Hydraulic mining itself is not new to Australia, having been used for more than a hundred years for alluvial and tailings deposits in tin and gold mining areas in Tasmania and Queensland. However, the techniques employed by Ross and Fraser Alexander today, are markedly different.
“We use much higher pressures, typically in the order of 30 bar, but variable to suit the conditions,” said Dave Prentice. “The high intensity jetting provides a consistent fine slurry to the mill for reprocessing, with no clay balls.”
“This allows us to use much less water,” he said, “and the water is also generally recyclable. The only water is between the monitor and the slurry pump, so evaporation losses are also minimised.”
Consistently high densities of 30-50 percent solids have been achieved, depending on the tailings characteristics, and this is the key to effective hydraulic mining production. “High slurry densities are achieved through constant vigilance, specialist techniques and skill,” said Prentice. “Otherwise many materials, particularly clay, tend to break into clods which settle out in launders or are caught on screens, reducing production. Our team is highly experienced, and has the skill to achieve a concentrated stream of slurry, inhibiting meandering, velocity losses and settlement of solids.”
The equipment can be track mounted, remote controlled, and utilises flexible supply hoses, making it highly manoeuvrable. This means infrastructure costs are kept very low.
“The process allows good visual control, to mine cleanly, safely, and efficiently, while protecting existing infrastructure,” said Dave Prentice. “We can operate under most weather conditions, and there is no requirement for trucks or haulers. Being a wet process, there are no dust emissions to control. It is the most cost-effective recovery method available.”
"We offer mine operators a cost-effective, safe and environmentally sound way to recover their tailings and reduce their footprint."
