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BEST BEST QUALITY QUALITY CIRCLECIRCLE

Donimalai Iron Ore Mine

Presents

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NMDC: India’s single largest Iron ore producer.

Formed on 15.11.1958 Core Competency in Iron

Ore, Diamond and Lime Stone mining. ‘Navaratna’ Status in Jan 2008 ISO 9001-2000 certification in February 1999. ISO 14001 certification Awarded in 2004. OHSAS 18001-2007 in Feb. 2010

NMDC Limited

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Scientific and eco-friendly mining

Mining by Mechanized meansQuality ControlMineral BeneficiationProper BlendingOptimum exploitation of precious mineral

Single largest producer of Iron ore

Planned to increase Iron Ore production to 50 million Tones by 2014-2015.Expansion of production capacity of existing mines.Iron Ore supply to international & Domestic markets is in the ratio of 85:15.

NMDC MAKES PEOPLE HAPPYAND NATION PROUD

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ProductsBaila ROM (Size :10mm - 150 mm)Baila Lump (Size :6 mm - 40 mm)DRCLO (Size :10 mm – 40 mm)Baila Fines (Size : -10 mm)Doni Lump (Size : 6 mm -30 mm)Doni Fines (Size : -10 mm)Panna – Rough Diamonds

Contribution to Indian EconomySo far earned foreign exchange in excess of Rs 16,000 crore.In recent disinvestment of NMDC shares by Govt of India fetched around Rs 9,930 crore.Paying dividend since 1990-91It has about 6000 employees.

NMDC MAKES PEOPLE HAPPYAND NATION PROUD

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1. Essar Steels.2. MMTC LTD 3. Ispat Industries Ltd. 4. JSW Steel Ltd. 5. Sponge Iron India Ltd. 6. KIOCL Ltd.7. Lanco Industries Ltd. 8. Tata Metalliks Ltd. 9. Aparant Iron & Steel Co. Ltd.10. Vikram Sponge Iron Ltd.11. Visvesvaraya Iron & Steel Plant 12. Rashtriya Ispat Nigam Ltd.( VSP)13. Kirloskar Ferrous Industries Ltd 14. Southern Iron & Steel Co. Ltd. 15. CG based Sponge Iron Units

Our Valuable Customers

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NMDC Projects under Production

Bailadila Iron Ore Mine Bacheli Complex

Bailadila Iron Ore Mine Kirandul Complex

Madhya Pradesh

Uttar Pradesh

Chha

tisga

rh

Karnataka

Donimalai Iron Ore Mine Donimalai Complex

Kumarswamy Iron Ore Mine Donimalai Complex

Panna diamond Mine Panna Complex

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Our Quality Policy

Donimalai Iron Ore Mine, an operating unit of National Mineral Development Corporation Limited, is committed to achieve sustained consistency in quality of Iron Ore mined, processed and produced by adopting and continually improving Scientific Quality Management Systems through active involvement of all the employees to ensure optimum satisfaction of all the stake holders.

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Name : BEST Quality Circle

Organization : NMDC LimitedProject : Donimalai Iron Ore

MineDepartment : Services

MechanicalWorking area : Dumper SectionPROJECT QC COORDINATOR : Sri O.P.Sahu, Mgr. (Mech.)-

HRD

Leader : Sri Wilson Fernandes

Members : 1. Sri M. Avinash: 2. Sri Hampa

Reddy: 3. Sri A.

ChandrashekarFacilitator : Sri T. HarishDate of Inauguration : 25th Apr’ 2007.Meeting Day : Every MondayMeeting Time : 12:00 - 13:00 Hrs.Average Attendance - : 89.5 %in meeting

QC Profile

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PDCA Cycle

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1. Difficulty in mounting front suspension to the chassis of 777D Dumpers.

2. Failure of Water Sprinkler coupling.3. Coolant foul smell in Machine Shop.4. Oil leakages in Water Sprinklers and 85 ton dumpers.5. Bucket hitting and body vibration in 85 ton dumper.6. Failure of fan pulley bearing in 85Ton dumper.7. Time consumption in house keeping in Machine Shop.8. Difficulty in marking of Machine Shop jobs.9. Difficulty in removing of bearing, bushings, hubs etc.10. Difficulty in removing and disposal of machine shop chips. 11. Failure of clutch in TIL cranes.12. Slow air buildup in BH-85 BEML dumpers.13. Air locking in Dumpers and Dozers.14. Difficulty of nitrogen gas charging in dumper suspensions.15. 200 ton hydraulic press jack setting problem.

