Clay hosted deposits seem to be lower grade, large volume....

Clay hosted deposits seem to be lower grade, large volume. Peruse Lithium Americas site for details on their Thacker pass project.

Easily mined, shallow overburden. If the metallurgy/extraction works out economically, both Thacker and McDermitt should be very large mining operation that could last for decades.

The bonus being they are in the USA when they are actively trying to become less reliant on imports.

Cultural and environmental issues also need to be considered. No different to other mining ops in developed nations.