jah mine to mill simulation

7/27/2019 Jah Mine to Mill Simulation

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Dynamic Simulation of

Size Reduction Operations fromMine-to-Mill

by

J.A. Herbst and W.T. Pate

J.A.

Herbst&Associat

es,

LLC

POBox2568

K

ealakekua,H

I96750-2568

[email protected]

om


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Kona

HawaiiMauiMolokai

Oahu

Kauai

Honolulu

Tahiti

California Mexico

Hilo

J.A. Herbst & Associates

Australia


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The Cost of Comminution

WorldwideEnergy Consumed Worldwide

2.6 x 1010 US$/yearWear Parts Consumed Worldwide

= 5 billion US$/year

100%100%

00

Product Size

EnergyEfficiency

50%50%


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Typical Breakdown of

Comminution Costs

Explosive Fracturing 1%

Coarse Crushing 2%

Fine Crushing 20%

Grinding 77%


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Mine-to-Mill Simulation

Real World Model Object

Flowsheet

Simulator


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Benefits of

Object Oriented ProgrammingA software object contains code and data which simulate the

pertinent characteristics of a physical device or stream

PROGRAM MAIN

CALL MINE ( )CALL TRUCK ( )

CALL CRUSH(FEED,CRUSHPROD)

CALL STORAGE ( )

CALL SCREEN(FEED,SCREENPROD)

CALL MILL(FEED,MILLPROD)

SUBROUTINE MINE ( )SUBROUTINE TRUCK ( )

SUBROUTINE MILL(FEED,MILLPROD)

SUBROUTINE STORAGE ( )

SUBROUTINE CRUSH(FEED,CRUSHPROD)

SUBROUTINE SCREEN(FEED,SCREENPROD)

Object Oriented Traditional

When process objects are connected bystreams they are linked for computation


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Conceptual Design of

MinOOcad

ProcessObject

Object

Properties

ObjectDisplay

Stream

Object

Stream

Object

( )ttO +2

( )ttO +1

( )tI

Object Menu

ContainerStream

Object #1

Stream

Object #M

Process

Object #2

Process

Object #N

ProcessObject #1

ProcessObject #3


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Implementation of

MinOOcad


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Models of

Flowsheet Elements

SLOW

FAST

INTERMEDIATE

0 1 10

Response

t/ Longest Dwell Time

Coarse Ore

Storage


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Dynamic/Multi-Components

Accumulation = Input - Output

+ Generation

Screen

Stream

P80

T

P

( )dt MOut,ij f Mij= - + sdMi,j

MIn,i,j

Particle Size Decreasing

ABAB

BB

AA


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Comminution Objects

- The Ball Mill

Feature 1Visualization

Feature 2Dynamic

PerformanceControl

Feature 3Scale-up/Design

Feature 4Capital/Operating Cost

$$

ManagerComputation

Procedures

Input and Output User Interface

Knowledge

Base

Ball Mill Object


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Comminution Objects

Mine

Truck

Storage

Crushers

Conveyors

Screens

Ball Mill - Pebble Mill

SAG - AG Mills

Sumps

Hydrocyclones


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Simulation Case Study

MinePrimary

Crusher

Primary

Mills

SecondaryMills

BallMill

Coarse Ore

Storage

SAGMILL

SAGMILL


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MinOOcad Flowsheet


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Tool Bar and Property Page


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Property Pages


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Zoom on Property Page


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Outputs

Date Time, hr Feedrate Feed wate Jetwater Mill rpm

6/14/98 18:00 0.00000 2037.9 673.3 75.0 10.01

6/14/98 18:02 0.03333 2010.7 672.4 75.0 10.01

6/14/98 18:04 0.06667 2021.5 673.0 74.9 10.01

6/14/98 18:06 0.10000 2051.2 673.6 74.9 10.01

6/14/98 18:08 0.13333 2080.9 677.6 74.9 10.01

6/14/98 18:10 0.16667 2059.8 690.0 74.9 10.01

6/14/98 18:12 0.20000 2076.0 687.8 74.9 10.016/14/98 18:14 0.23333 2096.1 682.5 74.8 10.01

6/14/98 18:16 0.26667 2116.2 678.1 74.8 10.01

6/14/98 18:18 0.30000 2112.2 679.5 74.8 10.01

6/14/98 18:20 0.33333 2099.1 675.8 74.8 10.01

6/14/98 18:22 0.36667 2095.3 675.5 74.8 10.01

6/14/98 18:24 0.40000 2093.0 665.2 74.7 10.01

6/14/98 18:26 0.43333 2090.6 665.4 74.7 10.01

6/14/98 18:28 0.46667 1507.2 666.8 74.7 10.016/14/98 18:30 0.50000 1663.9 684.5 74.7 10.01

Spreadsheet Graphic


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Base Case - At Steady State

SAG Mill%L=12

Ball Mill

%L=70

0.01

0.10

1.00

10 100 1000 10000 100000 1000000

Particle Size, microns

FractionPassin

g

Mine% L =0

Gyratory% L=0

Predicted

Operating Data


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Dynamic Situations

Simulated

Increase in Powder Factor at Mine

Increase in Truck Haul Time

Decrease in Stockpile Inventory


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Increase in Powder Factor

10000

100000

1000000

0 2 4 6 8 10 12

Time, hr

Mine,Crusherand

StockpileP80,

micro

ns

10

100

1000

SAGandBallMillP80,microns

SAG Mill

Ball Mill

Mine

Stockpile

Crusher

Powder factor increased by 150%

SAG Mill

Ball Mill

Mine

Stockpile

Crusher


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Decrease in Stockpile Inventory

10

100

1000

10000

100000

1000000

2 4 6 8

Time, hr

P80,m

icrons

100

200

300

400

500

Tonnage,mtph

Mine P80

Crusher P80

SAG m ill

tph

Stockpile tph

Ball mill P80

SA G mill P80

Ball Mill P80

SAG Mill P80

Stockpile tph

SAG Mill

tph

Mine P80Crusher P80


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Downstream Impacts

0

200

400

600

800

1000

2 4 6 8

Time, hr

Holdup,

torTonang

e,

tph

0

1000

2000

3000

4000

5000

Power,kw

Stockpile tonnage

SAG mill power

SAG m ill rock tons

SAG mill tonnage

Begin stockpile inventory change

50

75

100

125

150

175

2 4 6 8

Time, hr

P80,micr

ons

22

24

26

28

30

32

%o

fMagnetite

Liberated

Begin change in stockpile

inventory

Ball mill P80

Ball m ill magnetite liberated


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Future Possibilities Operating costs calculated on a minute-to-minute

basis over the entire flowsheet

Enterprise-wide control system capability integrated

into simulator

Incorporating the impact of maintenance usingrealistic wear and replacement models

Embedding into control system software for on-line

decision making


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Conclusions Comminution comprises the most energy intensive and

costly set of unit operations at a mine/mill site.

Opportunities exist to improve "enterprise-wide financial

performance" through understanding and exploiting

dynamic/steady state interactions between comminution

operations. A Windows based generic flowsheet simulator,

MinOOcad, has been developed to allow dynamic

simulation for any number of elements

Advanced comminution models embedded in well

designed software objects can provide realistic simulations

off all flowsheet elements.

Potential uses forMinOOcadare broad and exciting.

jah mine to mill simulation

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