Actual Report

Praveenya Institute of Marine Engineering and Maritime Studies

VIZAG PORT AND OHC:

Port of Visakhapatnam is one of the leading major ports of India. The Port is located on the east coast of India at a latitude of 17041' North and longitude of 83017’ East and the time zone is GMT + 5:30. The Port has three harbors viz., outer harbor, inner harbor and the fishing harbor. The outer harbor with a water spread of 200 hectares has 6 berths and the inner harbor with a water spread of 100 hectares has 18 berths.

Bestowed with natural deep water basins, the outer harbor is capable of accommodating 150,000 DWT vessels and draft up to 17 meters. The inner harbor is capable of accommodating vessels up to 230 meters LOA and draft up to 11 meters

Handling Facilities:

Iron Ore & Pellets:

Functioning of the Mechanical ore handling plant known as ore handling complex comprises of the receiving system and the shipping system

Dumpers (Receiving System)

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The ore received through wagons is tippled and conveyed to the stacker for stacking in the receiving system. The receiving system consists of three wagons tipplers (one twin wagon tippler of 2700 TPH cap. and another tippler of 3000 TPH capacity) to tipple the wagons.

Stackers (Receiving System)

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The shipping system reclaims the cargo from the stacks and conveys through the conveyors to the ship loader for loading into the ships’ hatches. The system consists of 3 bucket wheel reclaimers 4000 tons per hour capacity, a long overhead conveyor system (4.8 kms – one way), a surge bin of 2000 tones capacity and a ship loader with an assigned capacity to load iron ore at 8000 tons per hour. This shiploader which moves on rails can negotiate a 2100 turn and can dip deep into the hatch of a ship.

Reclaimers (Shipping Systems)

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The loading conveyors (7 nos.) are all overhead conveyors running at about 10 to 12 metres above ground level. The conveyors are supported by means of a pre-cast RCC frames founded on piles. The pre-cast frames are spaced at about 20.0 m c/c, a walkway of 1.0 m wide is also provided alongside of the conveyor for attending to maintenance. The conveyor is designed to run at a speed of 210 mtrs/min.

Ship loaders (Shipping System)

Coking Coal facilities:

A deep draft berth in outer harbor (General-cum-Bulk cargo berth) with a quay Length of 356 meters to handle vessels of draft up to 14.5 meters is available for handling imported coking coal. The berth is capable of handling 100, 00 DWT vessels. 2 floating cranes viz., Bulk Express (4 grabs–2 for loading and 2 for unloading; 7.4 cum. to 22.6 cum.) and Ravi B (11.5 cum. grab capacity) are available at the berth.

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In addition, 5 Multipurpose berths in inner harbor which can accommodate vessels of 11.0 m draft and 2 Multipurpose B.O.T berths operated by Vizag Seaport Pvt. Ltd., equipped with mechanized handling facilities are available.

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Other facilities include :

2Nos. Harbor Mobile cranes at WQ berthsOpen area at West quay berths/East yard dumps – 1.7lakh sq.m.4 LT capacityOpen area at GCB – 1.5 LT capacity Sidings with loading facility into wagons and well connected railway lines to GCB and inner harbor.rA fully mechanized facility for loading Alumina is available at the dedicated berth (WQ-5) with 241 meters length and permissible draft up to 11 meters. The facilities available at the berth include: 3 silos of 25,000 tons capacity each Mechanical wagon unloading system (1100TPH) Conveyor system for loading(2200 TPH)

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A deep draft Oil Tanker Terminal for berthing tankers of size up to 150,000 DWT and draft up to 17 meters is available. The facility is equipped with three unloading arms at the terminal direct discharge from berth to the refinery tanks at 5500 tons per hour through pipe lines.

Facility available for STS transshipment of crude from VLCC to smaller tankers.

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An exclusive jetty with draft up to 14 meters is available to discharge LPG. A Cavern facility for LPG first of its kind in South Asia – a mined rock Cavern at a depth of 200 mtrs. Below sea level (capacity: 60,000 T) is available. Two berths in the inner harbor are available for handling petroleum products A Cavern facility for LPG

Containers:

A state of art container terminal is being operated by Visakha Container Terminal Pvt. Ltd. The terminal is the deepest terminal of the country with a facility to accommodate main line vessels up to

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15 M draft. The terminal has a dedicated rail facility to handle full rake of 45 wagons. The terminal has a potential to handle 5 lakh TEU in future years and is ideally situated to serve as “Container Hub Port" on the East Coast of India Cargo handling equipment.

Cargo handling equipment:

Description Capacity Availability in Nos.

Electric Wharf Cranes 10T 09

Electric Wharf Cranes 15 T 10

Electric Wharf Cranes 20 T 04

Harbor Mobile Cranes (on hire) 140 T 02

Harbor Mobile Cranes (BOT operator)

104 T 03

Locos ( General Traffic) 1400 HP 08

Locos ( O H C ) 1430 HP 07

Locos (General Traffic) 3100 HP 03

Floating crane (Bheema) 140 T cap 01

Floating crane (Hanuman) 55 T cap 01

Bulk Material handling systems:

Reclaimer:

Reclaimers are designed to reclaim bulk materials from stockpiles at mines, ports, steel plants, power stations, etc. in a quick, efficient and orderly way. They are available in several main types, including bucket wheel, scraper and drum-type reclaimers, and in many configurations and sizes, with capacities

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from 500 to 2000 tons per hour and more. The choice of design depends on factors such as the size and shape of the stockpile, the type of material to be reclaimed, the required reclaiming rate and the need for blending or homogenization.

