Electraulic™ Actuation

• Minerals – Copper, Molybdenum, Platinum, Gold, Coal, and Phosphate– Separates sulfide ores– Reduces total material movement– Trend is larger cell size

• Locations– Dart Valves – Modulating

• Tank Froth Level Control– Consistent froth layer

» too thick – collapse» too foamy – poor transfer to

launder – Level consistency– Increase recovery % & grade

• REXA Eliminates “bath tub drain effect”

• Reduce energy consumption– Air Flow Control Froth

• Rexa Advantages– Stiffness

– Reliability

– 100% Duty Cycle

– Low Energy Consumption

Dart Valves

• Velocity increases as slurry exits. When plug is <20% open the decrease in pressure will cause valve to close with a pneumatic actuator

• Bath Tub Stopper Effect Impacts Process Stability and Pulp Level!!!

Pneumatic Actuator Position %

REXA REDUCED PV Range 43%! Note: 12 months

pneumatic and 4 Months REXA production data

Process Variable Variation

REXA Actuators

Pneumatic Actuators

• Four X2L10000 Actuators• 10,000 lbs. Force• Accumulator Fail Safe• Successful Retrofit

Total Return on Investment

Actuator Cost

-

Compressor Depreciation

-

Maintenance

-Energy

-Down Time

-

Improved Recovery

+

• Rexa Maintains Low Scavenger Tails Cu Grade During Upsets

Dart Valves

Assumptions:• 76k tons per day ore feed• 5% feed to tails• 3% process disruption time (43 min/day)• $3.25 Cu price per lb

• REXA Maintains Process Set Point• Less Copper is lost to Final

Tailings• Impact is 31,000 Cu Lbs/YR

returned to Rougher!

• High Electrical Costs• High Maintenance

Costs• Risk of Multiple

Actuator Fails with Loss of Air

Source: US DOE

• Electrical Cost Assumptions– 100 HP Motor for 10

Pneumatic Actuators– $.05 per kWh– 10 years– Compressor 80% loaded– 8400 hrs. per year

• Dallas Stadium– ~$60,000 each Sunday*

• 4 Pneumatic Actuators– $60K in 3.2 years

– $0.05/kWh

• 4 REXA Actuators– $4.8K in 3.2 Years!– REXA only 7.5%!

Dallas Stadium*EE Times 8/18/2009

• Slow to position during slurry flow surges often result in tank overflow and product loss

• Copper Mine• Cu Scavenger Cells • Fast Reaction to Set

Point Changes• Stiffness of Hydraulics• Low Maintenance

2000 lbf Thrust6 Inch (6mm) StrokeFail in Place

• Gold Mine

• Fast Reaction to Set Point Changes

• Stiffness of Hydraulics

• Low Maintenance

Model L2,000-6-B-P2000 lbf (8896N) Thrust6 inch (100mm) stroke6 seconds per inch

• Penasquito Gold Mine

• Actuator strokes closed until calibrated delta Pressure (dP) is reached– motor is turned off

– relay tells DCS the actuator has reached full “closed” pressure.

• Extended maintenance interval achieved– actuator adjusts for plug erosion

as compared to set position

20,000 lbf (88976 N) thrust22 inch (733mm) stroke10 seconds per inch

• Coal Mine • Coal Washing • Tank Liquid Level

Control• 2,000 lbf thrust

linear actuators• Over 100 Actuators

used in OEM Application

• Step Changes in decreasing air flow rate

• Production (Platinum)

Relative GradeA)1.0

B) 0.59

C) 0.38

Source: M. Kistner, L Auret, C. Aldrich

• Flotation Cells• Air Flow Control • 12 units installed

at Copper mine

• REXA R2500• Rotary Actuator• 2500 lbf•in (282

N•m) torque