I think the article I posted indicated that Tesla will need about 30K tonne per year in 2020 for cars and some for the factory itself but that is likely a one time installation. So the Albany deposit would last as long as 45 years with steady demand, less if demand increases.

I think you make a good point about Tesla cutting out the middleman, they seem pretty creative, but I doubt they will get ZEN for $1 billion even if its US$.