Boom-type bucket wheel reclaimer: Boom-type bucket wheel reclaimers are designed to reclaim large volumes of bulk material from stockpiles at mines, ports, power plants, steelworks etc. They can be mounted on rails or tracks, with exact design, boom length and control system tailored to suit the stockpile configuration, the type of material to be handled and the needs of the customer. Boom length can range from 10 to over 60 meters and the exact configuration, as well as the operational features, will always depend on the application.

Bridge-type bucket wheel reclaimer:Bridge-type bucket wheel reclaimer designs are for a more efficient blending purpose. This can be even more improved by means of a dual bucket wheel design. They are typically used in the coal, iron-, and steel industries for reclaiming material from stockpiles where homogenization is a primary requirement. The harrows are designed to promote homogenization and direct the flow of material to the base of the pile, where it is scooped up by the buckets and discharged on to a cross conveyor that either passes through the axis of the wheel, or is connected to the bucket wheel by means of an intermediate conveyor

Bridge-type bucket wheel reclaimer

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Portal scraper reclaimer : Full portal scraper reclaimers usually reclaim the material from the surface of the stockpile in a longitudinal direction from one side of the pile only, down the full length of the pile. They discharge the material on to a conveyor belt along the stockpile. Because of the reclaiming path from the surface, traveling portal scrapers have limited ability to homogenize the material, unless a strict and rather complicated material layering scheme is implemented. They can be a good solution for small to medium capacities and where homogenization is not a priority. Portal scraper reclaimer

Drum-type reclaimerEssentially, the drum-type reclaimer is the alternative to single- and double bridge-type bucket wheel

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reclaimer. It comprises a long rotating drum fitted with a large number of reclaiming buckets arranged radially along its length, into which material is fed uniformly by the harrow. The drum-type reclaimer is a good solution if good homogenizing characteristics are of paramount importance. Basic data for the most popular model is given in the table below.

Drum-type reclaimer

Technical Specifications of Reclaimer of OHC in Vizag :

GENERAL SPECIFICATIONS

Make : L&T., DEC-2000.

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Capacity : 4000 TPH.

BUCKET WHEEL DETAILS:

Bucket wheel diameter : 7.5 meter.

No. of buckets : 9

Bucket capacity : 850 Lit.

Bucket wheel speed : 5 RPM

BOOM DETAILS:

Length of the boom conveyor : 40 meter.

Slewing speed : 6-30mtr/min.

Hoisting and lowering speed : 3 meter/min.

Maximum position of boom : +80 to –9.50

BUCKET WHEEL BOOM CONVEYOR:

Belt width : 1400 mm

Belt shape (Troughing) :300

Belt speed : 210 meter/min.

TRAVEL MECHANISM:

No. of track wheels :32

No. of drive wheels : 6

Travelling speed : 3-15 meter.

Track gauge : 9.3 meter.

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TOTAL POWER REQUIRED : 510 KW.

Stackers:

Stackers effectively stockpile bulk materials in an efficient and orderly manner. Stationary or traveling, borne on rails or crawlers, they can be supplied in fixed, luffable or luffable-and-slewable boom designs, with capacities from 150 to 20 000 metric tons per hour (165 to 22 000 short tons per hour). The choice of design depends on factors such as the stacking method (Chevron, Windrow and Cone Shell) and size of the stockpile, the type of material, the required throughput and the demand for mobility. Tripper cars or tripper systems for transferring material from the yard conveyor to the stacker are considered part of the stacker.

Luffable and slewable stackers:

Luffable and slewable stackers

This type of stacker is able to luff and slew the boom and designed to service stockpiles on both sides of the rails. The higher initial cost of this stacker is quickly recovered by economies gained from their flexible mode of operation, as well as their ability to effect good layering and excellent blending. Boom length can range from 10 to over 60 meters, and the exact configuration, as well as the operational features, will always depend on the application.

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Luffable stackers:

Luffable-only stackers are used for applications where the stockpile is required to be stacked from one side only, with little or no demand for blending. The absence of a slewing mechanism makes them an economical option in the right applications. Boom length can range from 10 to over 60 meters, and the exact configuration, as well as the operational features, will depend on the application.

Standard stacking conveyors:

The standard range of movable stackers covers belt widths (650, 800, and 1000, 1200 and 1400 mm) each having different lengths up to 40 m. The movable stacking conveyors have a typical capacity range of 300 to 2800 metric tons per hour (330 to 3090 short tons per hour). A combination of movable feeder and stacking conveyor can be used to load barges or ships, or equal.

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The standard range of radial stackers covers 4 belt widths (650, 800, 1000 and 1200 mm) each having 5 different lengths (20, 25, 30, 35 and 40 m) for a typical capacity range of 200 to 1200 metric tons per hour (220 to 1320 short tons per hour). Adopting of the stacker conveyor allows stockpiles to be more strategically placed, more quickly processed and, when there is a series of stackers, it can work faster and more efficiently than fixed conveyors.

Technical Specifications of the stackers in OHC of Vizag:

GENERAL SPECIFICATION:

Make : MAMC., 1976 Capacity : 2700TPH Boom Conveyor length : 37m Maximum position of Boom : 14.35m Minimum position of Boom : 2.0m Maximum inclination of discharge Boom : +13o30’. -8 o30’. Slewing angle of discharge boom to tripper car : +95o, -95o. Hoisting & Lowering speed : 2.68m/min.

