Although uranium occurs in several areas of the state, much of the historic uranium and vanadium production is from numerous and relatively small mines in the Uravan mineral belt located in Mesa, Montrose, and San Miguel Counties. This area accounted for about 77% of the total uranium production in Colorado. The Uravan mineral belt mines produced almost 14 million tons of ore averaging 0.24 percent triuranium octoxide (U3O8) and over 356 million pounds of vanadium oxide. Uranium minerals formed irregular deposits in this area commonly referred to as roll-front uranium deposits. Vanadium typically occurs with uranium in these deposits. Most of these deposits are in sandstones of the Jurassic Morrison Formation. Roll-front deposits containing uranium also occur in other areas of the state like the Fox Hills Sandstone in Weld County. A different vein-type uranium deposit was mined in Precambrian gneiss and schist at the historic Schwartzwalder mine in Jefferson County. The Schwartzwalder was reportedly the single largest uranium mine in Colorado and produced 10.5 million pounds of U3O8 by 1978.
There are several uranium resources in Colorado including the Graysill property (vanadium and uranium), the Tallahassee Creek deposits in Park and Fremont counties, and the Maybell deposits in Moffat County as well as others. Although Colorado has been a producer of uranium in the past, there are currently no producing uranium mines or mills in Colorado. Uranium was last produced in Colorado around 2005 in Montrose County. Uranium reserves are abundant in Colorado and several companies continue to explore and maintain uranium mining permits in Colorado.
Although Colorado has been a producer of uranium in the past, there are currently no producing uranium mines or mills in Colorado. As of 2019, the proposed Pinon Ridge uranium mill located in Montrose County is on hiatus due to a 2018 court ruling. In 2019, uranium concentrate production from U.S. mines in 2019 was the lowest recorded since 1949. Uranium is listed as a critical mineral by the U.S. Geological Survey. In 2019, over 90% of uranium purchased and delivered to U.S. civilian nuclear power reactors came from other countries including: Canada (21%), Kazakhstan (18%), Australia (18%), Russia (15%), Uzbekistan (9%), and Namibia (5%). In July 2019, a presidential memorandum ordered the establishment of the U.S. Nuclear Fuel Working Group (NFWG) “to develop recommendations for reviving and expanding domestic nuclear fuel production.” In 2020, the NFWG announced a nuclear energy strategy which included strengthening the U.S. uranium mining and conversion industries and in early 2019, a federal judge lifted a ban on some uranium leases in southwest Colorado. The DOE Office of Legacy Management (DOE LM) restarted their uranium leasing program on uranium-rich public lands as it did in 2008. This program leases properties in the Uravan mineral belt area in Colorado. The DOE LM properties reportedly contain an estimated 13.5 million pounds of uranium resources and, as of July 2020, all the remaining tracts were leased.
As of 2018, the U.S. is the world’s largest generator of nuclear power by far. The U.S. generates about 31.7% of total world nuclear energy generation which is double the second-ranked country (France), and almost triple the third-ranked country (China). The nuclear share of the total U.S. electricity production in 2018 was about 19.3%. Uranium is used as a fuel in most U.S. nuclear reactors however, most of our uranium must be imported. In 2019, over 90% of uranium purchased and delivered to U.S. civilian nuclear power reactors came from other countries. Uranium concentrate production from U.S. mines in 2019 was the lowest recorded since 1949. In 2019, U.S. uranium concentrate was produced from five in-situ leaching facilities, four in Wyoming and one in Nebraska, and one underground mine. So far, relying on imports hasn’t been a significant problem for us, but it could soon become a problem as more nuclear plants are built around the world, as world supplies become more constrained, and as future uranium prices rise.
Colorado does not host any nuclear power plants at this time however, several mining companies are interested in mining and milling uranium and associated vanadium deposits in the state. An elongated area located in Mesa, Montrose, and San Miguel counties contains the Uravan mineral belt. This area contains uranium and vanadium deposits generally in the Salt Wash Member of the Morrison Formation. This area was historically mined for both of these commodities and contained about 1,100 mines that ranged in size. Historically, these mines were managed on land leased by the Atomic Energy Commission (AEC) and now managed by the U.S. Department of Energy and U.S. Bureau of Land Management. Historic AEC leases have recently been leased again in 2019 for the future mining of uranium and/or vanadium. In 2019, vanadium was primarily (~94%) used for as an alloying agent for iron and steel. Future uses of vanadium for batteries may increase the current demand.
