The extension would see Thiess continue full service delivery onsite for at least another three years until December 2016, the company said in a statement.

The contract also includes an option for an additional one-year extension until December 2017.

Operated by Thiess for the past 17 years, company managing director Bruce Munro said the recent decision further demonstrated the strong working relationship between Thiess and Glencore.

“This extension confirms the durability of this longstanding relationship and Thiess will continue to work with Glencore to deliver greater productivity,” he said.

Leighton Holdings CEO Hamish Tyrwhitt agreed with Munro, welcoming the extension for one of the Leighton Group’s longest running mines.

“Mount Owen is geologically complex and our ability to deliver value over such a long period through highly variable market conditions is a tribute to the mining expertise in the group,” Tyrwhitt said.