The U.S. Forest Service says it could be open to conducting a new environmental assessment of a uranium mine near the South Rim of the Grand Canyon. It comes after Arizona’s governor and attorney general urged the agency to study the mine’s possible impacts.
In a letter sent to Attorney General Kris Mayes on Sept. 20, Kaibab National Forest Supervisor Nicole Branton wrote that the agency is continually assessing new science related to the potential environmental effects of the Pinyon Plain Mine.
Branton did not commit to a new supplemental environmental impact statement (EIS), as Mayes had requested in August, but said the Forest Service is conducting an ongoing “interdisciplinary review” of the original analysis from 1986, which will eventually be released in a report.
“A reevaluation such as this has the purpose of determining whether there are substantial new circumstances or information about the significance of adverse effects that bear on the analysis,” wrote Branton. “Through this process, the responsible official considers whether the new information or changed circumstances are within the scope and range of effects considered in the original analysis.”
Branton’s letter is a response to Mayes, who wrote in August expressing her concerns about the nearly 40-year-old study. Mayes said the analysis is based on outdated science and the mine poses a threat to groundwater and Indigenous sacred sites.
“… a supplemental EIS is now necessary because scientific advances in groundwater modeling unequivocally show that the 1986 EIS’s claim that the Mine is not a threat to regional water supplies is wrong,” wrote Mayes. “Failure to supplement the EIS could result in devastating consequences for the region—especially for vulnerable communities like the Havasupai Tribe.”
Mayes’ office says it is reviewing Branton’s response but did not otherwise comment on the letter.
A spokesperson for Gov. Katie Hobbs, who called for a new analysis on Sept. 20, said the Forest Service’s reassessment is an important step and she stands with tribal nations.
“Last week, Governor Hobbs urged a thorough review due to significant changes and growing concerns about the protection of cultural sites, such as Red Butte Mountain, and the 2016 breach of a perched zone in the C-aquifer, which was not adequately considered in the original EIS,” said a statement from Hobbs’ office.
The mine’s owner, Energy Fuels, says the original 1986 environmental analysis for Pinyon Plain has been upheld in court and the operation doesn’t endanger groundwater.
In an August statement, Energy Fuels said that a 2022 aquifer protection permit issued by the Arizona Department of Environmental Quality also determined the mine would not negatively affect groundwater.
A company spokesperson wrote, “Energy Fuels continues to comply with all current approvals, regulations, and science to ensure protection of human health and the environment.”
The Pinyon Plain Mine is Arizona’s only ore-producing uranium mine. It is located within the Baaj Nwaavjo I'tah Kukveni – Ancestral Footprints of the Grand Canyon National Monument but was allowed to keep operating because of preexisting rights. It started producing uranium ore in early 2024.
