OK, had a good read through of OD6 met announcement. Very...

OK, had a good read through of OD6 met announcement. Very interesting that they didn't share aluminium and iron extraction (which MRD did), even though they state in their JORC table that "all material information from ANSTO included in the release" - maybe ANSTO don't analyse their samples for iron and aluminium so ANSTO didn't have that very material information?

Why is iron and aluminium important? Done a bit of reading, here's the conclusion I have come to:

• Iron and aluminium must be removed before making MREC. Every flowsheet shared by every clay hopeful has an Al/Fe impurity removal step before making MREC or you can't sell the MREC.
• You can't use cheap lime or limestone to do it, or you lose too much MREC https://www.sciencedirect.com/science/article/abs/pii/S0304386X20301134. Every clay hopeful flowsheet proposes to use more expensive ammonium carbonate, sodium carbonate, caustic soda or magnesium oxide for this reason.
• The cheapest non Ca based alkali is mag oxide, which is used by Ni miners to make MHP at around the same pH as MREC is made. In bulk qty it costs about $500 AUD/t rough numbers from QMAG.
• There is around 3% Al and 3% Fe in clays. This number comes from OD6's broker report (no clay MRE I have seen shares this data funnily enough).
• Let's use MRD as an example as they are only one of two ASX listed clay companies to have the balls to share Al/Fe extraction numbers. Their average Al extraction = 43%, Fe extraction = 52%.
• At 3% Al and 3% Fe in the feed ore that's 13 kg Al extracted and 16 kg Fe extracted from each tonne of feed ore
• Based on the precipitation chemistry, it requires 2.24 kg of MgO per kg Al removed and 1.08 kg MgO per kg Fe removed
• From this, you need 2.24 x 13 = 29.1 kg MgO for the Al and 1.08 x 16 = 17.3 kg MgO for the Fe per tonne of feed ore = 46.4 kg MgO per tonne feed ore for MRD's case
• 46.4 kg MgO at $500 AUD/t is $23 AUD/t feed ore.

For a "small" 5 mtpa operation that comes to $115m in MgO operating cost per year! If that's not "material information" for an REE clay project, I don't know what is..