Arafura Resouces Ltd Nolans Environmental Impact Statement volume three P Radiation Report Appendix P Arafura Resources Limited Nolans Project RADIATION REPORT Occupational and Environmental Radiation Measurements and Predictions Prepared for Arafura Resources Limited Nolans Project by Mark Sonter – Radiation Advice & Solutions Pty Ltd Jim Hondros – JRHC Enterprises Pty Ltd March 2016 Page 1 Arafura Resources Limited Nolans Project 1 Executive Summary ................................................................................................................ 4 2 Aim of Report ............................................................................................................................ 5 3 Introduction to Radiation .................................................................................................... 5 4 National & international regime for radiation control .............................................. 6 4.1 Overview ..................................................................................................................................... 6 4.2 ICRP System of Dose Limitation, ALARA, and Regulatory Limits ................................................ 7 4.3 Dose Limitation ........................................................................................................................... 7 5 Natural Background Radiation........................................................................................... 8 5.1 Radiation types and origins ......................................................................................................... 9 5.2 Uranium and Thorium decay chains ........................................................................................... 9 5.3 Radiation Dose Delivery Pathways ........................................................................................... 10 6 Historical and Baseline Studies ........................................................................................ 11 6.1 Overview of Studies .................................................................................................................. 11 6.2 ANSTO Studies .......................................................................................................................... 12 6.2.1 Gamma Monitoring .......................................................................................................... 12 6.2.2 Soil sampling ..................................................................................................................... 13 6.2.3 Vegetation Samples .......................................................................................................... 13 6.2.4 Groundwater Samples ....................................................................................................... 14 6.3 Arafura Studies .......................................................................................................................... 14 6.3.1 Overview ........................................................................................................................... 14 6.3.2 Soil Sampling ..................................................................................................................... 16 6.3.3 Gamma Surveys ................................................................................................................ 16 6.3.4 Dust Deposition ................................................................................................................. 20 6.3.5 Dust Concentrations in Air ................................................................................................ 21 6.3.6 Background Radon and Thoron in Ambient Atmosphere ................................................. 21 6.3.7 Radon and Thoron Decay Product Concentrations ........................................................... 23 6.3.8 Radon and Thoron emanation from ores .......................................................................... 24 6.4 Summary ................................................................................................................................... 25 7 Radiation Overview of Proposed Project ...................................................................... 25 7.1 Radionuclide Analyses .............................................................................................................. 26 7.2 Gamma Radiation Sources Quantification ................................................................................ 28 7.3 Predictions of Source Terms for Radon and Thoron ................................................................. 28 7.3.1 Radon from pit and pit dewatering ................................................................................... 28 7.3.2 Radon and Thoron from Beneficiation Tailings ................................................................. 28 7.3.3 Radon and Thoron from Processing Plant ......................................................................... 29 7.3.4 Radon source terms total .................................................................................................. 29 7.3.5 Airborne Dusts containing long‐lived alpha emitters........................................................ 29 8 Predicted Workplace Radiation Doses .......................................................................... 30 8.1 Gamma doserate and dose predictions .................................................................................... 30 8.2 Predictions of concentrations of radon & thoron & their decay products ............................... 31 8.3 Predictions of airborne Long Lived alpha‐emitters (LLα) in dust .............................................. 33 8.4 Environmental radiation sources .............................................................................................. 33 Page 2 Arafura Resources Limited Nolans Project 8.5 Resultant predicted doses ........................................................................................................ 33 8.5.1 Processing plant workers doses elsewhere ....................................................................... 34 8.6 Conclusions ............................................................................................................................... 35 9 Controls and Mitigation ...................................................................................................... 35 9.1 Radiation Control in Design and Operation .............................................................................. 35 10 Environmental Radiation Impact Assessment ........................................................ 36 10.1 Dust ........................................................................................................................................... 36 10.2 Radon ........................................................................................................................................ 37 11 Member of Public Dose Calculations, and NHB Assessment .............................. 37 11.1 Methods of Impact Assessment ................................................................................................ 38 11.2 Dust Concentrations and Deposition ........................................................................................ 38 11.3 Radon and Thoron .................................................................................................................... 39 11.4 Public Doses .............................................................................................................................. 39 11.5 Total Dose Estimates ................................................................................................................. 41 11.6 Flora and Fauna Impact ............................................................................................................ 41 12 Monitoring Plan and Responses .................................................................................. 43 12.1 Occupational and Environmental Radiation Monitoring .......................................................... 43 12.2 Action levels .............................................................................................................................. 44 12.3 Environmental Radiation Monitoring ....................................................................................... 44 12.4 Incident, Accident and Emergency Response ........................................................................... 45 13 Draft Radiation Management Plan .............................................................................. 45 14 References ........................................................................................................................... 47 15 Glossary ................................................................................................................................ 50 Page 3 Arafura Resources Limited Nolans Project 1 Executive Summary The Nolans Rare Earths Project (the project) is located approximately 10 km west of Aileron Roadhouse and 135 km north of Alice Springs in the Northern Territory. It comprises an open pit mine at Nolans Bore, an associated concentrator and processing plant, with ancillary facilities including a tailings storage facility (TSF) for the beneficiation tailings, and residue storage facilities (RSFs) for waste from the processing plant. There will also be a water‐supply borefield, gas‐fired power plant and accommodation village. The