Six miles south of Tusayan the 17-acre site of Canyon Uranium Mine has sat nearly unchanged for years. Development of the mine site began in 1986 but uranium price declines and legal battles have delayed the sinking of a shaft 1,500 feet below ground to access rich “pipes” of compact, high-grade uranium mineralization.

After U.S. District Court Judge David Campbell ruled earlier this month that the Forest Service’s 30-year-old environmental reviews of the mine are still valid and that new tribal consultations are not needed, the mine sent official notice that it will resume operations in late June.

But that action could be delayed further still with two impending appeals to the recent decision. The Havasupai Tribe filed a notice of appeal last week and the Grand Canyon Trust, another party in the lawsuit, plans to file an appeal as well and request an immediate injunction to halt the mine from moving forward, said Roger Clark, who heads the nonprofit’s Grand Canyon program.

However the legal battles shake out, it’s likely that Canyon Mine, owned by the uranium giant Energy Fuels Resources Inc., will someday begin pulling uranium ore from deep beneath the ground.

“We're not trying to stop the mine,” Clark said. “We just want the agencies to go back and update their information and hopefully add some measures to further prevent pollution of public resources.

And whether the mine moves forward this summer or a judge decides the Forest Service is required to redo its environmental analysis and tribal consultations, the fact remains that there are still significant gaps in scientific knowledge about the environmental impact of uranium mining, and those gaps will take years to fill, according to researchers who study the area.

Tracking plants and critters

The Canyon Mine lies within a nearly 1 million acre area that the Department of the Interior withdrew from new uranium mining claims in 2012. One of the reasons the department cited in its withdrawal decision was the lack of data about how plants and animals are affected by uranium mining in the region.

Jo Ellen Hinck, a Missouri-based biologist with the U.S. Geological Survey, is heading a project to begin gathering that information through studies near the Canyon Mine site. The team began by collecting dozens of the most common plants and animals in the vicinity of the mine in order to analyze the concentrations of certain contaminants, including uranium, in each species. That will give scientists an idea of natural contaminant levels before mining begins.

The team plans to go through the same process of collection and analysis when Canyon Mine is operating and after it has been reclaimed in order to see how or if contaminant concentrations change over the life of the mine.

The project also will examine how uranium and other contaminants could move through the local ecosystem, whether it be through animals drinking from the 2-acre detention pond on the mine site or plants accumulating contaminants that are blown from the mine area onto surrounding soil.

The final goal is to more fully understand the ecological risks at Canyon Mine and other sites. The scope of the study is long, though, and Hinck estimated that complete results might not be available for another 10 years.

The slippery study of water

The interaction between uranium mining and water sources is another area where research is still developing. For example, scientists have determined there are fracture pathways in the Grand Canyon region that can allow water to migrate from the surface to the Redwall-Muav Aquifer deep below, a fact environmental groups and other researchers say affirms concerns about uranium mining contaminating groundwater. But there isn’t information to support or deny that those fractures exist and are collecting water in the area around Canyon Mine, said Don Bills, a USGS hydrologist working on Grand Canyon region uranium studies.

There’s also uncertainty about the time it could take for dissolved uranium and other contaminants to potentially migrate from mines into groundwater. Impacts to springs could be delayed and not immediately apparent-- a "time bomb" effect, said David Kreamer, a hydrology professor at the University of Nevada, Las Vegas, who has studied springs near the canyon for the past 25 years. Kreamer said his research has found similarities in water quality between the monitoring well at Canyon Mine and the closest springs, indicating a possible hydrologic connection.

The USGS is immersed in several long-term projects to monitor levels of uranium and other contaminants in area springs, creeks and the Colorado River itself, Bills said. Researchers are doing spring inventories and springwater sampling around the Arizona 1 and Pinenut mines north of the Grand Canyon and are installing automated samplers at springs near various other active and reclaimed mines to measure how water chemistry might be changing over time, Bills said.

Other projects are measuring water chemistry at major drainages like Kanab Creek and Havasu Creek and on the Colorado River upstream and downstream of uranium mining.

So far, much of the data has shown that levels of trace elements, including uranium, haven’t varied very much, Bills said.

But there are exceptions. One is Kanab Creek where there were spikes in dissolved uranium and other trace elements after a major runoff event. Scientists determined that water was running by an old reclaimed mine site and likely eroded the reclaimed material and dumped it into the creek, Bills said.

Horn Creek is another. Scientists have documented elevated dissolved uranium levels that have been traced back to the Orphan Mine, a long-shuttered mine within Grand Canyon National Park that is now a superfund site. Some say mining tactics and regulations would never allow a mine like Orphan to exist today, but environmental groups point to Horn Creek as an example of what could happen to seeps and springs throughout the Grand Canyon area in the face of existing and future mining operations.


Even an initial USGS study of uranium’s hydrological and biological impacts published in 2010 has received mixed interpretations. Several environmental groups pointed to the report as definitive proof that mines were contaminating nearby water sources. The study found, for example, that “15 springs and 5 wells in the region contain concentrations of dissolved uranium that exceed the U.S. Environmental Protection Agency’s maximum contaminant level for drinking water and are related to mining processes.” But the report also found that 95 percent of the 1,000 samples taken were below the EPA drinking water standard for uranium. 

Energy Fuels spokesman Curtis Moore referred to other places in the report that stated data for several of the sites was few or limited and inconclusive. He also noted that in some places, uranium levels in water were above EPA drinking water standards before mining began.

Clark, of the Grand Canyon Trust, emphasized that the extent of information still unknown about uranium mining’s impacts on the Grand Canyon is why the organization continues to press for a more current environmental analysis of Canyon Mine.

“In the absence of information, when the consequences of contamination are permanent and irreversible, let’s err on the side of precaution,” he said.

Emery Cowan can be reached at (928) 556-2250 or