BOOM CONVEYOR : Width of Belt : 1200mm. Axle distance : 38.36m Belt speed : 210m/min. Belt shape(Troughing) : 35o.

TRAVELLING MECHANISM:

No. of track wheels : 12 No. of drive wheels : 8 Track wheel diameter : 630mm Gauge : 9.144m Travelling speed (maximum) : 21m/min

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TRIPPER CAR DETAILS:

Belt width : 1200mm Belt shape(troughing) : 35o. Belt speed : 160m/min. Belt loop : 16o30’.

TOTAL POWER REQUIRED : 190KW.

Shiploader:

Linear gantry and quadrant bridge type ship loader are constructed in proven, eco-friendly designs and a wide range of sizes to service vessels from 5000 to 250,000 dwt. Central to the philosophy is minimal disruption of the port during installation of the ship loader and its supporting equipment The process for off-site construction, assembly, testing, commissioning and heavy-load transportation is highly advanced, resulting in installation of fully operational ship loader with capacities up to 20 000 metric tons per hour (22 200 short tons per hour) in just few days.

Linear, slewing and shuttling Boom Shiploader:

Rail-borne gantry mounted, slewing and shuttling boom ship loader, which also have a certain luffing function, are designed to cover all hatches of the vessel through a combination of luffing, slewing and longitudinal travel. To enable vessels to berth, they are slewed parallel to the quay. Like all ship loader, they have advanced PLC control systems and can be tailored precisely to protect the environment.

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Linear, telescoping-boom shiploader:

Rail-borne gantry mounted, telescopic-boom ship loader, which have a steep luffing function, are designed to cover all hatches of the vessel through a combination of luffing, telescoping outreach and longitudinal travel. To enable vessels to berth, the boom is simply raised out of the way. Like all ship loader, telescopic models have advanced PLC control systems and can be tailored precisely to protect the environment.

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Radial quadrant, shuttling-boom shiploader: Radial quadrant, shuttle-boom ship loader has a slewing bridge that is pivoted on the inside and guided on a curved rail on the outside. The shuttling conveyor boom that also has a certain luffing function is located on the bridge. This enables full hatch coverage through a combination of luffing, slewing and variable outreach. Like all ship loader, radial quadrant models are equipped with advanced PLC control systems and can be tailored precisely to protect the environment.

Bucket wheel Reclaimer:

A reclaimer is a large machine used in bulk material handling applications. A reclaimer's function is to recover bulk material such as ores and cereals from a stockpile. A stacker is used to stack the material.

Reclaimers are volumetric machines and are rated in m3/h (cubic meters per hour) for capacity, which is often converted to t/h (tons per hour) based on the average bulk density of the material being reclaimed. Reclaimers normally travel on a rail between stockpiles in the stockyard. A bucket wheel reclaimer can typically move in three directions: horizontally along the rail; vertically by "luffing" its boom and rotationally by slewing its boom. Reclaimers are generally electrically powered by means of a trailing cable.

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http://en.wikipedia.org/wiki/Bulk_material_handling


Bucket wheel reclaimers use "bucket wheels" for removing material from the pile they are reclaiming. Scraper reclaimers use a series of scrapers on a chain to reclaim the material.

The reclaimer structure can be of a number of types, including portal and bridge. Reclaimers are named according to this type, such as "Bridge reclaimer". Portal and bridge reclaimers can both use either bucket wheels or scrapers to reclaim the product. Bridge type reclaimers blend the stacked product as it is reclaimed.

BUCKET WHEEL RECLAIMER:

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General Description:A Reclaimer constitutes an important part of the Ore handling Complex. It reclaims (collects) the ore that is stack piled using the stackers of the OHC. It then transfers them onto a boom conveyor from where it reaches a long overhead conveyor (4.8kms-one way). It is then transferred to the shiploader and then into the ship hatchets.

The Bucket wheel Reclaimer of the OHC operates in a forward-reverse direction with stockpile on both sides of the rail tracks. The machines operate in conjunction with unidirectional stockyard conveyors. The Bucket Wheel Reclaimer delivers ore to the stockyard conveyor.

The Bucket Wheel Reclaimer runs on two rails with base frame being supported at three points through equailising beam and fully compensated bogies. The base frame carries a slew bearing with integral gear ring. The upper half of the slew ring carries the boom and slew structure. The counter weight is connected to the tail boom, so that the stability of the machine is maintained under all 21 | P a g e


conditions of operation. The boom and the luff superstructure are raised and lowered by means of twin double acting hydraulic cylinders. The combined centre of gravity is at all times within the slew ring diameter.

The boom carries a bucket wheel assembly along with drive, chutes, etc at the extreme end of the boom. The reclaimed material from the bucket wheel is fed to a boom conveyor which in turn feeds to the yard conveyor. The operator’s cabin located on the boom provides the optimum visibility for the operator. Power to the slewing structure is fed through a cable drag chain arrangement.

Main Structure :

The main structure of the Bucket wheel Reclaimer consists of two major assemblies, the base frame, which is carried on the bogie assemblies and the superstructure comprising slew deck, boom, mast and tail boom(i.e. all above slew ring) enabling the superstructure to rotate about the base frame.

The slew deck provides the working base for the boom and its associated conveyor; hydraulic luffing system and slew drive units.

Opearator Cab:

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Situated on the boom structure the cab houses the reclaimer control desk and the PLC interface, interior lightening, air conditioner and window wiper.

