Assessment of radioactivity associated with a low ore grade open cast mine at Banduhurang, Jharkhand, India and estimation of occupational exposure to the miners

摘要

The study summarizes radiological characteristics of Banduhurang open cast mine which includes qualitative and quantitative behavior of ~(222)Rn concentration, external gamma radiation level over the mine pit as well as in its adjoining environment, long-lived alpha (LLα) activity concentration associated with the respirable size of ore dust and assessment of dose to the mine workers in 2006-2008. The investigations reveal that geometric means (x_g) of measured radon concentration were 36.39, 38.69, 26.64 and 24 Bq m~(-3)with respective geometric standard deviations (δ_g) were 1.52, 1.55, 1.36 and 1.68 Bq m~(-3) and x_g of gamma absorbed dose rates were 0.54, 0.64, 0. 45 and 0.15 μGy h-with respective δ_g were 1.63, 1.53, 1.52 and 1.72 μGy h-1 over the mine pit, ore yard, waste yard and in the surrounding environment within a 10 km radius to the mine, respectively. The x_g of LLα activity was observed to be 16 mBq m~(-3) with δ_g of 1.9 mBq m~(-3). The annual mean effective dose equivalent received by the member radiation workers of Banduhurang mine was estimated to 1.41 mSv y~(-1), which is about 7% of the prescribed dose limits of 20 mSv y~(-1).