/ The White Mesa Mill was constructed in the early 1980s and is the last conventional uranium mill operating in the country. There are multiple pools filled with radioactive material on site. Executives from Energy Fuels Resources, which owns the White Mesa Mill in San Juan County, announced last month that they had successfully produced a concentration of rare earth metals from something called monazite sand. And this week, they announced plans to import at least 2,500 tons of the sand a year for the next three years from a plant in the state of Georgia. Energy Fuels president Mark Chalmers told potential investors on a call Tuesday that the company plans to ramp up production in 2021.