TG6 hasn't yet advised iron grades for Burmeister ore. This is...

TG6 hasn't yet advised iron grades for Burmeister ore. This is one of the key risks and the Met test work will provide greater visibility on this.

TG6 have however indirectly confirmed that in one DD sample (TGRCD009 from 134.2m to 134.4m) grading 2.29% Li₂O the ore has iron grades under 1%. TG6 took this high grade sample and looked at the mineralogy (17 Jan 2024). The DD sample noted the Mineralogy below with the top 8 minerals representing 99.94% of the overall total. If there is iron in the pegmatite ore itself, it comes from one or more of these minerals.


Doing a web search on chemical formula's:

• Spodumene (LiAlSi₂O₆) doesn't contain iron oxide
• Quartz (SiO₂) doesn't contain iron oxide
• Microcline (KAISi₃O₈) doesn't contain iron oxide
• Albite (NaAlSi₃O₈) doesn't contain iron oxide
• Zinnwaldite (KLiFe++Al(AlSi₃)O₁₀(F,OH)₂) does contain small amounts of lithium and modest amounts of iron
• Columbite has different formats including Fe++Nb₂O₆. TSpeculation - is this the source mineral for the background Nb readings seen in soil samples
• Pollucite (Cs,Na)₂Al₂Si₄O₁₂.(H₂O)) doesn't contain iron oxide
• Apatite (Ca₅(PO₄)3(OH,F,Cl)) doesn't contain iron oxide

From Webmineral.com, the lithium element of pure spodumene is 8.03%. The samples observed Li2O grade in the DD cross section is higher than the overall sample because 35.9% * 8.03% = 2.89% Li₂O.


Zinnwaldite
In this sample Zinnwaldite is contributing to the lithium grade (4.83% * 3.42% = 0.17%). What is unclear is whether the conditions that created >2% Spodumene mineralisation also assisted Zinnwaldite. If they did, Zinnwaldite may be lower in material nearer 1.4% grades.

Zinnwaldite is a source of iron, but at 0.79% (4.83% * 16.44%) isn't high. Zinnwaldite does have a higher density of 2.9-3.1x so it is likely to concentrate in a DMS process. Its high iron content may mean it also can be removed effectively by LIMS or WHIMS. Ideally Zinnwaldite grades remain below 5% of Burmeister ore.



Other sources of lithium
Critically, sources of lithium like Lepidolite [K(Ki,Al) ₃(Al,Si,Rb) ₄O₁₀(F,OH) ₂] and Petalite [LiAlSi₄O₁₀] are not listed as minerals observed and are not competing sources of lithium (at least on the results and comments to date).