The installation of 19 Cavex® 400CVX10 hydrocyclones at OceanaGold’s Didipio gold and copper mine in the Philippines has led to savings of more than $800,000/y through a dramatic reduction in grinding circuit recirculation, according to Weir Minerals.

The Didipio mine, which employs more than 1,500 workers (drawn predominantly from the local community), has expanded throughput over the last few years in line with its transition from open pit to underground mining. This increased the incumbent cyclones’ feed density beyond what they could effectively manage, leading to a circulating load of up to 700%, according to Weir.

The Cavex 400CVX10 hydrocyclones significantly improved separation efficiency due to their finely tuned spigot liner diameter and the strength and corrosion resistance provided by its cast housing, according to Weir.

Thanks to these qualities, the introduction of the Cavex hydrocyclones reduced the circulating load from 620% to 374%, with the direct savings in power consumption, ball consumption, cyclone and pump maintenance costs exceeding $815,000/y.

Gary Webb, Processing Manager, OceanaGold Didipio project, said: “Having had good performance from Cavex hydrocyclones at our New Zealand sites (Macraes and Waihi), we were confident that retrofitting Cavex hydrocyclone cluster at Didipio, with an increased number of smaller cyclones than we had at the time, would help reduce our problematic circulating load and lever multiple benefits in doing so.

“The changeover to Cavex hydrocyclones has exceeded our expectations, enabling higher throughput and lower consumable costs without being penalised in grind size.”

The performance of Cavex hydrocyclones can be attributed to the 360° laminar spiral inlet geometry design, which provides a natural flow path into the hydrocyclone, Weir said. This shape allows the feed to blend smoothly with rotating slurry inside the chamber, reducing turbulence.

Mike Arakawa, Philippines Country Manager, Weir Minerals, said: “Working with customers across the globe, our expert engineers are constantly looking at how they can maximise separation efficiency, hydraulic capacity and extend the wear life of not just the hydrocyclone, but our customers’ overall processing plants.

“I’m proud of the results we’ve achieved together with OceanaGold. Reduced circulation means reduced power draw, fewer balls consumed and less equipment wear, creating a more sustainable mine.”

Didipio produced 114,985 oz of gold and 14,999 t of copper in 2018, with 120,000-130,000 oz and 14,000-15,000 t of copper slated for 2019.