TM Technology IsaMill in the Primary Grinding Circuit G Anderson - - PowerPoint PPT Presentation

IsaMill

TM Technology

in the Primary Grinding Circuit

G Anderson (Xstrata Technology) D Smith (McArthur River Mining) S Strohmayr (McArthur River Mining)

IsaMill

TM Development - UFG

• Developed to address ultra fine grinding requirem ents for McArthur

River and Mt I sa Pb/ Zn deposits

• McArthur River required 7 µm grind
• Conventional technology w as unsuitable due to poor efficiency and

surface contam ination

• Looked outside of the m ining industry
• Collaboration w ith Netzsch of Germ any – history of m anufacturing

stirred m ills for paint, inks, pharm aceuticals

• 1 .1 MW M3 0 0 0 ( litre) I saMill™ developed – becam e the enabling

technology for McArthur River Mine 1 9 9 5

IsaMill

TM Development - UFG

IsaMill

TM Development – Coarse Grind

• Requirem ent for larger scale I saMill™ identified by Anglo
• Inert and efficient grinding to improve mineral liberation and recovery
• M1 0 ,0 0 0 I saMill™ developm ent w ith Anglo/ Netzsch 2 0 0 3
• 1 st M1 0 ,0 0 0 in UFG at W estern Lim b Tailings Retreatm ent
• Developm ent of 3 .5 m m ceram ic m edia w ith Magotteaux
• 1 8 x 3 MW M1 0 ,0 0 0 I saMills™ installed w ithin Anglo
• F8 0 of 7 5 -1 0 0 µm ; P8 0 of 5 3 µm
• Further 4 x 3 MW on order for Anglo
• W orldw ide over 1 0 0 I saMills™

IsaMill

TM Development – Coarse Grind

IsaMill

TM Operation

McArthur River - 2006

Ore stockpile

Feeder Screen SAG Mill Verti Mill Primary Cyclones Flotation

McArthur River – Plant Trial

• Plant trial com m enced in May 2 0 0 7

Ore stockpile

Feeder Screen SAG Mill Verti Mill Primary Cyclones Flotation Magnetic Separator 1.1MW IsaMill

IsaMill™ Survey Data

1 10 100 10 100

Net Energy (kWhr/t) P80 Size (microns)

M20 Testwork Predicted Full Scale >300um Feed 150-200um Feed 200 - 250um Feed 250-300um Feed

55-60

Effect of Media Size

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 10 100 1000

Cumulative % Passing Size (um)

Feed 5-6mm Media Product 5-6mm Media Feed 3.5mm Media Product 3.5mm Media

P80 37µm P98 110µm P98 220µm 11kWhr/t 16kWhr/t

F80 350µm @ 12.8kWhr/ t

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 10 100 1000

Cumulative % Passing Size (um)

Feed Discharge

45 350

IsaMill™ Wear Performance

• I nitial 4 0 0 hour service life
• Disc and shell replacem ent
• Still beneficial to operate - trial becam e perm anent production m ill
• UFG m ills 2 0 0 0 hour service intervals
• Higher w ear a function of
• coarser feed/ media size
• mineralogy
• mill geometry designed for UFG

IsaMill™ Wear Performance

• Sm aller Diam eter Discs : 1 2 0 0 m m to 1 0 5 0 m m
• Service life increased 4 0 0 to 1 2 0 0 hours
• Max pow er reduced from 1 MW to 6 5 0 -7 0 0 kW
• Proportionally lim ited the throughput to m aintain grind perform ance

0.005 0.01 0.015 0.02 0.025 1200mm Discs 1050mm Discs Discs / MWh Mill Configuration

McArthur M10,000 IsaMills™

• Successful M3 0 0 0 trial – perm anent production m ill
• 2 x M1 0 ,0 0 0 installed for plant expansion Nov 2 0 0 8
• M3 0 0 0 developm ent w ork continued
• M1 0 ,0 0 0 com m issioned in UFG circuit - allow ed 2 x M3 0 0 0 for prim ary

grinding circuit

Primary Circuit Performance

• Plant throughput increased by 2 5 % from 2 6 0 to 3 2 5 tph
• W ith no I saMill™ case, P8 0 8 5 µm , OW i = 1 9 .3 kW hr/ t
• W ith 2 x I saMill™ case, P8 0 7 6 µm , OW i = 1 8 .4 kW hr/ t

Development

• I saMill™ Developm ent
• Alternative disc designs and configurations to recover power draw
• Shell design – M5000 IsaMill™ - can be retrofit to M3000 IsaMill™
• Allow geometrical ratios established with SDD in M3000 to be scaled up
• Circuit Developm ent
• McArthur River Phase 3 Development 2014
• Increase capacity to 5 mtpa
• M10,000 included in study for upgraded primary circuit
• Secondary or tertiary duty ahead of flotation

Conclusions

• Successful lab, pilot and full scale testw ork
• I saMill™ now integral, perm anent part of prim ary grinding circuit -
• perating for over 4 years
• I m provem ents m ade to w ear life and perform ance w ith further

developm ent w ork ongoing

• Success of the program
• IsaMill™ permanent part of grinding circuit
• 2 x M10,000 installation
• Further IsaMills™ under consideration for the Phase 3 expansion of the

primary grinding circuit