MINERAL Resources last week commissioned MinRes Airlie, the first of seven 124-metre transhippers to serve the company’s Onslow Iron project in the Pilbara.

The vessel successfully completed sea trials off the coast of Ningbo-Zhoushan. The barge/hull of the transhipper was constructed by the Cosco Zhoushan yard and launched at the end of March 2023, with outfitting of the transhipment system undertaken at Nantong.

Sea trials included testing the Articulated Tug and Barge (ATB) system, with the tug MinRes Odin (formerly the AHTS Mermaid Sound, converted in Batam) successfully interlocking with the barge to power the transhipper.

Other manoeuvers tested included speed, turning angles, stopping time and checks of the navigation and mechanical systems.

MinRes executive general manager marine Jeff Weber said the delivery of the first transhipper “on time and on budget” was an important milestone for the Onslow Iron project, which will unlock stranded iron ore deposits in the Pilbara.

“The sea trials are an opportunity for us to ensure all systems are working as they are intended to, with safe operations our utmost priority,” Mr Weber said. “The shallow-draft transhippers are pivotal to making Onslow Iron viable, with the fully-enclosed transhippers significantly reducing the project’s environmental footprint and capital investment, compared to dredging a deep-water port.”

Sea trials for the remaining transhippers will occur in a staged approach, with the first two vessels (the second is MinRes Coolibah) due to arrive at the Port of Ashburton in the coming months to commence operations mid-year. The transhippers, named after islands off the Pilbara coast, were designed by MinRes with the support of naval architects and engineering firms based in Australia and Canada.

Onslow Iron will see ore transported by fully covered road trains along a dedicated haul road from the Ken’s Bore mine, located 150 kilometres east of Onslow, to Ashburton. At the port, the ore is transferred to a 220,000 tonne enclosed negative pressure storage facility. From there, it will be moved via covered conveyors into the transhipper’s “hopper” storage area.

At 124 x 36 metres, the dust-free transhippers whave a seven-metre draft when fully loaded, and will be taken by a fleet of purpose-equipped tugs to the capesize bulk carriers anchored 22 nautical miles (40 kilometres) off the Pilbara coast. The innovative design drastically reduced the amount of seabed dredging required for the loading berth at the port.

Onslow Iron is projected to ship around 35 million tonnes of iron ore per year, with an expected mine life of more than 30 years.