Operator’s cab leveling arrangement:

Operator’s cab needs to remain in horizontally leveled position even when the boom structure luffs up and down with respect to horizontal. The system consists of 2 master cylinders and 2 slave cylinder arrangement which are connected by hydraulic pipes and hoses. Master cylinders are located near the slew deck and the slave cylinders are located below the operator’s cabin. When the boom luffs down the hydraulic oil from the master cylinder flows to the slave cylinders and thus maintains horizontally the operator’s cabin. Similarly when the boom luffs up the hydraulic oil flows out of the slave cylinder and enters the master cylinders and thus maintains horizontally the operator’s cabin.

Wind Speed Measuring System:

Operating the machine in high speeds can place the machine in an unstable position. For this reason, a wind speed measuring and warning system is incorporated in the machine design. The anemometer sensor fitted to the top of the operators cab, gives continuous signal to anemometer control unit located in the operator’s cabin. When the wind speed exceeds the present value 15.3 m/sec, anemometer control unit generates a signal which is fed to the PLC. If the wind speed persists for more than 10 seconds, an alarm will be given by the enunciator panel and it will then be the responsibility of the operator to travel the machine to the safety to the storm tie down position through following sequence.

Boom conveyor normal stop via PLC but only when belt is empty. Conveyor belt empty to be evacuated via belt weigher.

Slew bloom to approx. 0° (parallel to the track). Long travel the machine to forward limit and then travel back by approx 1 meter. Slew boom to approx 90°.

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Luff boom down and adjust slew angles as necessary to ensure boom locates above the storm tie-down arrangement.

Slew Deck:

The slew deck is driven by 2 electro-mechanical drive units. Each drive unit consists of electric DC motor, slipping clutch type coupling, EHT brake which drives a pinion via a cartridge shaft assembly.

The angle of rotation both in clockwise and anti-clockwise rotation of slew is controlled by absolute encoder which converts slew rotation into electric signal for processing in the PLC which in turn proceeds slew position display on the control desk. At the extreme points and are actuated by the striker brackets fixed to the lower face of the slew desk. These switches inhibit the slew motion beyond those points.

Slew Ring:

The slew ring is interposed between the base frame and the slew superstructure.

It is basically a large bearing on which the slew superstructure rotates. The inner ring is secured to the underside of the superstructure and the outer ring to the top face of the base frame. An external gear forms an integral part of the lower ring and it is with this gear that the slew drive pinion engages.

Boom assembly :

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General:

The boom projects forward from the machine superstructure. A boom conveyor mounted inside the boom structure is fitted with the switches to detect the belt misalignment. The conveyor is mounted on the Boom structure near the inner boom.

The boom structure has walkways running along both sides with handrail.

Boom Structure &Pivots:

The boom structure is secured to the machine superstructure by two pivots and is supported by a counterbalanced, hydraulically-operated luffing system to provide both positive and negative elevation from the horizontal.

Bucket Wheel Assembly:

The bucket wheel is located at the outer end of the boom and both the wheel and its drive are secured to the boom superstructure at an angle of 10° to the vertical. A semi-circular guide plate is mounted on the boom structure and closely follows the internal contour of the front portion of the bucket wheel to form an inner closure for the buckets. The guide plate periphery is covered with the manganese steel lines to protect the parent structure from the abrasive action of the material as the laden buckets are drawn over its surface.

A bucket wheel chute also mounted on the boom, projects inside the bucket wheel and closely follows the top portion of the bucket wheel radius.

Each bucket wheel is a mild steel fabrication and open at one end. An alloy steel lip is welded to the front and sides of the bucket.

Bucket wheel drive:

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The bucket wheel is driven hydraulically by a hydraulic motor. Bucket wheel is located on the left hand side of the boom structure (when looking from the slew deck) and is secured to the end of the bucket wheel shaft by a shrink disc. The speed of the bucket wheel varies from 0-6 rpm and is controlled by a power pack mounted on slew deck.

Conveyors:

General:

The boom conveyor forms the part of the machine. The reclaimed material is transferred onto the boom conveyor through the bucket wheel chute. The conveyor then carries the material to the slew deck where it passes through the chutes mounted on the slew deck and then base frame finally discharged onto the stockyard conveyor.

Boom conveyor:

The conveyor is an endless belt, running over pulleys, troughing and return idlers, which is driven by an electric motor. The belt is fitted with a underspeed switch, external scrapper (1 no) and internal scrapper (1 no), to remove debris from the belt surface.

The boom conveyor is powered by an electric motor, which is coupled to the pulley shaft through a fluid coupling, bevel helical gearbox and gear coupling. The gearbox has an integral oil bath lubrication system a disc brake assembly is interposed between the fluid coupling and the gearbox unit.

An electronic micro-processor based weigher has been provided on the boom conveyor to measure the rate of flow and total flow.

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Boom support and luff super structure:

The boom support and luff super structure consists of support tie-links, mast and tail boom, on which is located a series of ballast blocks and two luff hydraulic cylinders connecting mast with slew deck.

The mast pivots from the slew deck and is connected to the tail boom by tie-links.

Another set of tie-links connect the mast to the forward end of the boom structure.

Two hydraulic cylinders are able to move the mast forward or backward about its pivots.

A weather proof power pack is mounted on the slew deck. The maximum raise and lower angles of the boom are determined by limit switches.

Hydraulic system for luff operation:

This power unit for operating the luff system to lift/ lower the bucket wheel reclaimer boom.

The system mainly consists of the following:

450 l oil tank with accessories like thermostat, float switch, level gauge, temperature gauge, drain valve, filler/breather, filter etc.