Identification of Work Related Problems‘A’ Category Problems

Better be unlearned than ill- learned.

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16. Tar road damage due to Track Dozer shifting.17. Difficulty in giving torque to Differential side bolts.18. Difficulty in identification of spares in Service Centre.19. Brake and Accelerator pedal hard in BG825 grader.20. Difficulty in Crowd Motor shaft changing.21. Battery getting discharged in Dozers.22. Shearing of lead screw pin in NH22 Lathe.23. Oil spillage in shop floor.24. In water sprinkler engine runs at high RPM.25. No Blade floating system in BG825 grader.26. No platform in one side of EOT crane.27. Difficulty in fitting of rear hub in 85 ton dumpers.28. Insufficient water sprinkling in water sprinklers.29. Difficulty in air inflation of tyres in 85 ton dumpers.30. High noise at Dumper Maintenance and Dumper Major area.

‘A’ Category Problems

Identification of Work Related Problems

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31. Difficulty in collection of oil from used/drained oil pit.32. No proper schedule maintenance for TIL cranes.33. Starting trouble in Demag Shovel.34. Noise level in BH-85 BEML dumper is high.35. Frequent choking of econ valve of air system in BH-85 BEML dumpers.36. Frequent failure of pneumatic system in BH-85 BEML dumpers.37. Frequent failure of CLS system in dumpers.38. Rock ejector aligning problem in BH-85 BEML dumpers.39. Difficulty in checking Hydraulic oil level in BH-85 BEML dumper when

bucket in lifted condition.40. Frequent brake weak in BH85 BEML Dumpers.41. Delay in closing of arms in tyre handler.42. Frequent cabin overheating in BH85 BEML dumpers.43. Hard steering in BH-85 BEML dumpers. 44. Gear problem in escort cranes.45. Starting problem in TIL cranes.

Identification of Work Related Problems‘A’ Category Problems

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46. Starting trouble in DG.47. Difficulty in fueling water sprinkler.48. Difficult Washing and cleaning of Dumpers.49. Frequent linkage problem in exhaust box of BH85 BEML dumpers.50. Frequent failure of hydraulic system in 777D 85 Ton dumpers.51. Difficulty in changing the transmission breather in CAT 777D 85 Ton

dumpers.52. Frequent failure of shut off cock valves in BH85 BEML dumpers.53. Difficulty in rotation of engines at engine shop.54. Difficulty in the visibility level during fog at dark hours for dumper

running in haulage roads.55. Difficulty in greasing the drive shaft joint nipples in BEML dumpers.56. Frequent failure of brake cooler hoses in BH-85 BEML dumpers.57. Difficulty in placing the dumper at diesel bunk.58. Difficulty in aligning rear suspension top pin in 85 Ton dumpers

Identification of Work Related Problems‘A’ Category Problems

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1. Time consumption in Dumper washing.2. Difficulty in working in below area of TIL crane.3. Difficulty in EOT crane cable handling.4. Difficulty in welding at distant places when two or more dumpers are

standing for repair.5. Chocking of service centre drainage area.6. Damages to dumper tyres near diesel bunk.7. Improper infrastructure of shop floor and also difficulty in maintaining

the shop floor during rainy season.8. Leakage of roof in work shop areas.9. Poor illumination for engine shop and dumper shop.10. Improper illumination while working under dumpers.11. During rainy season dumper shop gets water logged.12. Shop floor slippery after water logging and oil spillage.

Identification of Work Related Problems‘B’ Category Problems

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1. Foul smell in Engine Shop.2. Dust pollution in Service Centre area.3. Risk of back fire in gas cylinders.4. Water leakage in Water Sprinklers.5. No rigger room, improper storage of Slings and D shackles.6. 85 Ton dumper unable to enter in Maintenance and Major Shop.7. Improper gas cylinder trolley.8. Effluent Treatment Plant not working.9. Shifting of Dozer to Screening Plant.10. Removal of Dozer cutting edges. 11. Shop floor& roof structure unsafe to work .12. Head light illumination of dumper is poor.

