Problems of Cargo Handling and Shipping of Bulkcargo and Container, Eurport 1973 Congress, Deutsche Verkehrswissenschaftliche Gesellschaft, Köln, Germany

P1973-1

Europort 73

congress

Friday, 16th November 1973

Glass Room - RAI Building

Theme: Problems of Cargo handling and Shipping of

Bulkcargo and Container.

This day is presented under the Patronage of the Consul

General of the Federal Republic of Germany in Amsterdam, The Netherlands, and under the Auspices of the Deutsche

Verkehrswissenschaftliche Gesellschaft e.V. in Cologne, Ger-many.

DEUTSCHE VERKEHRSWISSENSCHAFTLICHE GESELLSCHAFT e.V.

Dr.-Ing. Schneidersmann, Managing Director, Demag

_{Lauchhammer GmbH, DUsseldorf}

Unloading of Bulk Goods

In the first phase of the industrialization the smelting of _ores was effected at the locations of the exploitation of the mineral resources, as, fOr example, in the Siegerland. As reducing agent

the locally produced charcoal was used too. As, within _{the subsequen4} development, pit coal was used steel works grew besides the

coal mines in the Ruhr Valley. The geological _{process of formation}

seems to exclude deposits of -cOal and _{ore possible in the immediate}

vicinity and surroundings. So, a favourable shuttle traffic between the steel works for coal and those for ore resulted therefrom as, owing to the fact, that in those years abt. 2.5 tons of ore and

ton of coal were necessary for the production of _{one ton of} pig iron both showing abt. the _{same volume.}

But soon,an advantage of location could be observed at the works

on the Ruhr,situated in the vicinity of the major consumers, and tha' with regard to the fact as the transport of finished Products is

far more expensive than that of the _{raw materials} . For that reason

the Ruhr Territory remained the location of the steel works when the German ore exploitation descended to insignificance and almost

exclusively ores of higher quality

_{from overseas were smelted and}

even metallurgical coal was imported.

At the same time the first _{steelworks grew at the sea which,}

by saving of inland freight charges, promised a decisive advantage of location; at least with regard to rolled products supplied _into the restricted area or being determined for export _purposes.

The recently realized fusion of a steelworks in inland without waterways system to a seaport with a works at the Channel coast

possibly makes sure that, in the near future, semi-finished products as pigs or blooms may be produced at the coast and, for subsequent treatment, be transported into the interior close by the consumer groups. Another step seems to be a further

...refinement of the ores near the deposits. Those deposits aY.e

chiefly situated in the developing countries, as Brazil, West Africa and India but also in 'Australia. For the development of the domestic industry vast importance is due firstly to the

subsequent treatment of pellets but also to semi-finished products. So, the mechanical conveying and handling will soon be concerned with the problem of more favourable freight charges for transport of blooms to the refinement works in the areas of consumption.

Against that background a specific transport system developed from the actual situation of the navigation, whereby concrete requiremen were made on the individual links of that conveying chain, which, especially influenced the construction of the bulk goods vessel and its discharging means.

One of the first devices, especially constructed for the handling of bulk goods from ocean vessels on goods wagons, is this unloader designed as short bridge with a remote control trolley. The

machinery-house, arranged on the rear jib served for taking up the steam engine with the hoisting and traveling gear as well as the liftingngear, the latter effecting the topping of the cantilever arm in order to pase' withoutlindrance the masts of the sailing-shi and later on the superstructures of the steam vessels.

Only together with the introduction of the electric energy individu drives could be designed for the various working cycles, which

then were arranged on the trolley. An unloader with such a man trolley was equipped with a cantilevering pulley in _order

to be able to increase the effective outreach.

The type of vessel, common at that time, _{was a multiple purpose}

freighter with small hatches and tween decks. The engine was _arrange

- midships so that the main holds in--the

stern were cut by te

shaft tunnel. That kind made necessary a time-consuming trimming of the subdivided holds with a trimming bucket which, at the frequent travelling motions of the bridge was especially clumsy and sluggish. In order to improve its movability the slewing trolley was introduced which, _{at a length of 5 ms, can cover} a whole hatch without being forced to traverse _{the bridge.}

Thattupe of construction generally prevailed the European market as it is to be seen from that typical picture of the port of

Antwerp.

Together with the increasing dimensions of vessels the carrying capacity of such unloaders was raised up to 30 tons by the end of the fiftieth. From the economic point of view the end _{of that} development was reached as such a slewingtrolley has a deadweight of 150 tons, moved with an acceleration of I m/s2 on a nearly 40 rs, above sea level situated craneway at a speed of 4 m/s

working cycle.

The total Weight of the plant exceeded the 1200 tons limit although a projection over the quay wall _{of less than 30 m was sufficient} to unlOad even the largest, _{conventional vessels.}

But from now on the special bulk carriers prevailed more'and more. It is characterized by

the arrangement of the _{engine and}

-4-the bridge on -4-the stern, removal of disturbing and inconvenient masts between the holds, hindering up to now the motions of the unloaders, the large surface layouts of the hatch openings allowin the undisturbed access to the self-trimmings holds, free of

tween decks. For that reason we could desist from the more flexible mode of operation of the slewing trolley and give

preference-to a more 'favourable ratio of service load compared wit the deadweight. Whilst the ratio at the slewing trolley was

:

5,

it is at the man trolley abb. 1 :

2.5

and, at a rope

trolley I :

0.5.

Only in that way it had been possible, at the

limitation of the load hoists, to build plants with a carrying capacity of 50 tons without exceeding the total weight of the unloader of 1200 tons essentially.

For that type of design an optimal system for reaching a

horizontal loadway had to be found for which are four solutions possible, known from former developments and constructions once more executed in the sixtieth.

At the mechanically simple solution hoisting and closing ropes are reeved through the grab and fixed to the watersided end of the cantilever arm. But the disadvantage is that the grab can only be changed with great expenditure in order to adapt its capacity to the respective bulk weight.

So, contrary to the U.S.A., in Europe we passed over to the

mechanical or electrical differentials making possible the grab wi detachable shackles to be attached to the ends of the rOpes.

During the trolley travel towards to the shore side, the load

-5-either over a differential _{gear or the trolley travel motor}

works

as a generator and, over the _{LEONARDL.transformer, feeds the}

hoisting drive with that absorbed energy. The mechanical _differentia. was installed in the handling plant at Narvik and the electric

differential in the plant _{of the August-Thyssen-Steelworks}

at the . Rhine port.

