Science for Decision Making on Uranium Mining in Arizona

Laboratory Studies to Evaluate Mobility of Ore-Derived Uranium and Trace Metals in Aquifers

Regional Studies

Characterization of transport pathways of mining-related contaminants in water is a priority identified by the GCSP (PDF). The question of transport via groundwater is difficult to address, however, because of the scarcity of monitoring wells in the region and the costs and difficulty associated with drilling to deep aquifers. Laboratory studies will be conducted that will evaluate the potential mobility of uranium and trace metals derived from breccia pipe ores in groundwater. Experiments will expose water to different types of ore and different types of aquifer-hosting rock in sequence. The experiments will show how concentrations of uranium and trace metals can increase when water is exposed to ore, and then how those concentrations change when the water moves away from ore into aquifer-hosting rock. Geochemical modeling by computer simulations will be used to better understand the processes happening during the experiments that may also happen in the subsurface.


  • Concentrations of arsenic, cobalt, nickel, uranium, and zinc, and to a lesser extent molybdenum, become substantially elevated in waters exposed to breccia pipe uranium ore.
  • Mobility of cobalt, molybdenum, nickel, and uranium are minimally attenuated by reactions expected in downgradient aquifers and zinc is only partially attenuated.
  • Concentrations of antimony and thallium are moderately elevated in waters exposed to breccia pipe uranium ore but also minimally attenuated.
  • Downgradient aquifer concentrations of elements sourced from breccia pipe uranium ore will be strongly influenced by non-geochemical factors such as the quantities of water contacting ore, rock types along flow paths, and mixing with waters that have not contacted ore.



Specific Tasks

Task 6: Compare water transport mechanisms in mined and unmined breccia pipe
Task 7b: Collect/analyze water and sediment samples
Task 9: Drill and develop groundwater monitoring wells


1 Bern, C., Campbell, K., Walton-Day, K., and Van Gosen, B., 2022, Laboratory simulation of groundwater along uranium-mining-affected flow paths near the Grand Canyon, Arizona, USA: Mine Water and the Environment, volume 41, 370–386,

Principal Investigators

Kate Campbell-Hay
Research Chemist
Geology, Geophysics, and Geochemistry Science Center

Carleton Bern
Research Soil Scientist
Colorado Water Science Center

Photo Gallery

Small falls along Havasu Creek 2

Regional Studies Gallery