Estimation of radiological exposure levels in a mining area based on U-238, Ra-226, Th-232 and K-40 activity measurements: A case study for Beylikova-Sivrihisar complex ore site in Turkey

The study estimated the radiological exposure levels in a mining area for miners in the Beylikova-Sivrihisar (Turkey) complex ore site containing U-238, Ra-226 and Th-232. Sixty samples were collected from the study area based on a geologic map. The radionuclide activities were measured using a 78.5% efficient n-type HPGe detector. The measured mean activities were 1871 +/- 38 Bq kg(-1) for U-238, 1749 +/- 5 Bq kg(-1) for Ra-226, 3467 +/- 9 Bq kg(-1) for Th-232 and 309 +/- 2 Bq kg(-1) for K-40. From the measured results, the external effective dose was calculated to be max. 3.80 +/- 0.03 mSv y(-1) (mean: 2.04 +/- 0.03 mSv y(-1)) for inside gallery and max. 7.59 +/- 0.05 mSv y(-1) (mean: 4.08 +/- 0.05 mSv y(-1)) for outdoor. Additionally, the external exposure index was calculated to be H-ex = 33.5 +/- 0.2(mean: 18.2 +/- 0.3) and internal exposure index to be H-in = 45.9 +/- 0.3 (mean: 22.9 +/- 0.4). The results indicate that additional radiation protection measures should be taken during the mining process if an opencast mining is implemented in Beylikova complex ore deposit