BELT CONVEYORPresented By-

ALOK VARDHANADMISSION NO- 2013MT0078

MINING MACHINERY ENGINEERING

ISM DHANBAD

ContentIntroductionTypes of Belt ConveyorTypical Example of Belt Conveyor in a MineComponents of Belt ConveyorDifferent arrangement of Belt ConveyorCalculations in Belt ConveyorAdvantages of Belt ConveyorLimitations of Belt ConveyorConclusionReferences

IntroductionThe belt conveyor is basically an endless belt

moving over two end pulleys at fixed positions and used for transporting material horizontally or at an incline up or down.

Types of Belt ConveyorsPermanent: This type of conveyors is installed for the life of the mine. They are used

in main line, slope, long overland installation, preparation plants and stockpiles.

Portable: These are characterised by relative ease of assembling and disassembling to facilitate advances and recovery in development and retreat operations in underground mining.

Shiftable: Used in continuous surface mining this type of conveyor is mounted on skid or supporting structures aligned together and the whole can be shifted transversely to follow the advancing working face.

High Angle Conveyor: These are special type of conveyor belt arrangement used for negotiating steeper angle of inclination. Such belts can work in slope up to 70-800. Sandwich belt conveyor is a type of such belt conveyor.

Cable Belt Conveyor: Where the belt is carried on moving wire ropes and the tractive force is applied through the rope to the belt is known as cable belt conveyor..

Pipe Belt Conveyor: The belt is made to form a pipe while running the main length of the conveyor. At the receiving and discharge end the belt is like troughed belt conveyor. They are suitable for having spillage free transportation and free from risk of polluting the environment.

Cont… Mobile Transfer Conveyor: Mobile Transfer Conveyors are installed between Bucket

Wheel/Chain Excavators and the shiftable bench conveyor allowing multi block and multi bench operations to increase the block width and the block height. Thus, increasing the time between two shifting operations of the bench conveyor – results in a higher utilization of the mining system.

Grasshopper style Mobile Transfer Conveyors: Installed as a chain like one connected to the other are part of waste dumping. This can eliminate dump trucks from mines.

Mobile transfer conveyor

TYPICAL EXAMPLE OF BELT CONVEYOR IN A MINE

Apron Feeder

Scalping grizzly feeder

(Primary Crusher Discharge)Vibrating screen

(Fines)

Middlings

Gyratory crusher

To Tert. conv

Mining industry deploys conveyor belt for transport of materials in many ways

END PULLEYDRIVE PULLEY

SNUB PULLEYBEND PULLEY

RETURN IDLERSCARRYING IDLERS

GRAVITY TAKE-UP

TRIPPER

SKIRT BOARD

IMPACT IDLERS

DISCHARGE HOOD

SCRAPER

BELT CLEANER

Line diagram of belt conveyor

Components of belt conveyorBeltIdlersPulleyTensioning deviceDriveLoading pointDischarging point

Top Cover

Bottom Cover

(Carrying Side)

(Non-Carrying Side)

End CoverEnd Cover

Carcass

Construction of conveyor belt.

The belt works as a tractive element as well as load-carrying element. It may be used for different kind of material transportation at a higher speed ( 6-8 m/s). For this purpose the belt need to have the following essential properties:

Essential Belt Properties

Flexibility Transverse rigidity Low mass per unit length High strength Simplicity and inexpensive Longer life Should not stretch under normal working stresses ,i.e., low relative elongation. Wear resistant Fire resistant

Recommended maximum belt speeds

Speed (m/sec)

Speed (fpm)

Width (mm) Width (inches)

Coal, damp clay, soft ore, fine crushed stone, Over burden and earth

2.0323.0484.0645.08

4006008001000

457.2609.6-914.41066.8-15241828.8-2413

1824-3642-6072-95

Heavy, hard, sharp edged ore. Coarse crushed stone

1.7782.543.048

350500600

457.2609.6-914.4over 914.4

1824-36over 36

Rubber Interply

Cross section of a multi ply conveyor belt.

Belt Joining Processes

Belt Fastener

IdlersSeamless pipe of cast-steel moving on its own axle and ball

bearings filled with grease is attached.

