argentina uranium rock ball mill
Why rareearth mining in the West is a bust — High Country News. Jun 16, 2015 ... There's an open pit a few hundred yards wide, a power plant, ... geologists sent a curious rock sample to the Geological Survey. ... where a spinning, barrelshaped ball mill, loaded with iron spheres, pounded them to fine powder. ... of lead and trace amounts of radioactive barium, uranium and thorium.