Identification of Work Related Problems‘C’ Category Problems

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ABC CLASSIFICATION AND RATING METHODS

CATEGORY “A”

MINIUMUM INVOLVEMENT OF OTHER DEPARTMENTS.

CATEGORY “B”

INVOLVEMENT OF OTHER DEPARTMENTS IS A NECESSITY.

CATEGORY “C”

COMPLEX AND PRIOR MANAGEMENT SANCTION MAY BE NEEDED.

SL. NO

CATEGORY

NO. OF PROBLEMS

NO. OF PROBLEMS SOLOVED

NO. OF PROBLEMS TO BE

SOLVED

1 A 58 9 492 B 12 1 113 C 12 Nil 12

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Each member listed the following ‘A’ category problems according to the Safety, Production and Occurrence. Which are:-

1. ‘A’ Category Problem No. 40Frequent brake weak in 85 Ton BH-85 BEML Dumpers.

2. ‘A’ Category Problem No. 27Difficulty in fitting of rear hub in 85 ton dumpers.

3. ‘A’ Category Problem No. 55Difficulty in greasing the drive shaft joint nipples in BEML dumpers.

4. ‘A’ Category Problem No. 10Difficulty in removing and disposal of machine shop chips.5. ‘A’ Category Problem No. 36Frequent failure of pneumatic system in BH-85 BEML dumpers.

Problem Selection

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List of Problems selected

Avinash

Chandraiah

Ham

pa reddy

Chandrashek

er Total

Rank

Frequent brake weak in 85 Ton BH-85 BEML Dumpers.

7 5 6 7 25 II

Difficulty in fitting of rear hub in 85 ton dumpers.

5 8 3 4 20 IV

Difficulty in greasing the drive shaft joint nipples in BEML dumpers.

7 5 6 3 21 III

Difficulty in removing and disposal of machine shop chips.

3 8 4 4 19 V

Frequent failure of pneumatic system inBH-85 BEML Dumpers

9 7 9 9 34 I

By Ranking Method

0

5

10

15

20

25

30

35

40

0 1 2 3 4 5 6

Scale

1 - Low Priority

10 - High Priority

Tot

al p

oint

sProblems

Problem Selection

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Frequent Failure of Pneumatic System in BH-85

BEML Dumpers.

Problem Selection

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Impact of the Problem Breakdown of the machine.

Unavailability of dumpers for production.

Brake system problem.

Difficulty in troubleshooting of pneumatic system components.

Difficulty in cleaning the pneumatic system valves.

Delay in preventive maintenance of other equipments.

Manpower shortage for works in other planned jobs.

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Milestone ChartQUALITY CIRCLE NAMEBEST QUALITY CIRCLE

DEPARTMENT FACILITATOR LEADERSERVICES MECHANICAL T. HARISH WILSON FERNANDES

MEMBERS NAME

M. AVINASHK.M. CHANDRAIAHHAMPA REDDYA.CHANDRASHEKAR

PROJECT FREQUENT FAILURE OF PNEUMATIC SYSTEM IN BH85 BEML DUMPERS

PROJECT NO. 10MEETING DAY – MONDAYTIME – 12:00 PM

DATE OF BEGINNING : DATE OF COMPLETION:20-02-2012

Sl.NO. ACTIVITY WEEK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 TARGET ACTUAL

1 DEFINE THE PROBLEM 1 WEEK

2 ANALYZE THE PROBLEM 1 WEEK

3 IDENTIFICATION OF CAUSES 2 WEEKS

4 FINDING OUT THE ROOT CAUSE 2 WEEKS

5 DATA ANALYSIS 2 WEEKS

6 DEVELOPING SOLUTION 2 WEEKS

7 FORESEEING PROBABLE RESISTANCE 1 WEEK

8 TRIAL IMPLEMENTATION 1 WEEK

9 REGULAR IMPLEMENTATION

10 FOLLOW UP AND REVIEW

Planning

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Crushing Plant

Dumper shop

Engine Shop

Machine Shop

Crawler Shop

Dozer Shop

Raw Material flow

Service interaction

Departments/ Sub sections

High level flow Diagram of our organization

Electrical

Mining

Screening Plant

Loading PlantSe

rvic

es

Plan

t

Mechanical

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Problem Description Description of Pneumatic system in BH-85 Dumpers

BH-85 BEML Dumpers are haulage machines of 85 Ton capacity which are used for transportation of material from mine site to crushing plant area or waste dump yard. At present in our mine there are 12 nos. 85 Ton dumpers.In which 06 nos. are BH-85 BEML and 06 nos. are CAT 777D dumpers.