If we want to have the _{length of t-he rope of the hoisting.and} closing gear, getting free during the trolley motion, in reserve that may be effected by means of a double guide-system, which

may also be used as travelling drive of the trolley _{instead of the} otherwise used cable control. _{The first construction was effected}

in Holland in 1921, _{a more modern solution in the Weser-port}

at Bremerhaven in 1962.

Finally, that rope length, getting free, _{may also be kept in reserve} in horizontal reeving-in _{by an auxiliary trolley,}

travelling with half speed. That solution doubtlessly requires an optimal _constructio nal expenditure. The disadvantage of high _{rope costs may be limited} by a favourable arrangement of the _{rope drive and its components.} At the construction of a 50 t unloader _{transshipment quantities}

of 6,000,000 tons had been reached for one set of travelling _ropes

and 500,000 tons for the grab ropes as

normal service life.

The modern types _{of design show}

that during that _development

the improvements and progress of the applied _{technologies were} fully utilized. Whilst _{up to the fifties,}

_lattice

bridges were used, the supporting

structure from thereon has been designed _as box-type construction, _{when the welding}

technics governed the behavior of the permanent stability

_dynamically

stressed welding joints. But tests for many years were required in _{order to register} the permissible tension of the _{various notch}

cases under influence

6--

-6--of different load spectra and stress rotation cycles in special

calculation rules.

The construction types used nowadays are, at first, the two-beam

type girders with the trolley travelling on the upper flarge.

Endeavouring to utilize more favourable, with regard to stresses, the cross section of the cantilever lever, the single-spar cantilev(

was conceived. With the console-type designed trolley, we will reacl

an interesting and advantageous, unsymmetrical construction. The torsion arising only causes a trifling additional strain.

The symmetrical construction of the single beam girder, customary

for container cranes, requires the arrangement of the craneway

supports laterally. Therefore, it is necessary, to arrange the

bridge girder significantly higher, to obtain the same lifting height. Designwise, this type of construction is not so advisable, when all trolley drives are placed in a machinery house and

transmi-the movements to transmi-the trolley by rope systems.

Also the driving gears as well as the steering and control system of same were subject to a far-reaching change. The grab-Planetary winch, invented in the twenties, seemed to be the optimal solution. A hoisting motor drove the closing and holding drum via a sun

and planet wheel of a planetary gear. A closing motor was able

to Arive the closing drum via a cross-piece or to superimpoSe a

closing and opening motion during the lifting or lowering 6f the grab. Therefore it was possible to lower the closed grab through the ship hatch and to open it during the further lowering in the hold. Together with the developing control technics the same

-7-at which, by load distribution, both gears carried the grab, th-7-at

means the closing gear with abt. _{55% of the total load in order}

to prevent an opening of the grab, _{and for that reason it was}

.possible to layout dimensions of the ropes for 55% of the load,

whilst at the planetary _{gear the closing ropes had to be dimensioned}

on to 100 %. So, not only the diameter of the rope diminished but alsc

that of the drum and, _{as consequence, the take-off torque of the}

hoisting gear.

The further improvement of the direct _{current - technics made it}

possible to automate partially the grab-working cycle to enable the operator to pay full attention to the actual grabbing process. According to that system the grab is traversed on an optimal curve

above the receiving bunker, _{where it will be stopped with a}

deceleration , controlled by the swing of the grab, discharged and moved back to the defined position in the hold.

But the most decisive influence on the construction of the eouipment resulted from the incorporation into a system in which each single

function is effected by _{a ,single purpose device.}

The -classical quay unloader fulfilled all functions of transshipment within a combined method of working, and that as follows:

The goods, discharged from ship, could be entrained or be transshipped into a lighter alongside ship, or transported to the stockyard,

spanned by the bridge, _{or, reverse, from stock to the}

ship or

lighter or railway _wagon.

The scheme of such an arrival port of ore shows the _functional

separation of those transshipment operations by single purpose devices, which, in their own cycle , combined with continuous

conveyors, can develop an optimal _{efficiency. The ship unloader,}

the inland ship loader, _{the wagon loading station, the bucket wheel}

loaders or the transporters for loading and unloading _{of the}

stockyards.

-8-The focal point of such a system is the ship unloader, which is determinant for the performance of the plant and the demurrage of t

vessel.

Such a plant with three unloaders were established at EUROPOORT. They are equipped with a rope trolley the capacity of which is

50 tons..The installed bunker has a receiving capacity of 250 t and is seated on four pressure cells which, on the one hand, prevent an

overload and, on the other hand, control the speed of two dischargi

plate conveyors, dependent from the loading situation, in a way

that a nearly uniform loading of the belt conveyors will be reached

and the scales for the belt conveyors will also operate within thei.

optimal measuring range.

Furthermore, a material padding, for the protection of the plate

conveyors, is maintained.

The double-rail travel, all wheels of which are driven, supports

the plant at three points. At storm occurring a four-point support will be obtained in order to increase the crane stability by

automatically actuated, hydraulic cylinders.

The hoisting and closing gear as well as the trolley travel were

equipped with thyristor-controlled direct current-drive, which,

by means of a traversing and pendulum automatics, extensively relie

the crane driver.

According to the kind of material, type of vessel and discharging position, a working cycle of 35-45 seconds will result at which a net grab contents of 30 tons is unloaded, and the peak performanc

.wil1 be abt.

3000

tons per hour. The characteristic process

of the unloading performance of two unloaders at one ship of

140.000 tdw including all idkglosses shows, within the first phase of working abd discharging the loaded ship, a nearly continuous,

uniform and high performance. Carrying ore with high specific

density, only every other hold is loaded and the first half will be discharged in that cycle.

-9-Then the performance will heavily decrease and, within the phase

of trimming, and when using front loaders, it only shows a trifling

efficiency. The operation of several machines, also suitable to handle front loaders, improve the efficiency. A model test

indicates that similar characteristics for the discharging

performance will be achieved, when continuously working unloaders are applied, as for example one of the three alternative

solutions as shown on a drawing of

1963.

The operational behavior

of the devices working with a bucket chain is comparable with

constructions using a bucket wheel as reclaiming means.

