NO 21 DREDGER

No.21 Dredger was ordered by the State Electricity Commission of Victoria (SECV) in 1950 and commenced operation in the Morwell open cut in October 1955. The opening of the Morwell open cut in 1949 marked the beginning of the significant expansion of the activities of the SEC during the post-war growth and industrial expansion of Victoria.

No.21 Dredger was the third of four bucket wheel excavators with crowd on the bucket wheel boom purchased by the SECV. The crowd function, which was a feature of bucket wheel excavators developed in the interwar period, necessitated a number of special adaptations including a travelling counterweight, a thrust drive and an intermediate conveyer between the boom conveyor and the discharge conveyor. Progression in the technology of continuous extraction of brown coal from open cut mines was marked first by bucket chain excavators, then by bucket wheel excavators with crowd and later by much larger bucket wheel excavators with fixed length bucket wheel booms. All bucket wheel excavators ordered by the SECV after 1960 had fixed length bucket wheel booms.

No.21 Dredger was built by Lubecker Maschinebau Gesellschaft (LMG), of Lubeck, West Germany. It is mounted on crawlers and fitted with a slewable superstructure. It has a service weight of 725 tons. It was used for excavating overburden and brown coal from the Morwell open cut mine until August 1992 when it was retired. It was placed on display at the Powerworks Visitor Centre from 1995.

No.21 Dredger is of historical and scientific (technological) significance to the State of Victoria

No.21 Dredger is of historical significance as the first bucket wheel excavator to be used in the Morwell open cut mine.

No.21 Dredger is historically significant for its rarity as the oldest surviving bucket wheel excavator of those purchased by the SECV in the post-war period. It is also significant for its rarity as the only surviving bucket wheel excavator from the first generation with crowd mechanism.

As the only surviving bucket wheel dredge with crowd (thrust) in Victoria, No.21 Dredger is of scientific (technological) significance for its potential to yield information about the design of the first generation of bucket wheel excavators.

No.21 Dredger is of scientific (technological) significance for its capacity to represent the successful adaptation to the Victorian brown coal fields of continuous extraction technologies developed for German open cut brown coal mines.