Bauer installs cut-off wall at Hinze Dam, Australia

The acute water shortage currently affecting Australia means the Hinze Dam near Brisbane in South East Queensland, is undergoing its third upgrade.

Initially completed in 1976 and upgraded in 1989 to Stage 2 storage capacity (161000 million litres), the dam's storage capacity is being increased to over 309700 million litres. With the Stage 3 Project of upgrading the dam's supply level the Gold Coast City Council intends to ensure an adequate supply of water for the Gold Coast Region south of Brisbane over the next 50 years.

Increasing the storage capacity meant raising the height of the dam's embankment by 15 m to 108.5 m. To ensure the stability and water tightness of the structure, a two-phase cut-off wall, 840 mm thick and up to 50 m deep is to be installed along the existing dam structure.

The Australian subsidiary of Bauer Spezialtiefbau, Bauer Foundations Australia, was contracted to complete the AU$ 26.3 million (US$ 21.3 million) upgrade.

The construction of the cut-off wall is a huge technical challenge, explained Gerhard Zylowski, managing director of Bauer Foundations Australia. "To create the space for the cut-off wall, a large amount of material has to be excavated, primarily rock. Half of this material consists of extremely hard rock."

Construction of the cut-off wall started at the end of May this year. The plant on site includes a Bauer BC 40 diaphragm wall cutter, a rope-operated grab, a BE 500 desanding plant and a BS 50 desilter unit, a decanter and a bentonite mixing unit with a capacity of 1000 m3.

The contract, which is based on working double shifts six days a week, is scheduled for completion by the end of March 2009.