Mineral Resources Limited has reported a significant expansion in the Onslow Iron Project’s Mineral Resources and Ore Reserves, underpinning its long-term growth strategy in iron ore production.
- 89% increase in Mineral Resources to 744 million tonnes at 56.3% iron content
- 73% rise in Ore Reserves to 359 million tonnes at 57.5% iron content
- Inclusion of new deposits Upper Cane and Cardo Bore East in resource base
- Life-of-mine plan incorporates conventional open pit mining and planned wet processing from FY29
- Ongoing regulatory and heritage consultations with local Indigenous groups
Significant Resource Growth
Mineral Resources Limited (ASX: MIN) has unveiled a substantial update to its Onslow Iron Project (OIP) in Western Australia, reporting an 89% increase in Mineral Resources to 744 million tonnes at an average iron grade of 56.3%. This follows a comprehensive drilling campaign and remodelling effort that has also lifted Ore Reserves by 73% to 359 million tonnes at 57.5% iron content.
The expansion reflects closer spaced drilling and the reclassification of additional deposits, notably the inclusion of Upper Cane and Cardo Bore East alongside the established Ken’s Bore deposit. These deposits are expected to be the primary contributors to production over the next decade, reinforcing Onslow Iron’s status as a long-life, low-cost operation.
Operational and Processing Outlook
The project continues to ramp up production, with shipments having commenced in May 2024 and full nameplate capacity targeted during 2025. Mining is conducted via conventional open pit methods using hydraulic excavators and rigid body dump trucks, with benches ranging from 8 to 12 meters and flitch heights of 4 meters.
Processing infrastructure includes a dry crushing and screening facility producing direct ship ore fines, complemented by a planned wet processing plant scheduled to come online from fiscal year 2029. This wet plant will handle material with internal clays and improve overall project economics by enabling a lower cut-off grade and better resource extraction.
Economic and Market Considerations
The Ore Reserve estimate is based on a Platts 62% iron ore price of US$85 per tonne and an AUD:USD exchange rate of 0.70, assumptions aligned with Mineral Resources’ consensus pricing. A life-of-mine product off-take agreement is in place with Baosteel Resources Australia, securing between 50% and 75% of MinRes’ volume entitlement. Pricing discounts have been applied to reflect product specifications and impurities, validated by actual sales since May 2024.
Environmental and Regulatory Progress
Environmental approvals and heritage consultations remain active components of the project’s development. The company is working closely with the Robe River Kuruma people to manage heritage site constraints, which currently affect approximately 68 million tonnes of reported reserves. Ongoing negotiations and survey work aim to resolve these constraints to enable mining progression.
Primary approvals under Western Australia’s Environmental Protection Act and the Commonwealth’s EPBC Act have been secured for the mine and haul road, with secondary approvals underway to cover expansions and new infrastructure such as the wet processing plant and tailings facilities.
Technical Confidence and Future Work
The updated resource and reserve estimates have been prepared in accordance with the JORC 2012 Code and supported by rigorous sampling, drilling, and modelling techniques. Internal peer reviews and external audits have confirmed the robustness of the estimates. Further close-spaced grade control drilling and metallurgical test work are planned to refine the mine plan and processing strategies.
Mineral Resources’ Managing Director Chris Ellison highlighted the quality and longevity of the Onslow Iron Project, emphasizing the company’s commitment to unlocking further potential in the West Pilbara region and delivering value to stakeholders.
Bottom Line?
With its expanded resource base and advancing approvals, Onslow Iron is poised to cement its role as a cornerstone of Mineral Resources’ growth, though heritage and regulatory hurdles remain key watchpoints.
Questions in the middle?
- How will the planned wet processing plant impact operational costs and product quality over the long term?
- What is the timeline and likelihood of resolving heritage site constraints affecting significant reserve tonnage?
- How sensitive is the project’s economics to fluctuations in iron ore prices and exchange rates beyond current assumptions?