Gearless Mill Drives (Marsh)

www.marsh.ca www.marsh.com

Gearless Mill Drives

Machinery Risk Solutions Practice

2009

Matt Dugalic P.Eng., MARSH – MRSP Risk Consultant, VPKurt Tischler Dipl.-Ing., Siemens – Product Manager, Mining

1Marsh

WHY shift to the gearless drives in mineral processing ???

Mill size – grinding economies of scale

Relative lifecycle cost

Lower power consumption

Robust design

Avoiding critical open gear power trains

Variable speed

Compatibility with processing plants

Engineering design efficiencies

Availability

Minimal downtime

2Marsh

However,

from the machinery breakdown underwriting perspective, this

often creates a

critical, single point exposure !!!

3Marsh

Significant Mining Industry Property Losses (Jan 2006 – Jul 2009)

Class Loss Type Gross Claim

(MM US$)

Coal Flood +/- 603

Coal Flood +/- 550

Coal Flood +/- 450

Iron Storm / Flooding +/- 180

Manganese Smelter Explosion +/- 170

Platinum Flood +/- 140.3

Iron / Salt Typhoon (Glenda) +/- 122.4

Copper & Zinc Electrical Flashovers of SAG Mill Stator +/- 115

Iron / Salt Typhoon (Emma) +/- 107.7

. . .Siemens

www.marsh.ca www.marsh.com

Mastertextformat bearbeitenZweite EbeneDritte EbeneVierte EbeneFünfte Ebene

Confidential / Copyright © Siemens AG 2009

SIMINE Mill Gearless Drive

Siemens’ Gearless Drive Technology

Performance

Facts & Figures

October 2009 I IS MT MIKurt TischlerConfidential / Copyright © Siemens AG 2009

Content

Experience & References (5 minutes)

Maintenance, Service (2 minutes)

Major Problems and their Solutions (25 minutes)Cadia, Repairs, Lessons learned Chilean plant, Rotor failure

Performance: Downtime; Availability (10 minutes)

SIMINE Mill Gearless Drive Performance


Sydvaranger Norway

Gearless Drive 8200 kWfor a Ballmill of 21.3 ft ID

Start-up: 1980

SIMINE Mill Gearless Drive Experience First Gearless Drive in Mining


Sydvaranger Norway


Start-up: 1980

History:

1997: Shutdown of plantdue to low iron prices

2005: Mill and Gearless Drive sold to Zinifex Australia

SIMINE Mill Gearless Drive Experience


Sydvaranger Norway


Start-up: 1980

History:

1997: Shutdown of plantdue to low iron prices

2005: Mill and Gearless Drive sold to Zinifex Australia

2008: Restart in Zinifex’Century Zinc Plant



Start-up:1988

Altitude:3000 m

CODELCO Chuquicamata, 2 GD 8210kW, 32’First SAG-Mill Gearless Drives


Start-up:1991

CODELCO El Teniente, GD 12000 kW First 36’ SAG-Mill Gearless Drive


Start-up:1997

Altitude:2700 m

Freeport II; Indonesia, 20400 kW First 38’ SAG-Mill Gearless Drive


Start-up:1998

Cadia Australia, GD 20000 kW, First 40’ SAG-Mill Gearless Drives


kW233,542Total Power20 Gearless Drives

19808,20021.3Ball-MillNorwaySYDVARANGER

19888,21032SAG-MillChileCHUQUICAMATA 1

19898,21032SAG-MillChileCHUQUICAMATA 2

199011,20036SAG-MillChileEL TENIENTE

19904,00016.4AG-MillSouth AfricaGOLDFIELDS 1

19904,00016.4AG-MillSouth AfricaGOLDFIELDS 2

199112,00036SAG-MillUSAKENNECOTT

19919,65021.3AG-MillRussiaNORILSK NICKEL 1

19919,65021.3AG-MillRussiaNORILSK NICKEL 2

199312,00036SAG-MillChileCANDELARIA 1

199510,60034SAG-MillIndonesiaFREEPORT 1

199713,40036SAG-MillArgentinaALUMBRERA 1

199713,40036SAG-MillArgentinaALUMBRERA 2

199720,40038SAG-MillIndonesiaFREEPORT 2

199712,00036SAG-MillChileCANDELARIA 2

199913,31136SAG-MillChilePELAMBRES 2

199913,31136SAG-MillChilePELAMBRES 1

199818,00038AG-MillAustraliaOLYMPIC DAM

199812,00036SAG-MillChileANDINA

199820,00040SAG-MillAustraliaCADIA

Rated Power (kW) Start-upID of Mill (ft)Type of MillCountryPlant

SIMINE Mill Gearless Drive References



Scheduled 201122,00040SAG-MillChileANGLO Los Bronces

Project stopped20,00038SAG-MillVenezuelaLas Brisas

233,54220 above

200713,05036SAG-MillBoliviaSAN CRISTOBAL20077,83022Ball-MillBoliviaSAN CRISTOBAL20077,83022Ball-MillBoliviaSAN CRISTOBAL200319,40038SAG-MillChileEL TENIENTE200311,18624Ball-MillChileEL TENIENTE200311,18624Ball-MillChileEL TENIENTE200611,18624Ball-MillChileEL TENIENTE200612,50036SAG-MillAustraliaBarrick Cowal

