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Navajo Nation: Cleaning Up Abandoned Uranium Mines

Section 9 Lease Mines

The Section 9 Lease Mines are three abandoned uranium mine sites located near the Little Colorado River in Northern Arizona. The mines are located just outside the Navajo Nation and are about 10 miles southeast of Cameron, AZ. Under a 2016 Administrative Order on Consent, Babbitt Ranches agreed to perform a Removal Site Evaluation on the two mines on their property.

Concrete structure in a desert landscape


The Section 9 Lease Mines were operated in the late 1950s and early 1960s and include Abandoned Uranium Mines (AUM) 457, 458, and 459. The mines are located about 10 miles southeast of the Cameron, AZ, and are away from population centers. AUM 457, the farthest north of the three sites, also includes a concrete structure called an “upgrader”, which was meant to increase the concentration of uranium in the ore from local mines. AUM 457 is a priority mine site based on its potential impacts on the Little Colorado River.

In 2016, EPA signed a legal agreement called an Administrative Order on Consent with Babbitt Ranches. In this document, Babbitt Ranches agreed to place warning signs and perform an assessment called a Removal Site Evaluation on AUMs 457 and 458. AUM 458 is entirely on Babbitt Ranches property, while AUM 457 is partially on Babbitt Ranches property and partially on land administered by the Bureau of Reclamation. Babbitt Ranches also agreed to investigate whether contamination from AUM 459 is now located on their property.

EPA and Babbitt Ranches will continue to work with local officials to identify community members with Homesite Leases and Grazing Permits near the site, and to keep them updated on site activities.  EPA is also committed to providing information to Cameron Chapter officials and other interested individuals.

Current Field Work

Babbitt Ranches began field work on the Section 9 Lease Mines in 2017, under EPA oversight. Field work to date includes:

  • Biological and Cultural Resource Surveys
  • Placing warning signs at the sites
  • Gamma radiation scanning
  • Background study
Map of Section 9 Lease AreaSection 9 Lease Site Map (click image to enlarge) | PDF Format

Cleanup Progress Timeline

The Section 9 Lease mines were operated in the 1950s and 1960s. Under the 2016 Administrative Order on Consent, Babbitt Ranches agreed to perform assessments at the two abandoned uranium mine sites on their property. Click on the different years below to learn about recent and upcoming activities.

EPA completes a Preliminary Assessment of the Section 9 Lease abandoned uranium mines

EPA completes a Site Inspection of the Section 9 Lease abandoned uranium mines

EPA signs a legal agreement with Babbitt Ranches to perform assessments on mines on their property

DANGER - KEEP OUT with radiological symbol.A warning sign placed in front of a waste pile at AUM 457.
  • Babbitt Ranches completes cultural and biological clearances ahead of site work
  • Babbitt Ranches places warning signs at the sites
  • Babbitt Ranches begins gamma radiation and background studies