) is outlined in green. There

was a hi11 on the east side of the pit, with a valley floor in the east-northesst below the

5260 elevation. Solid lines represent areas where mining has reached the bench Iimits and

has been completed, and dashed Lines represent ümits not yet mined to. The hatched

materiai is broken rock, and the blast patterns show compIeted drill holes as cucles or

crosses for holes remaining to be drilled (5260). The drills and shovels are AutoCAD

solids capable of being rendered (shaded). An old drill ramp has been left in the no&

east of 5260 to be mined later. A new drill ramp has been completed on the north of 5260

for drill and blasting material access.

In the lower pit, 3 adjoining benches are being mined, following the rules for the

maximum number of adjoining benches open at once in a particular pit (typically 3 or 4).

The tonnage already mined on 4910 is double that mined on 4860, which is in tum at

least double that mined on 48 t O. These 'spread sheet niles' were ex plaineci earlier in

Section 5.3. The drill is located on the 4960 elevation, drilting Bench 4910 in an orderly

retreat towards the exit ramp. The planner will ensure that both this and the 5260153 10

drill access rarnps are flagged so that the operations personnel will not mine them.

On 4860, there is substantial broken rock and a new drill pattern is not a priority. The

sinking cut of 48 10 is almost complete and is being widened such that this will be a

major production bench in a few months. Movement of the lower drill and two lower

shovels between the three benches of Pit A is relatively simple, but moves should be as

few as possible to avoid lost production time.

Drilling priority is on 5260 as this pattern must be completed and loaded before the

shovel mines out the material in fiont. This shovel is operated for as many hours as

possible, as Pits A and B should have approximately equal production. Ore is primarily

mined on 48 10 and 4860, stockpile on 4910 and waste on 5260, but stringers of ore and

waste pockets appear Erom time to time making the mine planning more interesting.

Only one drill is operated at any the, and the drüi rate including moves etc., is about

one hole per hour. Of the three shovels, ody two are operated at any tirne, and together

move just less than 60,000 tons per day. Figure 5.28 is a plan view a week &er the

mining scheduled in Figure 5.27. Figure 5.29 shows an isometric view of Figure 5.27

with ore, waste, and blast numbers drawn on the benches.

New Ranp

Figure 5.28 - Mine Plan sbowhg tbc ph strtus oa ampktioa of* w e r b miaing The mu& ie the

southeast corners of 1810 and #6û b u bcca mime& whik 5260 hm bcem puskd to îhe west.

Pit operations for each day are described using a plain text 6ie of the format shown in

Table 5.5 and are converteci to the Gantt chart shown in Figure 5.30. In the chart, daily

2x 12 hour shift production for the drills and shovels is noteci, dong with idle and service

tirnes. The dates and locations of blasts are also shown, aii in the format

bench - elevation/blast-number. The tonnages remaining in each blast are indiateci in

the lower section of Figure 5.30. Each blast has the amount or or&ockpiiwaste

remaining at the end of the shift noted.

Figure 5.29 - Isomaric Vien of Figure 5.2% from the soutb wt dmviag the ore rad wrute availabk

for the week - Each blast is aumbed, aad slwns the locatioa dore, dockpile rad rasle. Tbis pki

cwld be used to prwide the GPS sbovcl cab display or be givcn to the surveyor ia order to strkc aat

the muckpile upon blastiag. Red repmats o m green for stockpile aad bluc for waste, rad corh hm

a difiernt batcb pattern.

tuesday, do not dig drill ranip 5260. do not dig drill ramp 5260

blast , 301 drill, 302 drill, casher , 201 shovel, 202 shovel, 203 shovel,

5260/18, 5260/38, 4910/41, 4910/53. 4060/21E, 4860/33W, 4810/4, ore ,

stockpile , waste .

idle/maintenance. drilling 4910/53.

operating, idle/maintenance,

4860/213 stockpile, 4810/4 ore. 0/0/11s000, 0/0/70000.

0/0/110000, 2aooo/24ooo/47ooo.

32000/46000/0, 60000/55000/57000,

179000/0/0. 15000, O 15000, 15000

O. 15000

4910/53 drilling 5260/39 idle/maintenance

SERVICE 5260/38 waste

4860/21E stockpile SKRVSCE

o/o/115ooo, 0/0/70000. 0/0/110000.

