Navajo EPA wants to use controversial technology for uranium cleanup

With its designation as a "time-critical removal action," the project will involve excavating approximately 6,000 cubic yards of abandoned uranium mine material across four areas of the Old Church Rock Mine. Incorporating technology known as high-pressure slurry ablation will allow for the permanent removal of up to 1,500 cubic yards of material from the site.

Although the goal for decades has been to remove leftover uranium waste from the Old Church Rock Mine, environmentalists, community members and critics have concerns and doubts when it comes to this type of technology and note that it isn't cleanup — it's extraction.

"There's a lot more that needs to be learned about this process," said Chris Shuey, senior environmental health specialist at Southwest Research and Information Center, during an April 28 Diné Uranium Remediation Advisory Commission meeting.

"We've said it before that this is a process that had been used to recover minerals. In the state of Colorado they don't view high-pressure slurry ablation as a remediation method, they view it as an extraction for production."

The Old Church Rock Mine is located 25 miles northeast of Gallup, New Mexico. Uranium exploration, development and mining at the site began in 1957. The first phase of mining, from 1960 to 1962, produced 77,965 tons of ore, while the second phase, from 1963 to 1982, yielded 238,286 tons. During this later period, the mined ore was transported to the United Nuclear Corporation uranium mill at Northeast Church Rock.

NuFuels Inc. acquired the Old Church Rock Mine in 2016. While the Navajo Nation Environmental Protection Agency agreed to the acquisition, it proposed integrating high-pressure slurry ablation technology into the time-critical removal action, which includes removing up to 1,500 cubic yards of abandoned uranium mine material from the site. Ablation uses water to create a slurry, which separates uranium particles from the rest of the material.

The project scope will also provide DISA Technologies with an opportunity to carry out a Phase 2 Verification Study of its ablation technology — licensed by the U.S. Nuclear Regulatory Commission — to demonstrate its effectiveness at a larger, commercial scale.

This effort builds on a 2021–2023 U.S. Environmental Protection Agency–funded treatability study, conducted in partnership with the Navajo EPA, which showed substantial reductions in uranium and radium-226 contamination and confirmed high-pressure ablation as a viable method for remediation and waste minimization of uranium waste material.

"We now have this private company taking up the responsibility and starting to do cleanup work," said Stephen B. Etsitty, executive director of the Navajo Nation Environmental Protection Agency, about NuFuels Inc. "This project represents an important step forward in advancing cleanup solutions that are safer, effective, and timelier. The Phase 2 Verification Study allows us to continue evaluating high-pressure slurry ablation treatment technology at a larger, more practical scale, on Navajo Nation terms and as authorized by Navajo law ... this effort will verify improved risk reduction to groundwater resources, the ability to minimize waste material volumes, and identify scalable solutions to accelerate the rate of cleanup for our communities."

What tests show about the cleanup technology

The U.S. EPA tasked Tetra Tech Inc. with evaluating high-pressure ablation as a method to remove metals and radionuclides from waste rock at the Navajo abandoned uranium mine sites. In 2018, the U.S. government intervened in three whistleblower lawsuits against Tetra Tech EC Inc., alleging false claims related to radiological work at the Hunters Point Naval Shipyard in San Francisco.

Tetra Tech, with USEPA’s concurrence, selected Disa Technologies Inc.’s ablation technology for evaluation in this treatability study. Over a two-week period in the summer of 2022, the U.S. EPA evaluated the use of high-pressure ablation as a treatment method for removing metals and radionuclides from waste rock at three abandoned uranium mine sites on the Navajo Nation: Cove Transfer Station waste stockpile at the CTS Complex in the Cove Chapter, Arizona; Old Church Rock Mine in the Church Rock Chapter, New Mexico; and Quivira Church Rock 1 Mine in the Coyote Canyon Chapter, New Mexico, according to a 90-page report finalized in 2023 on the technology.

The report said community acceptance for the ablation treatment system operated at the three uranium mine sites on the Navajo Nation is very positive. The technology relies on a mechanical, chemical-free process to remove radionuclides and metals from mine waste at abandoned uranium mine sites.

The treatment produces two solid outputs: a smaller volume of concentrated fine material containing the removed radionuclides and metals, and a larger volume of coarse material, primarily sand that has been stripped of mineralized coatings, according to the report.

"They did what's called bench tests, so they had a very small system," said Lynda Williams, a physicist for Nuclear Free Hawaii. "For the Phase 1 test, they went to Old Church Rock Mine, Quivira Mine and Cove transfer station. They only processed two five-gallon buckets of rock.
It's about 100 pounds per task, which is, you know, so they grab two, five gallon buckets and they processed it for four minutes, eight minutes and 30 minutes. And that's it. That's all the testing they did."