200610,50022Ball-MillAustraliaBarrick Cowal

200818,00038SAG-MillZambiaEquinox Lumwana200815,00026Ball-MillZambiaEquinox Lumwana200820,00038SAG-MillBrazilRPM Kinross

Project stopped20,00038SAG-MillVenezuelaLas BrisasScheduled 201015,50026BallmillChileLos PelambresScheduled 201015,00036SAG-MillChileLos PelambresScheduled 201018,30038SAG-MillMéxicoPeñasquitoScheduled 200918,30038SAG-MillMéxicoPeñasquito




Scheduled 201128,00040SAG-MillAustraliaCP –MiningScheduled 201028,00040SAG-MillAustraliaCP –MiningScheduled 201028,00040SAG-MillAustraliaCP –MiningScheduled 201028,00040SAG-MillAustraliaCP –MiningScheduled 201028,00040SAG-MillAustraliaCP –MiningScheduled 200928,00040SAG-MillAustraliaCP –Mining

Scheduled 201116,40026SAG-MillChileANGLO Los Bronces


Project stopped15,70026BallmillChileEscondida


520,310 above39 above

Scheduled 200928,00040SAG-MillAustraliaCP –Mining

Scheduled 201124,00040SAG-MillPeruXstrata Las Bambas

Scheduled 201116,40026BallmillPeruXstrata Las BambasScheduled 201116,40026BallmillPeruXstrata Las BambasProject stopped14,00034SAG-MillAustraliaAurox Balla Balla

Project stopped15,70026BallmillChileEscondidaProject stopped22,00040SAG-MillChileEscondidaScheduled 201111,19024BallmillPeruAntamina Scheduled 201120,14238SAG-MillPeruAntamina Project stopped17,00026Ballmill AustraliaAurox Balla Balla





Scheduled 201116,40026BallmillPeru or ChileXstrata 2Scheduled 201116,40026BallmillPeru or ChileXstrata 2Scheduled 201124,00040SAG-MillPeru or ChileXstrata 2


kW1’003,920Total Power64 Gearless Drives

892,942 above58 above



SIMINECIS Mill gearless drivesReferences

in operation: 33

in fabrication or installation: 21

project stopped: 4

order cancelled: 6


SIMINE Mill Gearless DriveClarification

No flashovers in Siemens’ SAG-Mill Stators


Collahuasi Chile: 40’ Gearless Mill Drive NOT Siemens supply

Escondida Chile: 38’ Gearless Mill Drive NOT Siemens supply

Escondida Chile: 25’ Gearless Mill Drives NOT Siemens supply

Antamina Peru: 38’ Gearless Mill Drive NOT Siemens supply

Antamina Peru: 24’ Gearless Mill Drives NOT Siemens supply

SIMINE Mill Gearless DriveClarification


SIMINE Mill GDExperience

Mill

Diameter16’ 21’ 24’22’ 32’ 34’ 36’ 38’ 40’

Ball-Mills SAG-Mills

1

2

3

4

5

6

7

8

9

10

Number

Gold-fields

Kolskaya

Syd-varanger

SanCristobal

Cowal

AntaminaEl

Teniente

Chuqui-camata Balla Balla

Freeport

PelambresSan Cristobal

Cowal Pelambres

AndinaAlumbreraCandelariaKennecottEl Teniente

AntaminaLas BrisasParacatu

PeñasquitoLumwana

El TenienteOlympic Dam

Freeport

26’

Xstrada 2Antapaccay Pelambres

Los BroncesLumwana

11

Xstrada 2AntapaccayCP-Mining

Los BroncesCadia


Total Operation hours

SIMINE Mill GD in Mining:

Machine years307

until September 2009





Machine days105,000




Content







Preventive Maintenance of Gearless Drive is performed during downtime for Mill Maintenance

No additional downtime for preventive Maintenance of Gearless Drive

SIMINE Mill Gearless Drive Maintenance, Service


SIMINE Mill Gearless Drive Recommended Maintenance Schedule


Preventive maintenance recommended

Four (4) actions (in total 13 minutes) once per month, during operation,

Eleven (11) actions (in total 247 minutes) once per 3 months, during operation,

Two (2) actions (in total 130 minutes) once per 6 months, during downtime for maintenance of mill,