One double vane type pump connects via bell housing t motor shaft. 2 No unloading-sum-relief block and 2 No direction control valve mounted on the oil tank 2- No cylinder mounted manifold blocks.

2 No hydraulic cylinders:

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Bore : 320 mm Rod diameter : 200 mm Stroke : 2000 mm Working pressure: 210 bar

Interconnecting pipe work:During operation of cylinders for raising the boom the pump delivers oil to the cylinders. Pilot check valves in the cylinder mounted manifold blocks avoid any runaway of load.

Electric Gantry:

General:

The gantry structure is basically a platform surrounded by a safety handrail, which is accessible from both sides of rail from ground level stairs. The gantry is situated in rear of the main machine structure, to which it is secured by pivot pins and is supported at its rear by single bogie wheelsIts function is to accommodate the electric house, electric power transformer and to support the power and control cable reeling drums.

Cable reeling drums:

Barrel type reeling drums, power and control, are located on either of the electric gantry. Each drum incorporates its own drive unit and braking system and each is capable of rotation in either direction. The power and control trailing cables transfer power and control signals to the cable drums from land based junction boxes situated at midpoint along the machine track. They

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are then guided onto the machine and then the drums by a set of guides one set for each direction of travel.When the machine travels toward the land based junction boxes the drums reel cables and when travelling away they unreel the cables. Each drum is fitted with tension limit switch and geared end limit switch for protection of trailing cables.

Long travel limit switches:

The normal travel limits are controlled by heavy duty V-lever type limit switches which are mounted on the machine leading and trailing bogie assemblies. These are activated by striker brackets, which are fitted on the ground outboard side of the bogie frames. When switch and striker plates coincide the resultant signal is used to inhibit further travel in that direction.Should the normal travel limit signal fails, excessive over travel is prevented by two additional V-lever switches. These are also mounted on the machines leading and trailing bogies assemblies and are actuated by the same strikers mentioned above operating in an identical manner as the normal travel switches.

Cable Drag chain with assembly:

The bucket wheel reclaimer is provided with a cable drag chain arrangement. Cables passing from the fixed part (electric gantry/base frame/bogies) to the slewing structure (slew deck) pass through the cable drag chain. The cable drag chain is installed in a fabricated steel housing. A guide frame is installed inside the drag chain housing to guide the drag chain during slewing operation.The drag chain assembly including housing, guide frame and drag chain is installed in the central annular opening of the base frame/slew deck/ slew ring. A towing arm guides the cables from the cable drag chain housing to the slew deck and provides space for vertical passage of the cables. The towing arm is connected at one end to the slew deck and the other end to the moving point of the drag chain.

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Machine Orientation:

Reclaimer operates on yard conveyor. The machine operates on the rail tracks. Throughout this document positions of the machine are termed as left-hand or Right-hand, forward and reverse. Forward is the direction faced whilst looking along the boom from the slew deck and with the boom central over the yard conveyor. Left and right are also determined from this position.

Control Philosophy:

The reclaimer control system is based upon programmable logic controller equipment.

Control System Structure :

The reclaimer system is broken down in such a way that the software requirement are defined by a number of sequences , which are either free running or event driven as appropriate.

A sequence in isolation provides the logic for the execution of a particular control system function or mechanical operation and is a component of the reclaimer control system.

The collection of sequences provides the total control system logic for the reclaimer equipment. Any operation that the equipment is called upon to perform is accommodated by the use of one or more

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sequences. Therefore, when an operator initiates an operation, a sequence is enabled which performs the selected operation, in doing so, several other sequences may be called upon.

Modes of control :

The reclaimer desk located in the operators cab incorporates the selection of the following control modes;-

1: Auto

2: Manual

3: Maintenance

Auto:

This mode is used for reclaiming the pile after machine has been set up in manual mode. All movement of machine is controlled by PLC in this mode.

The machine must remain within the travel limits for auto operations to continue. A machine fault will cause machine shutdown.

‘Auto’ control is dependent upon the prime interlocks being operative between on-board programmable controller and the land controller. Failure of these conditions inhibits reclaiming operations or shuts down the machine when appropriate.

Manual:

This mode of control is used for settings up the machine for auto and reclaiming. When manual is operational, the operator can stop the machine at will. The machine must remain within the long travel limits for manual operations to continue. A machine fault will cause machine shutdown. Manual control is dependent upon the prime interlocks being operative between on-board programmable

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controller and the land controller (provided by client). Failure of these conditions inhibits reclaiming operations or shuts down the machine when appropriate.

Maintenance:

This mode of control inhibits all normal desk operations and permits operation of individual drives direct from pushbuttons on the local control station. Local manual control is via the local control station and overrides many of the normal interlocks, therefore drive operation is generally on a push to run basis.

Reclaiming:

The machine is travelled to the start position and the boom luffed to bench 1 level. The boom is slewed and the travel position adjusted so that the bucket wheel just cuts the nearest edge of the stockpile at bench 1 level. The travel limits and hence bench length is determined by the operator and then reclaiming can commence. The theoretical slew speed will vary depending on the depth of cut, which is, in turn, dependent on the slew angle. At the end of each slew pass the travel stepping operation is initiated, but distance travelled is preset to suit the chosen reclaim rate.

It should be noted that the operator via the control desk may suspend reclaim cutting operation at any time during reclaiming; however, this will, unless supplemented by a shut-down command, leave the bucket wheel and conveyors running.

