Transcript Open Pit Planning and Design - Supplemental Teaching Resources

Open Pit Planning and Design
The Standard Approach for Open Pit
©2007 revised 2010 Dr. B. C. Paul
Note – This presentation includes screenshots from the MineSight® computer program
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
ideas expressed here can be found in numerous books and journals.
The Ajo Open Pit in Arizona
They mined around the
barren core
Lacks Clear Steps and Has A Lot of
Interaction – Computers Almost a
Necessity
 In general need to know you
have a large ore reserve
close enough to the surface
to be open pit mined
 Generally comes from
geologic data
– Open pit designs normally
represent ore reserves and
geology as a block model
 Slice and dice the ore reserve
up into small blocks that sit
end to end and on top of each
other
 10s of Millions of blocks
common
The Program We Will Use
 MineSight® is a suite of mining tuned computer
programs
– Heart is a 3D CAD graphics program called
MineSight®
– Has a wide array of mining calculations programs that
link production planning to the graphics functions in
the 3D CAD program
 MineSight® development started with first
computer routines in the 1970’s and list has grown
since
– Collection includes everything from old fortran
routines to modern python program language routines
MineSight’s ® Visually Linked
Calculation Routines
 MineSight ® Compass
– A windows like user interface built over a bunch
of old Dos, Fortran and Unix Programs
– Collection of over 400 routines
– Have the feel of old mainframe batch programs
 That’s because they are old mainframe routines and
subroutines with a modern windows like graphical
interface to feed them
– Looks new but has you do some things to set
up runs that are like old mainframe batch
routines
New Kids on the Block
 Built a Suite of New Programs that run in Python
visual language
– Economic Planner
 State of the Art Open Pit Metal Mining Optimization and
integrated together
– Activities Planner
 Microsoft Projects Gant Charts set up for Mining
– Data Analyst
 Ore Reserves Statistics and Geostatistics
– Interactive Planner
 Link between databases and 3D graphics for planning
– Strategic Planner
– Other procedures constantly being prepared
Editorial Commentary
 Lack of Consistency
– A 40 year collection and operating systems have run in fundamentally
different ways over the years
– Made to look windows like but can’t always hide the architecture
underneath
 Has bugs in it
– Most bugs are triggered by assuming people will input in a certain way –
and you don’t
– Mining has lots of local terms in it so wording can encourage you to do
unexpected things
– Most bugs are operator “error” triggered but it is rather unforgiving
– Very computer and graphically intensive
 Pushes hardware and designs to the limit and a lot of hardware and system
components misbehave when they are at their limit
 Its wonderful to have so much integrated power and routines all in one
semi-coherent package
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
Start
#3- Find MineSight®
And Highlight it until
A side menu pops out
#4- Click on the
MS3D icon
(note you do have
Icons for some of
The other routines
I mentioned).
#1 -Click Start
#2- Pick All Programs
Look for the Desktop Icon for MS3D
and Click on It
Ok – I Don’t Have One Cause I Don’t Start
That way – but some people do.
Programs “Splash Screen”
Mines or designs
Are kept as
Projects –
It can default
Start where the
Program lives
Or be sent to
Where you store
A project
If you have a
Project or design
Already you can
Have it loaded
And ready to go.
Operating the Starting Prompt
If you pull down the
Menu it will show
You were up to the
Last 10 projects
Worked on were
Stored.
You can also
Trigger a Windows
Explorer style
Pick using a
Browse function.
The strange looking
X symbol is
MineSight’s ®
Delete command.
It has typical Windows Options for Oking or Canceling
MineSight Opens ® (sometimes it
will prompt you to do something first)
Looks a little like
An Autocad for
Windows
It has a 3D display
Area similar to
Autocad.
Data Manager is
A two tiered
Windows
Exploring
Down below it
Has a message
And info window
Two Tiered Windows Exploring
Has two Levels
Top Level Shows You
The Folders
Bottom Level Shows
You the Files in a folder
(as a 3D geometry program
Has a variety of different
File types that support
The program logic – no
You probably won’t understand them on sight).
The X Box
You can close the
Whole program
The little red
X box closes
Things.
You can close
The “Windows
Explorer” like
Data Manager
You can close a 3D
Visualization
window
Driving Options
Uses the familiar
Drop down menus
Of a windows
Program
(some options do
Appear on more than
One drop down)
Also has a huge
Collection of icons
(They are short-cuts
To the most
Popular functions.
You also will only
Learn what these
Funny symbols stand
For by experience)
General Quirks and Observations
 MineSight ® does not have an “escape” key function
– You right click to finish a function which gets you out of it (but might also
finish a goof)
 MineSight® has a more enforced save structure
– Some drawing functions will not let you move on until you save you last
“group” of edits
 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
a good guess.
 MineSight® has limited “Undo” functionality
– 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
the last 20 things one at a time
– Undo 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
in and fetch a back up copy of what you screwed up.
