MinRes Lifts Onslow Guidance as Australia’s Newest Iron Ore System Absorbs Cyclone Pressure

Mineral Resources has lifted FY26 guidance for Onslow Iron, reinforcing the project’s emergence as one of the most important new iron ore systems brought into production in Western Australia in recent years. Onslow produced 7.8 million wet metric tonnes on a 100 per cent basis in the March quarter and shipped 7.2 million wet metric tonnes, even with cyclone disruption affecting crushing, haulage and transhipper loading through February and March.

The guidance upgrade is the central point. MinRes now expects Onslow Iron to deliver 17.7 to 19.4 million wet metric tonnes on an attributable basis in FY26, up from the previous 17.1 to 18.8 million wet metric tonne range. On a 100 per cent basis, guidance moved to 31 to 34 million wet metric tonnes, with costs tracking toward the lower end of the A$54 to A$59 per wet metric tonne range. 

Onslow’s quarter also showed how much operational complexity sits behind the production number. Mining remained aligned with the mine plan, with inventory being built ahead of and during cyclone season. Intra-mine haulage from the Upper Cane and Cardo Bore East hub continued to ramp up as part of the long-term product blending strategy, while the private haul road remained intact through Tropical Cyclones Mitchell and Narelle. Haulage stopped for three days in February and five days in March, but operations resumed safely after each event. 

The project’s logistics chain is now a major part of its commercial identity. During the quarter, 7.1 million wet metric tonnes were hauled to the Port of Ashburton across a daily average of 114 MinRes jumbo road trains, while 36 vessels were loaded with 7.2 million wet metric tonnes shipped. The sixth transhipper, MinRes Lily, was delivered at the shipyard in China and is expected to arrive at the Port of Ashburton in May before commissioning at the end of the June quarter. 

Higher fuel prices remain a pressure point, particularly in the June quarter. MinRes said diesel prices had doubled since March and estimated a June-quarter FOB cost impact of about A$4 per wet metric tonne at Onslow Iron. That cost exposure is being absorbed inside unchanged FY26 cost guidance, helped by the project’s scale and infrastructure model, including the Ken’s Bore mine site’s hybrid gas and solar power system. 

For the Australian iron ore sector, the significance of Onslow is that it is no longer just a ramp-up story. It is becoming a live test of whether a new, integrated Pilbara iron ore system can deliver volume, cost control and logistics resilience at scale. The March quarter did not remove execution risk but it did show a project gaining operating depth while still lifting full-year expectations.