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Improving Fine (
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Introduction to Northparkes Mine
Fine Copper Recovery at Northparkes
Magnetic Agglomeration
Experimental Design & Analysis
Study Conclusions
Questions
Presentation Overview
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Copper & gold mine
Joint venture 80% Rio Tinto & 20%
Sumitomo Group
Located ~ 390 km west of Sydney
Underground and open cut ore sources
Northparkes Mine
Sydney
Northparkes Mine
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Copper Minerals: predominately chalcopyrite (CuFeS2
) & bornite (Cu5
FeS4
)
Head grade: 0.83% Cu, 0.44 g/t Au
Recovery targets: 89.7% Cu, 79.0% Au. Grade targets: 34.4% Cu, 16.8 g/t Au
Facts about Northparkes Mine
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Northparkes Flowsheet
Ore processed through 2 parallel modules.
Planned milling rates: Module 1 245 t/h, Module 2 423 t/h
ML04
(5500x9400)
CY03 A-D
(20" CAVEX)
HP13
PP064/65
(12/10 F-AH)
CY04 A-O
(15" CAVEX)
Flash Float
Rougher
(Skimair)
Flash Float
Cleaner
(Outokumpu 5)
To Con
Pump
To Flotation Circuit
PP068 SUMP
(65VD-GPS)
To Primary Hopper
PP066/67
(14/12 FF-AH)
FT45
FT46
-
Ball Charger
BC02
Magnet(MA02)
CV10 Weightometer
Feeders
FE06-09
Oversize
Crusher
CR03
ML03
(8500x4300)
SV06
Svedala(2400x6100)
CV11
CV12
Ore
Stockpile
Ore
Stockpile 2Weightometer
Apron
Feeder
AF01
Ball Charger
Hopper
HP15
Trommel
TL04
Metal
DetectorCV21
MODULE 2 RECLAIM
(321) & GRINDING(330) CIRCUIT
SCATS
CV332
CV334
CV329
Splitter
CV330
PP091
(Frother)
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Northparkes Flowsheet
Ore processed through 2 parallel modules.
Planned milling rates: Module 1 245 t/h, Module 2 423 t/h
CY06 A-H
15" Krebbs
ML06
TK36
Conditioner 1 TK37
Conditioner 2
1st Roughers
(Dorr Oliver)
FT15-16
1st Scavengers
(Dorr Oliver)
FT19-20
Cleaner
Jameson
Cell
Jameson
Cell
Recleaner
TK57/58
Cleaner-Scavenger Feed
Conditioner
Cleaner-Scavengers
(Dorr Oliver)
FT23-26
MODULE 2FLOTATION (340)
CIRCUIT
To Concentrate Thickener
To Tailings
Thickener
From
Grinding
Circuit
Flash Float Con
PP223 SUMP
(65VD-GPS)
To HP41
Trommel
TL06
HP41
PP222
(12/10 F-AH)
PP080
(8/6 E-AH)
HP25
FT27
(8 Downcomers)
FT28
(3 Downcomers)
AG30/31
PP075
(8/6 E--AH)
BL01-03
Blowers
TO FLOAT CELLS
PP079
(12/10 E-M)
HP12
AG21
AG22
PP082
(4RV-AF)
PP076
(6/4 D-AH)
HP11
HP26
PP081
(6/4 D-AH)
PP115
(NaHS)
PP089/90
(Frother)
PP110
(Collector)
PP103
(Promoter)
PP112
(Collector)
Optional
Optional
Optional
Optional
NONC
CV453
CV454
CV457
CV459
2nd Roughers
(Dorr Oliver)
FT17-18
2nd Scavengers
(Dorr Oliver)
FT21-22CV452
CV451CV450
TK50
Pre-Float
PP69CV715
NCNO
Proflote Units
To Hopper 14
CY05 Feed
NC
NO
NC NO
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Fine Copper Recovery
+150+106+75+53
+38+20+11-11
Mass Distribution
Cu Dis tribution
0
5
10
15
20
25
30
35
40
%R
etained
Size Fraction (m)
Mean Copper and Size Distribution of Northparkes Module 1 final tail (2009)
Significant copper and mass losses in
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Magnetic Agglomeration (1 of 2)
ProFloteTM installed at Northparkes
Selective agglomeration of paramagnetic
minerals
Paramagnetic minerals become magnetised
when exposed to a strong magnetic field
Agglomeration of magnetised paramagnetic
minerals occurs when there is sufficientmagnetic attraction
ma VVVV rt
Vt = Total energy of attraction
Va= London van der Waals energy (attractive)
Vr= Electrostatic energy (repulsive)
Vm= Magnetic energy (attractive)
*
*Sourced from: Svoboda (1987) Magnetic Methods for the Treatment of Minerals, Elsevier Ltd., Amsterdam, Netherlands.