Some Rigidity in Menu and Icon
Structure
 Microsoft Office allows you to pick groups of
icons, call them toolbars and “dock” your
favorites in a certain position
– Vulcan has created some tool bar dockability
– MineSight ® has not
 MineSight ® does allow you to right click
and pull up an on the spot menu of recently
used and custom chosen functions
So Why Should I Learn
MineSight®
 CAD like mine design packages are rapidly
becoming an industry standard – knowing one
increases your marketability
 There is enough similarity in packages that
knowing one will allow you to learn any other with
greater ease (in case your employer didn’t make
the same choice for basic package as we did – or
if your employer changes his/her mind later).
 We are using it in this class and you don’t want to
even think about life without it.
Using the Data Manager
Upper Level
Determines which
Files are open
Lower Level
Controls individual
objects
To Open An Object
Highlight the object
And then right click
With your mouse
To bring up a
menu
Check the Menu for the Open (or
Close) option
Most Likely You Will Start With
Some Surface Information
(In Our Case It Will Already be Pre-Entered)
Our MineSight® operator read in or digitized surface topography and then had the
Computer create a surface that fit the data
You Can Play with the Surface View
Push and hold the left and right keys
On your mouse as you move it to
Rotate your object in 3D (so you can
Look at it from different directions).
You Can Move Your Surface Up and
Down (Pan Around)
Hold the right click button and the
Center button down (often the center
Button is a roller) and move the mouse
Around.
You Can Zoom In and Zoom Out
Hold the left click button and the
Center button down (often the center
Button is a roller) and move the
mouse around.
Now We Have A Tool Lets Consider
that Block Model
 Start by specifying block dimensions
 Look at drill and sampling data for how continuous
the mineralization is
– Use computer routines to estimate the ore grade of the
blocks using samples
– One of the most popular is Kriging (also polygonal and
IDS)
 Not going to study how interpolation is done in this class. (You’ll
be given a block model to work with)
 In the field your geologists may way give you your “Block
Model”
Your Assignment #5
 Copy a Prepared Starter File
 Start MineSight
 Bring up the Surface and Rotate and
Maneuver
 Bring up your block model and examine it.
– Are other do this tasks
Determine the Minable Ore Reserve
 Assume economics for material removal
 Look at geology for how steep the pit slopes can
stand without sliding in
 Have the computer analyze the largest set of
blocks that can be removed without taking stuff
that looses money
– This set measures the size of the pit that can ultimately
be mined (called the Ultimate Pit)
 Too complex to visualize
– Done with either a Floating Cone Miner or LearchGrossman computer routine (Easily Available in
MineSight)
Computer Views of Pits
Sequencing
 Start with an Unmined Surface and end up
with an ultimate pit
 Need to figure out how to get there
– One easy approach is to just mine from the top
down in layers
– But that is often not the way it is done
The Time Value of Money
 A Review for those with Engineering Econ
– Some new thoughts for others
– Would you rather get $100 now or $100 five
years from now
 Most would pick now
– One reason – if you put money in CD at 3%
interest in 5 years you would have $116
 You’d only need $86 now to earn to $100 in five
years so how can $100 not delivered for five years
be worth more than $86?
Handling the Time Value of Money
 Money can be multiplied by a discount factor to
adjust to how much right now money it is equal to.
 Mining commonly looks for investments to earn
15%
–
–
–
–
–
If you get $100 now its $100
If you get $100 in 1 year its like $87
If you get $100 in 5 years its like $50
If you get $100 in 10 years its like $25
You see the pattern – the longer the money takes to get
here the less it is worth
What Does the Time Value of Money
Do to Mine Plans?
$100,000,000
0
1
2
3
4
5
6
7
8
9
10
11 12
13
$100,000,000
Just adding up money gives $600,000,000 Total
But not all the money got here at the same time – if we apply discount factors and
Then 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
Forward in Time
$150,000,000
$50,000,000
0
1
2
3
4
5
6
7
8
9
10
11 12
13
$100,000,000
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 Expenses
$150,000,000
$0
0
1
2
$50,000,000
3
4
5
6
7
8
9
10
11 12
13
$100,000,000
Same Money Again but now the NPV is $197,374,000
Getting money early and putting off expenses makes project values improve
A WHOLE LOT!
How Can I Make That Happen in the
Field
 Suppose I mine my best and most valuable ore
first?
 Suppose I delay spending money stripping waste
material
– If I mine from the top down I will usually mine mostly
waste at first
– And wait a long time to get down to the best ore
 What I would like to do for a sequence is to ask
the computer to find me the best ore with the least
stripping first
– I will get the computer to identify a series of nested pits
that have the most value and use that as my draft
sequence
Developing a Practical Layout
 With a series of nested pit shells as a guide design a set of
pits that follows the guides but has benches, and roads
required for practical mining.
– MineSight is a 3D Cad program so I can draw in my roads and
benches
 Look at Further boosting earnings by running artificially
high Cut-Off grades at first and sizing mine production
– Can be done with VALP in MineSight
 Size up your equipment fleets and haulage times
– MineSights haulage program is still weak (we will use FPC)
 Develop detailed long term schedules of what will be mined
from where
– MineSight Strategic Planner can do this
– In for major refinement in March or April
 Collectively these steps are called long term mine planning