Leighton Holdings has signed $1.5 billion worth of contracts in Australia and Indonesia.

A spokesperson of the Australian-based company said that its subsidy, Leighton Asia, has struck a six year contract extension worth $1.1 billion for the expansion of mining services at MSJ coal mine in Indonesia for PT Mahakam Sumber Jaya (MSJ).

Leighton Contractors Indonesia, a unit of Leighton Asia, will expand its mining operations and is expected to generate more than 8 million tonnes of coal annually.

Hamish Tyrwhitt, managing director of Leighton Asia explained that the $1 billion conteract will increase Leighton Asia's workload to more than $7 billion.

“Our operation in Indonesia has been an outstanding performer for the past few years and we expect to continue to perform strongly in both mining and infrastructure,” Mr Tyrwhitt said.

Leighton's shares peaked at 93 cents or 2.9 per cent to $33.24.

Meanwhile in North South Wales, Thiess Services won a $405 million contract from BHP Billiton to remedy the Hunter River Remediation Project. The project includes remediation of river sediments left by former Newcastle Steelworks at Mayfield when it operated its industrial activities.

Thiess Services was actively involved with the Hunter River Remediation project for almost a year. Michael Wright, the executive general manager said the project has put the company as the leader of contaminated site remediation.

Thiess Services is a division of Leighton Holdings Limited since 1983.