ion Presentation

MINERAL PROCESSINGMINERAL PROCESSINGComminution

Peter GronHatch, Brisbane, Australia

COMMINUTION

Min

Com

• Comminution is a mineral processing technique used in extractive metallurgy to

d th ti l i f i l

neram

m reduce the particle size of a mineral ore.

• Comminution processes are employed b b t i ll

al Proinut

because subsequent processing generally requires finer particle sizes, where the valuable mineral is liberated from the oces

tion gangue minerals.

• Coarse particle reduction is completed via ssing

Coa se pa c e educ o s co p e ed aCrushing, while finer reduction is completed via Grinding.g

PRESENTATION OUTLINE

Min

Com

1. Types of Comminution Equipment– Crushers

HPGR

neram

m – HPGR– Sizers– Grinding Millsal Proinut 2. Comminution Circuit Configurations

3. Sizing Comminution Equipmentocestion

g q p– Comminution Characteristics– Bond’s Law

Si i C h

ssing

– Sizing Crushers– Sizing Rod & Ball Mills– Sizing AG & SAG Millsg Sizing AG & SAG Mills

TYPES OF COMMINUTION EQUIPMENT

Types of Comminution EquipmentM

iC

om Equipment Type Reduction Ratio neram

min

Jaw 3 to 4

Gyratory 3 to 4

Cone 4 to 5 Compression Crushers al Prnutio

Rolls Crusher

High Pressure Grinding Rolls

Sizers

3 to 6

Vertical Type 3 to 8

roceon Eq

Vertical Type 3 to 8 Impactors

Horizontal Type 10 to 15

Rod Mill 100

Ball Mill 1 000 Tumbling Type Grinding

Reduction Ratio P d t 80% P i Si (P ) / F d 80% P i Si (F )

ssinuipm

Ball Mill 1,000 Mills

AG & SAG Mill 5,000

= Product 80% Passing Size (P80) / Feed 80% Passing Size (F80)

g m

ent


JAW, GYRATORY & CONE CRUSHERS

CRUSHERS

Min

Cru • Jaw, Gyratory and Cone Crushers are

mainly used for the size reduction of neraushe

hard, abrasive materials.

• Range in size from large primary jaw and

al Proers Range in size from large primary jaw and gyratory crushers to cone crusher for secondary, tertiary and quaternary oces

qcrushing.

• Sticky material can be problematic in ssing

• Sticky material can be problematic in these crushers.

g

Jaw Crushers (Primary)Jaw Crushers (Primary)Min

Cru neraushe al Pro

ersocesssingg

JAW CRUSHERS

Min

Cru • Tonnages from 25 tph to greater than neraushe

g p g1000 tph

• Openings range from

al Proers Openings range from

17” x 25” to oces

to 47” x 63”ssing

• Product size from 38 mm to 300 mm

g

Gyratory Crushers (Primary)Gyratory Crushers (Primary)Min

Cru neraushe al Pro

ersocesssingg

GYRATORY CRUSHERS

Min

Cru • Tonnages from 400 tph to greater than

6400 tphneraushe • Sizes range from

30” 60”

al Proers 30” x 60”

to 72” 112”

oces

72” x 112”

• (Size refers to feed opening x crusher ssing

( p gcone diameter)

• Product size from -100 mm to +250 mmg

Cone Crushers (Secondary / Tertiary)M

inC

ru neraushe al Pro

ersocesssingg

CONE CRUSHERS

Min

Cru neraushe • Tonnages from 15 tph to greater than

2000 tph

al Proers 2000 tph

P d t i f 6 t 75

oces

• Product size from –6 mm to +75 mm

ssingg


ROLLS CRUSHERS

Rolls Crushers / d /(Primary/Secondary/Tertiary)M

inRol nera

lls C al ProC

rush

• Rolls Crushers are used for the crushing of oceshers

• Rolls Crushers are used for the crushing of medium-hard rock as well as for sticky and soft materials such as lignite and mineral ssing

soft materials such as lignite and mineral coal, clay, marble, limestone and similar raw materials.g

Rolls Crushers (Krupp)Min

Rol neralls C al Pro

Crush oces

hers ssingg

Rolls Crushers (McLanahan)Min

Rol neralls C al Pro

Crush oces

hers ssingg


HIGH PRESSURE GRINDING ROLLS

(HPGR)

HPGR

Min

HP • HPGR’S are an autogenous crushing

system based on inter-particle breakage neraG

R

y p gin a packed bed.

