Thickening expertise applied in coal maximises water efficiency

Paste and high rate thickening are emerging as a significant way to maximise water efficiency in Australia’s coal industry. Outotec has designed and installed the first-ever paste thickener in Australia’s coal industry and has won five further orders recently for paste and high rate thickeners. “Here in Australia we are leading the field in adoption of this technology into coal. We expect this to expand even further as environmental demands and risk management policies make paste and high rate thickening increasingly attractive,” said Outotec’s Global Technology Development Manager – Thickening, Brad Garraway.

“Thorough test work is essential for the correct sizing and configuration of thickeners,” said Garraway. “Outotec has a range of dynamic bench and pilot scale test work techniques, which accurately simulate the high-rate principle. Outotec deep bed test units for high compression and paste applications have been invaluable for the coal industry. Our reliable test work has also enabled us to give performance guarantees, that have been vindicated by subsequent results.”

Another emerging trend in the coal industry is the use of bolted tanks in the design. Outotec’s design radically reduces site installation time, as the bolted tank can be delivered pre-painted with no site welding required. Bolted thickeners are also much easier to relocate should future operations require. Bolted designs have been specified for:

  • Carborough Downs, QLD, 25 m Outotec® High Rate Thickener (HRT) bolted tank with patented Outotec TurbodilTM feed dilution system installed early in 2009. (Turbodil is a forced dilution system, upstream of the feedwell)
  • Stockton mine, NZ, 24 m HRT bolted tank supplied and to be installed in 2009 with Outotec Vane FeedwellTM. The recently launched, high performance Vane Feedwell is Outotec’s global standard feedwell
  • Mt Arthur Coal, NSW, 35 m HRT bolted tank with both Vane Feedwell and Turbodil 2010 supply and install
  • Clermont Coal, QLD, 12 m Outotec High Compression Paste Thickener (HCPT) bolted tank scheduled for installation in the first quarter of 2010
  • Bulga Coal, NSW, 18 m HCPT bolted tank installed September 2007
  • Cameby Downs, QLD, 22 m HRT piecewise tank with Turbodil, installed first quarter of 2010.  

At one major coal preparation plant, an Outotec paste thickener installation was designed to save water and also reduce the tailings space required. Outotec’s test work program was a key factor in the subsequent award for Australia’s first coal paste thickener, explained Garraway. “The client also weighed up factors including industry experience, process guarantees and value for money and Outotec’s thickening solutions really impressed in this regard,” he said. “Real total cost is also a prime consideration. More and more sites are now comparing not only initial capital outlay but also ongoing operational and maintenance costs. This is where some suppliers can really differ.”