Drastically reduced garnet consumption
Faster project turnaround
The RG Tanna Coal Terminal (RGTCT) is one of eight major wharf centres at the Port of Gladstone in Queensland. Originally known as the Clinton Coal Facility, the terminal was approved for construction in 1976-77 following BHP Co Ltd securing long-term contracts for the sale of coking coal to Japanese steel mills. In its first full year of operation in 1980-81, the terminal exported an impressive 4.3 million tonnes of coal, cementing its role as a critical piece of Australian export infrastructure.
Over recent years, ACR Tech has been subcontracted by Downers to carry out a comprehensive refurbishment of the terminal’s wharf structure. The scope of work centres on the removal of aged Coal Tar Epoxy coating that covers the headstocks and piles supporting the wharf over water. Once coating removal is complete, Downers proceeds with abrasive blasting the exposed surface before applying a fresh protective coating system to safeguard the steel structure well into the future.
Each headstock measures 35-40 metres in length with a diameter of 2.5 metres, while each pile is 8 metres long with a 2 metre diameter. The existing coating ranged from 1,000 to 3,000 microns in thickness, presenting a significant removal challenge across the full scope of the project.
Removing heavily built-up Coal Tar Epoxy from large marine infrastructure is no small feat. The coating on the RG Tanna headstocks and piles had accumulated to thicknesses of up to 3,000 microns in certain areas, well beyond what conventional removal methods could handle efficiently.
Traditional abrasive blasting approaches were only capable of achieving removal rates of 1-2m² per hour, depending on coating thickness. Given that each headstock covers approximately 350m² of surface area with 4 attached piles per structure, completing the coating removal by conventional methods alone would have required an enormous amount of time and resources on site.
Beyond the slow removal rates, relying solely on abrasive blasting would have also consumed vast quantities of garnet blasting media. The recovery and management of spent garnet in a marine environment adds considerable time and cost to any project, making it a significant logistical consideration for the client. A smarter, faster, and more resource-efficient solution was needed to keep the project on schedule and within budget.
ACR Tech deployed their RPR heat induction technology as the primary coating removal method ahead of abrasive blasting. The induction process works by generating intense, localised heat directly within the coating, thermally debonding it from the steel substrate without damaging the underlying structure. This makes it particularly well-suited to thick, tenacious coatings like Coal Tar Epoxy that resist conventional removal methods.
The equipment setup on site consisted of one RPR induction unit, one water cooling unit, and one 100kVA generator. A dedicated crew of two operated across 10-hour shifts, six days a week, working systematically across each fully scaffolded headstock to ensure safe and efficient access at all times.
The results were outstanding. By using heat induction as the first step in the removal process, ACR Tech achieved removal rates of 7-8m² per hour, representing a four to eight times improvement over traditional methods. Each 350m² headstock was completely stripped within a 6-day period, allowing Downers to move swiftly into the abrasive blasting and recoating phases without delay.
The reduction in coating thickness prior to blasting also meant significantly less garnet was required to achieve the desired surface profile, cutting down on both material costs and the time needed to recover and dispose of spent media after blasting. This streamlined the overall workflow considerably and delivered real, measurable savings for the client across the duration of the project.
