Modern Process Mineralogy: Two Case Studies...Modern Process Mineralogy: Two Case Studies N.O....
Transcript of Modern Process Mineralogy: Two Case Studies...Modern Process Mineralogy: Two Case Studies N.O....
Modern Process Mineralogy:Two Case Studies
N.O. Lotter, L. Kormos, J. Oliveira,
D. Fragomeni, E. Whiteman
Xstrata Process Support
MEI Conference Nickel ’10, Falmouth, June 2010
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XPS Groups – Sudbury, Ontario
Process Control - Identify and deliver robust process control technology and engineering solutions to achieve ‘Operational Performance Excellence.’
Process Mineralogy - Design, implement and optimize mineral processing flowsheets by matching the flowsheet to the mineralogy. Testwork, modeling and plant support to maximise operations efficiency.
Extractive Metallurgy – Provide specialized extractive metallurgy services (hydro-and pyrometallurgical). Flowsheet/project development using modeling and piloting, new process development and plant optimization.
Materials Technology – Improve the reliability of critical equipment through appropriate implementation of proven materials engineering practices at essential stages of design, procurement and operation.
“Adding Value… Reducing Risk…”
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Process Mineralogy
Process
Mineralogy
Sampling & Statistics
Mineral Processing Mineralogy
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Process Mineralogy
• Methodologies
• Representative Sampling
• Geometallurgical Unit Definition
• High Confidence Flotation Testing
• Factorial Design of Experiments
• Response Surface Modelling
• Mini Pilot Plant Campaigns
• Quantitative Mineralogy (QEMSCAN + EPMA)
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Case Studies
• Flowsheet Development at Nickel Rim South
• Process Diagnosis at Raglan
CASE STUDY 1:
NICKEL RIM SOUTH
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Location
Mill
Smelter
60 km
Nickel Rim
South
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Nickel Rim South Mine
• Discovered in 2001
• 100% Xstrata Nickel ownership
• 9.6 Mt at 1.57% Ni, 2.85% Cu, 1.20g/t Pt, 1.35g/t Pd, 10.2g/t Ag, 0.46g/t Au
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Objective
• Flowsheet Design
• New concentrator
• Strathcona Mill
• Strathcona Mill retrofit
• Testwork developed over several years as exploration program progressed
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Methodology
• Define and characterise geometallurgicalunits
• Quantitative mineralogy
• High confidence flotation
• Mini Pilot Plant campaigns
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Geometallurgical Units
Upper Footwall Mineralization
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Comparison of Geomet Textures
Main Zone Footwall Fringe Zone
Pentlandite
Chalcopyrite
Bornite
Plagioclase
Epidote
Cpy average size: 348µm Cpy average size: 122µm
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Flotation Testing of Geomet Units
1
2
3
C1
C2
C3
Tailings
1st Ro
2nd Ro
Scav
1 Lime, PIBX, Dowfroth 250
2 PIBX
3 Sulphuric Acid, Copper Sulphate, PIBX
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Flotation Testing of Geomet Units
Upper Footwall
Main Footwall
Fringe Footwall
Contact Sublayer
Contact FootwallBreccia
Low Sulphur PGM
Ni+Cu Rougher Grade vs Ni Recovery
5
10
15
20
25
30
35
0 20 40 60 80 100
% Ni Recovery
% Ni + Cu Grade
Po-rich Po-poor
+Mg
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Impact of CMC on Sublayer Ores
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20
Flotation Time, min
Ni Recovery %
Footwall Breccia Sublayer Breccia Sublayer Breccia w CMC
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New Concentrator Concept
Flash
Rougher
155µm
to
283µm 53µm
to
155µm 38µm
Regrind
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Staged Grind Flowsheet –Improvements over Strathcona
5.5 5.1
15.5
10.5
