The natural environmental radiation levels were assessed within a mine tunnel in Ijero-Ekiti, Ijero Local Government Area of Ekiti State. The assessment of the radiation level within the mine tunnel was carried out so as to know whether the radiation dose rates could lead to any radiological health implications to the workers on site as well as the general public by comparing the evaluated dose rates with the national standard exposure dose rate limit. Thermoluminescence dosimeters and radiation survey meter were used in assessing the radiation levels. Our results showed that the average evaluated dose rate; 8.433 mSv/yr and 7.924 mSv/yr for depth dose and shallow dose respectively within the tunnel was higher than the public exposure dose rate limit but fell below the international standard of occupational exposure limit of 20 mSv/yr. This was attributed to the level of radioactivity in the tunnel as a result of the high level of mining activities in the site and this may pose health risk to the workers on site if they are exposed to more doses of natural ionizing radiation more than the evaluated doses which was recorded at the tunnel when averaged over five years. It is therefore very important that workers should be encouraged to use radiation protective wears as well as radiation monitoring devices.

Keywords : Ionizing Radiation; Exposure Limit; Radiation Dose; Thermoluminescence Dosimeters; Radiation Survey Meter; Radionuclide;