The Victorian government will appoint an independent expert to investigate the exact cause of the disaster which occurred after a bank of the diverted Morwell River collapsed, allowing water into the ''eastfield'' mine – the primary source of coal for the power plant, according to The Age.

The Yallourn power station provides 22% of Victoria's electricity.

Approximately 500 megalitres a day is entering the mine while last week about 400ML/day was being pumped into the Latrobe River from the neighbouring “township” mine.

The $120 million river diversion, which was meant to give the plant access to coal to last until 2032, was expected to be capable of surviving a one-in-10,000 year flood.

Mine operator TRUenergy reportedly said the pipe would be able to carry the entire river by mid-August.

''Once this starts to come online we expect to be able to pump more water out of the mine than what is coming in,'' a TRUenergy spokeswoman reportedly told The Age.

''However, it is dependent on the weather.''

Water damage reduced the power plant's generation capacity to a quarter until last week, when the company was able to restart a conveyor transporting coal from the mine but it was still only operating at 50% capacity.