• The machine consists of 2 counter al Pro

rotating drums – 1 fixed while high crushing forces (300 MPa) are applied via h d li h h h h

oces

hydraulic rams through the other moveable roll shaft.Th hi ti i k d

ssing

• The crushing action occurs in a packed bed between the rolls.

• Polysius KHD & Koepern

g • Polysius, KHD & Koepern

HPGR

Min

HP • Main advantage of HPGR – lower specific

energy consumption.neraG

R HPGR & SAG Specific Comminution Power 1

Ball Mill

al Pro 20

25

30

r (kW

h/t)

Pebble CrusherSAG MillRolls Crusheroces

5

10

15

ecifi

c P

ower Secondary Crusher

Primary Crusher

1. Source: Innovation in Mineral Processing P

ssing

0

5

Spe

RollsCrusher

SAG Mill

Mineral Processing - P Reese: 2000 NZ Minerals & Mining Conference Proceedings 29 - 31 October 2000g

HPGR

Min

HP nera

GR al Proocesssingg


SIZERS

Sizers

Min

Size

• Sizers are used for primary, secondary and tertiary sizing / crushing of materials nera

ers

y g gsuch as: – Coal, Salt, Gypsum, Limestoneal Pro

, , yp ,• A feature of these machines is their

ability to handle very wet, sticky and oces

hard material either separately or together through the same unit.ssing

• The generation of fines is minismised.

g

DDC Sizers

Min

Size neraers al Proocesssingg

MMD Sizers

Min


Abon Sizers

Min



IMPACT CRUSHERS

Impact Crushers

Min

Imp • “Low-Abrasion” materials.

h h h l

nerapact

• A rotor spins in either the horizontal or vertical planes (thus horizontal or vertical impact crushers)

al Pro C

ru

impact crushers).

• Hammers are attached to the rotor and ocesushe

impact the material against breaker plates.ssing

rs • Historically “hammer-mills” were used for gold.g

Horizontal Impact Crushers

Min

Imp nerapact al Pro

Cru ocesushe ssing

rsg

Vertical Impact Crushers

Min

Imp nerapact al Pro

Cru ocesushe ssing

rsg


GRINDING MILLS

Metso / Bradken / Fuller / Krupp-Polysius / Outokumpu

Rod Mills (Primary Mill)Rod Mills (Primary Mill)Min

Gri nera

ndin al Prong M

• Limited Size (due to rods) Max – 14’ dia x 22’ocesM

ills

Limited Size (due to rods) Max 14 dia x 22• Feed is product from tertiary crusher• F80 9,500 m to 16,000 mssing

s

80

• Uniform size distribution in product• P80 1,000 m to 4,750 mg

Ball Mills (Primary/Secondary)Min

Gri

f d f l

nerandin

• Largest Size – 25 ft dia x 40 ft long– Predicting 26’ x 40’ with 15 MW Wrap

Around Drive

al Prong M

• Feed is product from tertiary crusher or (S)AG Mill or HPGR

• F 6 350 m to 12 700 m

ocesM

ills

• F80 6,350 m to 12,700 m• P80 < 50 m (mill discharge: grates or o/f)• Ball Size – 9.5 mm to 75 mm

ssings

g

(S)AG Mills – (Primary)(S)AG Mills (Primary)Min

Gri

• AG – Autogenous Grinding Mill: Feed is used as grinding media

nerandin

• SAG – Semi-Autogenous Grinding: Feed plus steel balls used as grinding media

al Prong M

p g gocesM

ills ssings

g

(S)AG Mills – (Primary)Min

Gri nera

ndin al Prong M oces

Mills ssing

sg

AG / SAG Mills (Primary)AG / SAG Mills (Primary)

