Bucket wheel excavator

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Bucket wheel excavator 1521 SRs1300 in Ferropolis
Bucket wheel excavator during dismantling in the Garzweiler opencast mine (1:40 min., Approx. 9 MB)
Size comparison between bucket wheel excavators (1556 SRs704) and mobile excavators in the Cottbus Nord opencast mine

Bucket wheel excavators are machines for mining of raw materials and for use on construction sites. Particularly large bucket wheel excavators - with dimensions of several hundred meters - are used in lignite mining .

Development and size

Bucket wheel excavators are among the largest and most spectacular excavators in the world and have been manufactured since the 1930s. There have been excavators since 1978 that can move up to 240,000 tons of coal or cubic meters of overburden every day . These 240,000 peaks are still the largest excavators in the world today. When they were commissioned and weighing more than 12,000 tons, they became the largest land vehicles on earth - even before the transport platforms for the moon rockets in the USA. The 1510 SRs6300 excavator built in 1978 by VVB TAKRAF Lauchhammer in the Lausitz area and the “288” bucket wheel excavator built by Krupp Industrietechnik in the Rheinische Revier in the same year were the first excavators in this performance class. The 288 excavator is currently working in the Garzweiler opencast mine ( RWE Power ). An almost identical example from the same period is the "Bagger 289", built by O&K ( Orenstein & Koppel ) and LMG ( Lübecker Maschinenbau Gesellschaft ), which works in the Hambach opencast mine .


Bucket wheel of a bucket wheel excavator

A bucket wheel excavator consists of a chassis, a rotating superstructure and the loading device. The chassis can be designed as a caterpillar or walking gear . The wheel arm is attached to the superstructure , with the paddle wheel at its tip. An important differentiating feature is the design of the wheel arm with or without feed, which influences technical parameters (e.g. structure and dead weight) as well as the extraction technology .

The paddle wheel can be pivoted, tilted or both to the wheel arm axis. The pivoting of the paddle wheel (around the vertical axis) is usually necessary to ensure the clearance angle for the paddle wheel drive attached to the side. The paddle wheel is tilted (around the wheel arm axis) in order to improve the emptying of the conveyed material .


The driver usually swivels the superstructure at an angle of 90 ° in the mining direction and, depending on the equipment, up to 35 degrees in the opencast mining direction . This absorbs the overburden or coal. The material to be conveyed is then - depending on the position of the wheel arm and the height of the dismantling disk - transported 30 to 180 degrees upwards until it hits the wear rails (a 45 ° inclined ramp / slide in the so-called paddle wheel discharge chute ) and then onto the conveyor belt of the wheel arm ("Radband") arrives and is transported to the undercarriage . There it falls a few meters lower onto a second conveyor belt that leads to the loading device . The latter connects the excavator with the bench belt system of the opencast mine, which either leads to the stacker , conveyor bridges , intermediate coal storage (coal bunker) or the power station . The “loading device” unit is permanently connected to the excavator and is therefore part of it. It is either a separately controlled device (so-called funnel car ) or - especially in the case of smaller bucket wheel excavators in coal mining - a swiveling boom with discharge funnel .

Technical specifications

RWE Power excavator (formerly Rheinbraun)