Test results showed that about 20–24% of the total mass becomes fine material containing a high concentration of uranium. This portion is removed and can either be disposed of or potentially sent to a mill. The remaining 60–80% stays on site with lower uranium levels, though it may still contain other radioactive isotopes, she said.

Bulk samples representing low, medium, and high concentrations of uranium and radium-226 were collected from each site and treated using a pilot-scale HPSA unit at 4-, 8-, and 30-minute intervals, the report said. The treated material was then size-separated at the DISA laboratory and analyzed.

Some of the key takeaways:

• The ablation technology achieved greater than 90% reduction in uranium and Radium-226 concentrations in the treated coarse fraction;

• The technology did not achieve conservative site-specific Navajo residential cleanup goals for uranium or background levels for Radium-226 for waste processed Old Church Rock Mine, Quivira Mine and in only one of three waste samples at Cove mine;

• The technology requires 13 gallons per minute of water for the slurrying of material. The treated coarse material may require a soil cover if cleanup goals are not met, among other findings.

Etsitty also noted that although the Old Church Rock work is not a pilot project, it will be another demonstration for this type of approach to cleaning up contaminated radioactive material. He said the equipment used will be larger and more waste will be treated and for a longer amount of time rather than the initial 30-minute treatment from the pilot project.

Etsitty said that either potable or non-potable water may be used. Initial equipment testing will require transporting water to the site, although the goal is to rely on a local source, as was done during the earlier treatability study. Efforts to identify appropriate water sources are underway, and most of the water used will be captured and continuously recycled throughout operations.

"EPA and Navajo EPA have been working on a back ground study. ... This is important. It helps answer the question of how clean is clean," Etsitty said. "This is action that will set the stage for more work to be done to assess the remaining cleanup, but it also provides us to test the technology and to do a permanent removal of what is expected to be the most contaminated parts of the soil after the treatment process, and then transport that from this site to the license facility off the reservation."

Water use, leftover waste questioned

Dooda DISA is a community-led initiative focused on raising awareness about DISA Technologies’ high-pressure ablation project on the Navajo Nation. The group contends that the technology operates as a uranium extraction process rather than a true cleanup method, leaving much of the remaining waste still radioactive. The group also says the process does not meet Navajo Nation cleanup standards.

Anna Rondon, who is a part of Dooda DISA and also project director of the New Mexico Social Justice and Equity Institute, commented about the use of HPSA during the community meeting. She said radioactive waste will stay on site, and only a few tons of the actual uranium particles will be taken from the Old Church Rock Mine. She emphasized the need for more community meetings to discuss this process.

"As I mentioned before about the water, are they going ask for water permits if they can't haul water?" Rondon said. "There's so much unknowns here and it's our political career officials, and some of our executive directors and division directors, they become consultants for these companies once they leave."

Although high-pressure ablation technology supposedly relies on a mechanical, chemical-free process, Rondon said that really isn't the case. An April 22 Nuclear Regulatory Commission letter said that DISA had to amend its license, "because at first they said they're not going to use chemicals. They're just going to use water. But now they're gonna use a couple of chemicals," Rondon said.

Despite claims that the ablation technology uses no chemicals, the letter from the NRC to DISA references the Mary Ann site in Montrose County, Colorado, raising questions about that assertion. "Disa stated in its license application that no chemicals are used during the HPSA process," the letter said. "However, DISA will use two innocuous substances for dust supression (necessary for radiation protection) and dewatering (necessary for purifying the clean coarse material)."

"Uranium is to be left in the ground," said Rondon during a webinar earlier this year. "For us as Diné people, the tribal council did approve uranium mining back in 1962, and now the executive branch is looking to mining uranium waste for commercial sale but DISA will be the ones receiving the profits."

Navajo EPA said the ablation technology has undergone independent technical evaluation, including verification by Idaho National Laboratory, as well as a multi-year federal licensing review by the U.S. Nuclear Regulatory Commission.

The technology is an extraction process rather than a cleanup method, Williams said. DISA’s system only removes part of the soil mass and concentrates uranium for removal, but it does not eliminate radium or other decay products. As a result, the remaining soil is still radioactive after treatment.

"DISA only removes uranium, important concept," said Williams, who said the DISA technology is clever but "it's a mechanical method of concentrating uranium from the waste. I still don't consider it clean up. I consider it extraction."