June 21, 2013

Heavy rainfall in Gippsland during the past week has impacted on the Yallourn Mine and work on the Morwell River Diversion repairs.

In June 2012, the Morwell River Diversion (MRD) failed, causing river water to flow into the open-cut mine.

While a temporary river-to-river pumping and pipework system has been operating since August and can hold up to 120 per cent of average river flows, the significant increase the river flows has meant water is again entering the Mine.

EnergyAustralia’s Group Executive Manager, Michael Hutchinson, said that, as previously indicated, the Yallourn Mine and work on the Morwell River Diversion repair would remain vulnerable to rain events until the diversion was completed.

“While the temporary river-to-river pumping and pipework is continuing to operate, as expected it is unable to carry the significant amount of water currently entering the river system from the heavy rainfall,” Mr Hutchinson said.

“Our contingency in the case of heavy rainfall events and rapidly increasing river flows has always been to allow excess water to enter the East Field section, and this is now occurring.”

There is just over 4 GL in East Field, with about 800 ML a day flowing into the active section of the Mine. Local rainfall run off is also impacting on water levels in the Mine.

One coal conveyor in East Field was flooded, however coal is still being transported to the power station by another coal conveyor. The conveyor is expected to be out of service for at least three weeks. All generating units at the power station are continuing to operate.

Mr Hutchinson said there had been no damage to the MRD repair works, however construction would not resume until the conditions in the mine improved, and this would impact on the completion date.

“We have always been clear that this work is weather dependent,” Mr Hutchinson said.

“Wet weather makes vehicle movements and work conditions difficult and this will impact the exact timing of opening up the diversion.

“EnergyAustralia will apply to the EPA for an emergency discharge licence to ensure we can protect our ability to supply power to Victorians.

“During our previous emergency discharge licences, we complied with the strict water quality and water volume limits set by the Environmental Protection Authority.”

Work on the MRD repair is continuing, and involves added design features such as a complex liner system and extra drainage to provide added protection to the new diversion.

The work has also involved more than 150,000 hours of work since January, and more than 1.3 million cubic metres of material such as clay being excavated or used as backfill.