[Rio]

Not sure about Alaska. There is an old mine in California and, I thought, a new site in Australia.

[hoosiermama]

More up to date information

http://web.mit.edu/12.000/www/m2016/finalwebsite/solutions/deposits.html

[joe fonebone]

I seem to remember in my ancient mind that the mine in california was bought by the chinese and then closed by the chinese.