APA Seaford-Aldinga Augmentation
APA Group
Seaford, South Australia
Diona was engaged by APA Group to complete the stage 3 of the Seaford – Aldinga high pressure network, which would ensure gas supply for the southern suburbs of Adelaide for years to come.
The gas network in the Seaford-Aldinga regions supplies 15,000 residential and commercial customers, with growing demand expected to exceed capacity within a few years. Diona constructed 3.3 kilometres of DN300 steel transmission pressure main and DN280 HP PE main in order to supply this future capacity. Diona was required to install a 300mm steel main under the Onkaparinga River by way of directional drilling.
The project was complex and challenging due to the diversity of elements, requiring careful consideration of environmental requirements as well as the client’s requirements for quality, time and budget together with Diona’s requirements for safety. Works involved a number of technical and environmental challenges as the site was located on the Onkaparinga River bank and in the Onkaparinga Recreational Park.
The presence of soft ground and large cobbles and gravel lenses made APA’s approved design difficult to construct due to anticipated fluid loss to the surface and a significant risk of damage to the product pipe during pullback.
Diona worked collaboratively with APA to achieve the desired outcomes by developing a new design line and a revised construction methodology for the underbore that had to be installed through these very adverse ground conditions. The construction of the final underbore was successfully completed using 12m lengths of steel pipeline which were stringed together by welding, sand blasting and coating the joints.
The project’s success was recognised by winning the South Australia CCF Earth Awards 2017 - Category 1 (project value up to $1 million).