Reclaiming is accomplished by boom across the face of the pile to the required slew angle. The slew speed is controlled by reference from the PLC. In auto mode the slew speed is adjusted to maintain the bucket wheel output by using the cosine of the slew angle and in manual mode the operator controls the slew speed to maintain a constant reclaim rate.

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At each end of the slew arc, the slew will decelerate to rest. The travel forward step is initiated to suit the desired reclaim rate. It is intended that the travel forward step is carried out during the slew deceleration/acceleration period.

This procedure will continue until the operator determines that the forward travel position has been reached, at which point the machine will be slewed clear of the stockpile and travelled back manually. The boom will then be lowered manually to bench 2 levels. Reclaiming of bench 2 will commence with a different slew range. Reclaiming will be continued until bench 2 has been reclaimed, at which point the machine will be returned manually as before to reclaim bench 3 in a similar manner.

Over travel:

Long travel:

In the event of over travel in any direction during normal operation, an over travel limit is tripped, which will signal the travel drive to perform a fast controlled stop. With the machine at rest, the brakes are applied and the drive main contactor opened.

Recovery from over travel is accomplished by using the travel forward or travel reverse pushbutton on the travel local control station, to drive the machine out of the over travel zone.

Having driven the machine out of the over travel zone, the cause of the over travel should be investigated prior to resumption of normal operations.

Slew:

In the event of over travel in either the left or right direction during normal operation, an over travel limit is tripped, which will signal the slew drives to perform a fast controlled stop. With the machine at rest, the brakes are applied and the drive main contactor opened.

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Recovery from over travel is accomplished by resetting the emergency stop circuit and using the slew left or right pushbuttons to slew the boom out of the over travel zone.

Having slewed the boom out of the over travel zone, the cause of the over travel should be investigated prior to resumption of normal operations.

SEQUENCES:

Prior to starting the plant, the following state of plant checks should be true.

State of plant:

Reclaimer is positioned with the boom positioned 90 degrees to the main conveyor, in which position the boom has been engaged with tie down point.

All drives are at a standstill. It is assumed conveyors are empty of material. Over travel has not occurred on the travel or slew motion. All emergency stop pushbuttons released. All conveyor tripwires are healthy. Wind speed is less than 20m/s. Storm locks on travel is lifted. Long travel drive brakes applied.

MECHANICAL PARAMETERS:

Travel drive:

8 D.C Drive motors of 10 kW (nominal) @ 1500rpm.

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Variable speed from: 3 to 15m/min.

Acceleration/deceleration period = 10 secs nominal.

Duty = continuous.

Slew drive:

2 D.C Drive motors, parallel operation ( 16 kW nominal) at 750rpm.

Maximum slew speed @ 750rpm = 32m/min.

Variable speed from 6.4 to 32m per min.

Acceleration/deceleration = 5 seconds nominal.

Duty = continuous.

Boom conveyor drive:

Belt speed: 3.5m/sec single speed. Acceleration rate set by fluid coupling.

Motor: 200kw, 1500 rpm

Boom luff system:

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Luff speed: 3m/min at Bucketwheel centerline

HPP Pump motor: 37 kW, 1500 rpm

Control cable drum:

Motor: 3 kW, (nominal)

Power cable reel:

Motor: 3 kW, (nominal)

Bucketwheel drive:

Bucket wheel speed: 6 rpm

HPP Pump motor: 300 kW, 1500 rpm

HPP cooler: 5.5 kW, 1500 rpm

MAINTENANCE INSTRUCTIONS

The standard of maintenance of the equipment strongly influences the reliable operation and life of the plant and equipment.

It is imperative that regular checks are carried out in respect of lubrication, operating efficiency and to replace worn out parts.

The painting should be subjected to routine checks and where necessary it has to be touched up in an efficient manner.

The frequency of such checks and the associated maintenance works are dependent on the length of operation and possible wear on machine parts.

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Contamination caused by spillage or other accumulation of dirt should be constantly cleared off. This also applies to the cleaning up of machinery as well as for steel structures, protection devices and walkways.

Rotating machine parts must only be cleaned when they are at a standstill whereby the respective safety and accident prevention regulations must be observed.

Damage to walkways and railings, which for instance can be caused by falling material, must be repaired immediately or at the earliest during the following repair shift. When temporary repairs are made to walkways, stairways or railings, adequate safety precautions should be taken.

Damage to load bearing steel structures, loose rivets, bolts or screws and also the peeling of mark must be reported immediately to the supervisor’s personnel.

Check clearance periodically. Lubricate through piping where possible. Lubricate conveyor with lubricant of proper grade

on a regular schedule with definite responsibility assigned to particular individuals for doing the work and making the signed reports.

Confirm the operation of conveyors to authorized employees only. Confine repair functions to trained maintenance employees only. Do not permit riding or stepping on conveyor. Do not load mechanical equipment beyond its capacity. If any sway motion in lateral direction of belt is noticed immediate attention is recommended. Equipment and accessories requiring general inspection shall be checked preferably at the

frequency as recommended by the manufacturers of various equipment as indicated in the respective catalogues / instruction manuals.

The floor on which the equipment is to be installed should be properly leveled and foundation for footing should be correctly marked.

Care must be taken to see that intermediate sections are chosen with their correct erection marks.

Belt and conveyor structure should be checked for perfect alignment. Drive machine should be checked for alignment. Ensure that reduction gear case and fluid coupling etc. are filled with oil to the correct level.