27 actions (in total 25 hours and 46 minutes) once per year, during downtime for maintenance of mill,

Five (5) actions (in total 8 hours) once per 3 years, during downtime for maintenance of mill,

Five (5) actions (in total 9 hours) once per 5 years, during downtime for maintenance of mill,

SIMINE Mill Gearless Drive Recommended Maintenance Schedule


Minimum work for maintenance of Gearless Drive,

average of 37 hours per year,

Normal electricians and engineers are requested for scheduled

maintenance,

Siemens offers maintenance and service contracts

SIMINE Mill Gearless Drive Maintenance, Service


Content







Cadia; AustraliaGearless Drive 20 000 kW for a 40 ft. SAG-Mill

Commissioning in May 1998

Elastic DeflectionsDuring Startup

Vibrations during operation

Observed Phenomena at the Motor of Cadia


f [Hz]0

10

20

0 1 2 3 4 5 6 7 8 9 10 11 12

P [MW]

OperatingrangeOperatingOperatingranrangege

7 Hz = 9.5 rpm

Resonance frequency of the stator system

Cadia: Investigation

Rated speed: 9.01 rpm

Rated frequency: 6.6 Hz

Maximum speed: 10.36 rpm

Max. frequency: 7.6 Hz


The resonance already appeared during commissioning in July 1998

The problems occurred at cold condition of the motor.

Reaching the operation temperature of the Ring motor the vibrations disappeared

and the Gearless Drive was operated using the complete speed range

Cadia:Resonance of the stator system


Pedestals with hydraulic jacks were installed at the stator bottom to increase stiffness of stator.

During commissioning stage Siemens provided preliminary measures to enable the operation of Gearless Drive and SAG-Mill also at cold condition.

Cadia: Resonance of the stator system; PRELIMINARY MEASURES


The preliminary measures were so successful that Cadia operated the SAG-Mill continuously at full throughput.

The preliminary measures allowed the operation in the complete speed range also in cold condition.

As a consequence Cadia allowed

access for investigation only during liner change,

six months after start of commercial operation.

Cadia: Resonance of the stator system; PRELIMINARY MEASURES


During liner change was performed the deflection measurement taken on the motor of Cadia with photogrammetric system

Cadia: Resonance of the stator system; INVESTIGATION


Foundation stiffness

Mill stiffness

Mill modeledas rigid body on springs

Stator modeledwith beam elements

Air gapelements

Cadia: Lessons learnedImproved FE model, considering non-linear air gap behavior

Non-linear air gap force vs. deflection

relation

Special airgap elementsallow a direct input ofexcitation current

Reaction forces are calculated on deformed structure

Dynamic reaction of structure is calculatedwith direct time integration



3rd mode shape: Ovalization



4th mode shape: Twisting


Modified form of the stator

Additional stiffener built on the stator

Cadia: RepairsModification of stator


The installation of the stiffener was performed during a

downtime of 7 days

parallel to a liner change of five days.

Cadia: Resonance of the stator system; End of 1999 the stiffener was installed on the stator


Cadia: Resonance of the stator system; Final solution: Stator with stiffener

Since installation of the stiffener, end of 1999, the Ring motor of Cadia does not show any vibrations any more.


Lamination core

Mill flange

Rotor flange

Rotor poles

Rotor support

Cadia: Rotor Pole Segments Cracks at support ribs


Cadia: Rotor Pole Segments Cracks at support ribs

Change of airgap at several spots was detected in 2003.

The problem was investigated during liner change.

Engineering analysis and repair concept was developed by Siemens together with Cadia and EAnD.

Cadia published a paper on the SAG-conference 2006 in Vancouver.Please find more details there.


Cadia: Rotor Pole Segments Repair

Repair was performed during a scheduled downtime of 15 days in June 2005 in parallel to a liner change, which normally needs four days.


Cadia Gearless Drive AVAILABILITY

Start-up July 1998 to 2003 mechanical & electrical: 98.5 %

From 2003 to 2005 electrical: 98.5 %

2005 Repair of rotor electrical: 95.5 %

2005 to date electrical: higher than 99 %Ring motor: 100 %


Cadia: Cracks of welding beams at rotor supportDesign Change

Lamination

Pressure plate

Flange plate

Divided ribWeld

Pressure bolt


Tensile load

Stress concentration

Magnetic pull

Stator core

Magnetic pull

Tensile load



The magnetic pull tries to bend the lamination and the rib welded on to it.

Through this a tensile load arises in the lower edge of the rib.

There is no stress concentration since the rib cross section is undisturbed.