2aooo/~~ooo/~~ooo, 17000/3iaoo/o,

60000/55000/57000, 164000/0/0,

Table 5.5 - Detail of one day in the planning text lue - Pit operations are Iisted and tonnages of

ore/stockpilelwaste at the start and end of the two 12 haur sbifts shown. The maintenance service

schedule and 'idle' times are a b notd for al1 equipment.

Figure 5.30 - Gantt Chart for the week -This outlines schedules for drills and shovels, and indirates

ore, stockpiie and waste remaining at shift end (ore on top, stockpiie centre and wwte bottom) for aU

blasu.

The status of the pit on the following Monday will seldom be as indicated in Figure 5.27

because of breakdowns and the many problems of operating a mine. Note that the shovels

and drills can be AutoCAD rendered in the figure, and can be moved as individual units

to their new locations on the plan each week, or be updated daily if required for

graphic information purposes

5.5.2 A Sample Plan using OPPR

OPPR was used to create a mine plan based loosely on the spreadsheet style schedule

created by Van Dusen et al (1999), in that an engineer running the OPPR would atternpt

to follow the order of mining benches put forward. It must be cleariy understood that the

spreadsheet mine plan has not guaranteed a practical mine plan, o d y that the numbers fit

Iogically, and truck hours have been smoothed. The OPPR m u t now be used to provide

that practical mine schedule many times over for the life of the mine. An exampIe pian

was created that encompassed the mining of three p h , A, B and C using periods of 1

year. The first four years of Pit A can be found in Table 5.6. Also note that unlike the

weekly plan, ore and waste have been estimated and located fiom distant spaced

exploratory drilling. Material close to rnined benches may utilise close production

sarnpling assay data, but for the most part, grades and tonnages could be 5% or more in

error (Rossi et al, 1999).

Table 5.6 - Sample Mine Plan - Fint 4 y e r n a( pit A. EIcb periad reprrscntJ 1 y e u of aiaing B k

cells represent w v t e mining and rcd cclls rrprewnt om mialeg. Tbcrc bm kca two yurs of p m

stripping nad afkr this p d p p i a g , wmte is aot mWd Cirst oa iuy bench.

Table 5.6 is arranged so that each period consists of two columns: a waste column and an

ore column. Wasîe tons mined during a specific period are coloured blue, and ore tons are

coloured red. The mine is designed to produce around 20,000,000 tons per year (IOM

waste, 10M ore at a 111 strip ratio), and each column is totalled at the bottom. Each waste

and ore colurnn (other than the first two years of pre-stripping) mines approxirnately 1OM

tons. Pre stripping is also performed in order to complete mil1 construction, and to

smooth the required truck operating hours (Section 5.3). Pit A was mined using a 0.30%

Cu cut-off, Pit B had a 0.20% cut-off and Pit C had a 0.20% Cu cutsff. These values are

extremely low for a mining operation, and provide a challenge for al1 involved, especiaily

the mine planning engineer. There was no 'live' stockpiling of ore near the msher. The

Pit A matenal between 0.2 and 0.3 was dumped in a special location near the msher for

later mining as ore should this be profitable. This 'stockpile' could be mined for periods

of a few months in times of ore shortages to partially feed the mill.

The planner was run using mining periods of 1 year each. The first task was to outline

each of the benches with polygons, using the 'Draw-Polygon' command. 'Calculate' was

used to get ore and waste tonnages for each of the polygons. Any material below îhe cut-

off grade was classified as waste, although the better grade waste was selectively

dumped. A sample display showing the 52 10 bench outline and reserve calculations c m

be seen in Figure 5.3 1. The reserve output files genwated by OPPR were importeci into

Excel, and organized into spreadsheet form. Period 1 was made of waste tkom benches

54 10-5260. Waste mining on 5260 carries over into Period 2, in order to slowly build

production. in Period 3, ore mining begins. Some ore mining occurs on benches 5360 to

5060 during this period.