Coming to the end I would like to try to extrapolate from the

outlined development to the future tasks and problems. With regard

to its capacity the intermittent operating quay unloader has

practically reached its limit. The rope drive consists of four

grab and travelling ropes of 50 mm diameter each. In order to be

able to confine to a minimum the interruption of _{operation owing}

to the rope change, motor driven auxiliary winches _{were installed}

for the retraction of the newkopes and hand-operated tensioning winches with indicators in order to effect easily and safely the

initial tension of the travelling rope._ system by coupling ropes. But a substantial increase causes and unreasonable expenditure and

that, with regard to the fact, that the _{ropes have a total weight of}

20 t, the travelling rope drum weighs 14 t and the largest rope pulley-diameter is 2.20 m

Only the installed _{power for the trolley drive and grab operation}

is already 3 _{x 600 kW. The 32 wheels, running on the quay wall,}

impose a max. load onto the double rail travel of 60 t. For that reason an essential increase of the discharging capacity can only be reached by continuously transporting and handling devices and that if two pre-requisites will be fulfilled:

1. The constructional weight has to be decreased in a way that it

-lo-will not exceed the wheel loads and number of conventional

unloaders.

2. The layout of hatches and holds must guarantee an effective operation df the continuously reclaiming and conveying devices inasMuch the shipbuilder will be able to reconcile it with the

stability of the hull.

The container transport offers an interesting alternative. After,

contrary to the opinion of many specialists, the lash system

(lighter aboard) has been introduced for the transport of general

cargo, presumably by taking into consideration strategic logistic

points of view, that system seems also suitable for the handling

of bulk goods. Floating containers. with a total weight of 375 t

are taken aboard the carrying vessel by means of a gantry crane

and will also be stowed. If, for example, a deposit would be near

the inland water ways as in Goa and the consumer on a navigable river too, for example, the "Steel Mills on the Rhine", such a

continuously floating traffic from the coal mine to the blast

furnace - stocks would be very attractive. But the deadweight of

the lighters and the limited utilization of the stowage cause a

tremendous increase of the freight charges. In case the container

would not be floatable its volume could be reduced to 1/3 and its

construction be considerably simplified. By omission of inland

transports on waterways it must compete with the common bulk

vessel which may be used for many other kind of operation as, for example, cereals and oil, even on return trips.

In that case a general competitive position is not.to be foreseen but for the'concrete case of a fixed shuttle traffic between the

place of exploitation and the consumer, advantages could result

under favourable marginal terms.

But insofar as the transport of semi-finished products, as bloom:

-11-pigs is concerned from the reducing plant on the ore depot to the plants for subsequent treatment in the centre areas of the consumer

a task is set which could only be solved by, the _{shipbuilder and the}

handling te.chnician combined _{as, the todays usual equipment do no}

more.correspond to the present economic _{requirements.}

Dipl.-Ing. Eberhardt Langheld, Project Manager, Claudius Peters AG, Hambur4

Port Facilities for Bulk Handling of Pulverized Materials

Increasing shipments of bulk cargo in general and of pulverized

materials such as alumina cement, potasium chloride, or phosphate

in particular in conjunction with stricter regulations for air. pollution control have made it necessary to put in operation new types of port facilities. The best combination of facilities in

regard to storage, transfer and loading, shipment as well as

un-loading , to handle pulverized-materials has to be evaluated.

Factors to be evaluated are - aside from cost, reliability, and

adaptability - capacity, number of points shipped from and shipped

to, availability and size of ships, as well _{as frectuency of loadin}

respectively unloading.

We will now take a look at the various links in the chain of shipping bulk pulverized materials:

1. Storage silos at the ship loading terminal

Storage silos serve the purpose of accepting materials either

at rates not comparable to the rates the ships _{are being loaded}

or at times different from those of ship loading or both.

Naturally the weekly or monthly or yearly rate _{of filling the}

silos determines the total tonnage being handled by the silos over the respective time interval.

Storage capacity of the silos, however, depends primarily on the number and size of ships being filled over a short period of time and secondly on the degree to which the theoretical

storage capacity can be utilized. The _{latter refers to the}

experience that normally _{simple silo constructions do not}

-2-For instance, if it is advisable.to fill two 10.000 tons ships within two days total time but refilling of the silos is being done at the rate of 100 t/h the theoretical storage capacity should be 15.200 tons.

2onsidering an emptying factor of 0.85, which means that

L5 % of the material always remains in the silo, the practical

7apacity becomes at least 18.000 tons, resulting in increased

!osts.

nother point of considerations is that storage silos may not desegregate the stored pulverized materials in any way, chemi-cally or by particle size distribution. This necessitates not only careful distribution of the stored material over the com-plete cross section of the silo but also careful material with-drawal from the silo. The well-known Claudius Peters Blending

Chamber Silo not only prevents desegregation but actually shows lower variations of the material at the discharge end than at the filling end. This blending factor ranges from 4 up to 11 depending on the sice and design of the particular silo. It is obtained by a special material aeration bottom and technique

which, in additiOn, allows for at least 95 % emptying of the

silo.

The rate of discharge from the silo should not vary greatly

since any variation directly influences the capacity and size of the equipment following the discharge end. Modern flow

con-trol de vices provide for only a few percent variation.

2. Conveying equipment

Material transfer from the silos to the loading site can be

done by mechanical or pneumatic conveying. Mechanical conveying

equipments such as screw conveyors or belts has the advantage

of relatively low specific power consumption, however it is in

general not as dependable as pneumatic conveying equipment.

Actually no other conveying system offers greater advantages

simpli-

-3-city, reliability, initial cost and power consumption. All pneumatic conveying systems - blow tanks, Peters pumps, aerolifts, aeroslides etc. - have in common a

simple method for dust collecting, whereas conveyor

b.elts have to be separately enclosed to contain and

collect all dust emitted over the length of the

con-veyor.

The conveying rate to the ships or the shiploader should be an optimum considering harbor fees, equipment costs as well as operating costs. Rates of 1000 t/h and more have already been obtained with a combination mechanical

pneumatic system.

Ship loading

Depending on the type of transport vessel the materials can either be loaded very simply by just connecting the conveying equipment to the ship or by a special ship loader designed to meet all requirements. Experiance is required to

establish design parameters solving such problems as tidal

differences, differences in the type and size of the ships number and location of cargo holds, movability of ship loader or vessel etc. The modes of speration thes loaders undergo necessitate sound and experienced structural steel design

and _{quality steel construction. Movability of the loader}

requires special equipment for material transfer from the conveyor to the moving loader, by using for instance conveyor

belts arranged to from a loop, which travels parallel _{to the}

loader.

Containing dust during loading requires the installation of

vertical telescopic _{chutes, which allow material to flow in the}

inside and dusty air in the outside perimeter. _{Virtually no dust}

is emitted during loading operation when using _{these chutes.}

Vessels

Several factors determine the type of vessel used for bulk trans-port. If many terminals have to be served from one source of if

the capacity is comparativel small as in the _{case of supply for}

ma-

-4--terials could be used. Such vessels are not unloaded by

portside equipment but use their own power and equipment for unloading which can be done either by pressurizing specially built tanks in the ship or by fluidizing with low pressure air the bottom of the ships holds and then conveying the

material to Peters pumps. Both types then use pipes to pneuma-tically convey to landside storage bins or silos. Tankers for cement have been built for capacities around 10.000 tons.

