Science for Decision Making on Uranium Mining in Arizona

Specific Tasks and Priorities for Grand Canyon Science Plan

Tasks were prioritized as high, medium, or low by the management oversight team. A table of task priorities and more detailed description of each task is available in the Grand Canyon Science Plan.

High Priority Tasks

  • Time Critical
  • Require long-term sampling or monitoring
  • Previously funded in 2010 and 2011 to address uncertainties associated with uranium mining

Medium Priority Tasks

  • Critical
  • Rely on results from high priority tasks or are not as time sensitive

Low Priority Tasks

  • Rely on results from high and medium priority tasks
  • Needed to fully evaluate the impacts of mining on the environment in the Grand Canyon region

Tasks are grouped by general themes, which follow a chronological order in terms of exploration and mining. The numerical designation of tasks is to improve organization and clarity but does not indicate prioritization of individual tasks.

Improve Understanding of the Genesis of Ore
Task 1 high Priority Evaluate the distribution and stratigraphic position of breccia pipes.
Task 2 high Priority Estimate the number of buried and concealed mineralized breccia pipes.
Task 3 low Priority Evaluate the role of regional hydrology on breccia pipe mineralization.
Task 4 low Priority Compare breccia pipe deposits to sandstone deposits
Characterization of Transport Pathways of Mining Related Contaminants in Water, Soil, Sediment and Biota
Task 5a high Priority Compile/evaluate existing and newly collected monitoring data from various agencies/sources.
Task 5b high Priority Collect/analyze water and sediment samples from streams and springs.
Task 5c high Priority Collect/analyze samples from biota with focus on Federal trust resources.
Task 6 high Priority Compare water transport mechanisms in mined and un-mined breccia pipes.
Task 7a high Priority Conduct habitat and species surveys.
Task 7b high Priority Characterize concentrations of uranium and other trace elements and radiation levels in water, sediment, and soil.
Task 7c high Priority Characterize concentrations of uranium and other trace elements and radiation levels in biota (including Federal trust resources).
Task 7d medium Priority Collect/analyze soils, including deeper horizons, to characterize vertical distributions of uranium and other trace elements.
Task 8a high Priority Evaluate and refine the isotopic uranium activity ratio (UAR) analysis in water and ore samples.
Task 8b low Priority Continue evaluation/analysis of ore geochemistry from historical and active mines.
Task 9 high Priority Drill and develop groundwater observation wells into the regional aquifer.
Task 10 medium Priority Update the Northern Arizona Regional Groundwater Flow Model (NARGFM) and test generic models to evaluate effect of the down cutting of the Colorado River on regional hydrology.
Determine Pathways of Exposure
Task 11 high Priority Characterize the wind dispersion characteristics of uranium and trace elements associated with uranium mining and the subsequent risk to biota.
Task 12 high Priority Monitor surface waters in Kanab Creek, Havasu Creek, and the Colorado River to determine the mobility and flux of uranium and other trace elements.
Task 13 low Priority Evaluate scenarios of impact from potential overflowing of wastewater ponds or disturbance of waste rocks from runoff events.
Task 14 medium Priority Determine the fluxes and storage of uranium and other trace elements in Lake Mead sediments.
Determine Biological Effects of Exposure to Contaminants
Task 15 high Priority Quantify the risk to native flora and fauna caused by chemical or radiation releases linked to uranium mining.
Task 16a medium Priority Develop chemical effect thresholds for uranium for biota inhabiting mining areas of the Grand Canyon region.
Task 16b medium Priority Develop radiation effect thresholds for uranium for biota inhabiting mining areas of the Grand Canyon region.
Task 16c high Priority Characterize the risks to biota chronically exposed to uranium such as genetic effects on species populations, density, ecosystem dynamics, and biodiversity.
Task 17 low Priority Evaluate the biological effects (synergistic, additive, antagonistic) of chemical exposure to uranium plus trace element mixtures.
Task 18 low Priority Evaluate the risk of radiation exposure for biota that spend prolonged periods of time in the subterranean environment.
Task 19 low Priority Determine the sensitivity of native wildlife receptors to chemical and radiation exposure encountered in the field.