I am not worried with opex of $ 10/kg for HPA (4N and better), but does this is not acceptable for SGA since the sale value is currently about $ 325/t or 35¢/kg .... I know there are by-products including RM and REE but do i miss something here ?

From the visit summary :

"- An Outotec oven will be ordered and received very shortly to replace the smaller and less efficient Harper ovens. This is understood to be the main component of the $15mm net capex increase. This HCl recovery system will allow greater efficiency and should help drive the opex down to $10k/tonne by year end, from a current level of approximately $20k to $30k/tonne. These opex levels are consistent with the guidance that the Company has been indicating for some time.

- Once installed, the Outotec oven will be a critical aspect of increasing the plant's production rate to the targeted 5 tonne per day rate by end of this year. Currently, the plant's production rate is slightly less than 1 tonne per day, but the aforementioned commissioning activities should result in a scale up to 3 tonnes per day by mid year and the 5 tonne per day rate by end of year."