As reported in the CGS publication B-40 Radioactive Mineral Occurrences in Colorado and Bibliography, Jefferson County has been a major uranium producer in the state. The Schwartzwalder Mine, one of the major vein‐type uranium mines in North America, has produced approximately 98 percent of all U3O8 in the county. As of May 1978, total production from the mine has been reported as 10,500,000 pounds of U3O8 making the Schwartzwalder the largest single uranium producing mine in the state. Twelve other mines in the county have produced uranium, but only a small percentage compared to the Schwartzwalder’s total production. Seven of the ten uranium mines in the county occur where a fault or breccia zone transects the Precambrian Idaho Springs Formation. Some of these mines, including the Schwartzwalder, are all clustered along three northwest‐trending faults or breccia systems within six miles of the fault system along the Front Range.
Other areas of Colorado contain potential uranium resources. The Tallahassee Creek uranium deposits in Park and Fremont Counties are located within the Eocene Echo Park Alluvium and Oligocene Tallahassee Creek Conglomerate. Uranium mineralization in these units is above buried geologic structures within the area and is associated with carbonaceous material, pyrite, carbonate and secondary silica in sandstones and conglomerates interbedded with the Wall Mountain Tuff. Several deposits have been identified including the High Park, Hansen, Picnic Tree, Taylor (James-Taylor lease), and several others. Between 1957 and 1972, 95,400 tons of ore averaging 0.25% U3O8 were mined, mostly from the Tallahassee Creek conglomerate. Some estimates by private mining companies indicate that the Hansen/Taylor deposit contains resources of 29,730,000 tons grading at 0.063% U3O8, or 37,480,000 pounds U3O8, and an inferred uranium resource of 43,681,000 tons with a grade of 0.058% U3O8 containing 50,443,000 pounds U3O8.
At the historic Graysill mining district in Dolores County, vanadium and uranium occurs in sandstones of the upper part of the Jurassic Entrada Sandstone just below its contact with the overlying Wanakah Formation. At the Graysill Mine, by 1971, 171 tons were mined at grades of 0.049% U3O8 and 1.907% V2O5 at the Graysill No. 1 Mine. At the Graysill No. 2, 31,778 tons were mined containing 0.08% U3O8 and 2.41% V2O5. Additional uranium and vanadium resources were mined in several other nearby areas within the Entrada Sandstone.
The Maybell uranium and vanadium deposits include tabular sandstone uranium deposits formed in locally tuffaceous, fluvial, arkosic sandstone in the Miocene Browns Park Formation. Uranium enrichment occurs mainly in the lower 150 feet of the Browns Park Formation in fine- to medium-grained sandstone that contains abundant clay in its matrix. The five largest producing mines of this district are the Rob Rollo Mine, the Marge Mine, the Gertrude Mine, the Sage-Buella Mine, and the Johnson Lease. Nearly 5,300,000 pounds of U3O8 have been produced from the Maybell mines over 28-years. Also, intermediate grade resources (0.01-0.05% U3O8) were identified in a 2 square mile area with an estimated 70 million tons of material in the Browns Park Formation containing 25 million pounds of uranium oxide. Also, there has been speculation that the Maybell area could contain at least 200 million pounds of uranium oxide in intermediate-grade resources. Shipments of ore totaling 48 tons and averaging 0.19 percent U3O8 and 0.10 percent V2O5 have been mined from the Sugar Loaf group.
A few publications on select uranium resources of Colorado are listed here first. Other CGS publications are listed below these.
Chenoweth, W. L., 1980, Uranium in Colorado: in Colorado Geology, Kent, H. C. and Porter, K. W., eds., Rocky Mountain Assoc. of Geologists, 1980, 221 p.
Chenoweth, W.L., 1981, The uranium-vanadium deposits of the Uravan Mineral Belt and adjacent areas, Colorado and Utah: in Western Slope (Western Colorado) New Mexico Geological Society 32nd Annual Fall Field Conference Guidebook, eds. Epis, R.C. and Callender J.F., p. 165-170.
Chenoweth, W.L., 1986, Geology and production history of the uranium deposits in the Maybell, Colorado, area: Rocky Mountain Association of Geologists 1986 Symposium, p. 289-292.
Dickinson, K.A., 1981, Geologic controls of mineralization in the Tallahassee Creek uranium district, Fremont County, Colorado: U.S. Geological Survey Open-File Report 81-735, 19 p.
Fischer, R.P., 1968, Vanadium deposits of the Placerville area, San Miguel County, Colorado: in San Juan, San Miguel, La Plata Region (New Mexico and Colorado), Shomaker, J. W.; [ed.], New Mexico Geological Society 19th Annual Fall Field Conference Guidebook, pp. 100-103.
