Hi Ryan2k
A couple of points. You say
"-mt weld is a hard rock mine like LIN. LIN is also a weathered carbonate and both monazite based."
Mt Weld is a weathered carbonatite in the form of a laterite. see
https://portergeo.com.au/database/mineinfo.asp?mineid=mn770
"A thick weathering/regolith layer (10 to >120 m) of laterite overlying the un-weathered carbonatite contains high-grade REO deposits and concentrations of niobium, tantalum, zirconium, and other 'rare' metals."
However, as far as I know, Lindian has not said it is weathered carbonatite in the main body. It looks like an vulcanic plug still sticking above ground making a small hill because it is harder than surrounding rock.
You say
"The positioning of Lindian's resource is favourable being on a hill so will be simple open pit mining, mineralised consistently from surface to depth. Lindian has minimal radioactivity relative to lynas. Yet to be seen but I don't think correct to say Mt weld mining costs will be less than Lindian."
The only thing I was trying to point out is that you have to be careful to say Lindian will be the lowest cost production at this point. We need the PFS.
I pointed to Iluka having monazite as a waste product. Its hard to beat that price. Mt Weld has Niobium and Tantalum, which are really high value compared to Nd and Pr. So Lindian may not even have the most valuable Monazite without the tantalum. etc
If we exclude the thorium, which if present (like Mt Weld), complicates the extraction process with some extra steps, then the full process for Monazite ore to a mix of soluble rare earths suitable for separation by ion exchange or solvent extraction is;
Carbonatite or laterite --> explosives? -->crushing --> milling --> gravity, electromagnetic, and electrostatic techniques --> Monazite --> treatment with concentrated sulfuric acid at temperatures between 150 and 200 °C --> mixed rare earth solution
Where Lindian stops at the Monazite stage and does not have any of the niobium etc. to lower the overall cost.
(see
https://www.britannica.com/science/rare-earth-element/Processing-ores)
This is compared to the production of a mixed rare earth solution from ionic clays, (which also usually contain some of the higher value heavier Rees) is;
Dig the clay --> add clay to tanks with fertiliser solution --> settle the clay --> precipitate the Rees from solution --> dissolve mixed Rees with dilute acid
*Where the fertiliser is ammonium sulphate and is recycled and all is done at ambient temperature.
This is an over-simplification, but you get the idea.
You need a PFS
