Navajo Nation will spend $3 million on test of new tech for cleaning uranium mine waste

The Navajo Nation is investing roughly $3 million in a commercial scale test of new technology for cleaning up uranium mine waste.

From the 1940s into the 1980s, close to 30 million tons of uranium ore were mined from Navajo lands. Over 500 abandoned uranium mines remain, a legacy of nuclear weapons and energy development.

Cleaning up those sites is a slow process, and often the U.S. Environmental Protection Agency’s preferred cleanup option — removing uranium mine waste from the reservation to a distant repository — is prohibitively expensive, according to Stephen Etsitty, Navajo Nation Environmental Protection Agency executive director.

A new remediation process developed by Wyoming-based Disa Technologies, in which uranium is separated from the bulk of the mine waste, reducing the radiation level of much of the waste, showed promise in a 2022 study. Disa Technologies’ leadership said using the technology could speed up uranium mine cleanup and reduce the cost.

“One of the things about the (high-pressure slurry ablation) treatment that I really would like to learn more about, but I’m really excited about it initially, is that it causes the treated material to have less of an ability to leach or to move in the ground,” Etsitty said. “And that is a protective measure against future, potential groundwater contamination.”

Abandoned uranium mine sites seem like the perfect application for the technology, said Disa Technologies Inc. CEO Greyson Buckingham, because the company can “restore those lands back to beneficial use, while also having the opportunity to recycle the uranium and put it to productive use.”

The company plans to use its technology at commercial scale on non-Navajo sites as well.

In September, the Nuclear Regulatory Commission approved a service provider license for Disa Technologies, authorizing it to remediate abandoned uranium mine waste across the country.

That allows the company to work at different sites without a site-specific environmental analysis for each one, according to Jeff Merrifield, who serves on the Disa Technologies board of directors and served nine years as a commissioner on the Nuclear Regulatory Commission.

The U.S. EPA is developing the scope of the work for the commercial-scale test on the Navajo Nation. Once that is finalized — likely by the end of October — the site of the commercial-scale test will be announced, Etsitty said.

The Navajo Nation has been pushing for the U.S. EPA to assist in funding the larger verification study, but the EPA declined to, Etsitty said.

The two-week study was performed at three locations on the Navajo Nation: Cove Transfer Station in Arizona and Old Church Rock Mine and Quivira Church Rock Mine in New Mexico. Both New Mexico sites are northeast of Gallup, one in the Church Rock Chapter of the Navajo Nation and one in the Coyote Canyon Chapter.

The 1979 Church Rock uranium mill spill was the largest release of radioactive material in U.S. history, heavily contaminating the Rio Puerco. The U.S. EPA considers the nearby Churchrock Quivira Mines one of the largest and most high-risk uranium mine sites on the Navajo Nation.

Tetra Tech Inc. conducted the study at the behest of the U.S. EPA.

The technology uses a mechanical process to remove radionuclides and metals from mine waste, resulting in a large volume of material without the metals and a smaller volume of concentrated material with the radionuclides and metals, according to the study.

Mine waste is fed into a machine along with water, and high pressure air smashes the waste together, knocking off uranium or other contaminants, according to Merrifield.

The larger volume of material may be clean enough to be managed on site as backfill or under a soil cover, the study says. The treatment can concentrate more than 80% of the uranium in treated mine waste into less than 30% of the total treated mass, according to the study.

During the study, high-pressure slurry ablation technology achieved a greater than 90% reduction in uranium and radium-226 concentrations in the larger volume of coarse material. The uranium in the concentrated waste could potentially be recycled.

The technology was not able to attain conservative site-specific cleanup goals for uranium — up to a 98% reduction in the concentration of uranium — but the study demonstrated the technology is a viable treatment for uranium mine waste.

The new study will run for at least three months and use larger equipment and process more waste material than the initial study, according to Etsitty. The initial study used a piece of equipment that processed 5 tons of material per hour, and it was never run for a full hour. It was tested on a four-minute cycle, an eight-minute cycle and a 30-minute cycle.

The scaled up test will use a 10-ton per hour piece of equipment that’s been updated and modified to be more effective, Etsitty said.

The Navajo Nation has developed a list of high-priority sites with Disa Technologies, concentrated in New Mexico, but also including some priority sites in the western part of the reservation.

The Navajo Nation Superfund program was created in the 1980s with help from the EPA. Since then, it’s been working alongside the federal agency to address abandoned uranium mine waste.

Site investigations started in the 1980s. There has been a lot of identification of site characteristics, data captured to help prioritize sites for cleanup, engineering evaluation, cost analysis and the development of remedy options.

The U.S. EPA has made decisions for over a dozen mines on the Navajo Nation, Etsitty said.

“So they actually have approved cleanup remedies right now, but there still hasn’t been one shovel full of dirt that has been moved yet,” Etsitty said. “No construction work has started, because the next stage usually transitions into this actual designing and the development of construction documents and engineering documents for how these remedies are going to be developed.”

In some cases, that involves permitting and approvals from state agencies, which could take years. Next spring, Etsitty hopes to see the first mobilization by the EPA or contractors for the companies responsible for cleanup at some of the abandoned uranium mine sites.

Disa has improved its equipment since the initial study, according to Etsitty and Merrifield.

“EPA and the federal agencies just seem to have a 100-year perspective on their remedies,” Etsitty said. “But these are contaminants that take four billion years plus to break down, to start breaking down. … I would much rather see a treatment process that can help mitigate and protect groundwater being employed now than to just put untreated waste in cap and place repositories all around the reservation, and then just rely on somebody over the next thousands of years to maintain and monitor them.”