Leighton subsidiary Thiess has secured a $126.5m one-year contract extension at the Queensland, Australia-based Tarong Coal Project Meandu mine.
Thiess, which originally secured the contract in October 2007, will operate the mine to December 2011.
Coal generated from the mine will supply the nearby Tarong Power Station, which represents a key source of electricity for Queensland.
Thiess CE Bruce Munro said the contract's extension covers complete mining services, including mine planning, drill and blast, coal mining, coal processing and maintenance of mobile and fixed plants.
Government-owned corporation Tarong Energy is a major power generator in Queensland.