Polonium the Curies while they were investigating the cause of pitchblende radioactivity. Pitchblende, after removal of the radioactive elements uranium and thorium, was more radioactive than the uranium and thorium combined. This spurred the Curies to search for additional radioactive elements. They first separated out polonium from pitchblende in July 1898, and five months later, also isolated radium. German scientist Willy Marckwald successfully isolated 3 milligrams of polonium in 1902, though at the time he believed it was a new element, which he dubbed "radio-tellurium", and it was not until 1905 that it was demonstrated to be the same as polonium.
Uranium mining also designated 22 inactive uranium mill sites for remediation, resulting in the containment of 40 million cubic yards of low-level radioactive material in UMTRCA Title 1 holding cells. Uranium mining Uranium mining is the process of extraction of uranium ore from the ground. The worldwide production of uranium in 2015 amounted to 60,496 tonnes. Kazakhstan, Canada, and Australia are the top three producers and together account for 70% of world uranium production. Other important uranium producing countries in excess of 1,000 tons per year are Niger, Russia, Namibia, Uzbekistan, China, the United States and Ukraine. Uranium from mining is used