ASSESSMENT OF DOSE RATE USING GAMMA RAY OBSERVATIONS IN THE MINING WASTE SAMPLES OF SIMBERI GOLD MINE IN PAPUA NEW GUINEA

Abstract

The specific activity of natural radionuclides were measured by gamma ray spectrometry with NaI(Tl) detector in the mining waste soil samples collected from Simberi gold mine in New Ireland province of Papua New Guinea. The isotope concentrations of 238U and 232Th in Simberi soil samples are 10.7 and 41.3 ppm respectively whereas the world average values are 2.64 and 11.1 ppm respectively. The average Radium equivalent activity in Simberi samples is 372.2±81.4 Bq/kg which is observed to be higher than the threshold safe value of 370 Bq/kg. The average internal hazard index for Simberi samples is found to be 1.4 which is higher than the maximum permissible value of 1.0. The Excess Lifetime Cancer Risk (ELCR) is calculated to be 0.00553±0.00122 in Simberi whereas the world average value is 0.00145. Radiation in Simberi is found to be higher which may be because Simberi is situated in the volcanic region of Papua New Guinea