BHP Billiton


Kalgoorlie Nickel Smelter (KNS)


Sulphuric Acid Railcar Replacement Project


Capital Works & Upgrades, Pressure Vessel Fabrication, Specialised Welding and Fabrication

Project Value


Scope of Work

This project involved the design and manufacture of twelve rail-mounted pressure vessels for sulphuric acid storage and transport. The vessels were 1.8m diameter by 12m overall length. They were fabricated from carbon steel. The services APMS provided under this project were detailed mechanical design to AS1210 Class I, material procurement, fabrication, NDT, hydrotesting, surface treatment and commissioning.

The vessels were required by our client BHP to replace existing vessels which had reached the end of their working life through internal erosion. The project required APMS to maintain a close working relationship with BHP to ensure the vessels were replaced with a minimum of disruption to production. A close interface with BHP was also essential during the commissioning stage to optimise loading and discharge capabilities. “Lesson Learnt” meetings were incorporated into the project process to share experiences and drive efficiencies.

Fabrication of the vessels required a number of welding processes – submerged arc, flux core and TIG. The vessels were subject to extensive non-destructive testing, including 100% RT, MPI, UT and finally hydrostatic pressure testing. Prior to commissioning the vessels were sandblasted and a four coat paint system was applied in accordance with the BHP Specification.

The successful outcome of the project was a result of all stakeholders, from the tradesman in the Workshop, through the project team to the end user BHP working together to achieve a successful outcome – delivery of the vessels to the required technical and quality standards, on time and on budget.

APMSGroup completed commissioning of completed pressure vessels and delivered to the Kwinana rail terminal for delivery to Kalgoorlie where the units were put into service.

This project was delivered across an 8 month duration.

Project Resourcing

The support team included:

  • Project Management
  • Project Engineer – Design Review
  • Quality Management (IIW Fabrication Supervisor / Inspector)
  • Project Supervision
  • Boilermaking and Coded Welding Personnel

Project Achievements

  • Approx. 5000 man-hours completed in the workshop and site commissioning with zero recordable incidents or accidents
  • Extensive interaction with our client to ensure design was in line with practical requirements of the rail cars at loading and unloading stations
  • Client selected local engineering and fabrication company to complete the works against overseas competitors


Various methods of welding the pressure vessels was performed for the project including:

  • Submerged Arc welding
  • Flux Core Welding
  • Gas Tungsten Arc welding
  • Combination of Flux Core and Gas Tungsten Arc Welding

All welding subject to 100% Non-Destructive testing and 3rd Party visual Inspection