If larger capacities are required or if several ships serve one or only a,few terminals from one source, shipment might be more economical by using bulk.carriers, with removable

hatch covers over cargo holds. These bulk carriers can have one or more decks and are emptied by portside unloaders.

5. Unloading equipment

Special unloading equipment has to be used in the case of material shipment by bulk carriers. Pulverized materials such as phosphate, alumina or cement de-aerate completely and some-times harden during transport especially across the sea, so

that unloading is not a simple task . The angles of repose

of the materials sometimes become more than 90° which means that these materials actually could arch over making unloading dangerous if the walls of material are allowed to form during the unloading process.

Any unloader therefor - if deaerated and hardened materials are

anticipated - has to have special equipment to loosen such

goods and has to allow for easy horizontal movement of such

equipment within the ships holds. By moving it horizontally

the bulk goods are unloaded in layers. Occasional material

walls at the sides of the holds are thin and - upon collapsing

-do not bury the equipment.

After loosening the materials are conveyed upwards either

mecha-nically or pneumatically. Mechanical equipment includes the old clam shell type unloader, however, because of costly spillage

and subsequent dust problems it is hardly used nowadays in mode]

installations. Another type of mechanical unloader uses a

verti-cal screw attached toa movable boom.

Pneumatic unloaders have the advantage of the absence of movabli

-5-rehability and completely dust free operation. The Claudius Peters system uses two rotating disks loosening the material and guiding it to a suction nozzle. It then is coveyed upwards and sideways to a gravity material seal inside a circular separator. The apparatus formed by the rotating disks and the suction nozzle hangs in joints from a boom, which can be moved in any direction. The complete unloader can be stationary or movable on wheels if, in the latter case, the ship may not be moved. All

auxi-liary equipment, as air blowers, _{winches or hydraulic}

oil pumps, motors and control cabinets are also mounted inside the unloader housing.

Underneath the air seal the pulverized goods _{can be}

conveyed by any means, however, advantageously _they

again are conveyed pneumatically to the _{storage silos}

or to loading equipment to load railroad cars or trucks

Pneumatic unloader have been constructed for _capacities

Obering. M.H. Kunz DEMAG Lauchhammor

. Maschinenbau und Stahlbau GaibH

J Diiaeldorf-Benrath/Germany

STOCKPILE YARDS FOR BULK GOODS IN PORTS

The ever growing demand for rew materials during

the last decades for the production of ateel and

aluminium, the increase in the UES of fertili2urs

and materials of construction has not only

in-fluenced

as we heard in the preceding reporta,

the development of shipbuilding and unloaders but

aleo the structure aad design of the stockpile

yards required in the porte of shipment and

deati-nation for the raw materials.

Stockpile yards are required to provide for a

compensation of the supply and delivery different

in time and quantity. In many ease3it nust be

possib/o te stockpile various kinds of mat,-Jrial

and to convoy them separately. eurthermore, it

pay be tho function of steckpile yarda ta atore

reserves of raw material in order to prever.t

rcatriotiona in production in case nf transport

difficuIties as they e.g. may occur in ,ainter

when the waterrays are frozen up.

-In ore.emporting colIntries like Canada or North

Sweden the stockpile yarda .atoro orea

continuoua17,-'Mined all over the yhoie year whereas w!.pply,

however, can only be made during the icofrce

Picture 1

-The different functions to be handled naturally influence tho stockpile yard system to he solecl

W1 well as

type

ad capacity of therused machin(

Up to the beginning of the fiftieth the ships t( te.loaded and unloaded had a iizo of 10 to 15,0(

tono. For loding and unloading grab cranes were

used, particularly loading-bridgee with grab ty] trolley or slowing jib trolley.

In th,o destination

porte the bridges hat to fula

filscv.wal tasks. Their span covered the stock.

yard required. On the waterside they were equip] vith a booM of such a length to reach not only

the hatches of the sea-going vessel but to per-mit also reloading of material out of the sew,

going vessel into outboard lying barges trans-porting the ore or coal.to-the-final user e.g. to the steel mill works in the interior.

Also in the ports of loading the bridges had to perform various requirements, to say, tho

stock-piling of the materialdelivered per wagon, tru,

or inland ship on the yard Rnd the loading of the sea-going vessels carrying out the export. Simple as.this system tay be its effici,ency is rather

limitcd4

The increasing dem,md fin- ray.

material mco.ce larger ships necessary which call

because of economical reasons - for 'short nloa

times in the ports and,

consequently, for

loaders with a high capacity.

-3-Picture 2

The various functions formerly executed by the

loading tridges.aothe,univers511 machine had

to be .transferred to different machines each

serving only one purpose. This changed the

conceptien of the stockpile yards. Now types

of machina work,' developed for the different.

functiona: unloading; stockpiling, stock

reclaiming, ahip or wagon leading.

In spite of splitting up the functions bridees

w:re kept fer'feeding and reclaiming stockpile

yarda at fira.

The picture shows a moiel of the ore stockpile

yard at Narvik designed in 1951/2. Stacking of

ore is made continuously by distributing bridge

with conveyor belts, reclaiming from stockpile

discentineously with ropa operated grab trolley

bridge, output 1000 t/h at a carrying capacity

Of )5.tons (grab + contents) ento.belts.

With the request to intensify the oeLput also

for reclaiming from stockpile, c:mtinuously

operating machines like bucket vhec,1 machines

were required.

For modern syntem5 with high caPacity generally

Picture 1

ateekerafor.piling up stockyards.will be uscd.

In consequence of tho characteristics of the slehires different basic principles have to

be observed.

In'most eoldom cases only it will bo possible

to lay out the stockpile yard in any size or

shape; in most cases, however, the stool:pile

area is limited in its sine or oven

its shape

is filted.

II shape or arca is given the heinht of th tc.c

pile yard is decisivo for its volume. As a matte

of course a leer yard in of loss volumetric

capacity than an high one. The height cf stock-pilo, however, is limited by the dome resulting from the angle of repose of the matertal to be

piled up in connection with the width. A high

stecknilo implies machines with longer booms 'ar

the inclination cf the conveyor belt is litlited.

Desiden,a reclaiming bucket wheel han to operat

in several slices and a triangular pilo is ver-3, tAnfavourabIe for a Luckst wheel

machina in the

upper cu:. bocausegit works in slew operation

and - while slowing - swings out of the ranga of the stockpile at very short intervalo.

