The ore mined at Olympic Dam contains radioactive substances. This means that care must be taken during all stages of the mining, processing and waste disposal parts of the Olympic Dam process to ensure that radiation is kept at safe levels.
An element is radioactive when the nuclei of its atoms naturally undergo spontaneous changes, and in doing so emit radiation. There are two basic types of radiation, one emitting rays called gamma rays, the other emitting particles called alpha or beta particles.
Described below are the potential effects of radiation on the air and on mine workers at Olympic Dam (IMPACTS) and the ways they are reduced (ACTIONS).
| Impact | Action |
|---|---|
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Gamma radiation can penetrate directly through most materials. It can penetrate the human body and cause damage to living tissues by changing genetic material in cells. Alpha or beta particle radiation is usually absorbed by the skin and does not penetrate the body. |
Gamma radiation cannot be prevented. However exposure of mine personnel can be minimised and is carefully monitored. At Olympic Dam, any mine employee who operates in a gamma-radiation producing area must wear a special badge called a "thermo-luminescent dosimeter" (TLD) badge, which measures their exposure over time. These badges are checked every month. These employees have strict limits on the amount of time they can spend in gamma radiation producing areas. Exposure of employees at Olympic Dam has always been very much lower than the internationally recommended safe limit. |
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If radioactive materials come into contact with food or drinking water they can be directly eaten or drunk (ingested). This means that both types of radiation (gamma rays and particles) can cause damage to cells inside the body. As well as causing radiation damage, most radioactive materials are also toxic. |
Mine employees wash their hands before eating, and shower at the end of each shift to rinse off any radioactive material. Monitors are provided in crib rooms (where mine workers eat) to enable workers to check their hands are clean of radioactive material before eating. Surfaces in crib rooms are regularly cleaned and checked. Employees' clothes are washed at the mine site, and all mine vehicles leaving radioactive areas are washed beforehand, to prevent transport of radioactive materials away from the mine. |
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When uranium ore is mined, radioactive radon gas (Rn) can be released to the atmosphere. If it is breathed in, it can damage the lungs and other parts of the body. |
In an open pit mine radon would be quickly dispersed into the atmosphere and would not be a problem. However, in an underground mine, or beneath ore stockpiles, radon levels can build up. Good ventilation (for example, extraction fans) is used to keep radon levels as low as possible. At Olympic Dam particularly, ventilation is so efficient that on average, the air is completely cycled through the mine every 17 minutes. This means that the mass of air that moves through the mine each day is greater than the mass of ore extracted daily from the mine! |
This Radiation Safety Technician is checking surfaces in a crib room to make sure they're clean of radioactive dust.
