Ann: Onslow Iron Resource and Reserve Update, page-3

The report is 35 pages, so heres a summary:

*Here’s a detailed summary of the Mineral Resources Limited (ASX: MIN) report titled “Onslow Iron Resources and Reserves update” released on 21 May 2025:

Overview

Mineral Resources Limited (MinRes) has significantly upgraded the Mineral Resources and Ore Reserves at the Onslow Iron Project (OIP) in Western Australia's West Pilbara region, a joint venture with the Red Hill Iron Ore JV.

Key Highlights

Metric	March 2025	September 2023	% Increase
Mineral Resources	744 Mt @ 56.3% Fe	394 Mt	+89%
- Measured + Indicated	508 Mt @ 56.8% Fe
- Inferred	236 Mt @ 55.2% Fe
Ore Reserves	359 Mt @ 57.5% Fe	207 Mt @ 58.1% Fe	+73%

• The resource growth is primarily due to infill drilling, remodelling, and reclassification.

• Grades of iron and deleterious elements remained consistent.

• Confirms Onslow Iron as a long-life, low-cost project.

Ore Reserve Details (as of 31 March 2025)

• Total Ore Reserve: 358.6 Mt @ 57.5% Fe

  • Proved: 14.8 Mt (in-situ + stockpile)

  • Probable: 343.7 Mt

• Other elements: SiO₂ 5.6%, Al₂O₃ 3.6%, P 0.08%, LOI 7.8%

• Based on:

  • US$85/t Platts 62% Fe price

  • AUD:USD = 0.70

Mining & Processing Strategy

• Mining: Conventional open-pit (Hitachi EX3600 + EH4000 fleet)

• Bench height: 8–12m; flitch height: 4m

• Ore processing: Dry crushing + screening → fines-only DSO

  • Wet plant added in FY29 for upgradeable material (e.g., clay-bound ore)

  • Wet plant yield: 90.5%; Fe upgrade: +1.02%

• Product moisture: 8.0%

• Ore Loss & Dilution: Handled via SMU model (25x25x4m)

Product Marketing & Sales

• Long-term off-take agreement with Baosteel Resources Australia (50–75% of MinRes volume).

• Price discounts applied based on Fe grade and impurity levels, verified by actual sales since May 2024.

Life of Mine (LOM) Strategy

• LOM plan integrates newer deposits: Cardo Bore East, Upper Cane, and Trinity Bore.

• Optimized to:

  • Lower strip ratios

  • Extend mine life

  • Improve product consistency

• Wet plant enables deeper extraction and more resource conversion into reserves.

Geological Context

• All deposits are Channel Iron Deposits (CID) hosted in palaeochannels of the Hamersley Province.

• Geology includes:

  • Goethitic hard cap

  • Primary CID ore (~19m thick)

  • Basal mixed zone (~6m thick)

• Deposits include: Ken’s Bore, Upper Cane, Cardo Bore East, Cochrane, Jewel, and Trinity Bore.

Resource Classification

Classification	Tonnes (Mt)	Fe (%)
Measured (in-situ + stockpiles)	17.7	~56.6
Indicated	490.6	56.8
Inferred	235.5	55.2
Total	743.7	56.3

• Reported above a 50% Fe cut-off.

• Based on extensive RC and diamond drilling (over 116,000m total).

Competent Persons

• Ore Reserves: Guy Davies, Stephanie Raiseborough, Gavin Shaw

• Mineral Resources: Ashok Doorgapershad

• All are members/fellows of the Australasian Institute of Mining and Metallurgy (AusIMM)

Risks & Approvals

• Regulatory approvals (including Mining Proposal, EP Act, EPBC referrals) underway.

• Community consultation, especially with Robe River Kuruma (RRK) people, will inform final approvals.

Forward Outlook

• Onslow Iron is expected to become one of Australia’s leading iron ore projects.

• Strong foundations for long-term production, with robust geological understanding and efficient operations.
  *gpt4o