Section 9 Lease Abandoned Uranium 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 (AOC), Babbitt Ranches completed a Removal Site Evaluation on the two mines on their property.

Background

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 Land Management. Babbitt Ranches also agreed to investigate whether contamination from AUM 459 is now located on their property. The work under this Administrative Order on Consent was completed in 2021.

EPA presented an Environmental Engineering/ Cost Analysis (EE/CA) to the community in November of 2024.  The EE/CA compared potential clean up alternatives and recommended a clean up alternative for the Site, the presentation of the EE/CA to the community began the public comment period.

In September 2025, after careful consideration of all received comments, EPA signed an Enforcement Action Memorandum (Action Memo) to move forward with the recommended clean up alternative. The clean up action includes the removal of waste from the banks of the Little Colorado River to a designed repository one mile away and restoration of the site. Design is expected to begin in 2026.

EPA remains committed to providing information to Chapter officials, community members, and other interested individuals and will provide updates to the community through the design and clean up phases.

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. Learn about recent and upcoming activities in the timeline below.

2025

In September 2025, EPA signed an Action Memo to move forward with clean up and design of a repository on Section 9, which is expected to begin in 2026.

2024

• On November 23, 2024, in a public meeting, EPA released the final Section 9 Lease mines Engineering Evaluation/Cost Analysis (EE/CA) (pdf) (328 pp, 26.94 MB) with a recommended cleanup alternative for the Section 9 Lease Sites.

2017

• 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

2016

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

2014

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

2012

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