Identification of the Requirement of Norm Regulations in Compliance with GSR Part 3 for Mineral Associated Industries in Sri Lanka

Even though Sri Lanka is a small oceanic country, it inherits a considerable geological diversity. About 90% of the land is made up from metamorphic rocks where mineral resources are abundant. Several industries have been established to exploit these resources. Namely, Pulmuddai Mineral Sand Extraction Facility (extracting Ilmenite, Rutile, Zircon, Garnet, Silica and Monazite as a residue), Eppawala Phosphate Mine and distributed Gem mining operations in Rathnapura and Elahera regions. This also suggests that, an occurrence of primordial radionuclide deposits and high concentration areas can be expected. A detailed radiation survey has been conducted in 2015 based on a request from the company (Lanka Mineral Sands Ltd.). The detailed survey conducted in Pulmoddai and some independent research work carried out in other mineral associated industries have raised the concerns regarding the safety of the workers in the scope of radiation exposure. Considerably high ambient gamma dose rates have been observed in certain areas of the Pulmuddai Mineral Sand Processing facility. Surface dose rates from 1 m above the ground; 1.78 ± 0.04 μSv/h in heavy mineral heap, 3.03 ± 0.01 μSv/h in highgrade crude Zircon heaps and 52.64 ± 0.05 μSv/h in crude Monazite go down region have been recorded. In the Monazite go down, 28 ± 1 kBq/kg concentration of Thorium (Th) – 228 and 3.2 ± 0.2 kBq/kg concentration of Radium (Ra) -226 were estimated by the in-situ gamma spectroscopy measurements. This suggests that the area shall be operated as a controlled area considering the occupational exposure threshold levels mentioned in the present radiation protection regulations in Sri Lanka (10 μSv/h for controlled areas) .Recommendations have been issued to rectify the gaps and establish the safety culture in compliance with the General Safety Requirements (GSR) Part 3 and General Safety Guidelines (GSG) No. 7 for NORM associated industrial facilities. Unlike the open-air facilities like Pulmuddai and Eppawala (A rock Phosphate deposit), the enclosed, underground environments of the Gem mining operations have a considerable health risk from the exposure to Radon (Rn - 222 ) and Thoron (Rn-220). (author)