The Pinyon Plain Mine is located south of the Grand Canyon in the Tusayan Ranger District of the Kaibab National Forest, approximately 7 miles southeast of Tusayan, Arizona, in Coconino County. Early exploration found low grade uranium during the late 1970s and early 1980s. A major uranium ore deposit was identified in 1983 and an area was subsequently delineated to determine an optimal location for the mine shaft1.
Surface development of the mine site began in the 1990s, paused, and resumed around 2012. As of February 2020, the mine is on standby. The mine is expected to produce approximately 82,800 tons of ore yielding 1,629,000 pounds of uranium oxide2. Ore extraction is expected not to exceed 3 years. No ore processing will be conducted on site, rather the ore will be shipped to a mill near Blanding, Utah3.
In 2013, water, sediment/soil (some also collected in 2015), and biological samples were collected by USGS at the Pinyon Plain Mine location and the surrounding area to determine baseline measurements for uranium and 41 other elements 4, 5, 6. The baseline measurements were them compared to samples collected during active mining and after reclamation of the mine 7, 8. Dust sampling with quarterly collection of samples is ongoing (2020).
Beginning in 2017, water, sediment, vegetation, and invertebrates samples were collected quarterly from the containment pond at Pinyon Plain Mine (for chemical characterization. These samples will evaluate any changes in chemical concentrations that occur in the pond throughout the mine life cycle.
Activities listed below are scientific research studies occurring at this site. Studies within the Grand Canyon region are grouped by theme and each theme has specific tasks (referenced by task number).
The View Activity button below each task will open a separate window with detailed activity information.
1 Pool, T.C., and Ross D.A., 2012, Technical report on the Arizona strip uranium project, Arizona, U.S.A.: NI 43-101 Report prepared by Roscoe Postle Associates Inc. for Energy Fuels Inc., 119 p.
2 Pool, T.C., and Ross D.A., 2012, Technical report on the Arizona strip uranium project, Arizona, U.S.A.: NI 43-101 Report prepared by Roscoe Postle Associates Inc. for Energy Fuels Inc., 119 p.
3 Alpine, Andrea E., ed., 2010, Hydrological, geological, and biological site characterization of breccia pipe uranium deposits in northern Arizona: U.S. Geological Survey Scientific Investigations Report 2010—5025, 353 p., 1 pl., scale 1:375,000
4 Hinck, J.E., Linder, G., Darrah, A.J., Drost, C.A., Duniway, M.C., Johnson, M.J., Mendez-Harclerode, F.M., Nowak, E.M., Valdez, E.W., Wolff, S., and van Riper III, C., 2014, Exposure pathways and biological receptors--Baseline data for the Canyon Uranium Mine, Coconino County, Arizona: Journal of Fish and Wildlife Management, v. 5, no. 2, p. 422-440
5 Naftz, D., and Walton-Day, K., 2016, Establishing a pre-mining geochemical baseline at a uranium mine near Grand Canyon National Park, USA: Geoderma Regional, v. 7, no. 1, p. 76-92
6 Hinck, J.E., Cleveland, D., Brumbaugh, W.G., Linder, G., and Lankton, J., 2017, Pre-mining trace element and radiation exposure to biota from a breccia pipe uranium mine in the Grand Canyon (Arizona, USA) watershed: Environmental Monitoring and Assessment, February 2017
7 Cleveland, D.M., Hinck, J.E. and Lankton, J.S., 2019, Assessment of chronic low-dose elemental and radiological exposure of biota at the Kanab North uranium mine site in the Grand Canyon watershed: Integrated Environmental Assessment and Management 15:112-125, https://doi.org/10.1002/ieam.4095
8 Cleveland, D., Hinck, J.E., Lankton, J.S., 2021, Elemental and radionuclide exposures and uptakes by small rodents, invertebrates, and vegetation at active and post-production uranium mines in the Grand Canyon watershed: Chemosphere, vol. 263, https://doi.org/10.1016/j.chemosphere.2020.127908.