Grand Junction, CO

Grand Junction, CO

Manhattan Project Mill at Uravan

From 1943 until 1945, Grand Junction, Colorado was the center of the Manhattan Project’s secret effort to mine and refine uranium ore from surrounding mills in the Colorado Plateau. By 1946, over 2,600,000 pounds of uranium oxide had been produced from Colorado Plateau material, representing 14 percent of the total uranium acquired by the MED. Though this domestic enterprise was small and expensive, it transformed the uranium industry and brought tremendous growth and money to towns like Grand Junction, Uravan, and Durango.


The Hunt for Uranium

Though the MED ultimately obtained 86 percent of its uranium from the Belgium Congo and Canada, General Leslie Groves insisted that an effort be made to obtain uranium from domestic sources. One of the richest areas of radioactive materials in the United States was the mesa country of the Colorado Plateau. This area contained impressive carnotite deposits—greenish-yellow compounds containing deposits of uranium, vanadium, and radium.

Vanadium, a hard, silvery-grey metal used as an alloy to strengthen steel, could easily be extracted from Colorado carnotite. Throughout the 1930s, the United States Vanadium Company (a wholly owned subsidiary of Union Carbide and Carbon Corporation) and the Vanadium Corporation of America mined the Colorado Plateau and expanded their holdings by purchasing previously owned radium mills.

In 1936, the United States Vanadium Company (USV) moved its mining operations to Standard Chemical’s old Joe Junior Camp and began building a new model town around it. The town was named Uravan for the principal ores of uranium and vanadium. USV constructed a number of homes for its 250 employees and erected a theater, medical clinic, store, community hall, churches, and a school to help alleviate the isolation.


Grand Junction's Uranium Refinery

UravanThroughout much of the 1930s, vanadium miners regarded carnotite’s uranium ore as a useless waste product of mining operations. Most of the unused uranium settled into the tailings piles at every vanadium and radium mill across the Colorado plateau. The discovery of nuclear fission in 1938, however, would transform uranium from a worthless by-product to the most important metal in national defense.

In December 1942, the MED began surveying vanadium-processing mills in the Colorado Plateau as a possible source of uranium. The analysis led to contracts to purchase tailings from the Vanadium Corporation of America, United States Vanadium, and the recently organized Metals Reserve Company. From 1943 until 1945, the MED also purchased tailings from mills in the Colorado towns of Naturita, Durango, Slick Rock, Gateway, and Loma.

With no mill of its own to process the material, the MED signed a top-secret contract with the United States Vanadium Corporation to operate its plant in Uravan for uranium procurement. The MED also agreed to build an additional mill to help process the material. Beginning in May 1943, the region’s uranium ore would be brought to Uravan and run through the plant to produce three tons of green uranium “sludge” per day. This material was then transported, along with a similar sludge from USV’s mine in Durango, to the MED’s newly constructed refinery in Grand Junction, Colorado.


Uravan during WWII

Uravan CommissaryThe MED’s secret operations in Uravan brought immediate changes in security. To protect the secret mill, the army enclosed the area in wire fencing and constructed a gate house at the town’s entrance. Military police were posted twenty-four hours a day around the site and no vehicle could enter the town without the proper identification. Most workers knew that they were producing the uranium sludge for the government, but they probably did not know what it would be used for.

Like many U.S. production areas, Uravan faced a severe labor shortage during the War. Three shifts were needed at both mills to keep the plants running around the clock, and the USV was granted special permission to hire boys as young as sixteen to help address the labor shortage. At one point, fifteen women were working in the Uravan mill. The sudden boom in uranium mining swelled the town’s population to roughly 400.

From 1943 until 1944, the MED processed over 500 tons of tailings at both plants in Uravan. An additional 80 tons were processed at USV’s mill in Durango. By late 1944, uranium sludge from the Colorado Plateau had been further refined into about 800 tons of uranium oxide. Adding up all the uranium from the Belgian Congo, Canada, and Colorado, the MED concluded that there was enough material to operate all of its bomb facilities through the fall of 1945.


Union Mines Development Corporation

Yellowcake CarnotiteGeneral Groves’ insistence that the MED learn as much as possible about the various deposits of uranium throughout the world led to the creation of the Union Mines Development Corporation (UMDC) in early 1943. To avoid suspicion, the UMDC operated as a subsidiary of the Union Carbide and Carbon Corporation under the pretenses that it was large international mining company interested in tungsten, molybdenum, and vanadium. In reality, the UMDC was tasked with finding out everything it could about uranium, from where it might be found to how it might be more easily extracted.

To head the operation, Groves selected Major Paul L. Guarin, a member of the Corps of Engineers who had extensive experience as a geologist for the Shell Oil Company. Guarin was aided by a small group of assistants, including Dr. George W. Bain, a professor of geology at Amherst College, and Dr. George Selfridge, a geologist from the University of Utah.

From 1943 until 1946, the UMDC examined all available literature on recorded occurrences of uranium ores and conducted field examinations in more than thirty-six states and twenty foreign countries. The UMDC also conducted geophysical research and helped improve portable models of the Geiger-Muller counters for radiation detection. The majority of field explorations occurred on the Colorado Plateau, and an office was established in Grand Junction in July 1943. Since the reports of the UMDC geologists were classified as secret by the MED, they could not contain the word uranium.



  • Boarding House in Uravan c. 1935

    Boarding House in Uravan c. 1935

  • Housing for miners in Uravan

    Housing for miners in Uravan

  • The Standard Chemical Company's Joe Jr. Mill

    The Standard Chemical Company's Joe Jr. Mill

  • The Standard Chemical Company's Joe Jr. Mill c. 1919

    The Standard Chemical Company's Joe Jr. Mill c. 1919

  • Uravan Baseball Team

    Uravan Baseball Team

  • Truck unloads carnotite ore

    Truck unloads carnotite ore

  • Union Carbide Ad

    Union Carbide Ad

  • Map of Uravan

    Map of Uravan

  • Uranium Waste holding ponds

    Uranium Waste holding ponds

Related Video: 

J. P. Moore's Interview

J. P. Moore worked as a chemist for US Vanadium Company and then as Chief Chemist at Grand Junction, where he analyzed uranium. The full transcript can be found on "Voices of the Manhattan Project."