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16.9
23.7 23.6
0
5
10
15
20
25
Ni Cu Pt Pd
% Recovery Improvement
Fringe
Low Sulphur PGM
These ore types represent only 10% of total resource
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Strathcona with Cu Pre-Float
Footwall Ore Contact Ore
Cu Pre-float Conc
Pri Ro Conc
Sec Ro Conc
Scav Conc
Scav Tails
P56 75µm P56 75µm
5.9
2.01.7
1.3
0
1
2
3
4
5
6
7
Ni Cu
% Recvoery
50/50
25/75
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Flowsheet Demonstration
• Each flowsheet option was demonstrated in the MPP
• Primarily from drill core samples
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Ni Rim South - Conclusions
3 retrofits recommended to Strathcona
• Cu Pre-float to minimise Ni and Cu losses
• Introduction of a CMC system to treat Sublayer ores
• Additional Cu/Ni separation capacity to allow for over 80% Cu recovery to Cu concentrate and allow for increased FW tonnages
• Metallurgical programme assisted by quantitative mineralogy was completed 2 years prior to commercial mine production
CASE STUDY 2: RAGLAN SURVEYS
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Raglan – Key Mineralogy
Massive Sulphides
Net-Textured Sulphides
Disseminated Sulphides
serpentinepyrrhotitepentlandite chalcopyrite
Massive Sulphides Net-Textured Sulphides Disseminated Sulphides
Pentlandite 291 78 68
Chalcopyrite 106 43 36
Pyrrhotite 386 68 60
Sulphide Grain Sizes
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Commissioned Flowsheet
Rougher Flotation
Final Concentrate
Final TailingsScavenger Flotation
Autogenous Mill
Secondary Mill
Rougher Flotation
Final Concentrate
Final TailingsScavenger Flotation
Autogenous Mill
Secondary Mill
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Comparison of Surveys –Ni Fe Sulphide Liberation in Feed
50
55
60
65
70
75
80
1998 2000 2003 2008
Pentlandite Liberation in Rougher Float Feed Varies
+106
+53
+25
CS1-3
CS4+5
CS6
CS7
Liberated
Middling
Locked0
5
10
15
20
25
30
% Ni Fe Sulphide
Size Fraction
1998Liberated
Middling
Locked
+106
+53
+25
CS1-3
CS4+5
CS6
CS7
Liberated
Middling
Locked0
5
10
15
20
25
30
% Ni Fe Sulphide
Size Fraction
Liberated
Middling
Locked
+106
+53
CS1-2
CS3
CS4-5
CS6
CS7
Liberated
Middling
Locked0
5
10
15
20
25
30
% Ni Fe Sulphide
Size Fraction
Liberated
Middling
Locked
-212/+106
-106/+53
CS1-2
CS3
CS4-5
CS6
CS7
Locked
Middling
Liberated
0
5
10
15
20
25
30
% Ni Fe Sulphide
Size Fraction
Locked
Middling
Liberated
78.9%
69.6%
65.3%
76.1%
2000
2003 2008
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Ni Fe Sulphide Liberation in Rougher Tailings
0
5
10
15
20
25
30
35
40
1998 2000 2003 2008
Pentlandite Liberation in Rougher Tails Varies
+106
+53
+25
CS1-3
CS4+5
CS6
CS7
Liberated
Middling
Locked0
5
10
15
20
25
30
% Ni Fe Sulphide
Size Fraction
Liberated
Middling
Locked
+106
+53
+25
CS1-3
CS4+5
CS6
CS7
Liberated
Middling
Locked0
5
10
15
20
25
30
% Ni Fe Sulphide
Size Fraction
Liberated
Middling
Locked
+106
+53
CS1-2
CS3
CS4-5
CS6
CS7
Liberated
Middling
Locked0
5
10
15
20
25
30
% Ni Fe Sulphide
Size Fraction
Liberated
Middling
Locked
-212/+106
-106/+53
CS1-2
CS3
CS4-5
CS6
CS7 Locked
Middling
Liberated
0
5
10
15
20
25
30
% Ni Fe Sulphide
Size Fraction
Locked
Middling
Liberated
39.2%
8.0% 7.4%
5.9%
1998 2000
2003 2008
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Changes from 1998 Survey
Rougher Flotation
To Final Concentrate
Final Tailings
Scavenger Flotation
Autogenous Mill
Secondary Mill
To Final Concentrate
Regrind Mill
Rougher Flotation
To Final Concentrate
Final Tailings
Scavenger Flotation
Autogenous Mill
Secondary Mill
To Final Concentrate
Regrind Mill
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Concluding Remarks
• Regular surveying identified flowsheetingopportunities
• These were implemented
• Grade and recovery maintained or improved
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Acknoledgements
Xstrata Nickel, for permission to publish this paper