Coalition for Eco-Efficient Comminution

VisionTo accelerate implementation of eco-efficient comminution strategies through promotion of

research, data and industry benefits

Patron Owen Hegarty G-Resources Group

BoardChair Elizabeth Lewis-Gray Gekko

SystemsDirector Prof Tim Napier-Munn JKMRC Director Dr Wayne Stange AMIRADirector Dr Mike Daniel CMD ConsultingDirector Dr Zeljka Pokrajcic Worley Parsons

CEEC Sponsors

Comminution Energy Consumption

4 – 9% Australia’s electricity consumption

30 – 40% total mine

Source: CSRP Eco-Efficient Liberation – Outcomes and Benefits 2003-2010

Comminution Energy Consumption

CO2 contributions for the stages of copper concentrate production, Source: Norgate and Haque, 2010

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1999 Leinster Nickel Operations CO2 Emissions

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Typical site comminution energy footprint

Source Le Nause, Temos 1992

• Understand mineral and gangue liberation characteristics

• Reject gangue or recover mineral in crushing step, prior to milling

• Recover mineral or gangue at coarsest particle size

• More crushing less grinding• Utilise new and more energy

efficient technologies

Eco Efficient strategies

Selection of the coarsest possible grind size

Energy & grind size

1.E-01

1.E+00

1.E+01

1.E+02

1.E+03

1.E+04

1.E+05

1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03 1.0E+04

Particle Size (micron)

En

erg

y (k

Wh

/t)

Source: Hukki RT, 1961

Optimum liberation

Coarser grind may improve recovery

More crushing – less grinding

• Ball mills only apply 5% of energy used to particle size reduction

• Fine crushing is more energy efficient

• Very low power consumed in supporting systems such as pumping and conveyors

“The most efficient way to break rock, is not to

break rock at all”

Dr Rob Morrison, JKMRC

• Blasting– Optimise fragmentation to maximise

fines in ROM ore– “Bricks and mortar”

• Screening:– ahead of, and in, the grinding circuit

• Gangue Rejection• Pre-concentration• Concentration

Improved ore presentation and flow sheets

• Fine crushing– VSI– HPGR

• Fine Screening• Ore Sorting• Gravity – continuous & batch

– InLine Pressure Jig– Centrifugal Concentrators

• Coarse Flotation

Improving technologies

Castlemaine Goldfields plant

New flowsheet with gangue rejection

• Recovery increased by maximising gravity recovery, finer grind, increased head grade to process plant.

Unit: CONVENTIONALWITH

PRECONC. Change:

Material Treated: Mt 21 21Grade:Au g/t 0.82 0.82

Contained Au: oz 554,000 554,000Gangue Rejection: Mt - 10

g/t - 0.13oz - 41,150

Process Plant Feed: Mt 21 11g/t 0.82 1.45oz 554,000 512,850

Production: oz 415,000 435,900 5%Process Plant Recovery: 74.9% 85.0%

Overall Recovery: 74.9% 78.7%Average Processing Power Demand: MW 68 50 -27%

Energy Effi ciency for gold produced MWhr/oz 1.44 1.01 30%Energy Effi ciency for ore treated: kWhr/t 28.5 20.9 27%

Benefits of New Process for site

• Lower Capital Cost for Greenfields Installation• Net reduction in energy consumption• Increased gold recovery• Increased gold production• Reduced $/oz operating cost of gold produced

CEEC Linked In discussion page

CEEC Linked In Discussions

• Ore sorting• Microwave technology• Blasting techniques• Comminution research• Conference blogs

CEEC – Website Home Page

CEEC – Key Papers

CEEC Sponsors

End