Excavator 255 Excavator 258 Excavator 259 260 excavator Excavator 261 Excavator 262 Excavator 271 Backhoe 275 Excavator 281 Excavator 282 Excavator 284 Excavator 285 Excavator 286 Excavator 287 Excavator 288 Excavator 290 Excavator 291 Excavator 293
Construction year: 1954 1957 1960 1962 1961 1966 1975 1976 1978 1978 1983 1995
Crew: 3 4th 5 4th 4th 4th 4th 4th 4th 5
Service weight: 5900 t 3850 t 7800 t 7800 t 7600 t 7386 t 13500 t 14,000 t 12840 t 13500 t 13500 t 14200 t
Nominal delivery rate: 110,000 m³ / d 110,000 m³ / d 110,000 m³ / d 110,000 m³ / d 100,000 m³ / d 110,000 m³ / d 200,000 m³ / d 200,000 m³ / d 240,000 m³ / d 240,000 m³ / d 240,000 m³ / d 240,000 m³ / d
Length: 210 m 171 m 210 m 195 m 220 m 195 m 210 m 225 m 220 m 225 m
Height: 66 m 50 m 70 m 67 m 70 m 67 m 92 m 95 m 96 m 96 m 96 m
Width of the chassis: 31 m 31 m 31 m 31 m 45 m 45 m 45 m 45 m
Number of caterpillars: 12 12 12 12 12 12 12 12 12 12 12
Drive power: 5,555 kW 9,478 kW 9,478 kW 9,500 kW 16,560 kW 16,560 kW
Driving speed: 2.8-9.6 m / min 2-8 m / min 2-10 m / min 2-10 m / min 2-10 m / min 2-6 m / min 2-10 m / min 2-10 m / min 2-10 m / min 2-10 m / min 2-10 m / min 2-10 m / min
minimum curve radius: 50 m 50 m 50 m 50 m 50 m 50 m
mean ground pressure : 12.5 N / cm² 12.3 N / cm² 12.3 N / cm² 12.0 N / cm² 18.0 N / cm² 17.1 N / cm²
Paddle wheel diameter: 17.0 m 15.0 m 17.3 m 17.3 m 17.0 m 17.3 m 21.6 m 21.6 m 21.6 m 21.6 m 21.6 m 21.6 m
Number of blades: 10 10 10 10 10 18th 18th 18th 18th 18th 18th
Nominal bucket capacity: 5.3 m³ 1.5 m³ 2.6 m³ 2.6 m³ 2.6 m³ 6.6 m³ 6.6 m³ 6.6 m³ 6.6 m³ 6.6 m³
Rated output of the paddle wheel motor: 1 × 1250 kW 2 × 750 kW 3 × 630 kW 3 × 570 kW 4 × 630 kW 4 × 840 kW 4 × 840 kW 4 × 840 kW 3 × 1680 kW
Current location: Inden opencast mine Garzweiler opencast mine Hambach opencast mine Hambach opencast mine Garzweiler opencast mine Garzweiler opencast mine Garzweiler opencast mine Inden opencast mine Inden opencast mine Inden opencast mine Garzweiler opencast mine Garzweiler opencast mine Inden opencast mine Hambach opencast mine Garzweiler opencast mine Hambach opencast mine Hambach opencast mine Hambach opencast mine

Excavators of the Central German and Lusatian district

Paddle wheel of the 1510 SR 6300 + VR in a preliminary cut, 2009

The bucket wheel excavators in the Central German lignite mining area ( Mibrag ) and Lusatian lignite mining area ( LEAG , formerly LAUBAG ) were manufactured exclusively by the TAKRAF combine . The total number of bucket wheel excavators manufactured in the GDR and used in the opencast mines of the GDR amounts to around 155. In addition, there are exports to other countries of the CMEA and some old excavator from before the 1945th

The main types of TAKRAF are:

  • SRs 315
  • SRs 500/630
  • SRs 630
  • SRs 630/800
  • SRs 702, SRs 703 and SRs 704 - approx. 2,500 m³ / h,
  • SRs 1200
  • SRs 1300 and SRs 1301 - approx. 3,500 m³ / h,
  • SRs 2000 - approx. 6,000 m³ / h,
  • SRs 2400
  • SRs 6300 - approx. 14,000 m³ / h

The term SRs stands for "bucket wheel excavator on crawler tracks, swiveling". The number indicates the volume of a single scoop in liters. Since the performance of the excavator could be increased in the course of development despite the constant bucket size (for example by faster rotating bucket wheels, more buckets and faster belts), it was later switched to detaching the number from the bucket size and relating it to a theoretical bucket volume which would have been used had the excavator been built in a conventional manner. The output of an SR 1300 roughly corresponds to the output of a classic excavator with a bucket capacity of 1300 l, although the SR 1300 only has a bucket capacity of 700 l. For example, the largest bucket wheel excavator of the type SRs 6300 built in the GDR has a bucket capacity of 3300 l - and still achieves the performance of a counterpart with 6300 l displacement. Two of these devices are used in the Nochten opencast mine (Saxony; built in 1978) and in the Welzow-Süd opencast mine (South Brandenburg; built in 1981). Another device (GDR No. 1550) of this size went into operation in the Breitenfeld opencast mine ( Leipziger Revier ) in 1988 , but was scrapped in 1996. Although their dimensions of 243 m in length, 57 m in width and 63 m in height are below those of the 288 excavator (RWE Power), they still achieve a significantly higher theoretical conveying capacity of up to 336,000 m³ / day. However, this theoretical delivery rate is rarely achieved, as ideal conditions (loose gravel, high impact, large disc height) must be present for this. However, delivery rates of around 275,000 m³ / day have already been achieved in practice.

