Science for Decision Making on Uranium Mining in Arizona

Build Database of Known Breccia Pipe Uranium Deposits in the Region to Reassess and Refine the Area Permissive for Breccia Pipes

Regional Studies

To improve resource estimates and gain a better understanding of the distribution of uranium-bearing breccia pipes in northern Arizona, areas where breccia pipe uranium deposits are known to exist, and could potentially exist, were identified based on available geologic information. Geospatial datasets1 were compiled and published in 2016. These GIS spatial datasets allow the user to plot and query all features listed below. The datasets contribute to efforts to improve the certainty of estimates of uranium resources in the region, as well as improve geologic and hydrologic understanding of the origin and distribution of ore deposits. Additionally, the GIS dataset that outlines the areas permissive for uranium-bearing breccia pipes, based on appropriate geology, can be used by land management agencies to outline the lands that could potentially see exploration, discoveries, and mining proposals in the future.

Published spatial data were compiled across the northern Arizona region, showing the locations for:

  • Identified breccia pipes that are known to contain uranium deposits; these breccia pipes include those mined and others confirmed to contain uranium mineralization through drilling (64 breccia pipes).
  • Mapped breccia pipes with unknown potential to host uranium (not drilled) (54 mapped breccia pipes).
  • Mapped collapse features that may be the surface expression of breccia pipes, and therefore potentially overlie a uranium-bearing breccia pipe (748 mapped collapse features).
  • Areas underlain by rock units (formations) that are permissive to contain a uranium-bearing breccia pipe; these areas were obtained from geologic maps of northern Arizona and southeastern Utah.

Map showing all identified breccia pipes and mapped collapse features in northwestern Arizona.

Known uranium-bearing breccia pipes in northwestern Arizona. Large hot pink dots are breccia pipes that have been mined; small yellow dots are other identified uranium-bearing breccia pipes. The three green stars (north are EZ complex 1 and 2 and south is Pinyon Plain Mine (formerly Canyon Mine)) are deposits being developed.



Specific Tasks

Task 1: Distribution and stratigraphic positions of breccia pipes
Task 2: Estimate the number of mineralized breccia pipes
Task 4: Compare breccia pipe to sandstone deposits


1 Van Gosen, B.S., Johnson, M.R., and Goldman, M.A., 2016, Three GIS datasets defining areas permissive for the occurrence of uranium-bearing, solution-collapse breccia pipes in northern Arizona and southeast Utah: U.S. Geological Survey data release,

Principal Investigators

Bradley S. Van Gosen
Central Mineral Resources Team


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Logging core at Canyon mine

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