Gamma spectrometric analysis of ore samples from Sandur of Bellary, Karnataka, India

In the present paper the gamma spectrometric technique has been used to study the natural radioactivity levels present in the iron ore samples collected from the Sandur of Karnataka, India. This region, a member of Dharwar craton, known as Sandur schist belt is rich in Manganese and Hematite ore (Fe). The entire belt is characterized by numerous bands of banded magnetite and hematite quartzite. The ore samples were collected and prepared as per the ASTM standard procedures. The gamma spectrometric measurements were performed using a HPGe detector (Eurosys) based high-resolution 8k multi channel analyzer. The detector has a relative efficiency of 50% and resolution of 2.0 keV for 1.332 MeV gamma energy of Co-60. The output of the detector was analyzed using a PC based 8k channel analyzer system. The mean activity concentrations of the U-238, Th-232 and K-40 in the ore samples were found to be 14.59, 16.54 and 25.29 Bq/kg, respectively. The mean absorbed dose rate and the annual dose equivalent were estimated to be 18.97 nGy h(-1) and 24.93 mu Sv y(-1), respectively, which is lower than the world recommended average of 1 mSv y(-1). The present work concludes that the natural radioactivity levels in ore samples of this region is within the natural limits and pose no health hazard to the public.