• Largest Size – 40 ft dia x 24 ft long

Min

Gri Largest Size 40 ft dia x 24 ft long

– Predicting 44 ft dia with 30 MW Wrap Around Drive

nerandin

• Feed is product from primary crusher• F80 up to 250 mm

al Prong M

• P80 as fine as less than 100 m• Ball Size – 75 mm to 200 mm

ocesM

ills ssings

g

COMMINUTION CIRCUIT CONFIGURATIONS

Two Stage Crushing CircuitFEEDM

inC

om

FEED

J AW CRUS HER

Typically

Availabilities are in neram

min

S I ZI NG S CREEN

CONE CRUS HER

– Availabilities are in the order of 80%-85% al Pro

nutio

• For U/G operations Jaw Crushers are often used as the U/G Crusher (Size allows shaft access)

ocesn C

ir

P RODUCT( t o Rod M i l l or Ba l l M i l l )

as the U/G Crusher (Size allows shaft access)• Third Stage can be added with addition of

another cone crusher / screen

ssingrcuits

• Generally lower tonnage operations

g s

Rod Mill / Ball Mill CircuitRod Mill / Ball Mill CircuitMin

Com nera

mm

in

P RODUCT

CYCLONE

al Pronutio ROD M I LL

( ope n c c t )

CYCLONE

ocesn C

ir

FEED

BALL M I LL( c l ose d c c t )T picall

ssingrcuits

( c l ose d c c t )Typically

– Availabilities are in the order of +95% g s the order of +95%

SAG / AG CircuitSAG / AG CircuitMi

Com nera

mm

in

COARSE ORE STOCKPILEPRODUCT

Gyratory Crusher

FEED

Transfer Conveyoral Prnutio

(S)AG Mill

Discharge ScreenApron Feeders & Transfer

Conveyorsroceon C

i

Pebble Recycle System

Cyclone Feed System

T picallssinrcuits

Typically

– Availabilities are in the order of +92% g s the order of +92%

(S)ABC(S)AG – BALL – CRUSHERM

inC

om

Gyratory Crusher

FEED

Coarse Ore

neram

min

Crusher

Transfer Conveyor

Coarse Ore Stockpile

al Pronutio (S)AG Mill

Discharge Screen

Pebble Crushing & Recycle System

Apron Feeders & Transfer Conveyors

ocesn C

ir

PRODUCT

Ball Mill Grinding CircuitTypically

– Availabilities are in ssingrcuits (S)AG Transfer

Pump

BM Cyclone Feed

the order of +92%

g s

BM Cyclone Feed Pump

High Pressure Grinding Rolls CctHigh Pressure Grinding Rolls CctMin

Com nera

mm

in Apron Feeders & Coarse Ore Transfer Conveyor

Coarse Ore Stockpile

Pre-Crusher Feed Bin & Apron Feeder

Pre-Crushing Circuit Screen Feed Bin

Apron Feeder & Double Deck Screens (Top Deck Arranged As A Scalping

Grizzly)

Oversize Ore Transfer Conveyor

Pre-Crushed Ore Transfer Conveyors

al Pronutio

HPGR Circuit Feed Bin

Gyratory Pre-Crusher

Crushed Ore Transfer Conveyors

Covered Crushed Ore Stockpile

HPGR Feed Conveyor

Covered Ore Stockpile Conveyoroces

n Cir

& Belt Feeder

HPGR

HPGR Product Transfer Conveyor

HPGR Circuit Screen Feed Bins, Apron Feeders, Double Decked

Screens (Wet) & Oversize Transfer Conveyors

HPGR Oversize Ore Transfer

Conveyors

Typically Availabilities Are:ssingrcuits Ball Mill Circuit

PRODUCT

yp y80% - 85% for prim crushing90% for HPGR

f d

g s

+90% for grinding Cct

COMMINUTION COMMINUTION

SIZING COMMINUTION EQUIPMENT

Process of Sizing Comminution EquipmentM

inSizin

1 Determine the ore’s

nerang C

om

1. Determine the ore s ‘Comminution Characteristics’.al Pro

mm

inu

2. Determine the ‘Required Comminution Power’.oces

ution E

Comminution Power .

3 Size Comminution Equipment ssingEquipm

3. Size Comminution Equipment based on the ‘Required Comminution Power’.g

ment

Comminution CharacterisationComminution Characterisation• AI – Abrasion Index: Indicates the

abrasiveness of an ore in crushing and

Min

Sizin ggrinding. Used to estimate media & liner wear.

