Abstract
In the extraction and refining of minerals from the earth large quantities of tailings, waste and scales are produced which may contain elevated levels of naturally occurring radioactive materials. The regulation and remediation requirements for such materials vary greatly depending on the industry producing the materials. In some cases strict controls are required, and in other cases there are no regulations. At some time in the future one of two events is most likely to occur. The material and the site will be abandoned or the site will be remediated in some fashion. In the case of the NRC and DOE regulated/administered sites there are established remediation dose limits which must be met. Additionally, the US Environmental Protection Agency in some remediation situations has specified dose limits. The vast majority of the sites do not fall within a regulatory framework. On a volume basis and most likely on a total activity basis, those sites which fall outside the regulatory framework make up the majority of the naturally occurring radioactive material waste.
Depending on the waste stream considered, persons occupying an abandoned site could receive exposures ranging from less than 1 mSv/y to greater than 400 mSv/y. Depending on the remediation and the waste stream, remediation costs range from about $6,000,000 to greater than $2,300,000,000 US dollars. Remediation costs range from $120 to $230,000 per man-Sv reduction.
The exposure to naturally occurring radioactive material waste stream is not trivial, and in some cases waste exceeds the allowable limit for the general public. If means can be provided to prevent intrusion of the waste layer, consolidating and covering is a reasonable option. Removal to a disposal site is the only sure way to limit exposure to less than the general population limit. Due to the volume of material, the cost of any remediation option is substantial.