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Installation of idlers The idlers should initially be squared with the path of belt for control running of belt. Power transmission machinery should be checked for proper alignment on assembly.

SAFETY PRECAUTIONS

Protective equipment, i.e., safety helmets, overalls, footwear, gloves, safety goggles must be worn when carrying our maintenance or repairs.

No machinery should be operated with any guard panels or inspection doors left open. Temporary guarding or scaffolding required whilst maintenance or repair work is being carried

out must be to standards laid down in statutory regulations. Personnel must only use designated platforms and ladders. Platforms and ladders must be kept in a clean condition and free from obstructions. Any remedial work which involves lifting or dismantling of heavy machinery or making safe

equipment whilst repairs are carried out must be supervised by qualified experienced personnel.

All lifting tackles must be approved and tested to withstand loads being raised as laid down in statutory regulations.

A qualified experienced engineer must be consulted before removing or replacing any major component of the equipment to avoid the possibility of affecting the stability of the machine or over stressing of any structural member of machinery.

The machines must be kept clean and free any materials which could cause a fire, dust or explosive hazard.

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The safety officer should be consulted before commencing any work which may cause a fire i.e., welding, drilling, grinding etc.

After maintenance or repair work has been completed. Checks must be made to ensure all tooling, lifting tackles or any articles which could cause injury or damage are removed from the machines and their working area.

All guarding and inspection panels must be replaced before the plant is put into commission.

Defects and Upgrading:

Communications :

Upgrade existing controls to reduce maintenance and troubleshooting efforts.

Benefit:

This upgrade reduces control wiring from field devices to the electrical house PLC panel. The upgrade eliminates long wiring runs for ease of troubleshooting. The upgrade can be supplied in two different methods:

Connect existing field devices, motor controllers, operator consoles and other equipment to a common communication link. Control wiring is eliminated from the first connection box to the electrical house. The equipment is connected to a Device Net platform. This method places I/O modules out at the junction boxes connected to field devices or "remote I/O." Control wiring from the junction boxes to the electrical house is drastically reduced. Trouble-shooting of wiring is reduced to "device to I/O modules" local to the device.

2. Man/Machine Interface (MMI):

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Computer based device between the operator and a PLC control system that can provide beneficial information to the operator.

Benefit:

Ability to control virtually all machine functions and provide operator with in depth messages regarding machine status, operations, maintenance and safety.

3 . Radio Modem Control System:

Replaces the existing control cable reel system and associated headaches.

Benefit:

Less maintenance, more reliable and no moving parts.

4. Laser Positioning System for Machine Travel:

Laser distance measuring device used to determine machine location.

Benefit:

Eliminates moving parts. Also eliminates slippage of the star wheel or fifth wheel during inclement weather conditions and needs no re-calibration.

5. Complete Machine Automation for Remote:

Controlled Automatic or Manual Operation

Benefit:

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Allows machine to be completely controlled from a remote location in manual or automatic mode.

6. Remote Troubleshooting Via Modem Interface:

Benefit:

Allows remote troubleshooting of PLC controllers from office.

7. Remote Condition Monitoring:

An enhanced service offered by Bulk Materials Handling that allows to assist your Maintenance Department through the periodic downloading and evaluation of selected equipment operating data, such as, motor current, speeds, and material through a monthly basis.

Benefit:

The review of operating data will permit to identify potential equipment problems and to recommend solutions to avoid consequential equipment downtime. Identification of an equipment problem by maintenance personnel, in advance of a component failure, can result in significant cost savings since measures can be taken to avoid costly equipment downtime.

STACKER RECLAIMERS:

8. Single Point Scanning:

Laser replaces the use of material probe and hoist.

Benefit:

No moving parts eliminate damage from recoil of the hoist rope when probe arm contacts the material pile.

9. Programmable Logic Controller:

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Complete automatic control or combination with manual.

Benefit:

Ease of adjustment of limits, rate selection, reduced maintenance and improves maintenance assistance - identification of problem areas.

10. Flux Vector on Slew Drive:

To add a flux vector duty motor and drive for AC slewing operation.

Benefit:

Smoother acceleration and deceleration yielding less wear and tear on the drive components. Less maintenance.

11. Flux Vector Drive on Travel Drive:

To add a flux vector duty motor and drive for machine travel operation.

Benefit:

Smoother acceleration and deceleration yielding less wear and tear on the drive components. Less maintenance.

12. Flux Vector Drive on the Bucketwheel Drive:

Addition of flux vector duty motor and drive for bucketwheel drive function.

Benefit:

Eliminates M.G. set on machines where the bucketwheel is run by a M.G. set.

13. Flux Vector Drive for Boom Hoist

Replaces the contactor-based controls on machines with cable hoists and wound rotor hoist motors.

Benefit:

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Eliminates the constant maintenance and run-away problems common to wound rotor controls.

14. Stainless Steel Operator's Cab:

Benefit:

Corrosion resistant, esthetically pleasing.

15. CAT Chain for Scraper Reclaimers:

Upgrades standard engineered chain to CAT sealed chain.

Benefit:

Provides longer chain life and less maintenance.

16. Upgrade Feeders and Modify Chutes to Improve Coal Flow That Will Meet Current Plant Requirements:

Benefit:

Eliminates flow restrictions and reduces spillage.

17. Replace Hydraulic Boom Conveyor Drive -Electro/Mechanical Drive

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Benefit:

Less maintenance and improved dependability. Hydraulic leaks are eliminated which require less cleanup.

