Leighton’s Gorgon jetty work continues

by on June 15, 2012 8:48 am GMT

The companies signed a contract in 2009 for a jetty and marine structures project on Barrow Island, at the Gorgon project off the coast of Western Australia, with work to be completed by December 2012.

But in a market update sent out today, Leighton Holdings chief executive Hamish Tyrwhitt said the facility would now be delivered in October 2013, as the scope of the contract had “evolved” since the initial award.

The 2009 award covered the design and construction of a 2.1 kilometre liquefied natural gas jetty at Barrow Island, as well as the supply, fabrication and construction of marine structures including a heavy lift facility, tug pens and navigation aids.

But changes since then included new facets of the project, Leighton said, such as additional fabrication and transportation of over two kilometres of pipe racks, and transportation to site of 24 pre-cast concrete caissons for the heavy lift facility berth.

“The project has also encountered some weather related challenges which have led to a revised execution methodology requiring the Consortium to provide additional resources to complete the work in a safe and timely manner,” Tyrwhitt said.

The jetty was to consist of steel trusses 70 metres long and be supported by 56 concrete caissons built at the Australian Marine Complex (AMC) in Perth, leading to the loading platforms about four kilometres from shore.

Tyrwhitt said 35 of the 56 caissons had been built at the AMC, with the remaining units well advanced, but only one had been placed to date.

The caissons weighed 4500 tonnes and were 26 metres in diameter, he said, having been lowered to the ocean floor through ballasting. Future caissons would be lowered in the same way.

Chevron is operator of the Gorgon project with a stake worth about 47.3%. Other stakeholders include ExxonMobil and Shell, each with 25%, Osaka Gas (1.25%), Tokyo Gas (1%) and Chubu Electric Power (0.4%).