WI B d W k I d (I l d

nerang C

om

• WI - Bond Work Index: (Includes Crushing, Rod Milling and Ball Milling Indices) The work indices of an ore are

d t l l t hi d i di

al Prom

minu

used to calculate crushing and grinding mill power requirements.

• AUTOGENOUS MEDIA COMPETENCY -

ocesution E

• AUTOGENOUS MEDIA COMPETENCY -Provides a qualitative guide to the suitability of an ore for autogenous or semi-autogenous grinding

ssingEquipm

autogenous grinding.g m

ent

Comminution Characterisation

• DWI - JK Technology Drop Weight Testing:Determines the ore breakage parameters for use

Min

Sizin g pin the comminution processing simulator, JKSimMet, which models crushers, (S)AG, ball and rod mills, along with classification systems.

nerang C

om , g y

• SMC – SAG Mill Comminution: Developed by Dr. S Morrell. Again the parameters can be used in simulations of comminution circuits

al Prom

minu

in simulations of comminution circuits

• Piloting – Pilot scale milling circuits (particularly (S)AG mills used for scale up).

ocesution E p

• HPGR – laboratory scale to pilot scale tests undertaken for power requirements and wear rates

ssingEquipm

rates.

g m

ent

Bond’s Law (1952 – Third Theory of Comminution)M

inSizin nera

ng Com

The power required to reduce the feed from the Feed Size (F80) to the required ProductSize (P80) is as per the Bond Equation:

10 10

al Prom

minu

Power Required (kW / tonne) = Wi x10

P80

10

F80

ocesution E

W i = Bond Work Index of the ore.

P 80 = 80% passing size of the mill product.

F 80 = 80% passing size of the mill feed.ssingEquipm Efficiency factors are used to take into account conditions in the grinding circuit. A total

efficiency factor (which is the product of all of the efficiency factors) is multiplied by theBond Power to determine the power required at the mill pinion shaft

g m

ent

Bond Power to determine the power required at the mill pinion shaft.

CrushersCrushers

• Bond’s Law can be used to determine

Min

Sizin

• Bond s Law can be used to determine power requirements for crushers.

nerang C

om

• Crushers are flow through devices and the tonnage and F80 / P80 sizings determines the ‘size’ of crusher required

al Prom

minu

the size’ of crusher required.

• The ‘Nordberg Red Book’ is one source of

ocesution E

The Nordberg Red Book is one source of performance data for crusher sizing (can be downloaded from the internet.)

ssingEquipm g

ment

Bond’s Law - Rod & Ball MillsBond s Law Rod & Ball MillsMin

Sizin EFFICIENCY FACTORSnerang C

om

EF1: Mill Type - For the same range of work dry grinding requires 1.3 times as muchpower as wet grinding.

EF2: Open Circuit Grinding - When utilising open circuit ball mills the amount of extra

al Prom

minu

power required is a function of the degree of control required on the product produced.(EF2=1 for closed cct) The inefficiency factors are given below:

Product Size Control (P80) Inefficiencyocesution E

( 80) y Reference % Passing Multiplier 50% 1.035 60% 1.050 70% 1.100ssing

Equipm

80% 1.200 90% 1.400 92% 1.460 95% 1.570

98% 1 700

gment

98% 1.700

Bond’s Law - Rod & Ball MillsBond s Law Rod & Ball MillsMin

Sizin nerang C

om EFFICIENCY FACTORS (continued)al Prom

minu

EF3: Mill Diameter Efficiency Factor

F Di 3 81 EF (2 44/Di )0 2ocesution E

For Diameters < 3.81 m EF3 = (2.44/Diameter)0.2

For Diameters > or = 3.81 m EF3 = 0.914

ssingEquipm g

ment

Bond’s Law - Rod & Ball MillsMi

Sizin

EFFICIENCY FACTORS (continued)

EF4: Oversized Feed Efficiency Factor - This factor is used to take into account situationsnerang C

om

4 ywhere the mill feed is coarser than the optimum feed size:

R + (W i - 7) xF - F o

al Prm

minu

R r

EF4 =

R r + (W i - 7) x F o

roceution E

R r = Ratio of Reduction = F80 / P80

F o = Optimum Feed SizessinEquipm

F o = Rod Milling = 16,000 x 13 / W i

g m

ent

F o = Ball Milling = 4,000 x 13 / W i

Bond’s Law - Rod & Ball MillsMin

Sizin


EF5: Finess of Grind Factor - This applies to fine grinding when 80% passing size ofth d t i fi th 75 i

nerang C

om

the product is finer than 75 microns:

