Radon concentrations and exposure levels in the Trepça underground mine: A comparative study

•Indoor radon measurements were carried out by two complementary techniques: scintillation and the ion chamber technique.•For the analysis of the results of the measurements, the comparative method was applied.•The temporal and spatial dependence of radon distribution in Trepça mine was investigated.•The influence of activity mining in radon distribution of mines was discussed.

This study presents the results of radon concentration measurements and radiation exposure levels in the Trepça (pronounced Trepcha) underground mine, which are important to assess the radiogenic hazards to occupational workers. Radon concentration measurements were carried out in selected locations of the Trepça mine using continuous radon monitor CRM-510 and portable radon monitor PRM-145. Results show that the radon gas concentration in the mine varied from 54 Bq/m3 to 691 Bq/m3. The radiation exposure doses of miners from radon and radon daughters were determined. The total annual effective doses varied from 0.4 mSv/y to 5 mSv/y. The effective dose has been found to be lower than the dose limits recommended by the International Commission of Radiation Protection. The comparison of indoor measurements shows that the highest time-dependent indoor values of radon concentration in the two lowest horizons decreased during the time period 2010-2015 and that their average values increased by about 10%. This means that five-year mining activities generated pathways for radon gas flow, causing the decreasing of the maximum values and increasing the average values.