Ann: Metallurgical Test Results Confirm Low Acid Consumption, page-9

Very good and detailed announcement from OD6 with lots of data shared. Only thing missing is impurity extraction rate (Al/Fe), so one must assume it's the same as MRD at this point, which is very high at around 50% Fe and Al average. Would have been good to release this data.

I am very suprised that given their H2SO4 leach results of ~40% MREE extraction at 20 kg/t consumption they are choosing to focus on HCl which achieves ~50% MREE extraction at 15 kg/t HCl consumption:

• HCl costs 3.5x H2SO4, so 15 kg/t HCl is equivalent to 53 kg/t H2SO4 on a cost basis, therefore the H2SO4 in their example above is significantly cheaper per unit MREE extracted
• HCl requires MUCH more expensive materials of construction for the plant, the cost for tanks, piping, pumps, filters will potentially be double or more to handle 2.5% HCl. See below basis on MOC requirements for H2SO4 vs HCl.
• HCl leaching generates chlorine in the process water. The only way to treat their discharge water to remove chlorine is with reverse osmosis, whereas sulphates (from H2SO4) can be removed with lime by bombing out gypsum. Clay processing requires a metric shed tonne of water to wash the clays post leaching and recover REE = lots of excess water to treat and discharge..