PUBLIC EXPOSURE TO EXTERNAL GAMMA RADIATION ON A MINE LANDFORM COVERED BY LOW URANIUM GRADE WASTE ROCK

Abstract

Abstract Public exposure to external gamma radiation on the waste-rock-covered-8.5-km2-planned final landform from rehabilitation of the Ranger uranium mine was assessed. The average above-background dose rate from external gamma radiation on the planned final landform was determined to be 6.0 × 10−3 mSv d−1. This dose rate was one order of magnitude higher than that for inhalation of radon progeny and two orders of magnitude higher than that for inhalation of radionuclides in dust on the final landform. The above-background annual effective dose to the public from external gamma radiation when the envisioned land use by Aboriginal traditional owners was averaged over the entire 79 km2 Ranger Project Area was about 4.1 × 10−2 mSv. The results of this study may provide general guidance to sites elsewhere on the relative importance of the external gamma pathway and assist in the development or assessment of rehabilitation plans for uranium mining sites.