Open Pit Planning and DesignOpen Pit Planning and Design

The Standard Approach for Open PitThe Standard Approach for Open Pit©2007 revised 2010 Dr. B. C. Paul©2007 revised 2010 Dr. B. C. Paul

Note – This presentation includes screenshots from the MineSight® computer program Note – This presentation includes screenshots from the MineSight® computer program developed by Mintec. The views and procedures identified in this presentation are developed by Mintec. The views and procedures identified in this presentation are

considered by the author to be common knowledge to those in the trade and many of the considered by the author to be common knowledge to those in the trade and many of the ideas expressed here can be found in numerous books and journals.ideas expressed here can be found in numerous books and journals.

The Ajo Open Pit in ArizonaThe Ajo Open Pit in Arizona

They mined around the barren core

Lacks Clear Steps and Has A Lot of Lacks Clear Steps and Has A Lot of Interaction – Computers Almost a Interaction – Computers Almost a

NecessityNecessity In general need to know you In general need to know you

have a large ore reserve have a large ore reserve close enough to the surface close enough to the surface to be open pit minedto be open pit mined

Generally comes from Generally comes from geologic datageologic data– Open pit designs normally Open pit designs normally

represent ore reserves and represent ore reserves and geology as a block modelgeology as a block model Slice and dice the ore reserve Slice and dice the ore reserve

up into small blocks that sit up into small blocks that sit end to end and on top of each end to end and on top of each otherother

10s of Millions of blocks 10s of Millions of blocks commoncommon

The Program We Will UseThe Program We Will Use

MineSight® is a suite of mining tuned computer MineSight® is a suite of mining tuned computer programsprograms– Heart is a 3D CAD graphics program called MineSight®Heart is a 3D CAD graphics program called MineSight®– Has a wide array of mining calculations programs that Has a wide array of mining calculations programs that

link production planning to the graphics functions in the link production planning to the graphics functions in the 3D CAD program3D CAD program

MineSight® development started with first computer MineSight® development started with first computer routines in the 1970’s and list has grown sinceroutines in the 1970’s and list has grown since– Collection includes everything from old fortran routines Collection includes everything from old fortran routines

to modern python program language routinesto modern python program language routines

MineSight’s ® Visually Linked MineSight’s ® Visually Linked Calculation Routines Calculation Routines

MineSight ® CompassMineSight ® Compass– A windows like user interface built over a bunch A windows like user interface built over a bunch

of old Dos, Fortran and Unix Programsof old Dos, Fortran and Unix Programs– Collection of over 400 routinesCollection of over 400 routines– Have the feel of old mainframe batch programsHave the feel of old mainframe batch programs

That’s because they are old mainframe routines and That’s because they are old mainframe routines and subroutines with a modern windows like graphical subroutines with a modern windows like graphical interface to feed theminterface to feed them

– Looks new but has you do some things to set up Looks new but has you do some things to set up runs that are like old mainframe batch routinesruns that are like old mainframe batch routines

New Kids on the BlockNew Kids on the Block

Built a Suite of New Programs that run in Python Built a Suite of New Programs that run in Python visual languagevisual language– Economic PlannerEconomic Planner

State of the Art Open Pit Metal Mining Optimization and State of the Art Open Pit Metal Mining Optimization and integrated togetherintegrated together

– Activities PlannerActivities Planner Microsoft Projects Gant Charts set up for MiningMicrosoft Projects Gant Charts set up for Mining

– Data AnalystData Analyst Ore Reserves Statistics and GeostatisticsOre Reserves Statistics and Geostatistics

– Interactive PlannerInteractive Planner Link between databases and 3D graphics for planningLink between databases and 3D graphics for planning

– Strategic PlannerStrategic Planner– Other procedures constantly being preparedOther procedures constantly being prepared

Editorial CommentaryEditorial Commentary Lack of ConsistencyLack of Consistency

– A 40 year collection and operating systems have run in fundamentally A 40 year collection and operating systems have run in fundamentally different ways over the yearsdifferent ways over the years

– Made to look windows like but can’t always hide the architecture Made to look windows like but can’t always hide the architecture underneathunderneath

Has bugs in itHas bugs in it– Most bugs are triggered by assuming people will input in a certain way – Most bugs are triggered by assuming people will input in a certain way –

and you don’tand you don’t– Mining has lots of local terms in it so wording can encourage you to do Mining has lots of local terms in it so wording can encourage you to do

unexpected thingsunexpected things– Most bugs are operator “error” triggered but it is rather unforgivingMost bugs are operator “error” triggered but it is rather unforgiving– Very computer and graphically intensiveVery computer and graphically intensive

Pushes hardware and designs to the limit and a lot of hardware and system Pushes hardware and designs to the limit and a lot of hardware and system components misbehave when they are at their limitcomponents misbehave when they are at their limit

Its wonderful to have so much integrated power and routines all in one Its wonderful to have so much integrated power and routines all in one semi-coherent packagesemi-coherent package

Lets Start this Puppy Up!Lets Start this Puppy Up!

