Construction to the Morwell River Diversion at Yallourn Power Station and Mine is now complete.
The diversion began taking partial river flows last September and full-river flows in October. Extensive rehabilitation and revegetation work continued throughout Summer.
On 6 June, 2012, the Morwell River Diversion failed. Water breached a tunnel under the diversion, damaging infrastructure and causing river water to flow into the open cut mine.
Yallourn’s Manager of Mining, Ron Mether, commended all those who had been involved in the recovery and reconstruction of the diversion.
“A significant amount of resources, time and effort have been committed to the diversion work during the past year and a half,” Mr Mether said.
“The reconstruction has been highly complex and has involved thousands of hours of work from hundreds of employees, contractors and external specialists,” Mr Mether said.
“From recovery to reconstruction, the dedicated team was focused on dealing with the complex and enormous task.
“While weather made the task more complex and often slowed progress, the safety of our workers was always our number one priority.”
The new diversion designs were extensively peer reviewed and incorporated a wide range of scenarios.
The reconstruction involved the addition of a complex liner system and extra drainage to provide added protection to the Morwell River Diversion.
The 800-metre liner system, which has multiple layers, is double seamed welded, with each joint sent away for quality testing.
The work has repairs to the entry and exit of two coal transport tunnels, with a third reconstructed and now being used as part of the extensive fire management system.
“Reconstructing the river diversion was more than just ensuring water could again flow – it was about ensuring the diversion mirrored an actual natural river flow,” Mr Mether said.
Rocks are positioned periodically along the site to mimic a river bank’s ability to draw away water, while rocks have also been placed at the bottom of the diversion to create ‘rock riffles’ to help reduce erosion.
The river drops 3 metres over the 3.5 kilometre diversion, so flat areas have been built into the system to help ease the drop, decreasing the water’s speed and stopping erosion.
A more extensive monitoring and cable system that sends real-time key river data, such as water pressure and levels, directly to the internal environmental team has been established. A set of alarms are set up to alert the on-site team of any major changes.
“It’s important the river’s health is kept to an exceptional standard so the natural animal and plant life is able to thrive,” Mr Mether said.
“We are monitoring the river’s water quality on an ongoing basis.
“During the winter and summer months this year, we will continue to plant more aquatic plants that are appropriate for this region.”