Development of an Innovative

Copper Flowsheet at Phu Kham

M F Young and I Crnkovic

Phu Kham Location in Laos

Phu Kham Plant Layout

Plant Layout showing

• Primary Grinding• Rougher Flotation• IsaMill Regrinding

Phu Kham Flowsheet

PROCESSWATER

COARSE ORE STOCKPILE

ROUGHER FLOTATION CELLS

1st CLEANER FLOTATION CELLS

2nd CLEANER FLOTATION CELLS

3rd CLEANER FLOTATION CELLS

ISAMILL

GYRATORYCRUSHER SAG MILL

No.1 BALL MILL

TAILINGS DAM

CONCENTRATETHICKENER

CONCENTRATETANK

CONCENTRATEFILTER

CONCENTRATESTOCKPILE

MILL CYCLONES

ROUGHERCONCENTRATECYCLONES

Phu Kham Flowsheet

• 12.8 Mt/a of copper-gold bearing ore from the open pit• Plant Feed Grades are 0.75% Cu and 0.33g/t of Au and 3.8g/t

of Ag• Concentrate quality is +25% Cu, 7 g/t of Au and 60g/t of Ag

• Primary Grinding Circuit contains– 34 ft × 18 ft (13MW) SAG mill– 24 ft × 39 ft (13 MW) ball mill

• Regrinding Circuit contains– M10,000 (2.6MW) IsaMill

• Ore has fine locking of copper and gangue minerals• Ore requires regrinding rougher concentrate to 38 microns to

make good quality final copper concentrate

• IsaMill currently grinds from 90 microns to 38 microns• Cleaner feed performance at 38 microns and 25 microns• Laboratory Flotation Tests

Cleaner Grade-Recovery Profile For Cu-Afternoon Test

0

10

20

30

40

20 40 60 80 100Cum Cu Recovery

Cum

Cu

Gra

de

No Regrind (PM) With Regrind (PM)

Cleaner Feed Performance

New Phu Kham Flowsheet

• Cleaning Circuit was overloaded at times

• Fine grinding to improve concentrate quality, slowed flotation rate and increase frothing issues in the cleaner circuit, decreasing the performance of the cleaner circuit

• Jameson Cell with froth washing was installed at the head of the cleaner circuit to increase cleaning capacity

• This new circuit allowed final concentrate to be produced from the IsaMill regrind product in one flotation cell and remove more than half the load from the existing cleaning circuit

New Phu Kham Flowsheet

PROCESSWATER

COARSE ORE STOCKPILE

ROUGHER FLOTATION CELLS

1st CLEANER FLOTATION CELLS

2nd CLEANER FLOTATION CELLS

3rd CLEANER FLOTATION CELLS

JAMESON CELL

ISAMILL

GYRATORYCRUSHER SAG MILL

No.1 BALL MILL

TAILINGS DAM

CONCENTRATETHICKENER

CONCENTRATETANK

CONCENTRATEFILTER

CONCENTRATESTOCKPILE

MILL CYCLONES

ROUGHERCONCENTRATECYCLONES

Layout of IsaMill and Jameson Cell

Jameson Cell Flotation at Phu Kham

• IsaMill Cyclone Overflow P80=20 microns• IsaMill Discharge P80=38 microns• Feed (Rougher Conc) Grade = 3-5% Cu

Phu Kham Jameson Cell Grade-Recovery Curve Performance

20.00

21.00

22.00

23.00

24.00

25.00

26.00

27.00

28.00

29.00

30.00

50% 55% 60% 65% 70% 75% 80% 85% 90% 95%

Cu recovery (%)

Cu grade

 (%)

Cyclone overflow only

Cyclone oveflow + IsaMilldischarge

Jameson Cell Size by Size Recovery on IsaMill Cyclone Overflow Stream

Phu Kham Jameson Cell Size-By-Size Recovery

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

0 10 20 30 40 50 60 70 80

Size Fraction

Rec

ove

ry %

Cu CYC OF 1 Cu CYC OF 2

New Cleaning Circuit Results

• Jameson Cell was initially commissioned on the regrind cyclone overflow

• Cyclone Overflow was fine (P80=20 microns) and well liberated• Jameson Cell produced 25.5% to 27.5% Cu grade at 75% to 90%

Cu recovery on this stream• Jameson Cell produced high recovery in all size fractions for this

stream

• Jameson Cell then treated cyclone overflow plus IsaMill discharge• Jameson Cell still produced high grade copper concentrate at 26% to

29% Cu grade at 55% to 60% copper recovery• The recovery of the coarser size fraction was lower due to the

locking and lower liberation in the size fractions

Redox Measurements in Plant

Low Eh reduces the copper mineral flotation performance

Impact of Inert Grinding - Chalcopyrite

The Effect of Eh – Mt Isa Cu Ore

The critical importance of the grinding environment on fine particle recoveryin flotation - Stephen Grano - 2009

Cu Grade-Recovery Curve-C1F

0

5

10

15

20

25

30

0 10 20 30 40 50 60 70 80 90 100Cu Recovery %

Cu

Gra

de %

C1F Without Aeration C1F With Aeration RCOF

Cleaner Feed Performance

The Effect of Aeration in Laboratory Float

Grade Recovery Curves (Total Cu)  IMD

0

5

10

15

20

25

50 60 70 80 90 100

IMD Without Aeration IMD With Aeration

IsaMill Discharge Performance

The Effect of Aeration in Laboratory Float

HYPERSPARGESupersonic Gas Injection

Fine Bubble GenerationAble to generate much finer bubbles for fast gas transfer rates

Supersonic GasInjection Nozzle for high intensity

mass transfer

Failsafe In LineCheck Valve to

preventSlurry Spills

Spool Piece and High Pressure Seal for safeInsertion and

removal

Compact Ball Valve for Secure

Isolation

Solenoid Control Valve and flexible connection hose

Sturdy Barrel Union

Connection for rapid

maintenance

k La

Gas Flow

Low PressureRing sparge

High Pressuresparge

HyperSparge

HyperSparge installed in IsaMill Discharge line

Phu Kham – Effect of AerationPlant Surveys

Phu Kham Jameson Cell PerformanceBefore and After Aeration

22.0

23.0

24.0

25.0

26.0

27.0

28.0

40% 45% 50% 55% 60% 65% 70% 75% 80%

Recovery % Cu

Gra

de %

Cu

Before Hypersparge After Hypersparge

Phu Kham Jameson Cell Size-By-Size Recovery

0.00%

10.00%

20.00%

30.00%

40.00%

50.00%

60.00%

70.00%

80.00%

90.00%

100.00%

0 10 20 30 40 50 60 70 80

Size Fraction

Rec

ove

ry %

Before HyperSparge After HyperSparge

Phu Kham – Effect of AerationPlant Surveys

Summary

• IsaMill regrinds rougher concentrate to 38 micron to improve thefinal copper concentrate quality

• Cleaner feed performance at 38 microns is 25-28% Cu in final concentrate

• and regrinding 25 microns can produce +30% Cu in final concentrate

• Jameson Cell installation was an innovative flowsheet change to removed load from cleaning circuit and increased plant capacity and decrease cleaner circuit frothing issues

• Aeration of Cleaner feed has improve performance and fines recovery and selectivity

• Jameson Cell has allowed the IsaMill to operate at Increase power to improve the circuit performance.