Assessment of exposure of miners to the alpha-rays of long-lived radionuclides associated with respirable ore dust in the Jaduguda U mine

The present work is intended to quantify the locational and operational int ernal exposures of workers due to the alpha-rays of long-lived radionuclide s associated with the airborne respirable particulate in the underground U mine at Jaduguda. The concentrations of the dust and the alpha-rays of the long-lived radionuclides in the mine air are log-normally distributed with respective geometric means (chi(g)) of 0.49 mg m(-3) and 21.25 mBq m(-3) an d geometric standard deviations (sigma(g)) of 1.7 and 1.88, respectively. T here exists a moderately positive linear correlation (correlation coefficie nt = 0.43) between the dust and the activity concentrations. The alpha-acti vity of the long-lived radionuclides in respirable dust, measured radiometr ically, assumes a chi(g) of 41.73 Bq g(-1) with a sigma(g) of 1.98 which is in close correspondence with the analytically evaluated value for the U mi ll tailings sand of identical particle size range. The internal radiation e xposure was estimated to be only about 5% of the annual effective dose limi t. (C) 2000 Elsevier Science Ltd. All rights reserved.