In development for several years, the slurry ash monitor was successfully trialled at several CHPPs in the Hunter Valley and is commercially available.

The fully patented product provides a continuous measure of the quality of the tailings which can be used to calculate the amount of recoverable coal in the tailings.

This data allows washery plant operators to help tweak the CHPP to deliver better productivity and save water.

During some trial runs, operators managed to improve the performance of the plant from a typical ash level of 60% in the tailings up to 85%.

TUNRA engineer Noel Lambert told ILN the slurry ash monitor measured both the slurry density and the solids concentration, along with other factors. With this data, the average particle density could be calculated and then correlated to the ash.

Technology used includes a microwave solid concentration meter and a vibrating tube density meter.

Lambert said the monitor was very easy to install and the company was building a skid-mounted version which could just be taken onsite and plugged in.

While there is plenty of scope to boost CHPP performance, it does depend on how plant operators use the data provided by the monitor.

“The main thing is you can use it to keep an eye on your plant so you can recover more coal,” Lambert said.

The monitor was online all the time, where operations had previously relied on intermittent samples of the tailings which had to be taken then analysed.

“They would take periodic samples of the tails and that period might be once a shift or once a quarter.

“Some pay more attention to it than others.”

TUNRA is marketing the product and is in discussions with a supplier, while also setting up a field services team in Queensland.

“We’ve had quite a few enquiries, several other mines certainly want to trial it,” Lambert said.

Sales have been made in NSW and Queensland.

Lambert said the idea for the product came from the recognition of a gap in the industry, with “nothing that reasonably accurately measures the quality of the tailings and the amount of coal in it”