Turning Mines into Habitat

Defense-Related Uranium Mine program closes mines dangerous to humans, protects bat roosts

by Kristen Pope

Driving down a rough, unpaved road in the canyon country of the Four Corners region, Subterranean Team Manager Shawn Thomas thinks about the day ahead. After reaching the road’s terminus, his three-person team will hike a short distance to the entrance of an old uranium mine where they will conduct their day’s work. As part of Bat Conservation International’s (BCI’s) partnership with the U.S. Department of Energy’s (DOE’s) Defense-Related Uranium Mines (DRUM) program, Thomas’s team is working to assess thousands of abandoned mines across the country, safeguarding hazardous mines to protect humans and bats.

After gearing up and donning self-contained breathing apparatuses—the type firefighters use—to protect them from inhaling radioactive gas and particles, two team members venture into the mine. One person will stay above ground as the surface safety attendant, making sure the other team members come out at the agreed-upon time. With about 45 minutes worth of air available in their oxygen tanks, the two subterranean team members search for signs of bats; collect microclimate data, including temperature and humidity; and chart the mine’s underground workings.

Most of the mines are fairly small. “You find all these mines and openings that maybe only go underground for 20 or 50 or 100 feet,” Thomas says. “So, somebody who was prospecting—looking for ore, for uranium—and didn’t find it, they moved on and started the process over again.” However, the production mines, where large amounts of uranium ore were extracted, are extensive. Thomas estimates these sizable mines make up about a tenth of the mines they assess. Miners kept finding ore in them, so they kept digging. These larger mines contain more workings and hazards.

Though a smattering of mines exists in the eastern U.S.—and there’s even one in Alaska—most of the over 4,200 DRUM sites are located in the western contiguous U.S., concentrated in New Mexico, Colorado, Utah, and Wyoming. These sites were mined for uranium ore, which the U.S. Atomic Energy Commission used for defense-related purposes from 1947 to 1970. Now, most of the abandoned DRUM sites are hazardous to human health and safety. Wayward explorers could be seriously injured or killed by anything from collapsing tunnels to sharp drop-offs and other hazards, so the U.S. government wants to safeguard them before people get hurt.

BCI is partnering with the DOE to serve as a “one-stop shop” for the DRUM program to assess and safeguard these sites. With mines located on federal, state, tribal, and private lands, surveying all of the sites is a complex and time-intensive project. The majority of the mines are expected to require physical safeguarding, like locked gates at the entrance, with many requiring environmental remediation work to ensure hazardous byproducts are not polluting nearby waters and communities.

“DOE has some inherent responsibility for the condition of these old mines,” says Brent Lewis, DOE DRUM Program Technical Lead and Project Manager. “Any one mine or mine feature could be a hazard, so looking at each mine comprehensively, mapping each mine for its related mine features, even prospect pits; sampling for radioactive footprint and heavy metals is very important. We generate a report for each mine, so it’s very comprehensive.”

While hazardous to humans, these abandoned mines provide valuable bat habitat—especially for Townsend’s big-eared bats—so many of the safeguarding techniques involve adding features like bat gates, which prevent human intrusion but allow bats free access.

Thomas estimates around a quarter of the mines his team assesses show signs of bat use, but that doesn’t mean team members always see the animals themselves. In addition to looking for bats, they also search for guano; staining on the ceiling; insect parts, since bats typically only eat an insect’s body, dropping the wings, legs, and other parts on the ground; and scratches bats leave on rocks. The team records information about each mine’s microclimate, noting microhabitat features they use to evaluate the quality of the habitat.

“Bats have been hammered from so many different angles—natural cave habitat with human visitation, White-nose Syndrome, wind turbines—there are so many pressures on them,” says Director of Habitat Protection and Restoration Jason Corbett. He notes abandoned mines provide a form of artificial habitat that allows bats to persist on the landscape.

In the Field
BCI started its DRUM fieldwork in late 2020 in southern Colorado. A mine was collapsing, and land managers were worried a nearby county road could be affected.

BCI conducted a bat survey and LiDAR scan to analyze the mine’s features. The handheld LiDAR scanner shoots laser pulses that ricochet off the mine’s walls to create a three-dimensional map
of the mine’s interior. The team then overlaid the LiDAR data on aerial imagery to understand the mine’s footprint. Learning the road crossed right on top of collapsing mine features, the Bureau of Land Management realized rerouting the road was likely the best option.

The first phase of the DRUM project will involve approximately 2,500 mines located on public land, a legacy of the uranium boom in the mid-20th century. The next phase, focusing on tribal land, will begin in 2023, followed by private property in 2024.

BCI staff members from the restoration, subterranean, geospatial, and compliance teams are all involved with the DRUM project. The teams work to prepare National Environmental Policy Act (NEPA) documentation, ensure compliance with regulations, conduct bat and environmental surveys, take water and soil samples, supervise radiological surveys, oversee cultural surveys, map mines, and assess safety hazards. They also manage contractors who safeguard the mines with bat gates or “destructive closures” where the mines are backfilled with dirt or sealed with polyurethane foam. Along the way, they document every part of the process and prepare reports.

“We bring a level of nimbleness that will be super helpful to the DRUM program and various partners,” Corbett says. “The way I describe our relationship is we’re a ‘force multiplier’ coming into this equation.”

One of the most challenging elements of the project is the incredible amount of coordination involved when working with federal and state agencies, tribal authorities, and private landowners. “It’s incredibly complex, logistics-wise,” Corbett says.

In many places, the land is a checkerboard of different land types, requiring a lot of organization and planning in order to even access a site, especially for mines surrounded on all sides by private land. “One of the real challenging parts for us is untangling who to talk to get to these sites,” Thomas says. “Will it involve opening a locked gate and traveling across private land, which we have to get permission to do? Working out navigational logistics is more time-consuming and difficult than the actual survey once we get to the mine.”

Despite the logistical challenges, the project provides an incredible opportunity to restore habitat in order to protect bats. “Part of BCI’s broader innovative approach to conservation is expanding how we think about protecting species and landscapes, and we’re now moving into the phase where we’re restoring degraded landscapes, and that’s really exciting,” says NEPA and Endangered Species Act Compliance Specialist Aaron Sidder.

BCI’s current agreement with the DOE is for five years, though the project has the potential to last for at least a decade. It’s an opportunity to build partnerships and protect bats.

“This represents an incredibly exciting opportunity for BCI as an organization and certainly for my team,” Corbett says. “The number of partnerships and folks we’re going to be working with on this is going to really, really enhance our ability to affect bat conservation throughout the western U.S. It’s an incredible opportunity, and we’re really excited about it.”

Staying Safe from Radiation
In addition to safeguarding against physical hazards, like collapsing workings, BCI’s subterranean team must also take precautions to protect themselves from radiation. The team uses Geiger counters to detect gamma radiation emitted from decaying uranium ore left in the mines, though they rarely come across significant concentrations at DRUM sites. “The miners were really good at extracting that ore,” says Director of Habitat Protection and Restoration Jason Corbett. If they find gamma radiation, they can mitigate it by physically moving away from it, sometimes by just turning a corner in the mine or stepping away. Luckily, it is rarely necessary for them to evacuate the mine, though it is a precaution they are prepared to take.

A more significant radiation hazard is alpha radiation from radon gas and the “progeny” particles created as the gas decays. These particles are electrostatically charged and easily adhere to dust particles, which can become lodged in the lungs and lead to cancer. For this reason, team members use self-contained breathing apparatuses when entering the mines to make sure they stay safe and don’t breathe in any radioactive particles.