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Stackers, reclaimers and stacker/reclaimers are the only major plantfitted at all key interfaces in the mineto end user chain - being required atthe mine consolidation facility, theexport and import terminals and, inmany cases, the end user such as asteel mill or power plant. So with thecurrent high demand levels for mostmajor bulks, stacker and reclaimermanufacturers are facing somethingof a bonanza of new orders.

Schade Lagertechnik, part of theAumund group, considers that whenthe amount of material in the bufferstockyards reaches a certain size andthroughput, automatic equipment forstacking and reclaiming the piles isthe viable choice for long term safeand economic operation of the han-dling facility.

Handling large quantities of bulkmaterial with bulldozers and bucketloaders is expensive in terms ofequipment costs, maintenance, fuel,labour requirements,etc. In addition,the safety risks related to large, rela-tively fast, mobile plant operating ininstallations using underground re-claim tunnels are considerable.

Noise and dust emissions origi-nating from the machines also im-pact on the environment, while theproduct quality can often suffer,mainly through crushing and creat-ing fines, especially when trackedvehicles are employed.

Heading upAt the mine head a combination ofstacker and bridge scraper reclaimeris typically used for the stockpile thatserves as the buffer between the mineand the wash plant. The bridgescraper reclaimer ensures a constantflow of material at the rate requiredby the processing plant, while at thesame time homogenising the chemi-cal and physical material propertiesto a consistent blend. This increasesthe efficiency of the various proc-esses of the preparation plant.

Train loading at the mine typicallytakes place in large batches at highload out rates. The ideal machine forfeeding the wagon loading station,considers Schade, is a portalreclaimer design, which can attainhandling rates up to 4000 tph.

Depending on the stackingmethod and stockyard management,the coal quality and quantity can beadjusted to suit the operators re-quirement, while the equipment isworking automatically during thetrain loading. Dust and noise emis-sions are kept to a minimum, ena-bling operation of the plant in sensi-tive environments.

Buffer zoneWhile the ultimate solution is to sup-ply the commodity to the export ter-minal on a JIT basis to be loaded tothe ship, in practice this does notwork, except for relatively smallthroughputs such as agri-bulks deliv-ered directly to the ship from farmsor off-site silos.

Accordingly buffer stockyards arerequired in the port area to ensureconstant ship loading rates even if thesupply chain is interrupted some-where upstream. Harbour areas areoften sensitive environments, so cov-ered stockyards are more and morepopular. The warehouse keeps dustand noise inside, while at the sametime protecting the product fromstrong winds and excessive rainfall,but requires a different type ofstacker/reclaimer than is employedfor a conventional open air stockpile.

These tend to favour large bucketwheel reclaimers with an integratedstacker, ie a conveyor system anddischarge spout fitted to the mainboom. Enclosed storage areas arebest served by a scraper typereclaimer, which in the case of adome silo has to be a radial type.

This enclosed storage and han-dling system is gaining greater ac-ceptance, despite increased invest-ment, in environmentally sensitiveareas, such as around power stations.To ensure highest availability in elec-

tricity supply, a coal stockyard con-taining at least one weeks supply forfull load operation must be locatedas close to the plant as possible tofeed the boiler bunkers.

While Schade argues this is bestachieved by a scraper reclaimer sys-tem, some power plant operatorshave opted for a cheaper option witha stationary radial stacker fed directlyfrom the train discharge station or aquayside, with the resulting pile then

Stockyards stock up on orders

Stockyard equipment can last foryears, as this shot of a vintage

MAN reclaimer under repair shows.

Commodity demand has fuelled the

demand for new equipment

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(TKF), with this being the secondreclaimer the company will supplyto PKT following the delivery of thefirst portal reclaimer in 2002. After

contracts for PT Pupuk Sriwidjaja(PUSRI) and PT Pupuk IskandarMuda (PIM), PKT is the third ferti-liser customer in Indonesia to placea repeat order with TKF.

The latest order is for a full por-tal scraper reclaimer for urea, with acapacity of 1100 tph and operatingon a rail gauge of 42.4 m. A featureof the machine is that it has a mainand auxiliary scraper boom, both ofwhich are in line - ie arranged onthe same side of the portal.

This design not only has the ad-vantage that the construction heightof the portal is kept as low as possi-ble and thereby allows an optimaladaptation to the shape of the stock-

pile, but also that remaining mate-rial at both ends and in the centrelineof the stockpile is reduced to an ab-solute minimum. The compact con-struction of the low portal also has acost saving effect on the design ofthe storage building itself.