An "a" or "n" appended to the type designation denotes types, of which there is an old variant (often types from before 1960) and a newer variant.

In addition to the (theoretical) bucket capacity, the full device designation also included the maximum mining thickness in high and low cut, as well as the length of the feed and the drive power of the bucket wheel drive. If a loading device was available, there was also the indication of the height difference that could be bridged. For example, the exact type specification for a SRs 1200a excavator was:

  • SRs 1200.24 / 4.12 (400 kW)

From this it can be seen that the excavator has buckets with a capacity of 1200 l each, can cope with a high section of 24 m and a low section of 4 m, offers a 12 m long feed and has a bucket wheel drive power of 400 kW. There were also different versions of excavators of the same basic type (e.g. SRs 702), which differed in terms of other mining thicknesses.

Towards the end of the GDR, even larger SRs 8000 excavators (excavator numbers 1580 and 1587) were planned for use in the preliminary cut of the Nochten and Jänschwalde opencast mines. Instead, TAKRAF realized the excavator 293 for the Hambach opencast mine under this type designation. This makes it the heaviest land vehicle in the world and, together with the 288 excavator, also the tallest.

The larger devices (from SRs 2000) are mostly used to transport overburden, while the excavators with the smaller bucket volumes are mostly used to extract lignite. Initially, smaller excavators (e.g. SRs1200) were also used to move debris.

Excavator in the Lausitz area

Bucket wheel excavator 1530 SRs 1301 in the coal of the Welzow-Süd opencast mine
Bucket wheel excavator 1571 SRs 2000 + VR in the preliminary cut of the Nochten opencast mine
Bucket wheel excavator 1510 SRs 6300 + VR in the preliminary cut of the Nochten opencast mine
Control of the overburden excavator 1510 SRs 6300 in the Greifenhain opencast mine (1984)

Today in the Lausitz area are still in use:

Jänschwalde opencast mine

  • 1504 SRs 1300 (coal)
  • 1506 SRs 1300 (coal)
  • 1523 SRs 1300 (coal)
  • 1557 SRs 2000 + VR (preliminary cut)

Nochten opencast mine

  • 1531 SRs 1301 (coal)
  • 1535 SRs 1301 (coal)
  • 1510 SRs 6300 + VR (preliminary cut)

Reichwalde opencast mine

  • 1575 SRs 704 (coal)
  • 1534 SRs 1301 (coal)
  • 1571 SRs 2000 + VR (preliminary cut)

Welzow-Süd opencast mine

  • 1496 SRs 630n (clay landfill)
  • 1530 SRs 1301 (coal)
  • 1532 SRs 1301 (coal)
  • 1519 SRs 6300 + VR (preliminary cut)

The following are still preserved in museums:

Excavator in the Central German district

Amsdorf opencast mine

  • 1447 SRs 1200a

Profen opencast mine

  • 1541 SRs 1300
  • 1553 SRs 1300
  • 1511 SRs 2000 + VR
  • 1580 SRs 2000 + VR

United Schleenhain opencast mine

  • 1548 SRs 320 (coal)
  • 1554 SRs 703 (coal)
  • 1566 SRs 703 (coal)
  • 1512 SRs 1300 (currently under reassembly)
  • 1517 SRs 1300 (coal)
  • 1528 SRs 2000 (preliminary cut)
  • 1552 SRs 2000 (preliminary cut)

Preserved in museums are:

Relocation to other opencast mines

In order to relocate a lignite excavator to another opencast mine, there is either the option of dismantling and reassembling it, which is very time-consuming, or - provided there are no major obstacles such as rivers in the way - of simply letting it drive overland. A lignite excavator has a chassis, travels at up to 10 m / min and is off-road. In recent years, Rheinbraun AG (now RWE Power AG) in particular used the latter method.

