Client: Queensland Alumina Limited
Contract: Design and Construct
McConnell Dowell is responsible for the design, supply, construction and commissioning of the Bauxite Waste Line 4 Replacement for Queensland Alumnia’s refinery at Gladstone.
The scope of works will be provided in three separable portions as follows:
Separable Portion 1 - The provision of design services, the establishment of the on-site storage compounds and the unloading and storing of pipe. No pipe installation and structural work was included in SP1. MCD achieved this milestone one week ahead of schedule.
Separable Portion 2 - All pipe installation and structural works, except for any works over the tidal area. No Planned Outage Period is allowed during SP2. MCD commenced SP2 works on the planned date.
Separable Portion 3 - The SP3 involves works in the tidal area and has been planned around the expected tidal levels. A permit from SERA to work in the tidal areas is expected by 1 July 2021.
During SP3 the WL4 will be shut down and taken off-line, with the duration of the WL4 shutdown limited to the Planned Outage Period. Removal of the existing WL4 will occur during SP3.
Currently MCD are working on construction and assembly of new lines while operations continue in the current assets, allowing the client to continue production operations with no system impacts while the new lines are being assembled. As a part of SP2, we are laying out approximately 5,000m of 350mm dia. mudline in parallel to the existing pipe rack that contains four operating line assets. Pipe stringing, welding and NDT have already commenced, and Field Joint Coating is scheduled to commence on 31 March 2021.
Once the tidal works permit has been received, an operational change will be made to take the current Line #4 out of operation, for a significantly reduced period than would have been needed if the new pipeline needed to be constructed in the alignment of the old asset. The old asset will then be cutdown into transportable sections, capped and transported to a disposal site for scrapping. In parallel, civil, structural and diving crews will start piling rectifications to extend life of the existing structure by another 25 years.
Once the old pipe removal has commenced, new pipeline installation will follow progressively. New pipe strings will be lifted by our lifting crews off the temporary supports that were used in the welding/ coating operations and placed onto the support foundations or into culverts as required for this project. Some of the pipe strings will be placed on the tidal areas using a specialised push/ pull method to reduce the construction footprint in the tidal areas.
After placing the entire pipeline on the existing structure, the pipeline will be tested hydrostatically to more than the operating pressure. After testing, pipeline will be de-watered and handed over to QAL Operations.