EF5 = (P80 + 10.3) / (1.145 * P80)al Prom

minu

EF6: Ratio of Reduction Factor For Ball Mills - This applies to ball mills only whenRr < 6. (Most often this factor is applied in regrinding operations.) The equation to use isas follows:

EF2 x (R r - 1.35) + 0.26oces

ution E EF6: Ratio of Reduction Factor For Rod Mills - This applies whenever the absolutel f (R R ) > 2

EF 6 =2 x (R r - 1.35)

ssingEquipm

value of (R r - R ro) > 2:

(R r - R ro) 2

EF6 = 1 +150

R ro = 8 + 5L / Dg m

ent

R ro 8 5L / D

Bond’s Law - Rod & Ball MillsMin

Sizin


EF7: Mill Liner Type Factornerang C

om

For Rubber Liners: EF7 = 1.07 For Steel Liners: EF7 = 1.00al Pro

mm

inu

EF8: Rod Mill Inefficiency Factor - When calculating power for a 'rod mill onlyapplication', an inefficiency factor of 1.4 is used when open circuit crushing is used tofeed the rod mill. If closed circuit crushing is employed a factor of 1.2 is used.

Wh l l ti f ' d ill b ll ill li ti ' i ffi i f t f 1 2

ocesution E

When calculating power for a 'rod mill - ball mill application', an inefficiency factor of 1.2is used when open circuit crushing is used to feed the rod mill. If closed circuit crushingis employed a factor of 1.0 is used.

EFT: Total Efficiency Factor

ssingEquipm

EFT: Total Efficiency Factor

EFT = EF1 x EF2 x EF3 x EF4 x EF5 x EF6 X EF7 X EF8

Power is calculated according to the Bond Formula and the Total Efficiency Factor is

g m

ent

Power is calculated according to the Bond Formula and the Total Efficiency Factor isapplied to arrive at a corrected power requirement.

Bond Operating Work Index Min

Sizin • An Operating Work Index can be calculated as follows:nera

ng Com Specific Energy (kWh/t) = E =

Mill Power Draw

(Fresh Feed Rate x Drive Efficiency)

al Prom

minu

10 10

E

O ti W k I d (kWh/t) W

ocesution E

10

P80

10

F80

Operating Work Index (kWh/t) = Wi Op =

ssingEquipm

• Bond’s Law can then be used to evaluate different tonnage and / or F80 - P80 scenariosg

ment

Rod & Ball Mill SizingRod & Ball Mill SizingMin

Sizin

• There are numerous models that may be used

nerang C

om

• There are numerous models that may be used to calculate Rod & Ball Mill Dimensions based on the Power Requirements, such as:al Pro

mm

inu 1. Kelly & Spottiswood Model.2 H & F M d l (B ll Mill O l )

ocesution E

2. Hogg & Fuerstenau Model (Ball Mills Only).3. Mular & Bhappu Model.ssing

Equipm g m

ent

Kelly & Spottiswood Rod & B ll Mill M d lBall Mill ModelM

inSizin

Power Delivered At Pinion =nerang C

om

Power Delivered At Pinion

8.44 x Dia2.5 x Length x KMt x KSP x KL al Prom

minu

Where:

Dia = Diameter inside linersocesution E

Length = Length inside linersKMt is the Mill Factor (1.0 for wet grinding, 1.3 for ssing

Equipm

dry grinding)KSP is a factor based on the mill critical speedK is a factor based on the mill charge

g m

ent

KL is a factor based on the mill charge

Kelly & Spottiswood ModelKelly & Spottiswood ModelMin

Sizin Factors For Calculating Power Draftnerang C

om 5.50

6.00

al Prom

minu 4.50

5.00

K L Ball Mill

Rod Millocesution E

3.50

4.00

ssingEquipm

3.0020% 25% 30% 35% 40% 45% 50%

Percent Mill Loading

g m

ent

Percent Mill Loading

Kelly & Spottiswood ModelKelly & Spottiswood ModelMin

Sizin Factors For Calculating Power Draftnerang C

om 0.220

0.240al Prom

minu 0.180

0.200

K S

Pocesution E

0 120

0.140

0.160

K

ssingEquipm

0.100

0.120

60% 65% 70% 75% 80% 85%g m

ent

Percent of Critical Speed

Kelly & Spottiswood Modely pMin

Sizin nerang C

om • By assuming an aspect ratio we can replace Length in terms of the Diameter & use ‘Goal