There-fore in not cases a compromise

has to be macie

anei a medium high stockpile yard

y'ith e flat

peak has to be strived

Picture 4

Picture

Picture 6

5

-If.the quantity which shall be stockpiled is

known and no dimensions required for the

cross-section of the yard, then the question rainea

whether a long narrow or a short wide stockpile

should be laid out.

Tho long narrow stockpile requires longer belts

and runways for the ¡achine.

On the other hand,

the booms of the machines may be shorter with a

narrow stockpile than vith a short wide one so

that the weight will become lo ss and the price

moro fabourable.

In an-ertremely vide nlant the material cannot

be reached anymore by the machines arranged

on

one side and has to be supplied by means of

dozers or shovel loaders. Another possibility ia

a movable conveyor belt ryatem. Both possibilitieo

involve additional co,,ts. Such

a system should

.be avoided in economic handling operation at

4p4 port.,

If stacker and bucket wheel reclaimer

are

arranged clewablo round a fized point. an annular

shanpd rtoc2ile is prodced. Th3 feeding of the

material ae well as the reclaiming will be made

via the central point. Stockpiles

_{of this type}

are, however, limited in respect of the volu.

A separation of sorts istdifficult. Such

a system

Picture 7

Picture 8

cannot be considered for stockyards in ports

wherever a certain flexibility is necessary.

If a mterial is sirlultane.ausly and onntinllsaELL

stacked and reclaimed vith thn oamo r::te a stoc'r;

pile - properly spoakina - is not required at al

in this case the material can be conveyed direct

nowover, a material will be

stoc-EDiled and

reclaimed nt differnnt tiu!es with one or differa

handling rates various systems of stockpiling

are possible.

In this lay-out the conveyance is arran-ed on

different se s of the stoakpile, the stacker

on one sido and the bucket

vheel on the other.

Both machines run en rails and the bucket wheel

machine must have a relatively long boom to

reach the other side of the stockpile.

Therefore

installationz have already been built where te

track or the bucket Oleel maellina isc

placec:

the center line of thn

In this case the rails are covered by

the nateri

and a special device on the machine

in needed fc

cleaninc. The bucket vhecl with a

relatively shc

boom then directs the material via a

connecting

belt cato a ;lopper car beside the

atockpile. Tb3

syte

i

only suitable fer the piling of one

- Picture 10

- Picture 11

ic situated within the Rama axle. The bucket

wheol machine hap then its starting position

between both-stockpiles in the middle.

Picturla

_{7f the bucket whool ia mounted}

_{en cremlo2h it}

may move also along the coator line of the

stockpile and may have a short boom.

If both_ru::!wats for the stacker

as woll es for

the bucket wheel machtne would be arrngezi

on rrne

stoek.oila, a second sio6tpile

ar.ranged on the other sido of the

_{runways could}

be reached by Clewing. Unfavourable

_{is ti:e}

obstacle of the machines movinp in

_lonitudlnal.

direction. The more, booms must be

_{BO long that}

thep roach beyond the runway of the

_{other mz.ohine.}

This disa,ivar.tagc will be eliminated

_{if for}

otacking vnd reclaiming only

_{one belt is used}

and if the stacker is arranoed

_{on rails in th4.,}

-center between the two stockpi les. The tucl,.et

wheel machin(, then is mounted on erawleY.s feeding

the material onto one of the two loading cars

arranged on the bolt systerz,

_{before snd behind}

the.stacker. This requires a pessage for the

bucket wheel to cross the bolt

_{cenvoyor in order}

to reach the second stockpile

too.,

Picture 12

_{As tIv}

_{aterial will be ztockpiled}

_anri

re-cictimed at different times

_{it may bo}

Picture_11

Dicturo i4

suitable te use a combined machine capable of stockPiling the material ene reclaiming too. In this case it is arranc;ed in the center line

between the stockpilesand

only ene conveyor belt

is necessary. In coRV the reclaimed material

should be conveyed in opposite

direction te that for stacking, that means the yard conveyor is

reversiUle, also a combined machine can be used. In ti s eizample the tripper car has two belts. The longer one is running in opposite direction and feeding the material tostack to the boom conveyor. The reclaimed material is feeded via

the central chute of the

machine

onto the yard conveyor bolt then reversed.

Instead of the inclined belt the elevating one of the tripper car my be lz,werable.

Before reclaiming the material from the stockpil the tripper car is separated from .the machine,

the belt lowerod and puched under the central. chute of the bucket wheel

machine.

.

Also a normal bucket wheel machine on crawlers with discharoe boom may operate as combined

machine. The material is transferred

fvom a

tripper car with transver;3e bel en to the

bucket wheel boom belt and te discharge boo::

belt throws the material on tc the stockpile.

Vico versa, for reclaiming the superstructure

Picture 1,1

Picture 16

of the excavator is

The buv.ket wheel

picks up the material from the stockpile and

'feed it. via the discharge boom belt

on to a

loading car located on the yard conveyor belt.

fri this

case, too, a coss-over has to be

pro-vided in e-:der to refp.;11 the second stockpile.

A combined machine may also be used if the

material is stacked and reclaimed at the E&Dle

time.

Let us first assume tbat the stacking ratG is

larger than the reclaiming rate. In this case

the combined machine will get a tripper

car with i

inc/inwd belt and between these two elements the

stream of material is split up. Cne part is

conveyed directly, while the other is directed

on the stockpile.

IsnI the reate o: reclaiming is larger than that

of stacking the combined machine

_{my add material}

reclaimed from the stockpile. Inboth cases the

additional reto is controlled by

_{a belt scale}

arranged on the conveyor belt.

Uhere two sorts of material shall be

stockpiled

which, however, must ife never stacked and

re-claimed at the same time there is

_{one single}

combined machine or one stacker and one bucltet

wheel sufficiont. It may also

happen, that the

two kinda of material have to be stockpiled at

Picture 17

Picture 13

-In this case two stackers aro necessary

travelling on the outuiden of the two Rtockpilez

The only one bucket wheel operaten in the center

lino between the two stockpiles.

On the other hand it is posible that tWo sorts

of material have to be reclaimed at the came tit,.

but stockpiled at different times. In that case

only one staeker is necessary and two bucket whe

machinas have to be arranged on the outside of t

stockpiles.

The systems shown may be extended by ar2'anging

e.g. three steckpilea side by side. The central

stockpile may then have twiori. thc width of the

outer stockpiles but can stiff be reached by twc

combined wachino s with normal long booms.