If Used Often MineSight ® has an icon that says“MS3D” (ie MineSight ® 3 D)

Can Also Do A Menu Fishing Can Also Do A Menu Fishing StartStart

#1 -Click Start #2- Pick All Programs

#3- Find MineSight®And Highlight it untilA side menu pops out

#4- Click on theMS3D icon(note you do haveIcons for some ofThe other routinesI mentioned).

Look for the Desktop Icon for MS3D Look for the Desktop Icon for MS3D and Click on Itand Click on It

Ok – I Don’t Have One Cause I Don’t StartThat way – but some people do.

Programs “Splash Screen”Programs “Splash Screen”Mines or designsAre kept asProjects –It can defaultStart where theProgram lives

Or be sent toWhere you storeA project

If you have aProject or designAlready you canHave it loadedAnd ready to go.

Operating the Starting PromptOperating the Starting PromptIf you pull down theMenu it will showYou were up to theLast 10 projectsWorked on wereStored.

You can alsoTrigger a WindowsExplorer stylePick using aBrowse function.

It has typical Windows Options for Oking or Canceling

The strange lookingX symbol isMineSight’s ®Delete command.

MineSight Opens ® (sometimes it MineSight Opens ® (sometimes it will prompt you to do something first)will prompt you to do something first)

Looks a little likeAn Autocad forWindows

It has a 3D displayArea similar toAutocad.

Data Manager isA two tieredWindowsExploring

Down below itHas a messageAnd info window

Two Tiered Windows ExploringTwo Tiered Windows Exploring

Has two LevelsTop Level Shows YouThe Folders

Bottom Level ShowsYou the Files in a folder

(as a 3D geometry programHas a variety of differentFile types that supportThe program logic – noYou probably won’t understand them on sight).

The X BoxThe X Box

The little redX box closesThings.

You can closeThe “WindowsExplorer” likeData Manager

You can close a 3DVisualizationwindow

You can close theWhole program

Driving OptionsDriving OptionsUses the familiarDrop down menusOf a windowsProgram(some options doAppear on more thanOne drop down)

Also has a hugeCollection of icons(They are short-cutsTo the mostPopular functions.You also will onlyLearn what theseFunny symbols standFor by experience)

General Quirks and ObservationsGeneral Quirks and Observations MineSight ® does not have an “escape” key functionMineSight ® does not have an “escape” key function

– You right click to finish a function which gets you out of it (but might also You right click to finish a function which gets you out of it (but might also finish a goof)finish a goof)

MineSight® has a more enforced save structureMineSight® has a more enforced save structure– Some drawing functions will not let you move on until you save you last Some drawing functions will not let you move on until you save you last

“group” of edits“group” of edits It is not consistent in when this happens but if the program stops taking It is not consistent in when this happens but if the program stops taking

orders a right click to finish what ever it thinks your doing and then a save is orders a right click to finish what ever it thinks your doing and then a save is a good guess.a good guess.

MineSight® has limited “Undo” functionalityMineSight® has limited “Undo” functionality– You can save the last set of edits and then go back and undo it.You can save the last set of edits and then go back and undo it.– It does not keep a step by step undo list that lets you go back and undo It does not keep a step by step undo list that lets you go back and undo

the last 20 things one at a timethe last 20 things one at a time– Undo function often requires you to save before it becomes availableUndo function often requires you to save before it becomes available– If you really goof it keeps back-up copies of everything and you can go If you really goof it keeps back-up copies of everything and you can go

in and fetch a back up copy of what you screwed up.in and fetch a back up copy of what you screwed up.