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The Pneumatic system of BH-85 dumpers is used for following system:1.Charging Circuit : This circuit comprises of a compressor driven by the

engine, which compresses the air and compressed air is stored in reservoirs.

2.Brake Circuit : This circuit is further divided into following circuits. a.Service Brake Circuitb.Retarder Brake Circuitc.Parking Brake Circuitd.Dump Brake Circuite.Emergency Brake Circuit

3.Hoist Control Circuit : The pneumatic cylinders is used to raise, lower and float the dump body.

4.Other Circuits : Air Horn Circuit and Lubrication Circuit

Problem Description Description of Pneumatic system in BH-85 Dumpers

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Circuit diagram for Pneumatic System of BH85 BEML Dumper

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Valves in Pneumatic System in BH 85 Dumpers.Problem Description

RE6 valve Dual brake valve Emg. Brake valve

Rear pressure convertor Hoist pneumatic cylinder

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Failure of pneumatic system in BH-85 dumper can be described asthe failure of the system to perform the operations required .

The following are the few examples :1.Non functioning of pneumatic valves.2.Partial engage of Parking brake.3.Leakages in Pneumatic system.4.Ineffective braking.5.Scoring of pneumatic valves.6.Failure of seals.

Or combination of the above said examples.

Problem Description

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Problem Definition

Failure of Pneumatic System in BH-85 Dumpers

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Objective and Goal

What is our Objective? To increase the life of pneumatic components.

What is our Goal? To reduce the breakdown time of pneumatic -

system by 85% by May 2012.

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Analysis of Problem ( 4W & 1H)What is the problem?Failure of pneumatic System.

Where is the Problem?In BH-85 BEML dumpers.

When the problem occurs?When the pneumatic system is in operation.

Who is affected by the problem?Brake system of dumper and dumper operator.

How the problem occurs?During dumper operation, valves of the pneumatic system fails to perform the required standards.

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Sl.No. Cause Reason

1 Moisture in the system Environment

2 Oil in the system Material

3 Improper assembly of valves Man

4 Faulty pneumatic connections Man

5 Ineffective air drier Machine

6 Leakage In the pneumatic circuit Material

7 Failure of pneumatic hoses Material

8 Failure of the air compressor Machine

9 Hose hardening Environment

10 Continuous application of retarder or service brakes Man

10 Low pneumatic pressure Machine

12 Failure of pneumatic valves Machine

13 Failure of solenoid valves Environment

14 Worn out valve seat Material

15 Unskilled operation Man

16 Mud accumulation Environment

Identification of CausesBy cause enumeration method

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FREQUENT FAILURE OF PNEUMATICSYSTEM IN BH 85 BEMLDUMPERS.

MACHINE

MAN

ENVIRONMENT

MATERIAL

MOISTURE IN THE ENVIRONMENT

OIL IN THE SYSTEM

IMPROPER ASSEMBLYOF VALVES

FAULTY PNEUMATIC CONNECTIONS

INEFFECTIVE AIR DRYER

FAILURE OFPNEUMATICHOSES

FAILURE OF AIR COMPRESSOR

CONTINUOUSAPPLICATION OF DUAL/RETARDER BRAKES

LACK OFTRAINING

LOW AIRPRESSURE

MUD ACCUMULATIONON VALVES

FAILURE OFPNEUMATIC VALVES

LACK OF TRAINING

UNABLE TO READ CIRCUIT DIAGRAM

LACK OFKNOWLEDGE

BRAKE WEAK

AIR LEAKAGE

WORN OUT GASKET

INEFFECTIVE COOLING

WORN OUTVALVE SEAT

ACCUMULATIONOF EMULSION

INEFFECTIVEAIR DRYER

AIR LEAKAGE

VALVE PROBLEM

RUBBER PARTETCHED OUTFOREIGN

MATERIALENTRY

UNFILTERED AIR IN SYSTEM

LEAKAGE INAIR CIRCUIT

POOR QUALITY

RUBBING OFHOSES

LOOSE CONTACTS

UNSKILLEDOPERATION

PARTIAL AIRLEAKAGE

WEATHERCONDITIONS

HUMIDITY INTHE ATMOSPHERE

IMPROPERCLEANING

HOSEHARDENING

EXPOSURE TO AIR

Cause & Effect Diagram

FAILURE OFSOLENOID VALVES

EXPOSURE TO HEAT

WORN OUT

INEFFECTIVEFILTERING

By cause enumeration method

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Finding Probable Root Causes