al Prom

minu

Length in terms of the Diameter & use Goal Seek’ or ‘Solver’ in Excel to calculate the Mill Dimensions based on the Grinding Power

d f d

ocesution E

Required from Bond’s Law.

ssingEquipm g

ment

BALL MILL SIZING EXAMPLEMin

Sizin

BALL MILL SIZING EXAMPLEBall Mill - 25' x 40' Pwr @ Pinion = 12,190kW

(F80 = 1.080mm P80 = 75micron)(Wet Grinding Mill In Closed Circuit With Grate Discharge and Rubber Liners)

nerang C

om

(Wet Grinding Mill In Closed Circuit With Grate Discharge and Rubber Liners)

Grinding Circuit Parameters

Feed Rate 931 tph

al Prom

minu

Mill Feed - F80 Passing Size 1,080 micronMill Product - P80 Passing Size 75 micron

Total Mill Charge (Ore plus Media) 28% vol/vol%ocesution E

Media Charge 28% vol/vol%

Liner Thickness 75 mm

Mill Speed 75% % criticalssingEquipm

Drive Efficiency 93% %

Ball Mill Work Index 15.50 kWh/tAbrasion Index 0.388 -g

ment

Power Required To Achieve Grind RequirementsMin

Sizin

q q

Net Power - kW Gross Power - kW

11,995 12,898

Net Power kW Gross Power kW

Bond's Law Power Required (Delivered To Pinion Shaft)

A l P D (D li d

nerang C

om

Net Power - kW Gross Power - kW

12,190 13,108

Ball Mill Dimensions

Actual Power Draw (Delivered To Pinion Shaft)

al Prom

minu

Ball Mill Dimensions - Inside Shell (feet)

Based On Bond's Law

Based On Actual Mill Power Draw

Calculation Methodocesution E

Law Mill Power Draw

Diameter Length Diameter Length

Kelly & Spottiswood 25.0 39.9 25.1 40.1ssingEquipm

Hogg & Fuerestenau 24.6 39.4 24.7 39.6

Mular & Bhappu 25.8 41.2 25.9 41.4

Average 25.1 40.2 25.2 40.4g m

ent

SAG & AG Power RequirementsM

inSizin

• There are numerous methods that may be

nerang C

om

• There are numerous methods that may be used to calculate SAG & AG Power Requirements. Two such methods are:al Prom

minu 1. the Barratt Method.

2 h A i M h d

ocesution E

2. the Austin Method.

• Both of these methods are very similar and ssingEquipm

• Both of these methods are very similar and yield similar results.

g m

ent

Barratt Method To Determine /SAG/AG Power Requirements

• Barratt proposed the use of an empirical f l b d B d W k I di t

Min

Sizin

formula, based on Bond Work Indices, to calculate the power requirements, where:

F F Si f F d

nerang C

om

FC = F80 Size of FeedPC = P80 Size of Equivalent Crusher Product

F P F Si f F d t R d Mill

al Prom

minu

FR = PC = F80 Size of Feed to Rod MillPR = P80 Size of Equivalent Rod Mill Product

F P F Size of Feed to Ball Mill

ocesution E

FB = PR = F80 Size of Feed to Ball Mill

P(S)AG = P80 Size of (S)AG Product

ssingEquipm g

ment

Barratt Method To Determine /SAG/AG Power RequirementsM

inSizin nera

ng Com

KR = Rod Mill Efficiency Factor (generally 1.0)KB = Ball Mill Efficiency Factor (generally 1.0)al Prom

minu

K(S)AG = (S)AG Efficiency Factor (generally 1.25)