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Magnetic Agglomeration (2 of 2)
Agglomeration (magnetic attraction energy) dependent on:
mineral magnetic susceptibility,
mineral particle size, and
distance between minerals and magnetic induction.
Mineral Reported magnetic susceptibility
(M3kg-1x10-9)*
Chalcopyrite 1596.0
Bornite 101.0
Quartz -5.7
Pyrite 1.0 5.0
Gold -0.15
*Sourced from: Svoboda (1987) Magnetic Methods for the Treatment of Minerals, Elsevier Ltd., Amsterdam, Netherlands.
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Magnetic Conditioning Previous Results*
Size Fraction Change in Cu Recovery (%)with magnetic conditioning
Level of StatisticalConfidence (%)
38 m +1.2 Very low
Total sample +1.4 96.0
ProFloteTM installed in Module 2 flotation feed stream in 2005
Randomised block statistical plant trial to assess its effectiveness
~6 months to complete trial
No difference in copper concentrate grade with magnetic conditioning
*Sourced from: Rivett, T., Wood, G. and Lumsden, B. (2007) Improving Fine Copper and Gold Flotation RecoveryA Plant
Evaluation. Proceedings of the Ninth Mill Operators Conference, The Australasian Institute of Mining and Metallurgy, Melbourne,
Australia. pp 223 228.
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Measuring Agglomeration Unrelated flotation study at Northparkes (December 2009) discovered
agglomeration could be observed using laser diffraction
Laser diffraction is an optical size distribution technique
Different sized particles scatter light, from a laser beam, at different angles
and intensities
Images sourced from: Malvern Instruments Inc, 2010. Available from http://www.malvern.com/processeng/processes/classification
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Measuring Agglomeration Stage 1
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0.1 1.0 10.0 100.0 1000.0
Volume%InSizeClass
Particle Size (m)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
0.1 1.0 10.0 100.0 1000.0
Volume%InSizeClass
Particle Size (m)
Magnetic ConditioningNo Magnetic Conditioning
Cleaner Feed (before sonication) average Cleaner Feed (after sonication) average
Natural agglomeration
% agglomeration estimated as change in % volume (of a size fraction) before and
after sonication
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Measuring Agglomeration Stage 2
ProFloteTM installed in Module 1 flotation feed stream early 2010
Rather than traditional plant trial, laser diffraction technique used to estimate
degree of agglomeration. Test work completed within 1 week.
Paired t-test analysis showed statistically significant increase in particle size
with magnetic conditioning
Mean Results
Size Fraction Copper Minerals (%) Agglomeration (%)*
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Correlating Magnetic Agglomeration with
Copper Recovery
Traditional on/off plant trial not conducted unstable feed conditions during study Previous trial showed 2.1% increase copper recovery for
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Conclusions
Agglomeration of paramagnetic copper minerals observed in cleaner feedstream following magnetic conditioning of flotation feed
Agglomeration occurring for copper minerals
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Paper Amendments
Page 224, Procemin 2010 Seminar ProceedingsCorrelation of Magnetic Agglomeration with Copper Recoverysection
Rivett et al [8] showed a 2.1% increase in copper flotation recovery for the
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Questions
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Acknowledgements
David Rahal, Technical Director, Knelson (Deswik) Milling Solutions Inc
Northparkes Mines, Rio Tinto
Professor G Jameson
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Magnetic Agglomeration (2 of 2)
Agglomeration (magnetic attraction energy) dependent on:
mineral magnetic susceptibility,
mineral particle size, and
distance between minerals and magnetic induction.
*Sourced from: Svoboda (1987) Magnetic Methods for the Treatment of Minerals, Elsevier Ltd., Amsterdam, Netherlands.
Vm = magnetic energy (attraction)o = magnetic permeability of a vacuum
1, 2 = volume magnetic susceptibilities of the particles
b1, b2 = radius of the particles
H = magnetic field strength
h = distance between the surface of the particles
3
21
23
2
3
121
)(9
)8(
bbh
HbbV
o
m
*