Obstacles of many kinds cause problems when laying. For example, overhead lines must be dismantled before the excavator arrives, and roads or railways must be closed and covered with a thick layer of earth for protection. Since lignite excavators are electrically powered, they are supplied with electricity from the 25/30 kV network during such operations. Due to the limited length of the cables, clamp connectors for the supply lines, called "submarines", are installed everywhere along the route. After typically 1000 to 1400 meters of travel, the excavator has to be switched from one “submarine” to the next.

Relocations carried out by RWE Power

Examples of the relocation of large open-cast mining equipment (excavators and spreaders ) at RWE Power :

  • 1982: relocation of the excavator 261, Frechen opencast mine to opencast Frimmersdorf / Garzweiler . The large machine crossed 63 obstacles: 16 district, country and federal roads, the federal motorway 4 (Cologne - Aachen) between Kerpen and Sindorf , 7 railway lines and a total of 16 watercourses. 23 power connections ( overhead lines ) had to be disconnected. Duration of transport: September 27 to November 20, 1982
  • 1986 laying of the excavator 287, the spreader 739 and the tripper carriage (BSW) 944 from the open pit Fortuna Garsdorf to Hambach . The large equipment crossed the federal highway 61 and two railway lines .
  • 1992 laying of the excavator 255, the spreader 737 and the tripper carriage (BSW) 939 from Garzweiler for opencast indene . The large equipment crossed the A61 directly at the Jackerath motorway junction .
  • 2001: Relocation of excavator 288 from Rheinbraun from the Hambach opencast mine to the Garzweiler opencast mine and relocation of excavator 259 from Bergheim to Hambach. Both excavators crossed Autobahn 61 in the process.
  • 2004: Relocation of the spreader 755 from Bergheim to the Garzweiler opencast mine and the simultaneous relocation of the excavator 260, the 744 and BSW 931 from the Garzweiler opencast mine to the Hambach opencast mine. The same route was sometimes used for transport.
  • 2009: Relocation of the last spreader 756 including the belt sander from Bergheim to the Hambach opencast mine from August 19 to September 2, 2009. The A 61 , the B 477 , the Erft , the Erftbahn and several country roads had to be crossed again.

Incidents during operation

  • In 1974 a lignite excavator slipped on a clay clod in Rheinbraun AG's Fortuna opencast mine and threatened to topple over. To secure and rescue it, an extensive action was initiated, which was probably the most complex measure to date for the recovery of a work machine in Germany.
  • In 1997 (end of November), ventilation systems in the overburden layers of the Hambach opencast mine leaked 35,000 liters of groundwater per minute at a temperature of approx. 32 ° C. The ingress of water could be sealed; RWE Power had to do without 200,000 tons of coal.
  • In 2001, an excavator got stuck in an old drilling pond while being transported from the Bergheim opencast mine to the Hambach opencast mine. Some chains and drives had to be replaced. The excavator was then able to drive clear with additional auxiliary equipment (bulldozers) and continue the transport.
  • In 2005 there was an accident in the Hambach opencast mine when a bulldozer got stuck in the ground. The excavator driver saw it too late, so that the excavator with the bucket wheel grabbed the nearly 40-ton CAT D8R and pulled it upwards, where it hit the bucket wheel discharge chute. However, the driver of the bulldozer was not harmed as he had got out earlier.
  • On August 29, 2012 at 3:45 a.m. in the United Schleenhain opencast mine , a slope fracture occurred on the old tip of the former Regis IV opencast mine . MIBRAG dredged over an old mining area in order to extract the residual coal there. The landslide was noticed in good time so that the 3 workers stationed on the devices could escape. However, it was no longer possible for the large equipment to escape from the danger area, so that the SRs702 1554 excavator and the 811 belt trailer got into a lopsided position. The belt wagon was recovered in October 2012 and was driven out of the landslide area by remote control from excavator 1566. The excavator 1554 could be erected in January 2013 using a strand lifting system.