Concrete contractsTKF has also received several newcontracts for blending beds compris-ing stackers and bridge reclaimersfrom Iran where the cement indus-try is expanding rapidly. Accordingto official sources, cement produc-tion increased by 5% to around 48mtp last year and is forecast to ex-pand to 70 mtpa by 2020. As thisvolume will exceed projected do-mestic demand, it will become nec-essary to export surpluses.

As part of this current wave of ce-ment capacity expansion, TKF hassupplied some 13 stackers and bridgereclaimers to Iranian mills. While themajority of these contracts are basedon standard designs modified to suitthe particular operational require-ments and site conditions, a bridgereclaimer ordered by MazandaranCement required a technical rethink.

This machine had to be suitablefor reclaiming a limestone and claymixture with a moisture content ofup to 14%. As a conventional hy-draulic rake system cannot be usedfor reclaiming this type of sticky, nonfree-flowing material, the reclaimerhad to be completely redesigned toaccommodate a new raking system.This comprised a travelling carriagesupporting an active rake on eachside of the bridge. Each of these ac-tive rakes comprises two separatemotorised scraper booms mountedon a common steel structure.

With the help of the motorisedscraping rakes, material slices are cutfrom the stockpile surface and con-veyed to the scraper blades locatedunder the bridge of the machine. Thescraper chain system located underthe bridge was re-designed, to reducethe gap between the active rake andthe scraper blades and achieve opti-mum transfer of material from onesystem to the other.

Top endWhile the volume business for themanufacturers may be in the smaller,highly specialised stacking/reclaim-ing/blending machines, interest isalso strong at the top end of the mar-ket, even in import commodity zonessuch as Europe. TKF, for instance,has recently secured the contract foran ultra large stacker/reclaimer forthe EMO terminal in Rotterdam.

The bucket wheel unit is rated at6000 tph stacking and 4500 tph re-claiming when handling iron ore. Itstheoretical coal rate is similar, de-spite the lower density, as conveyorand bucket speed can be increased.However, it is envisaged that a coalreclaiming rate of around 3500 tphwill be maintained to match the ex-isting conveyor networks.

The machine will be equippedwith a 60m boom compared to the45m booms of the existing fivestacker/reclaimers and will be one ofthe largest of its type in Europe. Asit will be sited in an expansion zoneat the terminal, new rail tracks willhave to be laid and a further 2400mof conveyor line added. The com-plete development is scheduled tobecome operational mid-2007.

Finally, Voest Alphine MaterialHandling (VAMH} is currently com-missioning two 1200 tph bucketwheel stacker/reclaimers and theconveyor links to the quaysidefor thenew Immingham coal terminal ex-tension in the UK.

EMOs new stacker/reclaimer from

TKF will have a 60m boom (45m

boom machine shown)

landscaped by a mobile scraper,such as a bulldozer grader, andfarmed to an underground conveyorto feed the daily bunkers on demand.

Blending inStacker/reclaimers must cover a verywide range of commodity types andin addition to their basic stockpilingmanagement function, can also beincorporated as part of the process-ing function by blending the mate-rial. Thus the actual product portfo-lio from a stacker/reclaimer manu-facturer can encompass anythingbetween a 6000 tph bucket wheelreclaimer and a 200 tp/h potash por-tal reclaimer and include radial

stacking systems with integratedreclaimer functions. In environmen-tally sensitive areas, they may haveto be enclosed in a dome structure.

Last year, PT Truba Jurong Engi-neering (TJE), Jakarta was awardedthe contract for the Urea Bulk Stor-age No.5 (UBS-5) project by PTKaltim Industrial Estate, a subsidi-ary company of PT PupukKalimantan Timur (PKT). The UBS-5 project is planned south of the ex-isting Urea Bulk Storage No.4 (UBS-4) of PKT area in Bontang, EastKalimantan, Indonesia.

TJE in turn placed the order forthe portal scraper reclaimer withThyssenKrupp Frdertechnik GmbH

P.O. Box 110 4300 AC Zierikzee The NetherlandsPhone: +31 (0)111 418 900 E-mail: grab@nemag.com Fax: +31 (0)111 41 61 54m www.nemag.com

The handling price per ton plays an important part in the entire bulk handling process, and is greatly affected by

the quality and purchase price of your grab. The obvio