Image: Sepon Copper - Innovative and complex copper leaching process

Minerals & Metals1 min read

Sepon Copper - Innovative and complex copper leaching process

OZ Minerals
2003 - 2005

The Sepon Copper project is a patented copper leaching process comprised of crushing, acid grinding, acid flotation, pressure oxidation and a solvent extraction electro winning circuit designed to produce 60,000 t/y of cathode copper, which has subsequently been increased by Ausenco to 80,000 t/y.

Ausenco’s EPCM contract delivery included the process plant and associated infrastructure including reagents, oxygen plant, cooling towers and infrastructure such as power supply, water supply, accommodation to house 4,000 personnel, roads, bridges, waste services and tailings storage.


  • EPCM US$235m for a 60,000 t/y SXEW plant and US$31m for the gold plant expansion
  • First acid milling hard rock grinding circuit in the world – use of large ceramic balls and stainless throughout – technical challenge
  • Completed 2 weeks ahead of a schedule and under budget
  • 70 km of complex piping and 260 km of cabling
  • Innovative and complex copper leaching process
  • Winner of 2005 National Engineering Excellence Award.