Sl.No. Probable Cause Validation Reason for Validation

1 Failure of Air Compressor Invalid Manufacturer has designed the compressor to work with effective cooling system.

2 Oil in the System Valid Compressed air may not be fully filtered.

3 Failure of Pneumatic Valves

Valid Entry of emulsion effects the functioning of the valves.

4 Worn out Valve Seat Valid Abrasive action of compressed air .

(By Cause Validation)

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Root cause analysis

Oil in the System Failure of Pneumatic Valve

Emulsion inside ValveCompressed air entering tank without filtration

Compressed air not filtered completely

Worn Out Valve

Abrasive action of Compressed air

Compressed air Contains Abrasive particles

Ineffective Filtering System

Unfiltered Compressed air Not provided by Manufacturer Ineffective Filtering System

(By why why method) on 19/03/2012

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Data AnalysisData source – Dumper Shop Work Register and Mining Planning cell.

Data collected for the Year 2009-10, 2010-11 & 2011-12. The observations are:-

Sl.No Year Air System Brake System1 2009-10 35.50 hrs 1388 hrs

2 2010-11 124.00 hrs 1483 hrs

3 2011-12 405.00 hrs 2961 hrs

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Data AnalysisData source – Dumper Shop Work Register and Mining Planning cell

( From April 2011 to March 2012)

Sl. no.Breakdown

ReasonsBreakdown

Duration (Hrs)

01 Tyres 234.0

02 Brakes 3040.0

03 Steering 2012.5

04 Electrical 335.7

05 Engine 4014.5

06 Transmission 873.0

07 Hydraulic System 2322.5

08 Air system 433.0

09 Suspension 714.5

10 Body/Cabin 2342.0

11 Starting Trouble 134.5

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The previous slide tabular column is shown in the form of pie chart

24%

19%

14%

14%

12%

5%4% 3%2%2%1%

Breakdown hours (2011-12)EngineBrake SystemBody/CabinHyd. SystemSteering TransmissionSuspensionAir SystemElectricalTyresStarting Problem

Data Analysis

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Since brake system is controlled and operated by pneumatic system, here the combination of the brake system and pneumatic system is taken into account.

Data Analysis

The total breakdown period is 3473 hours.

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Brake system in BH-85 Dumper is Hydro-Pneumatic system, which is combination of hydraulic and pneumatic.

Hydraulic Line

Dual Brake Valve

Relay Emergency Valve

Pressure Converter(Air chamber)

Pressure Converter(Hydraulic chamber)

Slack Adjuster Rear Brake ChamberPneumatic Circuit

Hydraulic Circuit

Data Analysis

Air Line

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Breakdown ReasonsMarch 2011-2012

(Numbers)

Leakage in Brake Chamber 5

Improper function of pneumatic valves 29

Leakage in Hydraulic hoses 8

Failure of Slack Adjuster 0

Failure of pneumatic valves 56

Leakage in pneumatic hoses 8

Breakdown details of Brake SystemData source – Dumper Shop Work Register and Mining cell reports

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Leakage in Brake Chamber

5%Improper Function of

Pneumatic Valves27%

Leakage in Hyd Hoses7%

Failure of Slack Adjuster2%

Failure of Pneumatic Valves52%

Leakage in Pneumatic Valves

7%

Pie chart for Breakdown details of Brake system

52% of breakdown hours are due to Failure of Pneumatic Valves and 27% due to Improper function of Pneumatic Valves.

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Num

ber

of t

imes

% O

f Cum

ulat

ive

Con

tam

inat

ion

of

Con

tam

inat

ion

of

Hyd

raul

icH

ydra

ulic oi

loi

l

40

60

80

100

20

80

60

40

20

100

Breakdown reasons

Vital FewVital Few Useful ManyUseful Many

Pareto Analysis

Impr

oper

func

tion

of b

rake

and

hois

t con

trol

val

ves

Failure of pneumatic valves

Improper function of pneumatic valves

Leakage in Hydraulic hoses

Leakage in pneumatic hoses

Leakage in Brake Chamber

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Developing Solution

By Root cause analysis and data analysis, the root cause for failure of Pneumatic system was found that is Failure or improper function of pneumatic valves.