Practically one material should be sta^ked on tk

middle stockpile and the other one on the two

outer stockpiles re that both kinds of material

will be reached by both machines.

If operation is Dever wade at one and the same

time one combined machine will be sufficient but

haz to Le trans:errca yip: a cross runway

from 0:

pile to ¡he other.

.If the system in exttnded te four stoe.:piles tw4

bucket wheel machines and three stackers are

Picture 20

Picture 21

oce, may be transferred at the

_{end of the}

stock-pils. If the several

_{materials are never}

_handled

at the same time the

_{individual stockpiles}

_for

the different sorts

_{may be arranged in tandem}

and will be oerved by

_{one belt and one combined}

machine.

Rationalization and automation

_{in procees ent,ineer}

ing, particularly in

_{the reduction of}

_{ores call}

for raw xaterial possibly

_{uniform in grain eize}

and analysis.

To meet customers'

_{requests in this}

_{respect the}

material supplied

_{from different mines}

_which

differs in its chemical

_{compoeition will be}

hemogenised in the perts

_{of shipping like}

_e.g.

In Auetralia. It is

_{conceivable that}

_{hceiiegenicing}

will be done in the

_{destination perts prior}

_to

trannportAante tha steel

_plante.

Because large quantities

_{have to be heeegenined}

the blendine bed is

_{the only economical}

_solution.

Two stocke,ile

_{yards belong to}

_{ons blending bed.}

Whfale the filled

_{stockpile is reciaimed the otner}

is stacked and vice versa. The

_{stacker places the}

material in layers

_{along the complote}

_{yard length,}

The reclaiming is done in transveree

_alisos

either by usirg

_{a slewable bucket}

_{wheel wheee}

boom end is equipped

_{with a rake}

_{or a cutter roll}

by

or/a bridge

_{type machine.}

-PiCturo_22

12

-Tho bridgc:typo

machine uay be

provided with on

or several

bucket wheels. The number of the

bucl

wheela may be

increased so far

until it forms a

drum equipped vith

buckets covering

the entire

width of the stockpile.

The two stockpiles

bebonging to one blending bei

may be arranged

in parallel or

in tandem. If

thi

stockpiles are parallel

the stacker moves on

ra

between the two

stockpiles and ny serve

veithe]

the one or the

other. The

reclaiming belts are

outside.

The bridge or

drum type machine

is transferred

from one steckpile

to the other by a transfer

If stockpiles arr

arranged in tandem the stacko

moves On one

sido. The stating position for th

bridge or drum.type

machine is in the

middle of

the two Stockyards. The.buckets

must be designe

in rch a way to

permit reclaiming

in both direc

O. Wichern, Managing Director, Demag Lauchhammer, Düsseldorf

EQUIPMENT FOR BULK MATERIAL HANDLING IN MODERN _STOCKYARDS

The preceding report gave you an outline on the arrangement of stockpile yards for bulk material featured _{as to their geometry} and the used machine systems by a great many of factors like A

available area

rate ofrreclaim and stackout number of different ores

simultaneous stacking and reclaiming blending

and many other components that have _{to be observed when selecting} an economic system reliable in operation.

When the system as such is selected it is necessary to optimize the individual machines and coordinaCe _{their capacity and} tech-nological layout in a way so as to yield including the continuous conveyors connecting the machines a high efficiency, that means, maximum availability of the plant at minimum installed peak output.

Now some criteria for the _selection

of the stacking

_{and reclaiming} machines

For building up the stockyard generally the belt conveyor

_stacker

in boom construction type is used nowadays, at any rate on the

high-capacity stockyard to which I am confining myself in this case. Special types like _{conveyor bridges with lowering devices}

e.g.

r--

2

--Picture 1 shows the simplest type of the stacker : rigid, not

slewable boom. This machine can only build up a stockpile with triangular cross-section and entails quite a number of

disad-vantages. The significant discharge height involves

grainsdes-tructions which may induce a deterioration of the material, it results in losses, if dusty material is drifted thus causing .secondarity cOntamination of enVironment and it 'leads to a

segre-gation of the material - the larger lumps lying in-the plane of the level.

Consequently, the use is practically restricted to stacking such materials which are not subjected to the above criteria as regards

consistency and quality. The selection is made in favour of this type if a stockyard is fed all over its whole length with one grade, starting with a discharge cone being then continuously extended in chevron type. Dust formation is thus reduced, tendency to fracture -limited but - sorry to say - segregation of the grain sizes not

prevented.

The tWo-wing stacker as per picture 2 shows of course the same operational behaviour but offers, though, at lower additional investments the advantage to cover at same runway length double the stockyard surface.

The next step leads with picture 3 to the stacker with hinged boom. The disadvantages consisting in dust losses, environ-mental contamination and tendency to fracture the ore, are

ex-cluded, as the discharge pulley can be kept close above the impact point, the segregation of the grain sizes, however, remains.

3

-Should the admissible ground pressure permit it very high conical stockpiles can be arranged as per pictures 1 - 3 with stackers that do not slew. But the reclaiming bucket wheel

machine has likewise to be aken into consideration.when

Se-lecting whether bucket wheel machines on crawlers or pn.rails. shall pick up the material; the high conical stockpile requires long booms i.e. heavy and expensive machines. Besides, at the top of the stockpile bucket wheels operate only with considerab-ly reduced capacity and that in return.involves a reduced uti-lization of all following connected machines and systems.

The fully slewable stacker - picture 4 - with hinged boom eliminates all aforesaid disadvantages causes, though,

con-siderable costs as to the machine itself, the runways, maintenance and spare part stocking,

As a rule, the stackers in stockpile operation move on rails which, in exceptional cases, can be shifted along with the veyor system like in mining operation if stockyards are con-cerned varying considerably in volume (to say, extremely wide stockyards).

Let us turn now to the bucket wheel machines. Here, too, the crawler travel mechanism is used, however, today preference is given to the rail mounted machine unless system criteria call for

The paramount advantages of the rail travel mechanism in catch-words are

Easier attendance

Possibility for full automation Reduced wear'

Use of identic components like with associated stacker (travel mechanisms, slew mechanisms)

Higher travel speed and consequently quicker change from one

stockpile

section to the other.

It is not so easy to draw a parallel between the different types and to which one preference should be given. This can only be carried out for the defined case

since

several factors have to be

taken

into account

:

costs

for rail runvay, loss of usable

stock-yard area for the runways of the crawler machine, loss of stacked material crushed by the crawler travel mechanism.

