High-Power Drives for Energy Efficiency and Abatement of Carbon Emissions in Mineral Processing

High-Power Drives for Energy Efficiency and Abatement of Carbon Emissions in Mineral Processing Prof. Jorge Pontt, IEEE S.M. Department of Electronics, Universidad Tecnica Federico Santa María-Chile Director MilleniumNucleus Industrial Electronics, Mechatronics and Process Control - NEIM e-mail: jorge.pontt@usm.cl

Contents Introduction Mineral Processing Background Performance and Energy Efficiency-Cases Mine HaulTrucks SAG millwithgmd Rectifier Syst. for Electrowinning Conclusions

Miningin Chile World Ranking Product Chile 2008 % World Production 1ª Copper 5365 MTMF 34% 1ª Nitrates 1.160 MTM 100% 1ª Litium 56.900 TM 62% 1ª Iodine 15.500 TM 60% 1ª Molybdenum 33.700 TMF 15% 5ª Silver 1.405 TMF 7% Ref.: Alvaro Lacoste, Gerente Estudios SONAMI, Situación y perspectivas de la minería en Chile, Agosto, 2009.

ProcessTechnologies a) Conventional(Sulphides Ore, chalcopyrite) Tailing Dryer Concentrate Mine Crushing Grinding Flotation Smelting Refining Fine Cu b) Leaching-Solvent Extraction-Electro-winning(Oxides Ore and secondary sulfides) Mine Crushing Leaching Solvent Extraction Electro- Winning Fine Cu Obs. No tailings, No Grinding, No Smelting.

Introduction: Investmentsin Mining, Chile NewSX New Concentrators Source: COCHILCO

Challenge: Improve Copper Mining for Sulphides Ore Concentrate Tailing Dryer Mine Crushing Grinding Flotation Smelting Comminution (size reduction) -Depends on hardness of ore Refining Fine Cu -Use high-power equipment -Highenergyuse: 65% -Steel use -Grinding balls -Liners -Safety and Reliability issues Interdisciplinary work: Electrical Eng. Mechanical Eng. Process Eng. Safety+Reliability, Risk Management

MINING AND EMISSIONS Directemissionsare causedby fuel (Diesel) consum. Indirectemissionsare causedby electricalenergyuse. 1 MWH causes emissionsofca. 0.95 Ton CO 2 e 1 tmfneeds 3.7 MWH/tmfofCopper

Loading

Transport

Grinding

Smelting

Case 1: Mine HaulTrucks CAT Model 795F AC, The 345-ton (313-tonnecapacity) 795F AC, 3400 Hp (Electric) CAT Model 797B 4000Hp 400 ton (345-tonne) capacity 797B Komatsu 960E 360 t (327 Tonnes) Dieselelectric

Komatsu 960E 360 t (327 Tonnes) Diesel-electric

CAT Model795F AC, 345-ton (313-tonne-capacity) 3400 Hp(Diesel - Electric)

Fig.1. Block diagram of the dieselelectric haul truck drive system Improvements: Better efficiency of Diesel engine and less lubricants Possible automated autonomus operation Enhanced lower emissions, 5-20% biodiesel

Case 2: SemiautogenousGrinding Circuit (SAG) with Gearless Mill Drive About65% energyisusedin comminution(sizereduction)

Gearless Mill Drives applied for Grinding in the Region

Fig.2. High-power gearless drive for a SAG mill

Fig.3 Typical Semiautogenous(SAG) Circuit A huge amount of mineral and slurry must be handled

Fig. 4. Positioning alternatives of the load cataract in a mill Problem: How to control: The internal charge motion The axial load transport

Systemequations

Fig. 5. MONSAG for a GMD

Fig.6. Improvement in Mill filling measurement. Comparison using bearing pressures and MONSAG

Fig.7. Improvement in throughput employing MONSAG instead of bearing pressures

Fig. 8. Improvement in specific energy consumption

Fig. 9. Measured (inspections) v/s estimated load filling 3 6 3 5 3 4 Measured Filling, % 3 3 3 2 3 1 3 0 2 9 2 8 2 7 2 6 2 6 2 7 2 8 2 9 3 0 3 1 3 2 3 3 3 4 3 5 3 6 Estim ated filling, %

Improvements -Application in a SAG circuit of 24.000 tpd (36000 tpd) with a GMD 15.000 Hp, 36x17 feet Mill -Production average was improved by about 3.2% and - Specific energy consumption (kwh/ton) was improved by 3.8%. - In addition it gives to the operator an early warning for filling levels over- and under the expected values.

Case 3: Avoiding Broken liners

Different pieces of liners, lifters, plates, pulp lifters, grates, etc.

Broken liners caused by steel-to-steel impacts

Hammered liners, The Problem: -A too high speed of rotation, the more harmful impacts steel-to-steel. -A too low speed of rotation, the lower the comminution inside the mill

Solution: ImpactmerSystem. Array of sensors around the mill to detect aggressive conditions to liners

Case 4: Power System- Power Quality- EMC issues Fig.11 High-power rectifier for Electrowinning of copper

Fig.11 High-power rectifier for Electrowinning of copper

Fig.12 Voltages at the busbars1, 3 and 5 of network fig. 11

Summary Mine Haul Truck (Diesel electric): Better efficiency of Diesel Engine Less Lubricants Better maintenance Possible automated autonomus operation Use of 5-20% biodiesel With 5-20% reduction of direct emissions

Summary SAG mill: A saving of 0,36 kwh/ton, beneficiation of 12.483.000 tons/year it represents a saving of 4494 MWh/year, with an emission factor of 0,95 Tons CO 2 /MWH, the impact is a saving of ca. 4269Tons CO 2 /year. SAG mill: In addition, reliability, process stability and optimization may be enhanced with improved knowledge, design, procedures and smart instrumentation.

Summary

Conclusions Large scale operations for mineral processing needs the most powerful equipment. SAG mills depends strongly on the stability of the controlled movement of charge. Need of new concepts for productivity, energy efficiency and carbon emissions. Reliability means less downtimes and less man-hours working in the harsh industrial environment, contributing to safety.

Applied R&D Improvements Process energy efficiency and emissions. -Engineering Design -Operation& Maintenance -Networking and Int l collaboration -Ackowledgementsto our partners

Universidad Técnica Federico Santa María Millennium Nucleus Industrial Electronics, Mechatronics and Process Control Center for Automation and Supervision for Mining industry Thank you!