When part of a mine collapsed in Ballarat this week, 28 workers made it to the safety of an underground pod. But what are these safety chambers?
A specialist rescue team brought 28 people safely to the surface following a rockfall at a Ballarat gold mine on Wednesday afternoon, though there was one fatality and another person remains in critical condition.
Thirty 30 workers were 500m underground at the time of the collapse, with two men becoming trapped beneath the rubble. Tragically, a 37-year-old miner lost his life in the incident, while the other remains hospitalised.
The remaining 28 workers were able to reach an underground safety chamber – a type of portable emergency shelter – where they awaited rescuers.
Safety pods are common in underground mines in Australia, with their critical function being to shelter workers in an emergency, providing oxygen and other essential supplies.
“A refuge chamber can provide a safe haven while waiting for the fresh air supply to be reinstated or a rescue to be mounted,” the Western Australia Department of Mines and Petroleum said.
Refuge chambers are typically equipped to provide clean air, water, humidity control, power, a communications link to a control centre, gas-monitoring equipment to measure air quality within chamber, first-aid equipment, a toilet, and food.
These chambers are either externally supported (wired to infrastructure on the surface) or self-sufficient. In the latter case, these chambers can support themselves for up to 36 hours – well within the timeframe typical for an underground mine rescue.
There are also strict rules around chambers which recognise that other personnel such as supervisors, surveyors, geologists and service technicians may also need to use the facility.
Some regulators in Australia require mine sites to provide a refuge capacity more than double the size of the locally operating crew, or implement a system to limit the number of personnel in the area.
At the time of the collapse in Ballarat, it is understood that the two men were conducting airleg mining beneath unsupported ground.
Airleg mining is a form of manual mining using hand-held tools. It is most commonly employed in low-grade operations or narrow veins where larger jumbos and drill rigs are unsuitable.
WorkSafe Victoria is conducting an investigation into the incident.
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