State environmental officials have issued final dust control permits for three uranium mines in the Grand Canyon watershed that, although more stringent than in the past, are still not stringent enough, say conservation groups.
The air quality permits issued to the owners of the Canyon mine near Tusayan and two mines north of the Grand Canyon allow for up to 26 million pounds of mined ore to be stockpiled out in the open to a height of 20 feet without a covering. The radioactive ore is to be watered to control dust, and the water must be discharged into a basin with an impervious bottom so that it does not reach the aquifer.
The permits also include requirements for annual soil and quarterly gamma radiation sampling, the installation of anemometers to measure the wind speed at the mines and a halt to truck loading activities if wind speed gets above 25 mph.
If dust or radiation levels reach a certain trigger, the ore stockpile must be reduced by half, covered with a tarp and protected by wind barriers. If problems persist, the stockpile must be reduced to 25 percent, according to the permits.
Conservationists had sought a denial of the air quality permits, stating there was no safe level of uranium mining in the watershed that would protect the Colorado River and nearby seeps and springs, and that full remediation in the event of contamination was unlikely and costly.
In comments on the draft rules, they had sought a tarp covering for the stockpiles at all times and a shutdown of the mines when dust triggers were reached until any soil contamination was remediated.
The Arizona Department of Environmental Quality halted the re-permitting process for the mines late last year following reports that uranium concentrations in soil near one of the mines measured more than four times background levels twice in a row.
The concentrations were recorded near Pinenut Mine located about 10 miles north of the Grand Canyon and ranged from 5.33 to 8.52 parts per million, which is two to three times the levels of uranium naturally found in the region’s soils. Those levels, however, are minuscule compared to uranium concentrations found in uranium ore, according to scientists with the U.S. Geological Survey.
Conservationists also had sought more frequent inspections and monitoring, all done by outside parties, not mine employees, as the new permits allow.
“Requiring more frequent samples when the dust pollutes the land outside the fence is not enough,” said Sandy Bahr of the Sierra Club’s Grand Canyon Chapter. “How will they prevent it? How will they make sure these companies clean up any mess?”
The groups also requested that ADEQ initiate monitoring of fine particulate matter and transportation-related uranium dust, noting the 24 trucks per day estimated to be coming and going from Canyon Mine when it begins operations.
In its written response, ADEQ denied the request, contending the dust, unlike smoke, did not contain fine particulates, which can lodge in the lungs. But it did require that tarps on trucks overlap the sides by six inches and be tied down.
“We have seen far too much contamination and far too many costs to the public from past uranium mining,” said Bahr. “This argument that these are new and improved uranium mines does not hold water.”