Cleanup of windblown tailings contamination at the Grants uranium mill.

Windblown material from the ore storage pads and tailings piles had, over 38 years of exposure, contaminated 500 ha of land around the site in New Mexico. The cleanup approach coupled gamma radiation detectors to global positioning systems to obtain high density gamma- count- rate data. This was correlated with Ra-226 in soil and a gamma-count-rate action level established, at the 95% confidence level, that corresponded to the Ra-226 concentration limit. A verification plan was approved by the US Nuclear Regulatory Commission that incorporated the use of high density gamma-ray data as a primary verification method with limited soil sampling as confirmation. About 1 500 000 m3 of contaminated soil was removed and consolidated with mill tailings. Significant cost savings were possible using this method, compared with conventional radiological survey methods.
Windblown material from the ore storage pads and tailings piles had, over 38 years of exposure, contaminated 500 ha of land around the site in New Mexico. The cleanup approach coupled gamma radiation detectors to global positioning systems to obtain high density gamma- count- rate data. This was correlated with Ra-226 in soil and a gamma-count-rate action level established, at the 95% confidence level, that corresponded to the Ra-226 concentration limit. A verification plan was approved by the US Nuclear Regulatory Commission that incorporated the use of high density gamma-ray data as a primary verification method with limited soil sampling as confirmation. About 1 500 000 m3 of contaminated soil was removed and consolidated with mill tailings. Significant cost savings were possible using this method, compared with conventional radiological survey methods.