The improper or failure of pneumatic valve was due to entry of foreign elements such as water, oil with water, burnt carbon into the valve.

So our team members decided to find out the source of foreign elements.

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The accumulation of sludge in the pneumatic system parts as shown above.

This was also observed in other pneumatic valves which are dual brake valve, hand retarder valve, air cylinders which are the parts of the pneumatic circuits

Pressure Converter Relay Valve

Developing Solution

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6

7

2 4

5

3

1

Existing Pneumatic Charging CircuitDeveloping Solution

FILTERED AIR

UNFILTERED AIR

PILOT AIR

3

4

5

6

7

1

2

COMPRESSOR

ECON VALVE

PURGE VALVE

DRIER CARTRIDGE

AIR DRIER

WET TANK

EMERGENCY AIR TANK

`

`

`

`

`

`

`

`

`

MAKEUP AIR

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By the study of the charging system it was found that partial air from ekon valve was entering the wet tank and emergency tank without filtration.

So the team members decided to modify the air charging circuit so that dry and clean air enter the tanks and the system.

Developing Solution

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Working of Econ Valve (During Charging Cycle)

From Air Compressor

To Air Drier

FromAir Governor (Inactive)

To Wet Tank & Emergency Tank

Developing Solution

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Working of Econ Valve (During Purge Cycle)

From Air Compressor

To Air Drier

FromAir Governor (Active)

To Wet Tank & Emergency Tank

Developing Solution

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Sl.No.

Solution by Brain storming

Feasible/ not feasible

Reason for acceptance/ rejection

1. Replace the charging system with only air drier

Not feasible

It will be unsafe and brake performance may get effected.

2. Modify the charging system so that only dry air enters the tanks.

Feasible Modification can be done but it should not effect the brake performance.

3. Provide another drier before wet tank.

Not Feasible

It will be addition of load on the air compressor.

By data analysis and brain storming session with our team members it was decided to modify the pneumatic system so that only dried air enters the air tanks.

Developing Solution

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Every time when there is non functioning of any pneumatic valve, our dumper shop staff used to disassemble the defective valve, clean the valve and reassemble the removed valve.

After reassembling the defective valve, it functions were restored.

Developing Solution

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FILTERED AIR

PILOT AIR

6

7

2

4

5

31

3

4

5

6

7

1

2

COMPRESSOR

ECON VALVE

PURGE VALVE

DRIER CARTRIDGE

AIR DRIER

WET TANK

EMERGENCY AIR TANK

Proposed Modified CircuitDeveloping Solution

`

``

MAKEUP AIR

UNFILTERED AIR

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Foreseeing Probable Resistance

By developing the solution as to modify the charging system, a demonstration was done with maintenance staff so that they caneasily understand the modified pneumatic circuit.

Sl. No Persons Resistance Solution01 Shift In-

chargeBrake performance may be effected

Modification is done only in air charging system, not with brake system.

02 Mechanics Performance of the Air dryer may get effected

It will not effect the dryer.

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BEFORE MODIFICATION AFTER MODIFICATION

Comparison of Air Charging Circuit

Air Dryer Econ valveEcon valve Air Dryer

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Trial Implementation(PDCA Cycle)

P

DC

A

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Trial Implementation(PDCA Cycle)

S No. Date Activity Responsibility

01 30/04/2012 Plan Equipment to be taken for trial ImplementationHP- 7B assigned to Hampa ReddyHP – 12 assigned to Chandrashekar

02 02/05/2012 Do Implemented successfully in the assigned equipments

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Date Dump No. Sch. Maint.

Inspected By Remarks

05-05-12 HP-12 600 Hrs

Chandrashekar No abnormality found

11-05-12 HP-7B 900 Hrs

Hampa Reddy No abnormality found

BH85 BEML Dumper Engine schedule maintenance is done in every 300 hrs.Inspection of Pneumatic valves and Brake system during dumper schedule maintenance.

Trial Implementation (PDCA – Check activity)

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During Check activity of PDCA cycle, air dryer cartridge removed for inspection during 300 hrs schedule maintenance and observed that it was filtering effectively.

