A NEW BACKGROUND SUBTRACTION METHOD FOR ASSESSING PUBLIC RADIATION EXPOSURE DUE TO RADON TRANSPORT FROM A URANIUM MINE.

Environmental radon progeny concentration data for the Ranger mine in the Australian wet-dry tropics were analysed. Concentrations in air at public receptor locations correlated with wind direction and were generally higher when the wind had a southerly component. The regional setting suggested that correlations were due to geography rather than the mine. The line of best fit to the radon progeny data when plotted against angle of wind direction was used to estimate background concentrations when the wind was from the direction of the mine. This differed from the standard approach of averaging concentrations when the wind was not from the direction of the mine. Background concentrations in mine-related wind directions using the line of best fit approach were generally higher than those predicted from averaging, as mine-related wind directions included a southerly component. Estimates of mine-related doses to the public were generally lower as a result.