The Ridgeway Concentrator at Newcrest Cadia was commissioned in 2002 as an ABC circuit to treat the ore from the Ridgeway sublevel cave (SLC) at around 5 MTPA. Consisting of a single pinion 32’ autonomous grinding (AG) mill and a single pinion 7 MW ball mill, it was a much smaller plant than the adjacent Cadia Hill Concentrator. Subsequent expansion of the circuit saw additional infrastructure added as the ore source transitioned to Ridgeway Deeps, a block cave below the original Ridgeway SLC. The key additions were a secondary crusher to reduce the semi-autonomous grinding (SAG) mill feed size and tertiary grinding for reduction in flotation feed size to maintain recovery.
The Cadia East mine, which consists of two large block caves, became the sole feed source for the Ridgeway Concentrator in March 2016. The Cadia East ore has a higher Bond ball mill Work Index (BWi) and lower A*b than ore from the Ridgeway mine or Cadia Hill open cut. This paper details the debottlenecking improvements made to the plant to further increase grinding circuit throughput despite the harder ore, including installing new equipment to tertiary crush the SAG mill feed, optimisation of mill liner design, upgrades to grinding mill drive trains and numerous smaller optimisation activities.