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Intellection Pty Ltd

Establishing the Links Between Ore Characteristics and Crushing &

Grinding Performance

W Valery & K RungeMetso Minerals Process Technology, Australia and Asia-Pacific

A R Butcher, T Helms, & P GottliebIntellection Pty Ltd, Brisbane, Australia

© Metso Minerals, Inc. 2004© 2005 Intellection Pty Ltd

What is Process Integration and Optimisation?

The development of integrated operating and control strategies from the mine to the plant that minimises the overall cost per tonne and maximises profitability.

Opt(blasting+..+ comminution + flotation..) = Max($$$)


How profitability can be increased with Process Integration and Optimisation?

increasing throughput

reducing costs

improving process efficiency (from mine to mill)

increasing mineral recovery

increasing availability of equipment


Traditional Process Optimisation

Blasting

Grinding

Separation

Grade & tonnes

Grind size & throughput

Grade & recovery


Integrated Process Optimisation

• Measurement of ore characteristics across different ore types- Blastability – Rock structure, rock strength- Grindability – Rock strength (breakage properties)- Separability – Mineral composition, grain size & texture, degree

of alteration

• Recognition that the operation of all processes impacts on the optimum performance of its upstream and downstream processes

• Development of relationships between ore characteristics and performance across all operations

Objective Maximise profitability


Process Integration and OptimisationOre Characterisation

RF ID Tags

Rock StructureRock Strength

Mineralogy

MineralogicalProperties


Process Integration and OptimisationProcess modelling and simulation

RF ID Tags


Process Integration and Optimisation

VisioRock

VisioRockRF ID Tags

VisioFroth

CCM

On-LineInstrumentation and Measurement

VisioRock

OreMarkers

OreMarkers

OreMarkers


Establishment of Ore Specific Size Reduction Targets

Crushing & Grinding

Unbroken Ore Blasting Liberation

Ore mineral

Particle size progressively reduced


Optimum Blast Fragmentation

• Blasting should be recognised as the first comminution process• Maximise throughput through subsequent grinding process• Optimise cost distribution between blasting and grinding

Cost Energy($/t) (kWh/t)

Drill and Blast 0.15 0.2Primary Crushing 0.75 2.0Milling (SABC) 3.75 20.0

Example of a gold operation, open pit, relatively hard ore


Optimum Grind Size

• Maximise recovery and grade achieved in the subsequent separation processes

• Balanced by the need to minimise costs of size reduction and maximise throughput

Average Grain Sizes in AB Rougher Feed

0

20

40

60

80

100

120

140

160

180

0 20 40 60 80 100 120 140 160 180

Average Particle Size (m icrons)

Ave

rage

Gra

in S

ize

(mic

rons

)

All_Material Pentlandite Chalcopyrite Pyrrhotite

Average Grain Size in Rougher Feed


MethodologyDefinition of Ore Domains

Structure

Strength

Mineralogical Properties

100000.1 1 10 100 1000Size mm

0%

20%

40%

60%

80%

100%

Cum

% p

assi

ng

In-SituBlocks

Ag/Sag Mill Product

ROM

Crusher Product

Establishment of OperatingTargets


Measuring Structure: Scan line mapping and Image analysis

(after Kemeny, 2001)


Results of structure characterisation: in situ block size distribution

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

OYGMD1 OYGMD2 OYGMD3 OYGMD4 OYPB STGMD1 STGMD2

Structural Domain

Insi

tu B

lock

Siz

e (m

3 )

X50

X80


Measuring Strength: Point Load Tests


Point Load Strength Results

0

5

10

15

20

25

30

1 2 3 4 5 6 7 8 9 10

Is50

Freq

uenc

y

BrechaDiorita

NorteSul


Measurement of Mineralogical Properties –QEMSCAN Analysis

Rims Inclusions

Disseminated

LaminatedExsolved

Interstitial

Ore Characterisation


Case Study: Polymetallic Ore


Galena Bearing Particles


Galena Grain Size Distribution

G a l e n a B i - S i z e D i s t r i b u t i o n

- 2 0

- 2 7 / + 2 0

- 3 8 / + 2 7

- 4 5 / + 3 8

- 5 3 / + 4 5

- 7 5 / + 5 3

- 1 0 6 / + 7 5

- 2 1 2 / + 1 0 6

- 3 0 0 / + 2 1 2

- 4 5 0 / + 3 0 0

- 6 0 0 / + 4 5 0

+ 6 0 0


Sphalerite Grain Size Distribution

- 2 0

- 3 8 / + 2 0

- 5 3 / + 3 8

- 7 5 / + 5 3

- 1 0 6 / + 7 5

- 2 1 2 / + 1 0 6

- 3 0 0 / + 2 1 2

- 4 5 0 / + 3 0 0

- 6 0 0 / + 4 5 0

+ 6 0 0


CaseStudy: Blast Fragmentation Modelling -Powder Factor versus Size Distribution and Costs

Powder Factor vs Particles Size (P80, P50, & P20) and CostCoronado - Square Pattern

0

2

4

6

8

10

12

14

16

18

20

0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00 1.10 1.20 1.30 1.40 1.50 1.60

Powder Factor (lb/tn)

Size

(inc

hes)

$0.00

$0.04

$0.08

$0.12

$0.16

$0.20

$0.24

$0.28

$0.32

$0.36

$0.40

Cos

t ($/

tn)

P20P50P80CostLinear (Cost)Power (P80)Power (P50)Power (P20)


Case Study: ROM and Primary Crusher Product

0

10

20

30

40

50

60

70

80

90

100

1 10 100 1000size (mm)

Cum

ulat

ive

% p

assi

ng

0

10

20

30

40

50

60

70

80

90

100

1 10 100 1000size (mm)

Cum

ulat

ive

% p

assi

ng

Normal Blast -Crusher Product

Improved Blast -Crusher Product

Improved Blast -ROM

Normal Blast -ROM

Case Study 3 Normal ImprovedPowder factor (kg/t) 0.44 0.63Throughput (t/h) 353 370Product size (µm) 93 93


Summary

• New technologies have been developed to characterise the blastability, grindability & separability of ore domains.

• Online and offline measurement systems are allowing the understanding of ore types in terms of their lithology, mineralogy, breakage properties & recovery characteristics.

• Modelling, simulation, integration and optimisation of all processes (blasting, crushing, grinding and separation) within the production environment are providing the industry with rapid and cost effective means of increasing profitability.


Acknowledgements

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