Wednesday, September 19, 2012

Digging in the Dirt

Uranium ore extraction has a long history in the American West, dating back to 1871 when very small amounts of uranium from gold and silver mines in Central City, Colorado found their way onto the European market. The discovery of radiation by Henri Becquerel in 1896 and the element radium by Marie and Pierre Curie in 1898 suddenly turned this element for dyes into the source of a cancer treating miracle!

Originally, the work of Becquerel used pitchblende, a blackish colored ore containing uranium oxide or UO2. Pitchblende is rich in uranium, but much harder to find than other uranium bearing ores. As fate would have it, a French chemist by the name of Charles Poulot, who, unable to use a sample of ore from the mines of western Colorado for his copper chemistry experiments, gave it to his professor Charles Friedel. Friedel promptly determined it was an as yet unknown uranium and vanadium bearing ore. That ore is what we today know as carnotite. 

The interesting thing about the name carnotite is no one really knows who gave it that name. Some authors claim it was Marie Curie herself, who on a trip to Colorado in 1899 named the ore after the French Inspector General of Mines, A. Carnot. Others say that it was in fact Charles Friedel, who after determining the ore was unnamed christened it carnotite after the same man. There is even a third story, where Marie Curie never visits Colorado, but names the ore carnotite after Monsieur Carnot anyways. Personally, I believe the third story is correct. In a 1921 article in the New York Times entitled "The Story of Radium," the writer never mentions that Curie visited Colorado during her trips to the United States.

Either way, carnotite was the name that stuck, and from 1898 until 1922 the radium business grew prosperous. In 1922, the Belgians discovered a large source of pitchblende in Belgian Congo (now the Democratic Republic of the Congo) and undercut their competition by selling radium at $70,000 (rather than upwards of $100,000) a gram. One of the radium mines in western Colorado that was shut down during this period was the Joe Junior Camp in western Montrose County. This site would sit dormant until 1936 when a subsidiary of Union Carbide, United States Vanadium (USV) would take over the town and rename it Uravan (uranium-vanadium). Uravan would in the ensuing decades become one of the centers of uranium mining and milling in the American West.


  1. Great post! I really liked it, and it brought a couple geology questions to mind... What "strain" of uranium was it (235, 238... other)? And do you know which mine it was found in?

  2. Naturally occurring uranium is a mixture of the isotopes U-235, U-238, and U-234. Of the three U-238 is the most commonly found in nature and comprises around 99% of the naturally found uranium in the Earth's crust. As to the mine Poulot had his sample from, Gary Lee Shumway, who wrote a history of the Uranium Industry on the Colorado Plateau in 1970 says it came from the Copper Prince Claim which according to a BLM source ( later became the Rajah Mine. Now I would strongly suggest you don't take any of that history at face value as every source I have turned to has a different explanation of what happened.