Figurc 5.31 - Outlined Polygon - On the leit is an wtlined bench (5210B). On the right is Cdculate's

main window sbowiag the gradcltonnage distribution eoataiaed by the polygoa

This scheduling of ore and waste continues throughout the entirety of Pit A, and the

pushbacks, B and C. Since the periods are each one year long, this represents a long term'

plan. This long-term plan only provides a general outline of what benches shodd be

rnined and when, for ore or waste. It does not provide the detail of when, within each

year, each bench should be mined. This sort of resolution requires monthly or weekly

planning.

in Period 6 (year 6) Pit B starts produchg ore whiie Fit A is d i being minad as the main

ore source. The planner was nin for muai periods up to and including penod 6.

'Remove' was used to mine al1 the polygons previously drawn around the fidi benches

from Periods 1-5 but not 6. As designed in the software, a polygon on say 5410 bench

would not expose al1 the material directiy below on 5360. Arouud the edges of the

polygon, blocks on 5360 would be classified as 'not open to the sky' such that a wall

slope would be incorporated between the two benches.

To show the monthly planning features of the planner, a three month plan was perforrned

on Bench 5260, Pit B, and Bench 4760, Pit A. As mentioned eatlier in this section, the

spreadsheet method of planning does not have enough resolution to show where and

when each shovel in the various pits will mine ore and waste. Brenda had three w o h g

shovels. Each of these shovels must be planned such that overall there is a 1: 1 stripping

ratio. The best-case scenario would have one shovel working in ore, one in waste and the

third in a 5050 split, At a 0.3% copper cut-off for Pit A and Pit B, Pit A will have

approximately a 70:30 ordwaste split. Pit B has an approximate 30:70 ordwaste split.

Therefore, one shovel will work on Pit B, mining ore and waste at 30:70 split, a second

shovel will be in Pit A, mining a 70:30 split. Either the second or third shovel will travel

back and forth kom Pit B to Pit A, probably once every month or so, to make up any

differences,

The first period planned represented just under one month of ore and waste mataial.

Figure 5.32 shows the plan of this first month, with the green polygon representing the

output fiom Shovel 1 on Bench 5260(B). The red polygon represents Shovel2 on Bench

4760(A), and the blue polygon represents Shovel3 on Bench 5260(B).

Figure 5.32 - Month 1 - T h m shovels are miaiag in the above figura Shovel 1 is io a 30:70 om:waste

split on Bench 526O(B), Shovel 2 Y in a 70:3û split on &mch J7WA) and S b 1 3 is making up t k

difierence io requireû production from the aetuil output of Shovels I rad 2.

Table 5.7 shows the polygon outputs ftom the three shovels. The combined stripping

ratio for the three shovels is approximately 1 : 1 .

1 6260 B Green1 1 0.30 210.60 0 s 7n.M 107l.W 27 4760 A Red 1 2 O.= 107#.00 0.H W.60 1618.I Ob 0260 B EIUCI 3 0.30 207.1 0.34 146.30 n m 0.7

1 Totsl: 1677.00 1473.30 3080.30 0.93

Table 5.7 - Polygoa Summay for Mwth 1

For the next month, Shovel2 is moving into higher grade materiai, and at the 0.3% Cu

cut-off exceeds its prescribed 70:30 spiit and attains a stripping ratio of O.3:l. Shovel 1

continues to mine ore and waste on 5260(B), at smpping ratio of 1.9: 1. Shovel3 balances

the other two shovels. Figure 5.33 shows Month 2's plan. The uncovered material on

Bench 52 1 O@) is separareci fiom the remaining material on 5260(B) by the blsck line.

Table 5.8 shows the output of three shovels for the second month of this plan.

Table 5.8 - Polygoe Sammvy for Macith 2

The third rnonth is slightly different than the first two. F i Shovel2 runs out of ore on

4760(A). Therefore, to make up the number of ore tons needed, Shovel 1 drops dom a

bench to Bench 5210(B) to mine the bigh grade ore in the northeast of the bench. Shovel

3 continues to mine mostly waste on the West end of Bench 5260(B). If shovel3

cannot handle the amount of waste needed to satis@ stripping requirernents, Lecause

maintenance problerns for example, Shovel2 can be brought up to 5260(B) to help.

Figure 5.34 shows the monthly plan for benches 5260/5210(B) and 4760(A).