Trial Implementation

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Performance review during trial implementation was done. Modified system was working effectively.The remaining BH-85 BEML dumpers (HP- 3A and HP-21A), the air charging circuit was modified.

Regular Implementation(PDCA – Act Activity)

Regular Implementation done on 21/05/2012

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Standardization (PDCA – Act Activity)

Standardization has been done in BH-85 BEMLdumper parts catalog and service manualregarding the modified circuit along with connectors and hoses.

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Breakdown Reasons April 2011 to March

2012

May – June 2012

(Numbers)Leakage in Brake Chamber 5 0

Improper function of pneumatic valves

29 5

Leakage in Hydraulic hoses 8 1

Failure of Slack Adjuster 0 1

Failure of pneumatic valve 56 12

Leakage in pneumatic hoses 8 5

Breakdown details of Brake SystemData source – Dumper Shop Work Register and Mining cell reports

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Chart showing Before and After implementation of Solution Regular Implementation

Numbers

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Num

ber

of t

imes

% O

f C

umul

ativ

e

40

60

80

100

20

0

100

Breakdown reasons

Pareto Analysis

Failure of pneumatic valves

Im. fn of pn. valves Lk in hoses

Leakage in pne hoses

50

After implementation of Solution

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The following tangible benefits were observed:-

1. Failure of Pneumatic Valves were reduced from 85% to 21% .

2. Man-hours were reduced for cleaning and reassembly of pneumatic valves from 1hour to 30 minutes.

Tangible Benefits

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The following intangible benefits were observed among the members :

1. Got familiar with Pneumatic system.

2. Learnt problem solving techniques.

3. QC activities developed.

4. Developed Team Work and Team Spirit.

5. Learnt about presentation skills.

Intangible Benefits

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QC Tools used in this project

Brain storming Cause & effect Diagram Pie chart High level flow diagram Line Graph Data collection Milestone chart

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Follow up

The team decided to regularly monitor the modified pneumatic circuit during schedule maintenance and to review any further improvements required.

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Milestone ChartQUALITY CIRCLE NAMEBEST QUALITY CIRCLE

DEPARTMENT FACILITATOR LEADERSERVICES MECHANICAL T. HARISH WILSON FERNANDES

MEMBERS NAME

M. AVINASH HAMPA REDDY.CHANDRASHEKAR

PROJECT FREQUENT FAILURE OF PNEUMATIC SYSTEM IN BH85 BEML DUMPERS

PROJECT NO. 10MEETING DAY – MONDAYTIME – 12:00 PM

DATE OF BEGINNING : DATE OF COMPLETION:20-02-2012 15-05-2012

Sl.NO. ACTIVITY WEEK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 TARGET ACTUAL

1 DEFINE THE PROBLEM 1 WEEK 1 WEEK

2 ANALYZE THE PROBLEM 1 WEEK 1 WEEK

3 IDENTIFICATION OF CAUSES 2 WEEKS 2 WEEKS

4 FINDING OUT THE ROOT CAUSE 2 WEEKS 2 WEEKS

5 DATA ANALYSIS 2 WEEKS 2 WEEKS

6 DEVELOPING SOLUTION 2 WEEKS 2 WEEKS

7 FORESEEING PROBABLE RESISTANCE 1 WEEK 1 WEEK

8 TRIAL IMPLEMENTATION 1 WEEK 2 WEEKS

9 REGULAR IMPLEMENTATION

10 FOLLOW UP AND REVIEW

Actual

Planned

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SUMMARY OF THE CASE STUDY

What was the problem ?Frequent failure of Pneumatic system in BH-85 BEML Dumpers.

What was the root cause of the problem?Ineffective filtering system.

What was the solution developed ?Modify the air charging circuit so that filtered and dry air enters the econ valve.

How much time was taken to complete the case study?13 weeks .

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APPRECIATION CERTIFICATE ISSUED BY HOD – SERVICES MECHANICAL

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Acknowledgement♠ We are thankful to Management & QCFI for

giving training on Quality Circle and inspiring us to join the Quality Circle movement.

♠ We are thankful to the Services Mechanical HOD, Section in-charge and members of dumper Shop who gave their valuable ideas without their support this project would have been incomplete.

♠ We are thankful to our facilitator for guiding us at different stages.

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