The rail mounted machine permits a perfect clearing of a corres-ponding level which would call for a most experienced driver when using a crawler machine I

Picture 5 shows the simplest design of a bucket wheel machine of the so-called rocker type. Bucket wheel boom and ballast boom form a unit linked with the slewable superstructure of the ma-chine via two bearings located in line.

-

5-The effect of lifting and lowering is attained with a minimum of cinematics or in other words with _{a few wear parts and hence} resulting insignificant maintenance.

By modifying the system to-a small extent only, viz, by

ar-ranging the attachment point of the counterweight _{boom upwards,}

.Ahe rocker system _{may also 'be used for the combined machine.}

for stacking and reclaiming _{- picture 6.}

Unfortunately, this specious design has also its limits

If a boom length of more than approx. 4o m is required this results in a disproportion between the fixing point of the lifting device on the boom - today nearly without

exception one or two hydraulic cylinders - and the total length of the systems. The unfavourable _{leverage leads to vibrations} and uncontrolled pressures in the hydraulics. Ideal would of course be a rocker machine with a momentum ratio _{of 1} : 1 between

wheel and coun.terweight boom thus permitting to attain the possib-ly'lowest design Weight but here the stockpile interferes near-ly always with the counterweight (picture

_5).

_{Increased deflection} of wheel and counterweight boom against each other only offers but a limited effect since the center

of

gravity of the system advances vertically thus describing _{a movement in horizontal} direction when lifting and lowering _{resulting in higher loads} of the ball slew assembly, of the lifting device and of the travel mechanisms.

Consequently, for machines with boom lengths up to and above 4o m other design types have to be _{selected - picture}

₇

-which in principle consist _{of a fixed central structure}

the base point ef which the boom is hinged. Ballast and machinery house for the luffing winch are either firmly cónnected with the superstructure or the ballast is of the mobile type.

Picture 8 shows a machine designed according to this prin-. ciple with a handling rate of

9,000

t ore/hour. In this

case the rocker system was abandoned already at a relatively small length of boom revealing that also the rate and hence the size of the bucket wheel influences the choice of the

system.

Picture 9 shows likewise a machine with fixed central structure but as combined machine with a rear boom hinged at a high

level.

Handling rate

3,000

t of ore per hour at a boom length of

67 m.

Special design

types for the combined bucket wheel

machine are then in question if the yard conveyor works in reversing operation, that means, if material supply and delivery are .oppositely directed.

Picture lo represents a collapsible tripper car in connection with a bucket wheel machine. Supply is made via conveyor 1, stacking via conveyor 2 of the bucket wheel machine. On the other hand, when reclaiming conveyor 2 directs the material

7

-to the central chute of the machine via which the now deliver-ing conveyor 1 is fed.

The solution.as per picture 11 offers the advantage that

the operation may be reversed practically without _{any loss.of} time since all conveyors and transfer stations are installed in a fixed manner; there _{can be no doubt this entails also} a saving in maintenance costs _{and time.}

When selecting a crawler machine two basic _{types are under} con-sideration, both of them of the rocker conception since craw-ler machines in stockpile operation will always have booms with a length of less than 4o m anyway.

Picture 12 shows a crawler machine with supported bridge, that means, with a connecting belt bridge between reclaimer and hopper car.

This type of machine should be preferred if always a fixed yard conveyor is to be fed. A follow-up control releases the machine operator from the supervision on the position of bridge and hopper car permitting _{same to devote himself} en-tirely to the reclaiming proeess.

The machine as per picture _{13 has a self-supporting slewable} discharge boom being also vertically adjustable. As a rule, such a machine will be chosen _{if different or changing}

The operation of such a machine is more difficult and implies a second man, besides, it is More sophisticated in its design (two independent slew mechanisms with movement

superposi-tion.)

With the procedure of stacking and reclaiming another process is nowadays often linked up : the blending of niaterials. The

essential contribution to the blending process is performed by stacking according to the motto : In any stockpile

cross-section all material types shall occur in their representative frequency, to say, distributed all over the whole cross-section. This task is solved by each slewable stacker with corresponding

automatics.

For the reclaiming of the so preblended materials simple slew mechanism machines on crawlers or rails, e.g., may be used or

bridge type machines.

Picture 14 shows a blending machine mounted on crawlers.

The bridge type machines are to classify in two basic types Bridge type machines with one or several bucket wheels running parallel to the bridge axis (picture 15) or the so-called

drum type machines (picture 16). The selection has to be done in connection with the possibilities of the stacking program

If the stockpile is built up in accordance with the just ex-plained motto then the blending effect may only diverge within practically negligible limits.

In addition'to the foregoing selection criteria now some notes about basic design features.

As per up-to-dated technics the plain web or box type' design will be favoured for the supporting

framework.-Apart from the advantages of easier maintenance _{an aesthetic} effect goes along.

Picture 17 shows a combined machine _{on a coal stockyard in} a combination of plain web and large member design.

Two factors are limiting this type : the length of the boom

and the capacity of the bucket wheel. _{A boom length of 45 m} is, say, the critical point where it becomes necessary to pass over to'lattice design.

In the outward appearance two _{types of substructure are} encountered with stackers and bucket wheel machines

four-point and three-point support of the rail travel me-chanisms.

Already in the stage of planning the entire conception

the decision for one or another solution is taken by settling on ballasted runways or on such with _{concrete foundations.} The dominant word will be pronounced by the soil mechanician. Wherever pcissible, preference is today given to the ballast-ed runway calling for a three-point support, or rather a

lo

In many cases the brace and belt solution has also yet been performed, viz, concrete runway and three-point support

en-suring absolutely that also with insignificant runway settle-ments the wheel loads and consequently the drive and braking forces are exactly define.d.

.As to the selection of the mechanical drives of all machines operating on a stockyard for bulk material handling two catch-words only shall be named

entirely enclosed design, dust- and oiltight. quick exchangeability in complete sub-assemblies.

A most important decision eludes a theoretic consideration the use of the cell-less or semi-cellular wheel. The selection

can only be underpinned by a comparing consideration of the two types operating in similar materials which shall be

re-claimed by the machine to be planned.

Predominant criterion is the wearing behaviour !

Still another few words with regard.to the electrical equip-ment for stackers and reclaimers starting with the current

supply.

As a rule, most machines are energized via cables and cable reels and also the interlocking of the machines to one system is made in this way, but then via separate control cables. The system of power supply and communication via conductor

rails could only be realized, though, with such machines moving on concrete runways. Besides, the relatively high

power consumption implieS the supply of h.t. three-phase

'current

being

'economically and safely fed via cable.

The simplest drive type for all movements would of course

be the a.. technics being absolutely acceptable _for

ma-chines with smaller outputs if no uniform average output is required, coming possibly close to the maximum handling rate and if no automation is needed (controlled _variable

speed).