Figure 5.35 - Montb 3 - Sbovei 1 is woncimg oa 521û(B), Sbmcl2 is finisbing 4760(A) and S M 3 is

on 5260m). ïôe b k k liue separam 52lO(B) finai 5260(B).

Shovel 1 is sinking imrnediately into the high grade pocket in the northeast of 52lO(B) in

order to reach the monthiy quota for ore, as 4760(A) will not produce enough ore to

hlfill monthly requirernents. The sinking cut will pmbably be a temporary one starting

on the pit NB interface on 5210. Shovel3 must therdore make up the waste portion of

the stripping ratio. Table 5.9 shows the polygonal outputs of Month 3.

3 5210 B Green 1 1 0.30 1193.10 0.37 217.90 1411.00 0.2 47W A Red1 2 0.N 560.30 0 . 1 41.50 m.80 0.1 5260 B Blue1 3 0.30 51.90 0.31 1411.00 1 ~ 2 9 0 27.1

1 Total: 1005.30 1ô70.40 3475.70 0.93

Table 5.9 - Poiygonal Sununary for Month 3

In the coming months, Shovel3 would move d o m to 52 1 WB) to continue mining waste,

Shovel I would continue mining a 30:70 split on 5210(B), moving d o m to 516qB)

when more ore is needed. Shovel2 would move d o m to and mine 47 IO(A).

5.6 Summary

The OPPR provided a flexible interactive graphic software package suitable for short

range to long-range mine planning. The computer pph ics and software were u s d to

assign polygons to individual areas on benches and report the ore and waste tonnage

corresponding to different cut-offs for those areas. The ore reserves indicated are

comparable to those from the 'spread shed scheduler that the plan broad1y follows, and

overall pit and mine graddtonnage summaries are similar despite the variation in cut-off

allowed by the OPPR. The Open Pit Planner is an invaluable aid in the design,

development, planning, scheduling and operating of open pit mines. The OPPR provides

the mine planning engineer with the ability to visualise potentiai problems, ensure the

availability of sufficient ore and waste, and select blasting areas providing a mix of ore

and waste to a11 loaders. These tasks c m be accomplished quickly with the aid of a

computer, allowing the mine planning engineer to make a substantiai conûiiution to

mining productivity, profitability, efficiency and safw.

Chaptcr 6

Conclusions and Recomrnendations

6.1 Conclusions

The software descnbed in this thesis consists of an AutoCAD based open-pit planning

system, allowing short, medium and long-term plans. The software was developed on a

South American gold bearing orebody, and ported to a Canadian copper bearing orebody,

the Brenda Mine.

From Chapter 2 it is apparent that wmputers wiil increasingly continue to be used in all

aspects of mining and mining engineering. It is important that Universities such as

Queen's train their mining engineering graduates in software techniques in order to at

least write the software specifications, and better, write the software. In order to do this

effectively, source code software examples and working programs must be made

available. Commercial systems have been described, and al1 offer the mining technician

and engineer a means to an objective such as mine planning. The programs are costly to

purchase and maintain, require learning £tom manuals and trial and enor, and updates

must be purchased regularly to obtain ongoing support. If new graduates are not trained

with source code software, what it does and how it works, who will mite the prograrns

for the commercial vendors to sel1 to an ever more sophisticated and technologically

advanced mining industry, and who wiU provide the interface b e e n competing

products.

The choice of AutoCAD as a three-dimensionai graphic design tool was justified in

Chapter 3. AutoCAD continues to improve and remains the most used cornputer aided

design package worldwide. Its 'open architecture' allows the user to conduct any work

easily and effectively, as demonstratecl in the thesis. Visual Basic for Applications was

selected as the customisation language, and was not without its' difficulties. As a new

addition to the A u t o 0 development system, there were obvious shortcomings such as

the inability to directly access the standard commands. No doubt this will be remedied in

future, and execution speed improved. However, the access to the drawing mode1 and

ability to manipulate entities made it an excellent choice for mine planning purposes, and

future researchers have Chapter 3 to guide them through any difficulties.