WI B d C h W k I d

ocesution E

WIC = Bond Crusher Work Index

WIR = Bond Rod Mill Work IndexWI B d B ll Mill W k I d

ssingEquipm

WIB = Bond Ball Mill Work Index

g m

ent

Barratt Method To Determine /SAG/AG Power RequirementsM

inSizin nera

ng Com )10(WIC

10 + )10(WIR

10KR +[al Pro

mm

inu

)( PC FC)( PR FR

-)10(WIB

10KB K(S)AG

[]oces

ution E )10(WIB10

KB

)( 110 FB]

ssingEquipm

)(WIB

110 P(S)AG

KB

g m

ent

SAG/AG SizingSAG/AG Sizing

• Most (S)AG Sizing Models use empirical f l t d t i th

Min

Sizin

formulae to determine the power required to rotate the various components in the mill charge:

nerang C

om

components in the mill charge:

» Rocks Slurry

al Prom

minu

» Slurry» Balls

h l h d b l l h

ocesution E

• This is accomplished by calculating the volume and weight of each component.

ssingEquipm g

ment

SAG/AG SizingSAG/AG Sizing• There are numerous models available to

determine (S)AG Power Requirements:

Min

Sizin q

1. Austin Model. 2. Morrell Charge Model.

nerang C

om

3. Morrell Empirical Model.4. Sastri & Rao Model.5 Morgardshammar Model

al Prom

minu

5. Morgardshammar Model.6. Hogg & Fuerstenau Model.7. Barratt Model.

ocesution E

8. Marcy Model.

• All of these models yield similar results.

ssingEquipm g

ment

Min

Sizin

SAG MILL SIZING EXAMPLEExample: SAG - 36' x 22' Power @ Pinion = 15,670 kW (F80 = 134mm P80 = 1.08mm)nera

ng Com

Grinding Circuit Parameters

Feed Rate 1,861 tph

SAG New Feed Size - F80 Passing Size 134 mmS G f S S

al Prom

minu

SAG Transfer Size - P80 Passing Size 1,080 micron

Total Mill Charge (Ore plus Media) 26% vol/vol%Media Charge 13% vol/vol%

Liner Thickness 75 mmocesution E

Mill Speed 75% % critical

Drive Efficiency 93% %

Crushing Work Index 16.00 kWh/tssingEquipm

Rod Mill Work Index 16.00 kWh/tBall Mill Work Index 16.00 kWh/t

Abrasion Index 0.230 -g m

ent

Min

Sizin nerang C

om

Power Required To Achieve Grind Sizing

Net Power - kW Gross Power - kWActual Power Requirements for a 36' x 22' SAG

al Prom

minu

15,670 16,850

Calculation Method Net Power - kW Gross Power - kW

Barratt 15,145 16,285

SAG

ocesution E

Austin 16,640 17,895

Calculated Average 15,895 17,090

ssingEquipm g

ment

SAG Mill Dimensions (To Draw Power Required To Achieve Grind Sizing)

SAG Mill Dimensions - Inside Shell (feet)Min

Sizin

Based On Barratt Method To Determine

SAG Power Requirements

Based On Austin Method To Determine

SAG Power Requirements

Based On SAG Power Requirements

For a 36' x 22' SAG

Calculation Method Used To Determine SAG

Dimensionsnerang C

om

Requirements Requirements

Diameter Length Diameter Length Diameter Length

Austin 35.2 21.5 36.2 22.1 35.5 21.7

al Prom

minu

Morrell Charge 36.0 22.0 36.9 22.6 36.3 22.2

Morrell Empirical 36.1 22.1 37.1 22.7 36.4 22.3

Sastri & Rao 36.7 22.5 37.7 23.1 37.1 22.7

Morgardshammer 36.4 22.2 37.3 22.8 36.7 22.4ocesution E

Morgardshammer 36.4 22.2 37.3 22.8 36.7 22.4

Hogg & Fuerstenau 36.5 22.3 37.5 22.9 36.9 22.5

Barratt 35.0 21.4 35.9 22.0 35.3 21.6

Marcy 35.3 21.6 36.2 22.1 35.6 21.8ssingEquipm

Minimum (Occurs With Barratt) 35.0 21.4 35.9 22.0 35.3 21.6

Average Of All Calculation 35.9 21.9 36.9 22.5 36.2 22.1

Maximum (Occurs

g m

ent

Maximum (Occurs With Sastri & Rao) 36.7 22.5 37.7 23.1 37.1 22.7

QUESTIONS

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