These results are being couched as "preliminary" and requiring " several iterations of test work to “crack the code” bla bla but they are simply horrible sorry to say.
pH4 Ammonium Sulphate leach rarely works well outside of Asia to date, a trend continued at Caroue. NdPr represents the loins share of REO basket value and an average 6% looks to be ionically bonded and recoverable at pH4. The acid consumption at pH1 is off the charts crazy high. That's 5 times higher than AR3 Koppamurra ICD deposit which is hosted on and around limestone...
Not sure there is a code to crack here, there are only so many levers to pull (pH, type of acid (Hcl vs H2SO4) and temperature being about it) and results are way below what most other ICD wannabes are achieving. Actually I take that back. Most other wannabes don;t have the honesty to release pH4 results and some don;t even release pH1 results, only releasing very aggressive leach liquor such as '20% HCl at 50deg C...
(20min delay)