LOCATION
Moomba Plant, SA
VALUE
Up to $1M
Scope of Work
Oily Water Holding Tank was taken offline, drained, cleaned and positively isolated for internal inspection. The internal surfaces were grit blasted to white metal finish to prepare for inspection. Due to the poor condition of the floor, the tank was recommended to undergo full floor replacement including the 100mm of the tank subgrade in accordance with API 650 and API 653.
The tank is 10m diameter, 8.2m high and 600m³ capacity.
A door sheet is required to allow access inside the tank to complete the above repairs. A detailed design report and engineering assessment was carried out by APMS to address the stiffening requirements on the tank prior to cutting the door sheet to retain adequate resistance to buckling during the proposed repairs.
A new floor plate was designed to comply with the latest edition of API 650 utilising an annular floor design including replacement of non-compliant sump. A 12mm thick bitumen fibre board was installed around the perimeter to provide separation and seal between the new tank bottom plate and existing concrete ring beam.
100mm of the old base course was replaced with new compacted asphalt Boral Bitupack cold mix.
On completion of the repairs, the whole tank floor and bottom 1m of the internal tank shell is to be coated with 1200 microns of Corrocoat Polyglass VEF. The new door sheet, all external coating surfaces damaged during the repairs were coated to comply with Santos paint system.
Project Resourcing
The project team included:
- Project Management
- AS1796 Cert 10 Welding Supervisor
- NACE 2 Certified Coating Inspector
- Project Supervision
- Boilermaker, Coded Welder, Rigger, Confined Space Sentry & Rescue and Blasting & Painting Personnel
Workshop Fabrication
The new floor, sump drain and door sheet were prefabricated in APMS workshop ahead of the scheduled site execution. All fabrication was in accordance with API 650 and welding to ASME IX. Lifting lugs were welded on all components to assist handling onsite. All welds were subject to 100% MT.
3D laser scan was carried out to capture as-built measurements and overlaid with the original tank floor layout to confirm fitment onsite.
Project Achievements
The tank was only able to be taken offline for a limited duration before impacting plant operations, requiring meticulous planning and seamless coordination between the APMS site team and key service providers. These included scaffolding, NDT personnel, inspectors, vacuum truck operators, and coating applicators, as well as offsite activities such as component fabrication and equipment servicing prior to mobilisation. Effective materials management also played a critical role, ensuring all procured items were delivered in line with the project schedule.
To further accelerate progress, APMS deployed additional crews working night shifts, supported by staggered rosters to maintain continuous productivity throughout the project duration.
All repair works were completed safely, with zero accidents or incidents, and in full compliance with applicable regulatory standards and client specifications. The project was delivered on schedule and within budget, with the tank successfully handed back to Santos and promptly returned to service, supporting operations for the next 10 years.
Key Activities
The success of the project was dependant on the successful execution of the following activities:
- Preplanning of works including site visits prior to site execution
- APMS previous experience working in Moomba Plant and personnel well versed on Santos’s safety and quality procedures
- Advance engineering and prefabrication of components
- Coordination of multiple service providers and materials suppliers ensuring everything is available on time and when required onsite
- Daily site reporting highlighting any potential issues/delays allowing mitigations set in place to reduce impact on schedule
- 100% pass rate for all NDT
- Support by Santos project coordinators and HSE personnel
- Manufacturers Data Report (MDR) was progressively compiled and submitted within a week of completion of works