To regulate the output of a reclaimer primarily the following working motions are speed-controlled

with a boom machine the slewing speed

with a bridge type machine the traversing _speed.

So, d.c. control should be favoured _{for the slewing and} tra-versing drives.

Only secondarily d.c. would be considered for the bucket

wheel drive, namely then if bulk material _{grades with} dif-fering discharging behaviour shall _{be handled (pellets, wet} fine ore) and if an infinitely variable speed regulation is deSired to achieveproper discharge.

For the travel drive of the bucket _{wheel boom machine,} how-ever, the a.c, drive will nearly always _do.

Just the contrary is the problem concerning the stacker The slewing speed of the boom does not play any part since

the slewing is a mere adjusting movement. Of eminent im-portance is the regulation of the travelling speed

particu-larly then if a blending bed with exactly defined volume oi" tlie individual rows shall be filled. That means prac-tically to control the travelling speed depending on belt

loading.

In this connection the barrel type bucket wheel reclaimer may likewise be mentioned. Its reclaiming rate is defined by the advancing speed of the barrel, therefo're, also in this case direct current for the travel drive is preferred.

It is known that hydraulics offers a nood control possibi-lity for drives. The use of hydraulics entails at the same time an ideal overload protection. Today hydraulic pumps and motors are available for all drives being in question and quite a number ok full and partial hydraulic machines are

successful in operation.

Nevertheless, we as suppliers still encounter a certain passi--vity towards hydraulics with the utilizers as far as it goes

beyond the fully accepted hydraulic cylinder with clear force direction and constant speed.

From various discussions with customers and makers I draw the following conclusion : If a customer is expérieneed

al-- 13

-ready in hydraulics and disposes of a specialized personnel

for

maintenance the hydraulics may be recommended with good conscience.

If someone has, however, the intention to procure

for his

pIaflt being located, beside , far away from respective'

service stations an individual machine I would today advise

.

against hydraulics solely from the view of maintenance.

From the part of the makers a great deal has _{already been} done to remove a certain aversion against hydraulics, _e.g., by using subgroups that can quickly and easily be inter-changed; however, certain special knowledges for _the

sub-sequent

repairwork

_{and adjustment are needed.}

Sure, there are still more viewpoints contributing to the choice of the maehine type and its design which have not been mentioned. Perhaps _{you may extend and deepen the theme} in a critical discussion.

Dipl.-Ing. Kalia, Director, Eisenwerk Weserhate.AG, Bad Oeynhausen

Transfer handling- and transportation of

bulk goods in the future - problems and limits

The progressive increase of the earth's population, especially in the economically underdeveloped

countries, and the rapidly growing demand for

goods of all kinds in the industrial countries

-cause problems of many kinds.related not onlY to

political and sociological aspects. Adequate

supply services to the population demand increased

productivity in all branches of industry by

rationalisation and the use of new technologies.

. New dfficult problems arise in particular also

in respect of bulk good transportation, due to the 'simultaneous increased demand for goods, the raw

material shortage and the population density in the areas of industrial concentration as well as due to progressive interiinhinçj of wrli econry, characterized.by division of labour and a more intensive exchange of goods. Future transportation

tasks must he viewed from the aspect of

_zncdern"

structural planning, means of transportation and transfer handling procedures which are to be

developed must satisfy higher requirements relating to caPacity performance, economy and protection of

the environment.

The following reflections on the transportation of bulk goods are not limited purely to loose

bulk materials, _{but include all merchandise and goods}

which are transported in quantities and which differ in volume, weight and transport procedures from

(1)

typical individual goods. Moreover, the concept

"transporttion" does not only imply the conveying

of bulk goods from one location to another, but _alsO

their transfer handling, according to the _classical.

definition the transfer of the goods from one means

2.

with.the contents .of a railway truck. It seems

logical, however, to extend this concept even further as transfer handling of bulk goods is also carried

out for the purpose of building up supplies, also

for levelling out irregularities in production,

in gettinq or winning and/or within the transport cha:

for carrying out blending, separation and dressing

processes, or for collecting or distributing the

transported material. The transfer handling of

bulk goods is consequently almost always connected.

with warehousing or storage. The transport path

from the original to the Final location by different

means of transportation, with repeated transfers or

transshipments and warehousing represents the

"transport chain". Picture 1 shows sections of

such transport chains for different bulk goods

with diagrams of the means of transportation,

transfer handling and warehousing facilities..

Even though it may be assumed that transportation

of bulk goods generally will continue to increase

considerably, predictions relating to the traffic

carried by the various transport paths and the

share of the various bulk goods carried in,

say,

the year 2000, are very difficult. It is only

natural that the experts' views on future development

diverge widely, as their calculations are based

on many complex and'partly uncertain assumptions. Thus, for instance, it cannot be predicted with

certainty-at present how individual traffic will

develop during the next decades. If, for instance,

it is possible to develop a suitable rechargeable

storage battery during the next 15 years and

provided various other premises are met, it might

be conceivable that electric automobiles with

plastic bodies may be used predominantly around the

year 2000. Many millions of tons of mineral oil

and iron ore would then not be transported at all, o:

for quite different purposes and probably to differe)

3.

energy providers coal, oil and natural gas will depend on the success of the endeavour to obtain electrical energy in adequate amounts in nuclear,. tidal, hydroelectric, wind and solar power stations or by utilizing geophysical heat sources and to convey the power thus obtained without losses over

long distances. In any case, many of the known

deposits will have been exhausted in the foreseeable future and limits are therefore set to further

increases of tonnage for energy raw materials.

Apart from such technological developments, the social, economic and political changes during the next decades will affect the extent of bulk good transportation and the transport paths in the same

way or even to a greater extent. If for instance

Japan which is highly industrialized but poor ih raw materials could establish its own i-2on and steel works in the countries from which it now purchases the iron ore and coal, the transport volume for the Japanese steel industry would be halved. However, stable political and economic relations

in and among the countries concerned _{would be a}

primary condition , in order to guarantee

long-term safeguards against expropriation and other

reprisals.

Unfortunately, even detailed investigations of

future developments like those of the "Club of Rome"

-do not provide facts from which it would be possible to calculate- with some certainty what bulk goods

in what quantities and in what form _{will have to be}

transported between which locations of the earth in

the year 2000. _{It is, however, possible to answer}

the question of the limit conditions of bulk goods

transportation approximatively _{by starting from}

the assumption that at some point in time a double,

threefold or multiple quantity of a buik material may have to be transported, and by then investigati