Boral Quarries Reclaims 2.4 Million Cubic Meters of Waste Material with McLanahan Filter Press
Boral is Australia’s largest vertically integrated
construction materials company, supplying asphalt, concrete, cement and
quarry materials for building the nation’s infrastructure since 1946.
At Boral’s Bacchus Marsh quarry, the company is operating a McLanahan Overhead Beam Filter Press to better manage its tailings. After the material is processed through the wash plant, all the tailings – which consist of the undesirable material removed during the washing process and the water used to remove that material – are sent to the McLanahan Filter Press.
The Filter Press is a liquid-solid separation device that dewaters the waste slurry to generate a drip-free solids portion and an immediately reusable process water.
“The McLanahan Filter Press is about 7 years old, and during that time, we’ve processed just shy of 2.4 million cubic meters of material,” said Quarry Operator Matthew Thorpe. “To put that into perspective, the MCG, which is the largest stadium in Melbourne, would hold about 1.5 million cubic meters, so we’ve almost filled up that stadium twice.”
Before installing the McLanahan Filter Press, Boral stored its tailings in slime cells, or dams. These slime cells would then have to be dug out, which took time and labor, and when the slime cells got too full, they would be capped off until they could be further managed. Thorpe said the McLanahan Filter Press has allowed Boral to eliminate the slime cells altogether.
“We don’t use them anymore whatsoever,” Thorpe said.
With the McLanahan Filter Press, Boral is able to recover around 70% of its process water for reuse in the wash plant, which provides environmental sustainability benefits along with saving the costs associated with purchasing as much freshwater. The solids material goes back to the pit to be used as part of the rehabilitation program.
“The McLanahan Filter Press has made a big difference to the way we operate here without the slime cells and the need for wastage,” Thorpe shared. “We’re able to use whatever runs through the McLanahan Filter Press for rehabilitation, as well as the water that gets recycled back through the plant, so we’re relying less on the reservoir that we have to buy the water off as well as being able to reuse the waste material, so it’s made managing the pit much easier.”
Thorpe said the Filter Press is easy to operate and maintenance is limited.
“Even though it looks like an incredibly complicated machine, it actually runs very simply,” said Thorpe. “It’s not labor intensive, which makes it a lot easier to teach and wrap your head around how it works.”
The McLanahan Filter Press has proven to be a valuable part of Boral’s Bacchus Marsh operation.
“Without it, this site wouldn’t run,” said Thorpe. “At the moment, it’s the only way to process and maintain the tailings that are coming out.”