New soil tests show significantly high levels of radioactivity at an abandoned northern Nevada mine, renewing health and safety concerns and prompting federal land managers to restrict access to the 3,600-acre site, U.S. regulators told The Associated Press.
State and federal experts said there is no imminent danger to residents of the rural community of nearby Yerington. But for the first time, soil samples show high levels of uranium and radium are present at the old Anaconda copper mine. The levels are far above what occurs naturally and are likely the result of decades of chemical processing of heavy metals.
The new concerns are based on results from nine of 100 soil samples taken in June at the open pit copper mine where groundwater tests earlier found concentrations of uranium in wells at up to 200 times the U.S. drinking water standard.
One of the new soil samples shows alpha radiation levels nearly 200 times more than natural "background" levels and four other samples are in the range of 25 to 90 times normal, Bureau of Land Management officials said.
"Nobody is used to having this sort of radiation levels at an old abandoned copper mine," BLM project manager Earl Dixon told AP.
Leaders of the watchdog group Great Basin Mine Watch said the samples are further proof the mine 55 miles southeast of Reno poses significant health and safety dangers and should be declared a Superfund site - something Gov. Kenny Guinn has opposed.
"This is really serious," said Elyssa Rosen, the group's executive director.
The tests show radiation is present in dust, some of which blew off the waste heaps into Yerington until steps were taken to control it in recent years, Rosen said.
"This is the same stuff that was plowed into farmers fields years ago. So we now know some of the stuff is in the food chain," she said.
Steve M. Dean, the Environmental Protection Agency's regional Superfund radiation expert, said the test results are higher than expected but are "way down from what would be associated with extremely dangerous radiation levels."
"Nothing we've found says there is any imminent risk, but this site is certainly no place to be playing," Dean said.
Officials at the EPA's regional office in San Francisco said Wednesday that they will press for round-the-clock security at the site until more tests are done and new safety standards adopted for cleanup workers.
"What the samples told us was that we need to immediately restrict access," BLM spokeswoman Jo Simpson said.
EPA also wants air quality tests to make sure radioactive dust isn't making its way into nearby neighborhoods and reservations.
The agency also advocates interviewing residents about reports that some potentially contaminated soil was used for area construction as fill for road beds and housing foundations, said Jim Sickles, EPA's remedial project manager for the site.
"We want to make sure no one is getting into these areas. We want to keep the dirt bikers from running around there stirring up the dust. As long as dust is staying where it is and nobody is sitting on it, we're OK."
The lab tests were ordered after a BLM surveyor questioned the high radiation readings on his hand Geiger counter, Dixon said.
"He just didn't believe his meter was reading this high so he took soil samples as well," he said.
The highest readings were in the processing areas and in the drain areas where trucks were washed, Simpson said.
The new tests measured for levels of radiation in uranium, thorium and radium radionucleides. More results are expected next week, she said.
The mine site is owned by Atlantic Richfield Co. The Anaconda Copper Co. mined the site for copper from 1953-78 and used the 200-acre processing area to extract copper concentrate from ore rock using sulfuric acid leaching. ARCO officials did not immediately return a telephone call seeking comment.
Jim Najima, chief of the Nevada Division of Environmental Protection's Bureau of Corrective Actions, said BLM, EPA and state officials plan to meet Monday to develop information to be distributed to area residents "so people are not alarmed but also are informed."
Since receiving the test results, Najima said the state has marked the processing area, which has always been off limits to the public.
"Not many people go where all the `stuff' used to be so we are not overly concerned about that," he said.