Some Rigidity in Menu and Icon Some Rigidity in Menu and Icon StructureStructure

Microsoft Office allows you to pick groups of Microsoft Office allows you to pick groups of icons, call them toolbars and “dock” your icons, call them toolbars and “dock” your favorites in a certain positionfavorites in a certain position– Vulcan has created some tool bar dockabilityVulcan has created some tool bar dockability– MineSight ® has notMineSight ® has not

MineSight ® does allow you to right click MineSight ® does allow you to right click and pull up an on the spot menu of recently and pull up an on the spot menu of recently used and custom chosen functionsused and custom chosen functions

So Why Should I Learn So Why Should I Learn MineSight®MineSight®

CAD like mine design packages are rapidly CAD like mine design packages are rapidly becoming an industry standard – knowing one becoming an industry standard – knowing one increases your marketabilityincreases your marketability

There is enough similarity in packages that There is enough similarity in packages that knowing one will allow you to learn any other with knowing one will allow you to learn any other with greater ease (in case your employer didn’t make greater ease (in case your employer didn’t make the same choice for basic package as we did – or the same choice for basic package as we did – or if your employer changes his/her mind later).if your employer changes his/her mind later).

We are using it in this class and you don’t want to We are using it in this class and you don’t want to even think about life without it.even think about life without it.

Using the Data ManagerUsing the Data Manager

Upper LevelDetermines whichFiles are open

Lower LevelControls individualobjects

To Open An ObjectTo Open An Object

Highlight the objectAnd then right clickWith your mouseTo bring up amenu

Check the Menu for the Open (or Check the Menu for the Open (or Close) optionClose) option

Most Likely You Will Start With Most Likely You Will Start With Some Surface InformationSome Surface Information

(In Our Case It Will Already be Pre-Entered)(In Our Case It Will Already be Pre-Entered)

Our MineSight® operator read in or digitized surface topography and then had theComputer create a surface that fit the data

You Can Play with the Surface ViewYou Can Play with the Surface View

Push and hold the left and right keysOn your mouse as you move it toRotate your object in 3D (so you canLook at it from different directions).

You Can Move Your Surface Up and You Can Move Your Surface Up and Down (Pan Around)Down (Pan Around)

Hold the right click button and theCenter button down (often the centerButton is a roller) and move the mouseAround.

You Can Zoom In and Zoom OutYou Can Zoom In and Zoom Out

Hold the left click button and theCenter button down (often the centerButton is a roller) and move the mouse around.

Now We Have A Tool Lets Consider Now We Have A Tool Lets Consider that Block Modelthat Block Model

Start by specifying block dimensionsStart by specifying block dimensions Look at drill and sampling data for how continuous Look at drill and sampling data for how continuous

the mineralization isthe mineralization is– Use computer routines to estimate the ore grade of the Use computer routines to estimate the ore grade of the

blocks using samplesblocks using samples– One of the most popular is Kriging (also polygonal and One of the most popular is Kriging (also polygonal and

IDS)IDS) Not going to study how interpolation is done in this class. (You’ll Not going to study how interpolation is done in this class. (You’ll

be given a block model to work with)be given a block model to work with) In the field your geologists may way give you your “Block In the field your geologists may way give you your “Block

Model”Model”

Your Assignment #5Your Assignment #5

Copy a Prepared Starter FileCopy a Prepared Starter File Start MineSightStart MineSight Bring up the Surface and Rotate and Bring up the Surface and Rotate and

ManeuverManeuver Bring up your block model and examine it.Bring up your block model and examine it.

– Are other do this tasksAre other do this tasks

Determine the Minable Ore ReserveDetermine the Minable Ore Reserve

Assume economics for material removalAssume economics for material removal Look at geology for how steep the pit slopes can Look at geology for how steep the pit slopes can

stand without sliding instand without sliding in Have the computer analyze the largest set of Have the computer analyze the largest set of

blocks that can be removed without taking stuff blocks that can be removed without taking stuff that looses moneythat looses money– This set measures the size of the pit that can ultimately This set measures the size of the pit that can ultimately

be mined (called the Ultimate Pit)be mined (called the Ultimate Pit) Too complex to visualizeToo complex to visualize

– Done with either a Floating Cone Miner or Learch-Done with either a Floating Cone Miner or Learch-Grossman computer routine Grossman computer routine (Easily Available in (Easily Available in MineSight)MineSight)

Computer Views of PitsComputer Views of Pits

SequencingSequencing

Start with an Unmined Surface and end up Start with an Unmined Surface and end up with an ultimate pitwith an ultimate pit

Need to figure out how to get thereNeed to figure out how to get there– One easy approach is to just mine from the top One easy approach is to just mine from the top

down in layersdown in layers– But that is often not the way it is doneBut that is often not the way it is done

The Time Value of MoneyThe Time Value of Money

A Review for those with Engineering EconA Review for those with Engineering Econ– Some new thoughts for othersSome new thoughts for others– Would you rather get $100 now or $100 five Would you rather get $100 now or $100 five

years from nowyears from now Most would pick nowMost would pick now

– One reason – if you put money in CD at 3% One reason – if you put money in CD at 3% interest in 5 years you would have $116interest in 5 years you would have $116 You’d only need $86 now to earn to $100 in five You’d only need $86 now to earn to $100 in five

years so how can $100 not delivered for five years be years so how can $100 not delivered for five years be worth more than $86?worth more than $86?

