270 likes | 281 Views
This presentation provides information on radiation safety and managing the risks of naturally occurring radioactive material (NORM) in mining operations. It includes the science of radiation protection, NORM radionuclides, types of ionizing radiation, and comparisons of mining radiation levels with other NORM exposures. Learn how to protect workers and the environment from the harmful effects of radiation.
E N D
Please read this before using presentation • This presentation is based on content presented at the Mines Safety Roadshow held in October 2009 • It is made available for non-commercial use (e.g. toolbox meetings) subject to the condition that the PowerPoint is not altered without permission from Resources Safety • Supporting resources, such as brochures and posters, are available from Resources Safety • For resources, information or clarification, please contact: RSDComms@dmp.wa.gov.au or visit www.dmp.wa.gov.au/ResourcesSafety
Toolbox presentation Radiation safety Naturally occurring radioactive material (NORM) and managing the risks
Radiation protection – what is it? Science of protecting people and the environment from the harmful effects of ionizing radiation, which includes both particle radiation and high energy electromagnetic radiation
Radiation protection in mining is more commonplace than you may think 40 years of mining, processing and transporting radioactive minerals AMC Bemax BHP Cable Sands Doral Hanwa Iluka Isk Minerals Jennings Lynas Rio Tinto RGC Rhone Poulenc Sons of Gwalia Talison Minerals Tiwest Western Mining Western Titanium Westralian Sands Beenup Bunbury Capel Chandala Cooljarloo Eneabba Fremantle Geraldton Gingin Greenbushes Kalgoorlie Kintyre Kwinana Mt Weld Mt Walton Narngulu Picton Pinjarra Yeelirrie
NORM – what is it? Naturally-occurring radioactive material (NORM) — term describing materials containing radionuclides that exist in the natural environment Parent radionuclides have decay times (half-lives) comparable with or longer than the age of the Earth, so they have always been present in the Earth’s crust and within the tissues of all living species
NORM – radionuclides The radionuclides of interest include long-lived radionuclides such as uranium-238 (238U) uranium-235 (235U) thorium-232 (232Th) and their radioactive decay products such as isotopes of radium radon polonium bismuth lead and individual long-lived radionuclides such as potassium-40 (40K) rubidium-87 (87Rb) indium-115 (115In)
Radiation – what is it? Radiation— energy travelling through space. Sunlight, radio waves and microwaves are forms of radiation at low-frequency end of energy spectrum Type of radiation created by uranium is ionizing radiation Background radiation — everyone exposed to naturally occurring ionizing radiation from space, radioactive atoms in the air, the Earth and even our own bodies Most atoms stable and will never change, but certain atoms are always changing or decaying in a process by which they eventually become stable as completely different elements (e.g. uranium will naturally turn into lead after billions of years) As an unstable atom decays, its atomic structure changes, releasing radiation as gamma rays and alpha and beta particles
Types of ionizing radiation Alpha (α) radiation consists of a fast moving Helium-4 (4He) nuclei and is stopped by a sheet of paper. Beta (β) radiation, consisting of electrons, is halted by an aluminium plate. Gamma (γ) radiation, consisting of energetic photons, is eventually absorbed as it penetrates a dense material. Neutron (n) radiation consists of free neutrons, which are blocked using light elements, like hydrogen, which slow or capture them.
Mining radiation levels compared with other NORM exposures Comparative values using 1 as typical gamma radiation level/hour in WA 1 natural background in Western Australia 3 typical for exploration site with 0.05-0.06 wt % U mineralisation (Lake Maitland) 4 natural background in some areas of Perth Hills some cement 5 typical for exploration site with 0.10 wt % U mineralisation (Lake Way) certain phosphate fertilisers 6 some ceramic tiles 7 typical for exploration site with 0.14-0.15 wt % U mineralisation (Mulga Rock) coal burning slag 10 on board a local WA flight 14 phosphate mine 16 titanium minerals
Mining radiation levels compared with other NORM exposures (continued) 20typical for exploration site with 0.40 wt % U mineralisation(Kintyre) 22 zirconium minerals 25 geothermal energy generation waste 40 heavy mineral sands concentrate 60 on board an international flight 80 tin concentrate 120uranium mine or processing plant 250 rare earth mineral processing plant 400 coal mine (underground water discharge points on the surface) 500 some areas of titanium dioxide pigment plant 1000 contaminated equipment from oil and gas industry 2500 rare earth mineral (monazite) 10
Mining radiation exposure levels in perspective Typical radiation dose a worker could receive at a uranium mine (5 mSv/year) **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** **************************************** ********** ********** ********** ********** ********** ***** Maximum radiation exposure limit in one year (50 mSv) Amount of radiation (1000 mSv) that may cause you serious harm
What is special about ionizing radiation? • Everyone exposed to radiation, often without knowing it • Human senses cannot detect it • Historical association with nuclear activities • Impossible to determine if there is exposure level below which there is no effect ARPANSA
Uranium 238decay Main difference between exploration phase and mining phase is the chemical processing used in mining to extract uranium Processing frees up decay products that remain in waste and can cause health or environmental issues if not managed correctly
What are the relative risks of radiation exposure? Relative risk of 1-in-a-million chances of dying from activities common to our society Smoking 1.4 cigarettes (lung cancer) Eating 40 tablespoons of peanut butter Spending 2 days in Sydney CBD (air pollution) Driving 65 kilometres in a car (accident) Flying 4000 kilometres in a jet (accident) Canoeing for 6 minutes Receiving 0.1 mSv of radiation (cancer)
Radiation Worker's Handbook More information on radiation protection available in Radiation Workers’ Handbook Download from Australian Uranium Association http://aua.org.au/
Regulation of U mining in WA based on national and international standards
MSIR Part 16 – Radiation safety • Exemptions • Dose limits • Monitoring requirements • Radiation management plan • Radiation Safety Officer • Defects • Notifications • Supervised and controlled areas • Young and pregnant persons • Designated employees • Dose reduction • Exposure control
MSIR Part 16 – Radiation safety (continued) • Respiratory protection • Reporting • Record keeping • Approvals • Import and removal of radioactive material • Storage • Stockpile control • Waste disposal • Using best technology • Discharges • Abandonment 18
Radiation management plan (RMP) 16.7. Preparation of radiation management plan (1) Each responsible person at a mine must ensure that a plan for the safe management of radiation at the mine that complies with subregulation (2) is prepared — (a) in the case of an existing mine, as soon as is practicable after the commencement day; or (b) in any other case, before mining operations commence at the mine.
RMP - minimum requirements • Reporting to regulators • Environmental considerations and site radiological clean up • Training • Transport of radioactive material • Pre- and post-activity background monitoring (including ground water sampling where practical) RMP complexity Processing > Mining >> Exploration • Company and site details • Employee workgroup details • Type of activity (drilling, mining, processing) • Work and hygiene practices • Radiation monitoring equipment • Activity and personnel monitoring • Storage of radioactive material • Disposal of radioactive material • Decontamination of equipment • Recording of monitoring data
General principles of dose control Personal TLD badge
General principles of dose control Personal air sampler 24
General principles of dose control Workplace air sampler 25
Use hierarchy of controls What PPE is likely to be used? Overalls, safety glasses, P2 dust mask, safety boots, gloves Importance of good hygiene Personal and clothing Safe work practices 27