The decision to replace the existing spirals was taken following extensive testwork performed by both Northam Chrome Producers and Multotec. Based on the outcome, Northam Chrome Producers decided to replace the existing spirals, which had reached their end of life.

“Tests showed that by using the Multotec spirals, the plant would be able to increase recoveries by an additional yield of 6%,” said Multotec’s Graeme Smith.

Multotec was tasked with removing 172 spiral assemblies from the recovery plant and replacing them with 72 Multotec spiral assemblies. These comprised Multotec HX5 and Multotec HX3 spirals with feed tonnage capacities ranging from 4-9t/h per start.

One of the biggest challenges of the eight-week long project was retrofitting the new spirals into the existing structure. Extensive work was done by Multotec’s in-house drawing office, which undertook all the drawings and confirmed the new layout of the plant, while also presenting the modifications needed to the structure to accommodate the new installation.

The plant was commissioned in February 2015 and plant yield is now closer to 30%, compared to the average of 21% in 2014.