The fire-ravaged plant, rebuilt to withstand a significant increase in temperature, was to have restarted during the past week.

BlueScope’s general manager of manufacturing, John Nowlan, said the delay was caused by  technical issues. 

In the meantime, the sinter plant would revert to the interim operating arrangement.

“As part of our testing and recommissioning process controls, additional instrumentation recently installed has identified elevated temperature levels of char in the Waste Gas Cleaning Plant,’’ Mr Nowlan said. ‘‘Whilst BlueScope is committed to restarting the WGCP as soon as practicable, our priority is to ensure that this is done in a safe manner.’’

Mr Nowlan said BlueScope would use the next few weeks to  prepare for  a safe restart in early January. A testing program would be in place to  monitor emissions.

A fire on October 13, caused by heat from gas much hotter than normal,  caused   a fibreglass chute to collapse.

The hot gas was probably the result of a stagnant char zone within the waste gas cleaning plant.

The cost of the cleaning plant reconstruction was within the original  $10 million to $12 million estimate, Mr Nowlan said.