The 1452 excavator of the former Berzdorf opencast mine can be viewed on Lake Berzdorf near Görlitz .

A bucket wheel excavator is located in the Hessian lignite mining museum in Borken. It was designed in 1952 by Orenstein & Koppel Luebecker Maschinenbaugesellschaft and was used in the Borken lignite mining area for coal extraction. The large-scale extraction device is around 14 m high and around 30 m long. It will be demonstrated to museum visitors in demonstration mode.

In Ferropolis , an open-air museum near Dessau , a whole range of decommissioned open-cast mining equipment can be viewed, including a bucket-wheel excavator of the type SRs1300 (GDR No. 1521).

Furthermore, in the Bergbau-Technik-Park in the Leipziger Neuseenland directly on the Autobahn 38 , not far from junction no.31 (Leipzig-Süd intersection), there is a spreader (A2Rs-B10000.110, GDR no. 1115) and a bucket wheel excavator (SRs1000n , GDR No. 1547) for viewing. ( → map )

The Merkers Adventure Mine is home to the largest underground bucket wheel excavator in the world, manufactured by VEB Schwermaschinenbau Georgi Dimitroff Magdeburg (built from 1986 to 1988).


As part of the definitive series Industry and Technology of the Deutsche Bundespost , a 100 pfennig stamp with a paddle wheel was issued on May 15, 1975.


  • Günter Kunze, Helmut Göhring, Klaus Jakob: Construction machinery. Earthworks and opencast mining machines . Ed .: Martin Scheffler. Vieweg, Braunschweig / Wiesbaden 2002, ISBN 3-528-06628-8 .
  • Walter Durst, Werner Vogt: Bucket wheel excavators . Trans Tech Publications, Clausthal-Zellerfeld 1986, ISBN 0-87849-057-4 .
  • Jiří Pajer, Friedrich Kurth, Manfred Pfeifer with colleagues. by J. Hojdar: Large opencast mining equipment and universal excavators (=  conveyor technology . Band 4 ). 2nd Edition. Verlag Technik, Berlin 1978, DNB  202258122 .
  • Ludwig Rasper: The bucket wheel excavator as an extraction device . 1st edition. Trans Tech Publications, Clausthal-Zellerfeld 1973, DNB  790134365 .

Web links

Commons : Bucket Wheel Excavator  - Collection of pictures, videos and audio files
Wiktionary: Bucket wheel excavator  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. a b Turning brown coal into energy ( Memento of October 8, 2006 in the Internet Archive ) (PDF, 566 kB).
  2. ↑ Collective of authors: Basics for the calculations of opencast mines. 3. revised u. exp. Edition. VEB German publishing house for basic industry, Leipzig 1982.
  3. ↑ Collective of authors: Opencast mining technology. Volume I, 1st edition. VEB German publishing house for basic industry, Leipzig 1979.
  4. Tenova Takraf: Bucket-Wheel Excavators - TAKRAF. Retrieved May 25, 2017 (English).
  5. The World's Largest diggers: in pictures . In: Telegraph.co.uk . ( telegraph.co.uk [accessed May 25, 2017]).
  6. ^ The World's Biggest Land, Sea And Air Vehicles . ( digg.com [accessed May 25, 2017]).
  7. Profen opencast mine. In: Ostkohle.de. Retrieved August 30, 2014 .
  8. Ralf Aben: A Giant Moves (1983). January 14, 2012, accessed August 31, 2018 .
  9. ^ RBW large equipment transport October 1986
  10. RP ONLINE: Biggest excavator in the world comes to Garzweiler: Giant meeting on the autobahn. Accessed August 31, 2018 .
  11. Information on RWE's move ( Memento from June 18, 2010 in the Internet Archive )
  12. Lignite excavator records bulldozer - no longer available, refers to https://www.monsterpark.de
  13. Mining Technology Park in the Leipziger Neuseenland