Browns Range and some others with low grade of HREEs are also...

Browns Range and some others with low grade of HREEs are also relatively low in LREEs, which means extractions are simpler and would require less reagents.
The path forward would be to create a mixed carbonate concentrate near the mine which they could ship to a refinery like LYNAS or better. It’s a wholly different scale of operations which most likely can’t support its own refinery.

But would LYNAS need more HREE once they are refining their own from Mt Weld?

That’s not a simple question to answer. The need for DyTb has been dropping as both China and Japan have found ways to thrift it whilst still providing necessary magnet metrics, one being GBD or grain boundary diffusion where Dy is not throughout the magnet but instead applied only to the outside of magnet domains or grains. 2025 is actually the year that Toyota thought they would be masters of manufacturing of the “Toyota Magnet” which requires extremely small magnetic domains and little if any DyTb. THAT SAID, DyTb makes it easier to make better magnets more cheaply.

however, if we ignore putative or speculative advances in magnet construction, we can state with some certainty that about 1% by weight DyTb is required for the best magnets. If I understand correctly, and that’s an important question, that’s not 1-2% of the NdPr weight but of the total magnet weight, which is only ~30% NdPr, so the amount of Dy needed relative to NdPr production would be closer to 3-6%.

There’s no way LYNAS can produce enough DyTb to equal 1% of their NdPr. Their own resource estimates states Proven Reserves as 285,000 tons of NdPr and 4210 tons of Dy, which is closer to 1%.

Bottom Line: imho, anyone who manages to bring a DyTb, MREE or HREE concentrate to LYNAS’s door would find themselves happy.