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Highlights

  • Mineral Resources shares fall 0.9% to AU$24.34, despite broader ASX 200 gaining 0.5%.

  • Onslow Iron Project resources increase 89% to 744 million tonnes, ore reserves rise 73% to 359 million tonnes.

  • Management says results reaffirm Onslow Iron as a long-life, low-cost asset.

Shares of Mineral Resources Ltd (ASX:MIN) slipped 0.9% to AU$24.34 in early Wednesday trade, underperforming the S&P/ASX 200 Index, which was up 0.5% at the same time. The decline comes despite the release of a positive update regarding the company’s Onslow Iron Project, located in Western Australia.

The diversified miner, which operates across lithium, iron ore, and mining services, reported a significant increase in both mineral resources and ore reserves at Onslow Iron. According to the company’s statement, the update reflects figures as of 31 March 2025 and shows an 89% increase in mineral resources since September 2023, bringing the total to 744 million tonnes at 56.3% Fe (iron).

In addition, the company said ore reserves have grown by 73% to 359 million tonnes at 57.5% Fe, following a re-estimation that took mining depletion into account through to the end of March. The Onslow Iron Project is being developed by Mineral Resources in collaboration with the Red Hill Iron Ore Joint Venture.

Despite the growth in reported resources, the Mineral Resources share price remained in negative territory. Market analysts suggest that the muted investor reaction may be linked to ongoing concerns surrounding global iron ore demand and pricing pressures, rather than any direct issues with the project update itself.

According to the company, the increases in resources and reserves were driven by closer spaced drilling and supported by comprehensive remodelling and reclassification of additional deposits. The grade quality of iron and associated deleterious elements was said to remain consistent with the levels reported in the previous assessment in September 2023.

With Wednesday’s decline factored in, Mineral Resources shares have fallen approximately 69% over the past 12 months.