Survey of associated radioactivity in coal in Leshan, Sichuan

To understand the levels of NORMs in coal mining industry in Leshan City, Sichuan Province, onsite air absorbed dose rate γ measurement was made in Shawan District, Ebian County, Jiajiang County, Emeishan City, and Wutongqiao District for determining the specific activities of 238U, 232Th, 226Ra and 40K in coal samples by using of the HPGe γ spectrometer. The results showed that air absorbed γ dose rate on the surface of raw coal heap is 151 nGy/h, on average, and the specific activity of 238U, 232Th, 226Ra and 40K in raw coal is, respectively, 150 Bq/kg, 82 Bq/kg, 113 Bq/kg and 294 Bq/kg. The external γ maximum annual effective dose to workers near the coal pile in Leshan is 0.252 mSv/a; According to the Monitoring Scope and Objective of NORM Contamination Sources of 2007, the coal mining industry in Leshan City is among the second category of pollution source. (authors)