In the five years since the U.S. Department of Energy (DOE) began to clean up the old Atlas Mill site, crews have hauled 7 million tons of waste away from the 130-acre pile. In June alone, they moved almost 77,000 tons of tailings from the edge of the Colorado River to a long-term disposal cell near Crescent Junction.
Grand County UMTRA Liaison Lee Shenton stands on the overlooks above the pile during his weekly visits to the site, and he’s impressed by the noticeable drop in elevation. Before the cleanup work began, the pile was more than 80 feet thick; it contained an estimated 16 million tons of uranium mill tailings and contaminated soil, according to a DOE overview of the project.
“You can already see down to the floor,” Shenton said. “It looks like they’ve moved a lot more than [44 percent].”
When he first began to visit the site, the northwestern end of the pile didn’t stand out so much; according to Shenton, it sat at roughly the same level as state Route 279.
But Shenton said he’s noticed a real difference in the last couple of years, as lead contractor Portage, Inc., and its team came up with more efficient ways to excavate and remove the mill tailings.
“They’re just learning new things that work better than they did three or four years ago,” he said.
However, Shenton expects that the overall pace of cleanup work will slow down as the project team shifts more of its attention to the southern end of the tailings pile.
While the northern section closest to Arches National Park’s main entrance was about 65 feet deep, Shenton estimates that the pile at the other end of the property is 50 percent deeper.
“It looks huge from the river,” he said.
The southern toe of the pile also stands out for the kinds of waste it contains.
When the Atlas Mill was decommissioned in the 1980s, the mill’s operators dismantled and demolished structures that stood on the property.
But instead of hauling that material off site, the company dumped chunks of concrete and rebar, mangled metal sheeting, steel cables, pipes and still-unidentified pieces of mill equipment in the area, according to reports from former Atlas employees.
“Folks who were there at the time said that some of the pieces were — if not buried whole — at least buried in large parts,” Shenton said.
The UMTRA Project team is now in the process of sorting through that debris, and it’s using the southwestern edge of the pile as a staging area for the material that crews unearth.
Shenton said that crews are working to break the rebar-laden concrete into manageable sizes. But any pressure they apply to the aging material can send bits and pieces flying in all directions, he said, so they have to be very cautious.
“It turns out not to be a simple thing to break up these chunks of concrete,” he said.
There’s also a concern that discarded sections of piping may contain residual traces of chemicals, or that pieces of equipment may be contaminated with higher levels of radioactivity, according to Shenton.
“Each one of these issues makes them stop and handle everything more carefully,” he said.
Despite those challenges, Portage Project Manager Jeff Biagini plans to begin shipping the debris to the Crescent Junction-area disposal cell at some point in the next federal fiscal year, which begins on Oct. 1.
“They still believe that they can get the mill debris — at least the majority of it — moved in the next two years,” Shenton said.
Rail shipments are still the preferred way to get the debris to the disposal site, and extra padding or cushions could help protect the sealed metal containers from rough or jagged material.
“They are working very hard to find a way to properly ship that debris using the existing containers,” Shenton said.
But the project team is also preparing for the possibility that some unwieldy pieces of debris may have to be shipped via truck, depending on the size and shape of the material, Shenton said.
Once they’ve shipped the mill debris to the disposal cell, Shenton said they’ll also have to be careful when they bury it. Any uneven “voids” in the disposal cell could create sags or slumps that lead to erosion, he said.
Ahead of that work, crews are adding protective layers and final cover materials to sections of the disposal cell that have already reached the maximum design height.
The long-term cover is nine feet deep and is made up of multiple layers, including a four-foot-thick barrier of Mancos shale.
“It defends not only against erosion, but against plants and animals and percolation (into the aquifer),” Shenton said.
To learn more about the project, go to: www.moabtailings.org/, or visit the DOE’s project website at: www.gjem.energy.gov/moab/.