InDaily understands Alinta told workers at Northern and Playford today the proposed closure date March 31 will now be pushed out to May 8 2016.

In November, Alinta’s Leigh Creek coal operations closed, cutting about 240 workers.

The Australian Services Union has asked Alinta for a written explanation about the changed date and a meeting with senior management.

The ASU has also called for an urgent meeting of all unions to discuss the extension.

“Members may have concerns that this development could have an impact on the timing of redundancy payments or an ability to leave the business for future employment opportunities,”  ASU secretary Joseph Scales said.

An Alinta spokeswoman told InDaily the March date had been “flexible” and was extended as coal stockpiles at the power station were larger than expected.

“The Port Augusta power stations were initially forecast to close on or around 31 March 2016, based on our expectation of remaining coal volumes at the time Alinta announced closure.

“As a result of coal stockpile volumes being greater than expected, it is now forecast that the power stations will close on or around 8 May 2016.

“We appreciate that this change may impact some of our employees.

“We will continue to support those employees and all of our people in successfully transitioning to new employment through a range of support services tailored to suit our employees’ needs.”