Chief executive Ian Smith this morning announced that only one of two processing trains at Telfer were operating, owing to a series of problems with the mine's gas turbines.

The problems began when the company had to shut down Telfer's gas turbine No. 2 as a result of a switch board failure.

While full power to the project was maintained courtesy of the project's other two gas turbines, a "subsequent maintenance issue" with the air chilling system on those turbines "impacted the capacity to supply full power"

Smith said rectification works would require a 40-hour power outage, during which back-up diesel generators would maintain power to the project.

Full power is expected to be restored by the middle of next week.

During the shortages, operations at the mine's openpit and underground works will continue, with ore being stockpiled for later treatment.

While Newcrest says Telfer's production guidance for financial 2007 remains unchanged, the power outages represent the latest in a string of operational issues at Australia's largest gold mine.

Misinterpretation of grades has contributed to a string of missed production targets at Telfer, while cyclones through the area have also caused problems.

Telfer produced 657,196oz and 38,374 tonnes of copper in fiscal 2005-06, short of its guidance of 700,000oz gold for the year and well shy of the 1 million ounce per annum capacity originally forecast for the mine.

Shares in Newcrest were off 2c to $22.48 in morning trade today.