Fischer, R.P. and Hilpert, L.S., 1952, Geology of the Uravan mineral belt: U.S. Geological Survey Bulletin 988-A, 16 p.
Hon, K., 1984, Geology of volcanogenic uranium deposits within the Tallahassee Creek Conglomerate, Tallahassee Creek uranium district, Colorado: U.S. Geological Survey Open-File Report 84-219, 53 p.
Isachsen, Y.W., Uranium deposits in the Skull Creek and Uranium Peak districts, northwest Colorado: Rocky Mountain Association of Geologists, Guidebook to the geology of Northwest Colorado, p. 124-125.
Kirkham, R.M., O’Leary, W.J., and Warner, J.W., 1980, Hydrogeologic and stratigraphic data pertinent to uranium mining, Cheyenne Basin, Colorado: Colorado Geological Survey Information Series 12, 31 p.
O’Keeffe, M.K., Che Zabri, M.Z., Mahatma, A., and Fitzgerald, F.S., 2021, Digital map version of the radioactive mineral occurrences of Colorado and bibliography: by Nelson-Moore, J.L., Bishop-Collins, D., and Hornbaker, A.L., 1978, Radioactive mineral occurrences of Colorado and bibliography, Colorado Geological Survey Bulletin 40, 1054 p., 12 plates: Colorado Geological Survey ON-B-40M (online map).
Nelson-Moore, J.L., Bishop Collins, D., Hornbaker, A.L., 1978, Radioactive mineral occurrences of Colorado and bibliography: Colorado Geological Survey Bulletin 40, 1054 p.
Reade, Jr., H.L, 1976, Grover uranium deposit: A case history of uranium exploration in the Denver Basin, Colorado: The Mountain Geologist, v. 13, no. 1, p. 21-31.
Reade, H.L., 1978, Uranium deposits: northern Denver Julesburg Basin, Colorado: Rocky Mountain Association of Geologist – 1978 Symposium, Energy resources of the Denver Basin, p. 161-171.
Scarborough, L.A., 2001, Geology and mineral resources of Park County, Colorado: Colorado Geological Survey Resource Series 40.
Shawe, D.R., 1976, Geologic history of the Slick Rock District and Vicinity, San Miguel and Dolores Counties, Colorado: U.S. Geological Survey Professional Paper 576-E, 19 p.
Shawe, D.R., 2011, Uranium-vanadium deposits of the Slick Rock district, Colorado: U.S. Geological Survey Professional Paper 576-F, 80 p.
Sheridan, D.M., Maxwell, C.H., and Albee, A.L., 1967, Deposits of the Ralston Buttes district, Jefferson County, Colorado: U.S. Geological Survey Professional Paper 520, 121 p.
Sims, P.K., and Sheridan, D.M., 1964, Geology of uranium deposits in the Front Range, Colorado, with sections by King, R.U., Moore, F.B., Richter, D.H., and Schlottmann, J.D.:U.S. Geological Survey Bulletin 1159, 116 p.
Theobald Jr., P.K. and Chew III, R.T., Geology and uranium deposits of part of the Browns Park Formation, Colorado, Wyoming, and Utah – a preliminary report: U.S. Geological Survey Trace Elements Investigations Report 423, 39 p.
A list of other CGS publications related to uranium deposits is included below.
Aurand, Harry A. “Bulletin 22 – Mineral Deposits of the Western Slope.” Mineral Resources. Bulletin. Boulder, CO: Colorado Geological Survey, 1920. https://coloradogeologicalsurvey.org/publications/mineral-deposits-western-slope.
Coffin, R. C. “Bulletin 16 – Radium, Uranium, and Vanadium Deposits of Southwestern Colorado.” Bulletin. Denver, CO: Colorado Geological Survey, 1921. https://coloradogeologicalsurvey.org/publications/carnotite-radium-uranium-vanadium-deposits-colorado.
Collier, James D., A. L. Hornbaker, and William L. Chenoweth. “MS-11 Directory of Colorado Uranium and Vanadium Mining and Milling Activities.” Uranium and Vanadium Mining. Map Series. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1978. https://coloradogeologicalsurvey.org/publications/uranium-vanadium-mining-milling-map-colorado.
Colorado Geological Survey, Robert M. Kirkham, and Four Corners Environmental Research Institute. “OF-81-01 Preliminary Report on Potential Sites Suitable for Relocation and/or Reprocessing of the Durango Uranium Mill Tailings Pile.” Uranium Processing. Open File Report. Denver. CO: Colorado Geological Survey, Department of Natural Resources, 1981. https://coloradogeologicalsurvey.org/publications/potential-sites-relocation-reprocessing-durango-uranium-mill-tailings-pile.
