The South Australia government has celebrated the 25th anniversary of the Heysen Tunnels.
Opened to traffic in March 2000, the tunnels were the largest road project ever undertaken in South Australia at the time. They diverted traffic from Mount Barker Road, and the infamous Devil’s Elbow, onto the new section of the South Eastern Freeway. The opening significantly improved safety and travel times for drivers between Adelaide and the hills.
Using a SW200 tunnelling machine, typically deployed in heavy mining operations, crews excavated 500m of rock for each tunnel, up to 60mdeep, progressing at an average of 21m per week.
Project engineer Tim Wheaton said it was a very complex and challenging project.
“The natural terrain site was very steep with limited access. To clear the land around the tunnels, they used a bulldozer which would be lowered down the hillside, connected to a cable and pulley mounted to another bulldozer located at the top. This was also how the head contractor, MacMahons, worked on the Mount Buller ski slopes which they owned at the time,” he said.
“Every time we did any blasting, we’d have to stop traffic and do a sweep through the area to make sure there weren’t any wayward bushwalkers in the vicinity.”
Tunnelling was completed in 1998 and the excavation paved the way for the South Eastern Freeway realignment, making the Heysen Tunnels – named in honour of renowned artist Sir Hans Heysen – the first twin tunnels on the National Highway.
Prior to the opening of the tunnels in 2000, a party was held on the newly laid road, and Tim Wheaton was among the hundreds of guests.
“There was a charity gala prior to the opening, with the who’s who of Adelaide in attendance. The tunnels were chockers with people. They had the tables all in one tunnel, with the kitchen in the other so all the food was coming through the cross-passages,” he said.
A A$150m refit and safety upgrade[https://www.tunnelsandtunnelling.com/news/heysen-tunnels-upgrade-completed/] of the tunnels was completed in December last year.
The project included upgrading the tunnel lighting and ventilation, installation of a new automated fire suppression system, and upgrading the Intelligent Transport System. The work included the installation of more than 1,000 LED lights, six overhead gantries and more than 140 CCTV and incident detection cameras.