1. Carrying idler

2. Return idler

3. Self aligned idler

4. Impact idler

5. Wing idler

Advantages of troughed shape of Belt ConveyorDeal with large outputs(10-15% more than

flat belt).Reduce spillage.Lower power consumption.Assure higher life.Silent in running.

pulleyDrive pulleyBend pulleySnub pulleyTandem pulleyCrowned shape pulleyLagged pulleyReturn pulleyDischarge pulley

TANDEM PULLEY DRIVE

SNUB PULLEY DRIVE

LAGGED PULLEY DRIVECROWNED SHAPE PULLEY

Tensioning Arrangement

• To allow for stretch and shrinkage of the belt.• To ensure that the minimum tension in the belt is sufficient to prevent undue sag between idlers.• To ensure that the tension in the belt in the rear of the drive pulley is sufficient to permit such pulley to transmit the load.

The purposes of take-up are:

Types

1. Screw Take-up system2. Loop Take-up system3. Gravity Take-up system

Screw take-up

Gravity Take up

Various Gravity Take up Arrangement

Drives

•Squirrel cage induction motor is used (for lighter conveyor).•Slip-ring induction motor is used(for longer and heavier conveyor).•worm and worm gear box is used.

Level Conveyor receiving material at tail end and discharging at head end

Level Conveyor receiving material at any point through travelling Hopper and discharging at head end.

Level and inclined Conveyor receiving material at and near tail end, having vertical curve to incline, and discharging at head end.

Level and inclined Conveyor with chute. Material received from bins too close to elevated head end to permit use of vertical curve.

Belt conveyor calculationCapacity calculation

T=capacity of the belt(tph)a= cross sectional area of material on the belt(m2) b=bulk density of the material(tonne/m3) v=belt speed(m/s)Empirical equation:W=width of the belt(m)

a=W2/10 to W2/12

Power calculation

Pe=power required to run the belt in empty condition

Pm= power required to convey the material at loading condition

Pr=power required to raised the material

PT=Total system power

MOTOR POWER

Belt Strength

Advantages A wider range of material can be handled which pause problems in other

transportation means. Belt conveyor can be used for abrasive, wet, dry, sticky or dirty material. The lump size of the transported material is limited by the width of the belt. Belts up to 3000 mm wide are used in mining industry.

Higher capacity can be handled than any other form of conveyor at a considerably lower cost per tonne kilometer. Conveyor belts with capacity of 11000t/h and even higher can be deployed to match with higher capacity mining machinery.

Longer distances can be covered more economically than any other transportation system. A single belt conveyor or a series of belt conveyors can do this. Belt conveyors can be adopted for cross-country laying.

Cont… It carries materials continuously and silently. It can operate up or down on all but the steepest gradient.Highly reliable.Specific power consumption is very less. It is much safer.By the use of many forms of ancillary equipment such as

mobile trippers or spreaders bulk material can be distributed and deposited wherever required.

It can be horizontal, incline or decline or combination of all.Minimum labor is required for the operation and maintenance

of belt conveyor system.

Limitations The loading and transfer points need to be properly designed.

Numbers of protective devices have to be incorporated to save the belt from getting damaged by operational problems.

The belt needs higher initial tension (40-200% of useful pull).

The use of belt is restricted by the lump size. If the maximum diagonal of a irregular lump is X then the belt width (B) is approximately given by:

B>=Xa+200Where, B: Belt width, mm X: Longest diagonal of irregular lump, mm a: Factor to account for grading. a is taken as 2.5 for graded material and 3 for un-

graded material. However, for particular material these values must be properly estimated.

Conveying of sticky material is associated with problems of cleaning and discharge causing poor productivity.

Higher elongation of the belt (4% elongation may take place at the working load).

ConclusionConveyor belts are widely used in mineral industry.

Underground mine transport, opencast mine transport and processing plants deploy conveyor belts of different kinds to adopt the specific job requirements.

The capacity of belt conveyor is near about 1100 tph and it is also used for abrasive, wet, dry, sticky or dirty material.

Longer distances can be covered more economically than any other transportation system.

So Belt Conveyor system is more useful in mining industry.

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ISBN 0-87335-260-2 "Stoppage of limestone supply to Lafarge Surma Indian SC issues showcause notice

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Rines, George Edwin, ed. (1920). "year=1920". Encyclopedia Americana. Hounshell, David A. (1984), From the American System to Mass Production, 1800-

1932: The Development of Manufacturing Technology in the United States, Baltimore, Maryland: Johns Hopkins University Press, ISBN 978-0-8018-2975-8, LCCN 83016269

"Mobius band". Daviddarling.info. 2007-02-01. Retrieved 2013-03-27.