———. “OF-82-02 Preliminary Report on Potential Sites Suitable for Relocation and/or Reprocessing of the Grand Junction and Rifle Uranium Mill Tailings Pile.” Uranium Processing. Open File Report. Denver. CO: Colorado Geological Survey, Department of Natural Resources, 1982. https://coloradogeologicalsurvey.org/publications/potential-sites-relocation-reprocessing-grand-junction-rifle-uranium-mill-tailings-piles.
Colorado Geological Survey. “RockTalk V09N2, Fall 2006 – Uranium – It’s Hot!!” RockTalk, Fall 2006. https://coloradogeologicalsurvey.org/publications/rocktalk-uranium-colorado.
Hornbaker, A. L. “MS-10 Metal Mining Activity Map of Colorado (Excluding Uranium and Vanadium).” Metal Mining Activity. Map Series. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1978. https://coloradogeologicalsurvey.org/publications/metal-mining-map-uranium-vanadium-colorado-1978.
Kirkham, Robert M. “EG-11 Promises and Problems of a ‘New’ Uranium Mining Method: In Situ Solution Mining.” Uranium mining. Environmental Geology. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1979. https://coloradogeologicalsurvey.org/publications/promises-problems-uranium-mining-method-in-situ-solution.
Kirkham, Robert M., William O’Leary, and James W. Warner. “IS-12 Hydrogeologic and Stratigraphic Data Pertinent to Uranium Mining, Cheyenne Basin, Colorado.” Information Series IS-12. Denver, CO: Colorado Geological Survey, Department of Natural Resources, 1980. https://coloradogeologicalsurvey.org/publications/hydrogeologic-stratigraphic-data-uranium-mining-cheyenne-basin-colorado.
Nelson-Moore, J.L., Bishop Collins, D., Hornbaker, A.L., 1978, Radioactive mineral occurrences of Colorado and bibliography: Colorado Geological Survey Bulletin 40, 1054 p.
Wallace, Chester A., James A. Cappa, and Allison D. Lawson. “OF-99-03 Geologic Map of the Gribbles Park Quadrangle, Park and Fremont Counties, Colorado.” Geologic. Open File Report. Denver, CO: Colorado Geological Survey, Division of Minerals and Geology, Department of Natural Resources, 1999. https://coloradogeologicalsurvey.org/publications/geologic-map-gribbles-park-quadrangle-park-fremont-colorado.
For an excellent summary about uranium in Colorado, see the CGS RockTalk.
CGS Publication ON-B-40D — Radioactive Mineral Occurrences of Colorado and Bibliography — This data download includes locations and descriptions of over 2,000 radioactive mineral occurrences in Colorado. Originally published as CGS Bulletin 40 (B-40 Radioactive Mineral Occurrences of Colorado and Bibliography), locations on the original plates were combined with the information provided in the text document to create a comprehensive spreadsheet, electronic bibliography, county summary document, and GIS data download. Location information includes the original mine name, location notes, mine development information, production, background radiation measurements, host rock types, alteration, mineralogy, structure, and references.
CGS Publication ON-B-40M — Radioactive Mineral Occurrences of Colorado and Bibliography — This online map includes descriptions and the locations of over 2,000 radioactive mineral occurrences in Colorado. Originally published as CGS Bulletin 40 (B-40 Radioactive Mineral Occurrences of Colorado and Bibliography), locations on the original plates were combined with the information provided in the text document to create this informative map. Location information includes the original mine name, location notes, mine development information, production, background radiation measurements, host rock types, alteration, mineralogy, structure, and references. Data associated with this map includes county summary text, a spreadsheet, and the GIS data files that can be downloaded via the link provided for ON-B-40D.
CGS Annual Colorado Mineral and Energy Industry Activity report — This annual report covers all aspects of mining and extraction in Colorado. This report includes current and historical data for uranium and other commodities produced in the state. Data includes production, prices, and other mining related subjects relative to Colorado. The following are links to these reports by year: 2018-19 — 2017-18 — 2016-17 — 2015-16 — 2014-15; — 2007
U.S. Department of Energy — Information about the uranium leasing program.
U.S. Energy Information Administration — Information about U.S. and worldwide uranium consumption and production.
U.S. Geological Survey — Information about U.S. uranium resources.
World Nuclear Association — The WNA is the international organization that represents the global nuclear industry.
