Yerington Mine Site
Fugitive Dust Radiological Dose Assessment
Foxfire Scientific, INC
September 19, 2004
Prepared by:
Ian Scott Hamilton, Ph.D., CHP - link to bio
Matthew G. Arno, Ph.D., CHP - link to bio
1. SUMMARY
This report conveys the results of a highly conservative radiological dose assessment for
exposures to fugitive (windblown) dusts by individuals on- or off-site. The purpose of this study
is to determine if individuals in the vicinity of the mine are being exposed to radiation in the
form of technologically enhanced naturally occurring radioactive material (TENORM1), and what
the calculated whole body doses would be. The total effective dose equivalent was determined
for several different hypothetical scenarios that are not meant to represent actual people, but that
bound what actual exposures might be. This report was prepared with assumptions that are so
conservative as to be bounding.
The doses calculated in this report from potential exposure to fugitive dusts from the evaporation
ponds and tailings study area are minuscule. The highest annual dose calculated was 0.0015
mrem. The State of Nevada does not regulate Naturally Occurring Radioactive Materials
(NORM) or Technologically Enhanced NORM (TENORM) and the material in the tailings area
and evaporation ponds are classified as TENORM. Therefore, there are no applicable exposure
limits for members of the public. However, the exposure limit for members of the public for
materials that are regulated is 100 mrem per year. The doses calculated in this report are more
than a factor of 66,000 lower than this limit. As a point of comparison, each person in Nevada
will receive up to 300 mrem a year to the whole body (internal and external doses combined)
from natural radiation sources. The doses calculated in this report are more than a factor of
200,000 lower than this amount of natural background radiation dose. Finally, it should be noted
that, in the context of these bounding dose estimates, the actual doses to a real person would be
much lower; additional data and effort would be required to estimate actual doses, but such effort
is unwarranted, given the small bounding doses estimated in this study.
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