Is below $800M realistic? CLQ at the PFS stage was talking under...

Is below $800M realistic? CLQ at the PFS stage was talking under $800M for a 2.5Mtpa operation, then when reality hit, it turned into 1.5B, and who knows what it will be before the end. Why would ARL be able to do it at half the price as CLQ? Forget that CLQ says their process saves steps and money relative to traditional HPAL. In my head, this thing is going to cost a lot more than $800M, but open to hearing if anybody has real info or insight into how they can build their mine for half the price of a neighbor with a very comparable operation.