18. Monospiral Power Cable Reel Upgrade:

Replaces existing bulk wrap and level wind reels. Also provides replacement of existing Monospiral torque motor and hydraulic driven reels.

Benefit:

New magnetic coupling with standard motor replaces eddy-current, torque motor and hydraulic drives. Lower maintenance and fewer winter problems. Fewer components to provide increased availability.

19. Rewind Wound Rotor Boom Hoist Motor for Vector Duty:

Allows the existing motor to be reused with a flux vector drive.

Benefit:

Eliminates the need for motor, motor base, and brake changes. Cost is lower than a new Vector duty motor.

20. Auto Adjust Slew Speed Based on Bucketwheel Current

Automatically reduces slewing speed when high bucketwheel current is detected.

Benefit:

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Eliminates bucketwheel drive trips, machine stress and over-digging.

21. Automatic Pile Management

Allows the yard to be divided into sections for different materials.

Benefit:

Prevents intermixing of materials. Machine automatically knows where each material is located in the storage yard.

22. Microprocessor Based Field Control Regulators

Allows the existing MG set to be reused.

Benefit:

Eliminates the amplidynes or other outdated controllers. Cost is lower than new SCR drives.

23. Higher Capacity Bearings and Improved Seals for Bucket Wheel Shaft Main Bearings

Replaces the existing bearings with larger ones and replaces the tube seals with lip seals.

Benefit:

Longer life, better lubricant retention, and better contaminant exclusion.

24. Higher Load Capacity Slew Bearing

Employs larger diameter ball bearings.

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Benefit:

Longer service life.

Note: To be considered at the time the slew bearing needs to be replaced.

25. Slew Drive Torque Control Coupling

Replaces the lubricated friction cone type control coupling.

Benefit:

Dry friction type is less likely to go solid than the type used on earlier machines. Thus will provide more predictable protection. (Must be used with proper stalling protection.)

26. Hydraulic Assisted Conveyor Take-Ups

Replaces screw type conveyor take-ups.

Benefit:

Easier to set up and better control of belt tension.

27. Cell Less Bucket Wheel

Replaces the original cell type wheel. Drive modification is required.

Benefit :

Provides better discharge and increased capacity for same weight.

28. Shrink Disc Mounting for Bucket Wheel

Replaces taper fit method. Can also be provided with a safety nut on end of wheel shaft if required.

Benefit:

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Less complicated to apply and with a straight shaft, less likely to lose the bucket wheel due to improper mounting/overload.

29. Equalization System for Leveling Cylinders

Automated machine leveling system installed on rail truck leveling cylinders.

Benefit:

Replaces the cumbersome hand pump.

30. Shock Absorber Type Torque Link for Bucket Wheel Drive

Replaces the solid link connection.

Benefit:

Reduces shock loading and wear on pins and links.

31. Flow Switch for Bucket Wheel Drive Reducer

Pressure Lube System

Benefit:

Shuts down drive (in sequence) if flow is lost - saves bearings and gearing.

32. Electrically Driven Lube Pump for Bucket Wheel Drive Reducer

Benefit:

Can be set up to start before main drive motor to protect gearing and bearings.

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33. Luffing Velocity Fuse Modules

Benefit:

Eliminates excess piping, increases reliability and safety.

34. Luffing Cylinders Upgrade

Replaces existing with new style heavy duty mill type.

Benefit:

Increased rod bearing area, improved piston seals. Increased factor of safety. Decreased maintenance.

35. Luffing Hydraulic System Upgrade

Modify the system to the load sensing type for improved control of acceleration, deceleration.

Note: Acceleration and deceleration controlled electrically.

Benefit:

Eliminates boom bounce and surge.

36. Spring Set/Hydraulic Release Rail Clamps

Benefit:

Replaces the obsolete original rail clamps with new modular design.

37. Rail Clamp Modification

Modify the hydraulic unit by installing the automatic dump valve and eliminating the spool type valve.

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Benefit:

Avoids problems of spool valve silting up.

38. Slew Programmable Limit Switches

Replaces cam type limit switches.

Benefit:

Ease of adjustment from cab by operator.

39. Roof Mounted A/C Units for Operator's Cab

Benefit:

Better visibility and better cooling action.

40. Travel Drive Plugging and Over Speed Control

Benefit:

Better reliability and reduced brake maintenance.

41. New Operator's Cab

Replaces the outdated existing operator's cab.

Benefit:

Better visibility and improved control layout and room.

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42. Planetary Gear Reducer for Bucket Wheel Drive

Replaces right angle helical/spur gear reducer.

Benefit:

Less weight and can provide higher gearing service factor.

43. Retrofit Luffing and Slew Position Encoders

Replaces the cam type limit switches.

Benefit:

More reliable position detection.

44. New SCR Slew Drives

Eliminates M-G sets. Provides better control than earlier SCR drives.

Benefit:

Provides accurate load sharing between motors thus helping to prevent gear box damage.

45. Caliper Disc Brake with Rotor (For Older Machines)

Replaces the brake band and weight.

Benefit:

Fewer parts, better control of operation and easier maintenance.

46. Install Dust Collection in Conveyor Transfers and Feeder Discharge Areas

Benefit: Reduces dusting and cleanup of the transfer areas.

References: Larsen and Toubro maintenance manual provided by OHC.

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Wikipedia.Sandvik Mining official website

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Actual Report

Documents

board programmable controller

bucket wheel chute

bucket wheel drivereplaces

local control station

cable drag chain

flux vector drive

harbor mobile cranes

fast controlled stop