TWO workers at Rio Tinto’s Yarwun alumina processing plant, near Gladstone in Queensland, were rescued after being stranded in the toxic alumina tailings dam for several hours.
Rio had to employ RACQ Capricorn Helicopter Rescue Service and firefighter emergency services to rescue one male Rio employee and one female contractor, when the machine they were operating overturned into the dam of toxic red sludge.
At the time of the incident, the workers were on board the machine, known as an amphibious amphirol, attempting to flatten and condense the red mud processing by-product.
However, when the machine rolled both workers were drenched in sludge.
A helicopter was deployed to lower fresh clothes and equipment to the workers, who had managed to climb atop the roof of the machine.
Although neither worker was injured, both were treated by ambulance officers before being taken to the site’s medical centre for further observation.
“The employees became stranded at 7.30am [on October 4] after the specialist piece of equipment that they were operating in the Residue Management Area overturned,” Rio said in a statement.
“Both are safe and in good spirits.” Red mud is a toxic by-product of the industrial processes that refine bauxite or raw aluminium ore into aluminium oxide or alumina.
The raw materials are bathed in a hot, strong base solution of sodium hydroxide (caustic soda) to dissolve the aluminium compounds. The undissolved wastes that remain are known as red mud.
As this was the second incident of its kind at the site in less than a year, Rio has announced an investigation to determine how the accident occurred.
In December 2012, a 40-year-old man similarly had to be rescued after the amphibious amphirol he was operating broke down in a dam of red mud.