The fundamental computa planning twls described in Chapter 4 allowed volumes

represented by graphics and databases to be easiIy 'mined' and iinmined', and statistics

regarding tonnage, grade and strip ratio to be generated. These and other tasks are

precisely those that were accomplished 30 years ago with slide rule, calculator, note pad

and mine and geological maps. With the Open Pit PlanneR (OPPR) such tasks can be

completed many times more quickly, with minimal chance of error, and with associated

graphics to explain the mine plan to others.

The practicalities of mine planning, the short-tenn plan and the medium to long tenn plan

are described in order in Chapter 5. Mine planning demands experienced mining

engineers with the ability to interface to the pmcessing plant that they must supply

regularly with ore, and the maintenance personnel who ensure the wntinued reliable

operation of mine equipment. Open pit mining is foremost a low cost, high volume,

materials transportation business. Poorly planned mines limit productivity, leading to

high cost, and several examples of poor practice are presented as a guide to others

researching the field of mine planning.

The methods for daily to weekly planning d e s c r i i allow mining operations to proceed

while satisfjing the requirement for continued ore production and timely waste removal.

The needs of the mil1 m h e r and processing plant, and of pit equipment maintenance are

adequately addressed in the plan. Finally in Chapter 5, the OPPR is used to generate the

first few years of a long-term plan (by year), which is then stopped to generate a medium

term plan for several months.

The most important concIusion fiom the work was that only by using software such as - the OPPR to interactively study the extraction sequence can any open pit mining

operation guarantee that production gods and profitability will be wntinuously met. This

is especially tme when ore does not materidise as expected, when equipment is

unreliable or insufficient for the task, and when processing plants have difficulties such

that the mine planning must be conducted to avoid mixing various types of ore, e.g.

supagene vernis hypogene gold ores.

The work also identifiai shortwmings in the predictability of metal pkes and opetating

costs, and in the so called 'optimisation' of such as mineral inventories, pit limits, cut-off

grades and spread sheet planners. These techniques may be optimal in themselves, but are

reaily only a guide to the mine planner who works with information h m many sources

in ensuring goals are met. The problems in summary are,

grades and tons predicted by the mineral inventory do not materialise

pit limits do not reflect this error

r ore is not located such that the optimal cut off grade can be maintained at al1 times

0 equipment cannot be rnovd continually to obtain the required production fiom

diffwent pits when oniy part of a loader's production is required in the spread sheet

schedule

metal prices do not meet expectations, or costs exceed predictions

Only a skilled mine planner equipped with suitable computer graphic tools can adjust the

mine plan to overcome the problems which are faced by al1 mines at some tirne in their

lives.

From the design, programming and application of the developed software, the followiag

conclusions can be cirawu:

VBA is an excellent addition to AutoCAD's customization laquages, allowing

the programmer fidl access to the drawing mode1 and entity manipulation.

The Open Pit Planner, a software-based planner built for AutoCAD, wiii provide

most of the bnctionality of planning modules that exkt for today's integrated

mine software packages.

The planner can perfom short, medium and long-term plans, applying cut-off

grades to tonnage data. Cut-off grades may be determined by lookiag at the

stripping ratio, metal price, operating costs and oîher variables. Multiple cut-off

cornparisons allow for different scenarios to be developed in order to minimize

risk and cash losses h m equipment failures or changing metal prices.

AutoCAD is relatively inexpensive to purchase and maintain, and will run on N d

to low range personal cornputer systems. Alternative integrated mining packages

are expensive, with a high cost of ownership through support charges. They also

require high-end personal computers or UNI. based machines in order to perform

adequately. AutoCAD is easy to use and most enginm have experience with it,

resulting in reduced training delays and costs.

VBA is not searnlessly integrated with AutoCAD Like other customisation

languages such as LISP. VBA is excluded h m using the AutoCAD comrnand

'pipeline', making simple drawing tasks very wmplex. VBA is an extemally

interpreted tanguage. Unlike LISP, VBA is not interpreted by AutoCAD, but is

interpreted by a Microsoft VB interpreter. VBA files cannot be compiled. This

leads to sIower performance in some areas. With large amounts of data, such as

the Breda orebody, there was some minor slowing in execution tirnes.

The user can easily customise the Open Pit Plmer. The source code is not

hidden, allowing mining engin- to m d i the program to suit their needs.

