Under the variation, Thiess will mine additional volumes following a new development consent obtained by Glencore.
Thiess will continue to provide mine planning, design and execution, drill and blast, overburden removal and coal mining services until June 2021 under the amended contract.
Parent company Cimic Group CEO Michael Wright said Mt Owen was Thiess' largest coal mining operation in New South Wales.
"This award reinforces Thiess' long-term commitment to delivering value-add solutions to Glencore at Mount Owen, and further reinforces Thiess' strong presence in the Hunter Valley where we provide mining services at three mines," he said.
Thiess managing director Douglas Thompson said the company had actually built the mine back in 1994....