The NPV calculator I posted allows for one to determine the impact of project delays. A delay of one year for both phase 1 and phase 2 dropped the NPV for Thacker pass by less than 10%. 

As I understand it, lithium spot pricing in China is in the $6-7/kg range, but battery grade lithium in Korea and Japan has stayed in the $10-12/kg range. Given that the US currently produces 2% of global lithium supply, I would be tempted to assume battery grade lithium might trade at a premium here compared to Asia. Just my feeling, I could be wrong.