Heavy rare earths company Northern Minerals has been granted a new mining lease that more than doubles the tenure area at its Browns Range project, in Western Australia’s East Kimberley.

The ASX-listed company said on Wednesday that Mining Lease M80/650 had been approved following the receipt of native title consents, replacing the previous M80/627, which was voluntarily surrendered.

The new lease increases the footprint under mining tenure from 4 923 ha to 10 458 ha by converting existing exploration ground, and carries an initial 21-year term to September 2046, with the option for a further 21 years. Northern Minerals holds 100% of the lease.

The expanded area includes several priority near-term exploration targets and provides additional support to the development pathway outlined in the definitive feasibility study (DFS) for Browns Range.

The DFS, released earlier in the week, positions Browns Range as one of the most advanced heavy rare earths developments outside China, with first production targeted for 2028. The project will focus on dysprosium and terbium – two of the most critical elements in the manufacture of permanent magnets used in electric vehicles, wind turbines and defence technologies.

The study outlines a production plan based on the Wolverine deposit, which contains one of the highest known proportions of dysprosium and terbium outside China. Browns Range is forecast to supply about 8% of current global dysprosium/terbium output, addressing an expected shortfall as demand grows and supply diversification becomes a strategic imperative.

The ore reserve is estimated at 5.18-million tonnes at 0.88% total rare earth oxides (TREO), or 45 800 t of TREO, with dysprosium/terbium accounting for 70% of the basket value. Mining will begin with openpits before transitioning to underground operations, supporting an initial 11-year mine life.

Under the base case, Browns Range is expected to produce 17 500 t/y of xenotime concentrate, containing about 4 350 t/y of TREO. Preproduction capital is estimated at A$592-million, while operating costs are forecast at A$31.25/kg TREO. The project will deliver average yearly earnings before interest, taxes, depreciation and amortisation of A$175-million, a pre-tax net present value (NPV) of A$187-million and an internal rate of return (IRR) of 12%.

An upside scenario, based on higher price forecasts, could increase the pre-tax NPV to A$705-million and the IRR to 21%.

Northern Minerals has secured an offtake agreement with Iluka Resources to supply concentrate to its Eneabba rare earths refinery, supporting Australia’s efforts to build a sovereign critical minerals supply chain.