david seaman

7/27/2019 David Seaman

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Separation efficiency improvementof a low grade copper-gold flotation

circuit

Newcrest Mining LimitedDavid Seaman, Peter Manton & Paul Griffin


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Contents Process Overview Mineralogy Circuit Modification Installation Details


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Telfer Flotation Overview Dual train (underground and open pit) ~ 23Mtpa Typical head grades 0.1-0.2 % Cu; 1-2g/t Au; 1-5% Sulphur Gold distribution free gold/copper minerals/Pyrite (~5g/t) Copper minerals Predominantly Chalcopyrite and Chalcocite Copper concentrate produced - ~16% Copper

Tailings

Cu Ro

Cleaner Cleaner Scav

ReCleaner

Copper Con

Grindingcircuit

FFCC

Py Rougher


CIL

Copper Circuit

Pyrite Circuit


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Copper Concentrate MineralogyFinal Copper Concentrate Mass Distribution

0%

10%

20%

30%

40%

50%60%

70%

80%

90%

100%

Telfer - T1 Telfer - T2 Cadia Ridgeway BulkSulphide*

NSG

Other SulphidePyriteOther CuOther Cu SulphidesCpy


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Copper Concentrate Mineralogy Significant quantity of liberated

NSG diluting copper concentrate Copper minerals well liberated Opportunity to replace NSG withPyrite

improve gold recovery Increase copper concentrate grade0

10

20

30

40

50

60

70

80

90

100

T1-FFC T2-FFC T1-CuRon T1 Cu ReCl T2 Cu ReCl

other

Pyrite

Ch

Cpy

NSG

Cu Con Liberation (Cu) - Q1

0102030

405060708090

100

T1 FFC T2 FFC T1 Cu RoCon

T1 ReClCon

T2 ReClCon

Total Ternary (%)

Total Binary (%)

Liberated (%)


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Gangue Characteristics Size Predominantly fine and well liberated

Mostly Quartz & Feldspars


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Mechanism of Gangue Dilution Dilute Hot Flotation tests - ~5% solids

0

20

40

60

80

100

0 20 40 60 80 100

Mass Recovery (%)

G o

l d R e c o v e r y

( % )

T1 Ro Con A (May) T1 Cu Con

T1 ReCl Con (May) T1 ReCl Con

T1 Ro Con B

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

Mass Recovery (%)

G

o l d R e c o v e r y

( % )

T2 Cl Con T2 Cu Ro Con

20% of Mass (NSG) can be rejected by further cleaning with negligible change to overallrecovery

NSG is not being recovered by true flotation


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Cleaning Circuit limitations Cleaner cells heavily loaded Cells have insufficient launder capacity Residence time constraints do not allow for

further dilution in cleaners to reduce entrainment

%solids (min)Cu Ro 34.3 15.0Cu Cl 10.5 13.6Cu Cl Scav 9.2 14.4

Cu ReCl 10.1 20.7

Cu Recleaner Cells


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Reconfiguration of the Cleaning Circuit Simplified AMIRA P9 model:

Various reconfigurations simulated using Monte-Carlo Minor improvements could be made using existing equipment:

open-circuiting the Cl Scav Con (to Recleaners) diluting the Cl/Cl Scav bank to reduce Rw

Additional capacity required to make a significant improvement Jameson cell chosen as new capacity

published performance data (>50% stage recovery at high grades) ability to reject entrainment by froth washing Incorporated in model using the dilute batch float selectivity

wwij

wwijij R ENT Rk

R ENT Rk R

)1)(1()1(


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Modified Cleaner Flowsheet Installation of one Jameson cell per Train fed by Cu Ro Con

Similar approach to recent installations at Phu Kam and Prominent Hill Open circuit Cl Scav Con to allow additional dilution of Cleaners Modelled improvement consistent with mineralogical characterisation

RoA Ro B


ReCleaner

Ro Con A

Final Con

COF

Grinding circuit

FFCC

12

13

14

15

16

17

18

19

20

21

22

-6 -4 -2 0 2 4 6

R e c l e a n e r

C o n c e n t r a t e

G r a

d e -

% C u

Copper Recovery from Cyclone Overflow (diff erence) % Cu

Baseline Jameson Cell Installation


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Jameson Cell Technology

The Downcomer

Slurry is pumped through a slurry lens orifice athigh pressure (150kPa)

Air is entrained into the downcomer

Mixing zone is formed in the downcomer where

particles and bubbles contact

Internal recycle of cell content allowing the use of

a fixed speed pump, designed for approximately

2:1 (downcomer flowrate: fresh feed)

Cells are fitted with wash-water trays to allow

effective froth washing to reduce entrainment


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Telfer Jameson Cell Installation


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Installation Details 2 x E3432/8 Jameson Cells Designed to treat up to 60tph fresh feed each (350m 3/h slurry) Concentrate and tailings flow by gravity Each cell driven by a 75kW Warman 10/8 pump (700m 3/h) Wash water utilisation ~ 30-100m 3/h Major equipment direct purchased by Newcrest, installation carried

out under a lump sump EPC - reduced project delivery time Timing

Oct 2010 Project initiated to address NSG in concentrate May 2011 Order placed for major equipment November 2011 New cleaning circuit commissioned


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Jameson Cell Actual vs Predicted

Similar selectivity observed to date, high stage recoveries achieved (>80%)for Cu and Au


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