Magnetic pull

Tensile load

Stator core




Design Change was implemented 2005 and is in operation in all Siemens Gearless Drives since then.


The 38’ SAG-Mill is in operation since September 2003

During the weekend of August 31, 2008 the SAG-Mill stopped several times and was restarted. Finally the air gap supervision tripped the motor and did not permit to restart it again on September 1, at 4:48 a.m.

Air gap and rotor were revised and there was found a crack of a weld of the rotor segment support (Picture next page)

Specialists from Siemens Germany arrived on September 3 at site and investigated the motor. They found another crack at the same segment and another segment with cracks.

They started the repair on September 4 and the mill restarted on September 8, 2008 at 9:10 a.m.

38’ Gearless Mill Drive, ChileCracked Weld at rotor support


Chilean Plant Cracked Weld at rotor support


The mechanical stress is caused by three effects

Constant stress by constant magnetic force, (does not cause fatigue)

Fatigue is caused by variable stress

Variable stress by gravity,

Variable stress by changing magnetic force over the circumference, due to air gap deformation

Chilean Plant Origin: Fatigue by mechanical stress


Normal air gap deformation during operation

Small air gaphigher force

Large air gapsmaller force

Chilean Plant Variable Stress around the circumference


Chilean Plant Provisional Repair of Rotor Segment


Chilean Plant, Provisional Repair of Rotor Segment


Siemens investigated the possibility of similar damages in other Ring Motors and informed in September 2008 three other users to inspect the rotors:

Other Chilean PlantInspection was performed during mill maintenance in February 2009: no findings

Australian plantInspections were performed during plant maintenance in November 2008 and February 2009:cracks were found and provisionally repaired; 2 additional days of downtime;

Indonesian plant Inspection was performed during plant maintenance in April 2009 cracks were found and provisionally repaired; 12 additional hours of downtime;

Defect of rotor segments; Consequences for other users


The final repair of the rotor segments were planned from June 30, 2009 to July 14, 2009, parallel to a mill maintenance (liner change) .

After replacing 4 segments, turning of motor for positioning wasinterrupted by earth fault.

There were found foreign objects in the air gap, which had damaged stator windings and rotor coils.

Repair of windings and coils was finished August 10, 2009without completion of rotor segments.

A failure of the feeding switchgear delayed the restart of production for another two days.

Caused Downtime: 43 days minus 4 days for mill maintenance

Chilean Plant Final Repair of Rotor Segment


Content



Major Problems and their Solutions (25 minutes)Cadia, Repairs, Lessons learned Chilean Plant, Rotor failure




Major downtimes for repair:

Cadia, Vibrations,

Cadia, defect at the rotor segments,

Chilean Plant, defect at the rotor segments,

Australian plant, defect at the rotor segments

Indonesian plant, defect at the rotor segments

SIMINE Mill Gearless Drive Downtime, Availability


Cadia; Vibrations

Downtime for repair: 7 days minus 5 days for liner change


Cadia; Defect of rotor segments

During 2003 Cracks of welds at rotor support were found and provisionally repaired. Downtime: 5 days for investigation and repair

minus 4 days for liner change.

In 2005 the final repair was performed with a downtime of 15 days.

Downtime for repair: 15 days minus 4 days for liner change


Chilean plant; Defect of rotor segments

September 1, 2008 the air gap supervision of the 38’ Ring motor tripped the mill. Cracks were detected and provisionally repaired. September 8, 2008 the 38’ mill was restarted. 9 days of unscheduled downtime

First part of final repair in 2009 including repair of occurred damages: Downtime: 43 days minus 4 days for mill maintenance

Scheduled completion of final repair in 2010: Downtime: 15 days minus 4 days for liner change



Major downtimes for repair:

Cadia, Vibrations: 2 days

Cadia, defect at the rotor segments: provisional repair: 1 day….

final repair: 11 days

Chilean plant, defect at the rotor segments: 2008: 9 days First part of repair in including repair of damages 2009: 39 days

final repair, scheduled 2010: 11 days

Australian plant, defect at the rotor segments: 2009: 2 daysfinal repair, scheduled 2010: 14 days

Indonesian plant, defect at rotor segments: 2009: 0.5 daysfinal repair, date to be defined: 10 days

Total sum 99.5 days





Machine days105,000

With major downtimes of in total 99.5 machine days




Thank you for your attention!

Contact:

Kurt TischlerSiemens AGMetals TechnologiesMining IndustryW-v-Siemens-Str. 5091052 Erlangen / GermanyPhone: +49 (9131) 7-42420Mail: [email protected]

Gearless Mill Drives (Marsh)

Documents

Transcript of Gearless Mill Drives (Marsh)