The dramatic potential for a meltdown and the dilemma posed by spent fuel tend to dominate discussions of nuclear power's drawbacks, making it easy to forget the front end of that equation: uranium mining.
The United States imports the bulk of its nuclear fuel, but there are large deposits of uranium, mostly in the western part of the country, that could be mined. A new report from the U.S. Geological Survey looks at one such parcel of land in the Grand Canyon watershed area. It suggests that previous mining activity in the region has not resulted in serious contamination of soil or groundwater, but environmental groups and others are still trying to halt what they fear could become a huge upsurge in uranium mining activity.
The study focused on an area covering about 1 million acres around the Grand Canyon — including land within a few miles of the Colorado River — where the Department of the Interior enacted a land segregation order in July 2009. That order started a two-year period during which the DOI will assess the impacts of extracting the resource and will eventually decide whether or not to "withdraw" the land from consideration for mining under the Mining Law of 1872; that withdrawal would last 20 years.
Roger Clark, the air and energy program director at the environmental group Grand Canyon Trust, said that commercial interest in uranium mining swung in the last decade when the price of the fuel shot from around $5 per pound to over $100 until settling recently to just below $50.
"With that upsurge in price of milled uranium, the demand has gone up, and the number of claims around the Grand Canyon has surged," he said. "More than 10,000 new claims were filed in the last five years."
Uranium mining in the geologic formations known as breccia pipes that abound in the area around the Grand Canyon did occur during the 1980s but diminished as the prices dropped. Now, in spite of the thousands of new claims, only one mine in the area is currently operating. Clark said Grand Canyon Trust has filed a lawsuit attempting to block it because of a lack of a thorough environmental impact assessment, but for the moment, the mining is ongoing.
Huge Uranium Deposits
The USGS report found that within the almost 1 million acres of segregated land there is an estimated 163,000 tons of uranium oxide, from which yellowcake or enriched uranium can be extracted. This represents about 12 percent of the total amount in the northern Arizona area.
It's difficult to estimate how much of the total uranium in the country that would be, "because for the last 30 years, there has been no federal assessment of minable uranium," said James Otton, one of the study's authors and the project chief with the USGS for the Uranium Resources and the Environment project.
The Energy Information Administration, part of the Department of Energy, estimated in 2003 that the total uranium oxide reserves that could be mined — outside of restricted areas — at a price of $50 per pound is 445,000 tons (or 890 million pounds), but Otton said they will most likely update that quantity in the near future. The Obama administration and members of Congress have started pushing for a nuclear power revival after years of little new nuclear activity.
The 104 nuclear reactors currently operating in the United States use between 25,000 and 27,500 tons of uranium oxide per year, Otton said. Previous federal protections have already cut off about 460,000 tons of uranium oxide from mining in the Grand Canyon region.
Even if the DOI does extend the moratorium out to 20 years on the 1 million acres up for discussion, some mining might still occur within that area. Claims that have already been filed and that are determined by the Bureau of Land Management and the Forest Service to have "valid and existing rights" to mine the uranium will be allowed to move forward.
Otton said he expects the one currently operating mine, the Arizona No. 1 mine run by Denison Mines, to receive such an exemption, but it is unclear how many of those 10,000 or more relatively recent claims would eventually result in mining.
"We don't know what percentage of the resource may eventually prove to be minable simply because of valid existing rights," Otton said.
The other portions of the USGS report looked at the impacts of uranium mining on soil and water. According to Andrea Alpine, another author of the USGS report and the director of the USGS's Southwest Biological Science Center, the study was "unable to discern any contamination coming from previous mining activity."
The investigators analyzed more than 1,000 water samples, some new and some from historical samplings of mining sites, and found that 95 percent of the water samples had uranium concentrations under the safe drinking water limit of 30 micrograms per liter set by the Environmental Protection Agency. There were 15 springs and five wells that had uranium concentrations well above that limit, but those sites were in direct contact or close contact to the ore itself.
Clark said that there is ample reason to think that mining could contaminate water sources, though.
"Opening up those vertical columns [of ore] known as breccia pipes allows the oxidation of the uranium mineral, which is highly soluble in water," he said. "That opens up the opportunity and the risk of contaminating groundwater, and the springs in the Grand Canyon are fed by that groundwater."
Clark added that there are historical examples, most notably on Navajo lands in the Southwest, where uranium leached into rivers and rendered them unfit for human use.
"Those are irreversible damages," Clark said. "Once you pollute groundwater with radioactive materials, there is no proven way that you can remediate that problem."
Otton and Alpine, however, said that the well-publicized water contamination issues occurred when mining practices differed, and that modern techniques for breccia pipe mining are safer. Ore is now carried off site to be milled, and the need for large tailings ponds with substantial uranium-contaminated waste is reduced, they said.
"You'll hear stories that uranium mining is going to contaminate the drinking water of 30 million people," Alpine said. "We can't definitively say that that is not a possibility, but most of our work and what most people who are familiar with this say is that that is a very remote possibility."
She added that there are still gaps in our knowledge of the water-related impacts, including the directions that even small amounts of contaminated groundwater flow in the deep underground aquifers that eventually supply drinking water in the region.
Clark noted other impacts of mining, including the fragmenting of wildlife habitats by new roads and electricity transmission lines that would need to be built for each new mine.
"It would mean industrializing the wild land around one of America's greatest national parks," Clark said. The USGS report noted that about 100 species of plant and animal in the region are of concern, and Alpine said more does need to be learned regarding the effects of uranium on species other than humans.
In Clark's view, the withdrawal of the land by the DOI is the most promising avenue by which uranium mining might be slowed in the Grand Canyon area, but there are other possibilities as well.
Congressman Raul Grijalva (D-Ariz.) introduced the Grand Canyon Watersheds Protection Act in 2009, intended to restrict mining in similar areas to that of the DOI investigation. The bill is currently in the House Natural Resources Committee.
There are also what Clark called "stop-gap measures" to hold mining companies off until a comprehensive moratorium is established. The lawsuit attempting to stop Denison's Arizona No. 1 mine is one such attempt.
"There are a large number of claims at stake in this administrative action," Clark said of the DOI's ongoing investigation. "We think protecting the Grand Canyon and its watersheds are priorities, so we feel confident that the Secretary of the Interior will make the right decision and go ahead and extend the two-year moratorium to 20 years. And ultimately we think that an act of Congress will further secure that."