Handling the Time Value of MoneyHandling the Time Value of Money

Money can be multiplied by a discount factor to Money can be multiplied by a discount factor to adjust to how much right now money it is equal to.adjust to how much right now money it is equal to.

Mining commonly looks for investments to earn Mining commonly looks for investments to earn 15%15%– If you get $100 now its $100If you get $100 now its $100– If you get $100 in 1 year its like $87If you get $100 in 1 year its like $87– If you get $100 in 5 years its like $50If you get $100 in 5 years its like $50– If you get $100 in 10 years its like $25If you get $100 in 10 years its like $25– You see the pattern – the longer the money takes to get You see the pattern – the longer the money takes to get

here the less it is worthhere the less it is worth

What Does the Time Value of Money What Does the Time Value of Money Do to Mine Plans?Do to Mine Plans?

0 1 2 3

4 5 6 7 8 9 10 11 12 13

$100,000,000

$100,000,000Just adding up money gives $600,000,000 Total

But not all the money got here at the same time – if we apply discount factors andThen add we get $1,670,000 – almost even money (at 15% interest)

(A Total After Multiplying by Discount Factors is called a Net Present Value –The more a project is worth the hotter the item!)

Same Money But Some is Moved Same Money But Some is Moved Forward in TimeForward in Time

0 1 2 3

4 5 6 7 8 9 10 11 12 13

$100,000,000

$150,000,000

$50,000,000

Same money but I collect more money sooner and less later

NPV is now $57,100,000 instead of $1,670,000

Get more of your money faster = Better NPV!

Put-Off ExpensesPut-Off Expenses

0 1 2 3

4 5 6 7 8 9 10 11 12 13

$150,000,000

$0 $50,000,000

$100,000,000

Same Money Again but now the NPV is $197,374,000

Getting money early and putting off expenses makes project values improveA WHOLE LOT!

How Can I Make That Happen in the How Can I Make That Happen in the FieldField

Suppose I mine my best and most valuable ore Suppose I mine my best and most valuable ore first?first?

Suppose I delay spending money stripping waste Suppose I delay spending money stripping waste materialmaterial– If I mine from the top down I will usually mine mostly If I mine from the top down I will usually mine mostly

waste at firstwaste at first– And wait a long time to get down to the best oreAnd wait a long time to get down to the best ore

What I would like to do for a sequence is to ask What I would like to do for a sequence is to ask the computer to find me the best ore with the least the computer to find me the best ore with the least stripping firststripping first– I will get the computer to identify a series of nested pits I will get the computer to identify a series of nested pits

that have the most value and use that as my draft that have the most value and use that as my draft sequencesequence

Developing a Practical LayoutDeveloping a Practical Layout

With a series of nested pit shells as a guide design a set of With a series of nested pit shells as a guide design a set of pits that follows the guides but has benches, and roads pits that follows the guides but has benches, and roads required for practical mining.required for practical mining.– MineSight is a 3D Cad program so I can draw in my roads and MineSight is a 3D Cad program so I can draw in my roads and

benchesbenches Look at Further boosting earnings by running artificially Look at Further boosting earnings by running artificially

high Cut-Off grades at first and sizing mine productionhigh Cut-Off grades at first and sizing mine production– Can be done with VALP in MineSightCan be done with VALP in MineSight

Size up your equipment fleets and haulage timesSize up your equipment fleets and haulage times– MineSights haulage program is still weak (we will use FPC)MineSights haulage program is still weak (we will use FPC)

Develop detailed long term schedules of what will be mined Develop detailed long term schedules of what will be mined from wherefrom where– MineSight Strategic Planner can do thisMineSight Strategic Planner can do this– In for major refinement in March or AprilIn for major refinement in March or April

Collectively these steps are called long term mine planningCollectively these steps are called long term mine planning