Resources Safety and Health Queensland (RSHQ) urges persons with safety and health obligations to ensure that exposures to heat are being effectively managed to an acceptable level of risk at their coal mine sites.
Coal mine thermal conditions can change daily and the mines safety health management system (SHMS) must incorporate processes to recognise and effectively manage heat exposure and to protect coal mine workers from heat-related illness.
When identifying hazards associated with heat and the onset of heat-related illnesses, a risk assessment will assist in determining the severity of the heat exposure, action required, whether the existing control measures are adequate and what action should be taken to control the risk to an acceptable level.
Some of the risk factors are air temperature and humidity, amount of air movement, the radiant temperature of surroundings, clothing breathability, physical manual work, acclimatisation status of workers, the hydration level of workers, and the fitness level of workers.
The use of effective temperature is prescribed for use in the heat stress assessment process applied in underground coal mines due to the unique conditions in that environment.
There are several other heat stress indices available that can be considered for use in open cut surface mines, including Wet Bulb Globe Temperature, Predicted Heat Strain and Thermal Work Limit.
The selection of which heat stress indices to use should be determined based on the specific factors relating to the site and conditions.
When selecting controls for implementation, the approaches include modifying the environment to suit the work, modifying the work to suit the environment or a combination of both.
When the body’s core temperature exceeds 37°C, it reacts by increasing the blood flow to the skin, producing sweat that cools the body when it evaporates.
Most people feel comfortable when the air temperature is between 20°C and 27°C and when the relative humidity ranges from 35 to 60 per cent.
When exposure to heat exceeds the body’s capacity to maintain hydration and thermal balance, heat-related illness can occur.
Coal mine workers and first aid officers should be trained to recognise the signs and symptoms of heat-related illnesses and to take preventative actions to prevent illness or injury.
The proper management of heat-related illness will require coal mines to use risk analysis techniques to identify the hazards, assess the risk, determine effective controls, and continually review control effectiveness.