Canstruct has completed their major new marine engineering project in New Caledonia.
Canstruct’s first major task was to come up with the design and methodology with Design Engineers, Madsen Giersing to ensure the pipeline stability. The client, Vale New Caledonia required that the new section of pipe was ballasted to withstand full air buoyancy and also remain stable for the extreme weather conditions of the combined wave and currents along the length of the pipeline for a 200 year ARI cyclonic event.
Canstruct purchased a 1,000 tonne capacity purpose-built barge, the Aquane together with a 150 tonne crane to lay the pipe. It was extremely challenging logistically to move the barge and crane from Adelaide, South Australia to New Caledonia. It was necessary to lift them both out of the water, place it on the deck of a large container ship and then discharge it again in Noumea. The total lift weight of the Aquane and the crane was 628 tonne and the lift took more than 5 hours to unload from the heavy lift ship the AAL Hong Kong.
The manufacture of the pipe supply was completed in February 2015 and was then transported to Noumea. This was a very fast turnaround as the job only commenced in January 2015. The pipe welding works were carried out in Noumea by local contractor, Eau & Environnement. The 11.8 m long pipe sections were welded into ten pipe strings (1 x271 m long and 9 x 365m long). Once each string was welded, it underwent a pneumatic pressure test. Then the ballasting and launching of the string began and continued for all of ten pipe strings.
In order to sink the pipeline and maintain its position on the bottom of the ocean, specially designed concrete anchors have been attached to the pipeline at every six metres. In total there are 620 anchors, each weighing approximately four tonnes. The fabrication works were sourced locally in Noumea and completed by TECBAT Sarl. The anchors were designed to prevent the pipeline from re-floating and will be capable of withstanding a 200 year ARI cyclonic event.
The first pipe tow went out on April 14. The Tug Boat the Marcel Viratelle towed the first pipe string of 271 metres in length and at 300 tonnes in weight from Noumea to Port Boise. The tow distance is 90 kilometres and the seas are subject to significant winds, often 25 knot winds. It was the first of 10 tows.
Canstruct staff were jubilant on June 2 when a major milestone was achieved with the laying of the final pipe-string. All pipe strings totaling 3,567 metres in length have now been laid on the ocean floor, in water up to 58 metres in depth. It was not an easy task as there was only a narrow pre-existing corridor and there was already an operating pipe in this space.
Canstruct is working with South Australian company Maritime Constructions and local New Caledonia Company Calbat Sarl on this major project for Vale Nouvelle Caledonie. Adrian Murphy was unstinting in his praise for Calbat Sarl “Fred Bouttier from Calbat Sarl has been absolutely fantastic and really helpful in organising the huge amount of logistics needed for this job. We simply couldn’t have done it without him.”
He also paid tribute to the hard work put in with our colleagues at Maritime Constructions to re-fit the Aquane specifically for this project – “Thanks to Maritime Constructions for working seven days a week for several months to fit out the Aquane for us. It has certainly been working hard for us!”
On June 3, the DSV (Dive Support Vessel) the Skandi Protector with a crew of 70 people and 9 saturation divers was mobilised to undertake the connection between the new and old pipelines, up to 58 metres below sea level and to attach the 750 concrete anchors. Saturation diving a very technical operation. The Divers had to be confined to a pressurised part of the ship at four atmospheres so they could descend each shift in the Diving Bell.
The Skandi Protector is a massive ship, 100 metres long and worth over $220 million. It has the state of the art technical capabilities needed for this job, including being able to maintain its exact position even in 40 knot winds. Before connecting the new and old pipes a flushing campaign was carried out to remove scale from the old pipe.
By July 1, Canstruct achieved Practical Completion for Phase One of this project which was an excellent result.
Project Manager, Adrian Murphy commented:”The connection of the new pipeline to the old pipeline occurred on July 1 which completed Phase One of the New Caledonian pipeline project. We were very pleased to have been involved in such a challenging and important project for Vale New Caledonia. I’d like to acknowledge the Vale NC Project Manager, David Turk in making this project a success. I also want to thank all of the people that made this happen, including personnel from Maritime Constructions, DOF Subsea, local sub-contractors and Canstruct’s own personnel. In particular, our own staff here – Blue Cashion and James Spasevski have put in a huge effort and I thank them.”
David Turk from Vale New Caledonie wrote on July 16, 2015: “The project is integral to the operation of the VALE NC hydrometallurgical process plant and Canstruct have completed this project on time and on budget. Working internationally has numerous unfamiliar constraints in terms of legal,social,cultural and language. Canstruct have managed all necessary preparation efficiently to avoid project delays. Canstruct have proven that their professional approach to project execution results in success.”