VBA is an intuitive language, and any person (be they engineer or not) with rnid-

range or higher programming skills can easily modiQ the code. The code was

changed for application to differe~lt orebodies within a matter of a few hours.

Cornputer systerns and software will continue to improve, with larger storage capabilities

and lower prices. AutoCAD 2000i, the latest vasion, has been released and future

venions will be more timely in opetation, allowing for tighter integration and better

support with customisation languages such as VBA. This added power will allow the

mine engineer on-site to write significantiy more powerfùl software rivalling proprietary

integrated mining software.

6.2 Recommendations for Further Work

The author accepts that improvements can and will be made to the OPPR. The process of

allowing the researcher in University or the engineer on-site to prepare a planning

program for a particular property, with the ability to adapt the code as required to the

almost daily changing of parameters that occm in the mining industry has started.

Future development of mine planning software for AutoCAD may requise fixrther related

research as folIows:

If newer customisation languages appear for AutoCAD, these must be explored

for theu usefulness. VBA is a significant improvement an LISP and VisualLISP.

Future tanguages may be faster and more p o w d than VBA fw AutoCAD, and

allow quicker and easier mine planning with AutoCAD.

The current software OPPR m u t be upgraded and enbanced to automatically

configure itself to whatwer orebody it is applied. The software must be mdified

to aI1ow even more mining periods or numbers of polygons per periwl. Code must

be made more efficient in order to increase program execution speed.

intelligent routines must be developed that automatically check for conflic&

between blasting and mining on various benches, and between haui ramps of

different pits.

Blast design and mine design (pushback and ramp location and optimisation)

components must be added.

The development of the Open Pit Planner in standdone Visual Basic wouid be a step

backward in that VB has merely replaceci Fortran as the compiler. Although providing

needed execution speed (through program compilation) now, the effort would be wasted

when AutoCAD improves their VBA praduct, Prognrm and foxm design would be more

robust in VB because of the additional controls available in the full version. Future

versions of stand-aione Visual Basic rnay be abie to use ActiveX conüols to import

AutoCAD drawings diredy into a Visual Basic program, so VB nms the plmer not

AutoCAD. These drawings would be displayed within VI3 generated forms, and could be

manipulated without even opening AutoCAD itself'.

6.3 A Final Footnote

In the fast changing world of computers, operating systems and software, the decision to

use AutoCAD and VBA in the Windows 2000 environment will probably be seen as the

correct one in the hture. The OPPR uses commonly available CADD and Basic s o h a r e

with a large user base, and the author hopes that other researchers, mining engineers and

mining students will experiment with, rnodib and add to the OPPR.

Chapter 7

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List of Programs & Sample F i

A.l List of Program Files

The following table lists al1 programs written for OPPR and it's support programs. It

contains the number of code lines, cornment lines and blank lines.

Splash Sub-pmgmm 5 O O a-ChangePaametenSub-prognm 226 22 i l

b-OrawPolygon Sub-pmgnm 324 32 16 c-LoadPolygon Sub-progrun 671 67 33

d-Calculate Sub-pmgnm 333 33 16 e-Remove Sub-pmgnm f88 18 9 f Unmine Sub-pnopnm 7?S TI 38 KSMERG Program 52 5 2

M W Program 501 50 25

A.2 Sample Polygon Fiie (4810lC1AugOOl.pol)

A 3 Sample Resewe F i e (reserve MlOlBl JANOLdat)

C u t - Thousand tons ore

1701.5 1701.5 1701.5 1701.5 1691 .1 1618.5 1473.3 1245. O 1110 .1 850.8 684.8 518.8 373.5 269.8 186.8 124.5 93.4 62.3 41.5

G r a d e O r e Au g/t

0 .48 0.48 0.48 O .48 0.48 0.49 0 . 5 1 0.55 0.57 0 . 6 1 O .65 0.69 0.73 0 .78 0.82 0.87 0 . 9 1 0.95 0.98

Thousand tons waste

00.0 00.0 00.0 00.0 10.4 83 . O 228.3 456.5 591.4 850.8 1016.8 1182.8 1328. O 1431.8 1514.8 1577.0 1 6 0 8 . 1 1639.3 1660. O

A.4 Sample Micromap File (Map4960.dat)