Silver Celebration: Heysen Tunnels mark a quarter century

Sunday, 9 March 2025

The Heysen Tunnels, a vital link in South Australia's transport network, are celebrating their 25th anniversary, coinciding with the completion of a significant safety upgrade.

Opened to traffic in March 2000, the tunnels were the culmination of a $151 million project announced by the then Prime Minister, Paul Keating, in 1995.

This ambitious project was the largest road project ever undertaken in South Australia at the time, and 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.

Utilising a SW200 tunnelling machine, typically used in heavy mining operations, crews excavated 500 metres of rock for each tunnel, up to 60 metres deep, progressing at an average of 21 metres per week.

Tim Wheaton was a project engineer as part of the 1,500 strong workforce on the project, and says construction was a mammoth task and a major spectacle.

“There was so much going on, it was incredible; earthworks, roadworks, tunnelling, drilling and blasting, bridge construction, landscaping and revegetation, it was a very complex and challenging project,” he said.

“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 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.”

“It was real hive of activity, with a lot of works hidden away from the travelling public who were using temporary roadways for a lot of the time… every time we’d have to do 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.”

Such was the significance of the project, one worker reportedly held his wedding at the tunnel’s southern portal during construction, complete with the release of white doves.

“It was a very unique project at the time. In the 1990s there hadn’t been any projects of this size in South Australia for a long time so a lot of our local workforce had gone interstate, so coming back for this was somewhat of a homecoming for a lot of us,” Mr Wheaton said.

With tunnelling completed in 1998, 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 roadway, and Tim Wheaton was among the hundreds of guests.

“There was a charity gala prior to the opening, with the who’s who of Adelade 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. There were a few stages and just people everywhere.”

Legendary entertainer Rhonda Burchmore was called in to wow the VIPs, and says managing multiple stages along the tunnel required her to stay on her toes.

“I’ve never performed in such an extreme venue in my life. I flew in from Singapore and was driven to this tunnel, where I had to perform in two places! My long legs, in a glamorous gown and high-heels had to run between the spots along the tunnels, but I sung and danced and everyone had a wonderful time,” she recalls.

“The sound was challenging as it was bouncing off the walls. I remember singing ‘Get Happy’ and doing a couple of other songs, the folks putting on the event were absolutely thrilled that I managed to cover such a distance and perform up close and personal with so many of the guests, considering the very unusual venue.”

On opening day, a large green ribbon was strung across the tunnels’ entrances. The new freeway and tunnels immediately enhanced safety and reduced travel times for the 10,000 daily commuters who previously navigated the winding hills. In the quarter century since, the number of daily drivers between the hills and the city has increased to around 50,000.

“On the day it opened, we sat and watched people driving through and they’d almost check their watch to time themselves. What would have been a 20 minute journey winding through the hills was now half that time right through the tunnels,” Mr Wheaton said. “We all knew this project was going to be a game changer for Adelaide and South Australia,” Mr Wheaton said.

“You do feel a bit of pride when you look at these projects after they’re done, we all have a sense of ownership on them after the work we did on them. We were very proud. The project was completed on budget and on time”

The completion of the tunnels created signification economic and social opportunities for communities both in the hills and the metropolitan area. Lifelong hills resident Sue Johnson says their construction and completion changed her and her family’s lives.

“It opened up so many opportunities for people living in the hills, for example all our kids went to school in the city, which is something we wouldn’t have considered before the freeway opened. They could go to university and socialise in ways I certainly couldn’t when I was their age,” she said.

“As a young woman and even when I started working, getting to the city just wasn’t convenient, it was a long haul down and a long haul back up. Going to the city was something we did for special occasions, otherwise we stayed in the hills.”

Prior to the tunnels' construction, Mount Barker Road had served as the primary route for over a century. With the shift of the Princes Highway to the new freeway, Mount Barker Road was repurposed, with a section transformed into a bike path leading to Mount Lofty, popular with cyclists bound for Mount Lofty.

The majority of traffic now utilises the freeway, although memories of the often-treacherous former route remain for many.

“When I was working in the city and I’d drive in, it was daunting,” Mrs Johnson said, “My little Mini SS up against semi-trailers going around Devil’s Elbow was a nightmare!”

“When we heard about these tunnels being built, we all thought it was fantastic, we were finally going to have a proper freeway, it’d be so convenient.”

Prior to the tunnels opening to traffic, members of the community were invited for an up-close look inside. Sue Johnson recalls some surprises as she and her family joined thousands of others.

“When it opened, we went for a walk through the tunnels as part of a community open day. I had my two boys and was pregnant with my daughter and remember being so surprised at the grade of the road, we didn’t expect it to be that steep.”

This year's anniversary is cause for more celebration with the completion of the recent major safety refit.

The Australian and South Australian governments committed $150 million (80:20) to deliver the Heysen Tunnels Refit and Safety Upgrade, as part of the broader South Eastern Freeway Upgrade, which saw major work completed in late 2024, and final testing occurring earlier this year.

Department for Infrastructure and Transport Chief Executive Jon Whelan says the refit was an important upgrade for a vital piece of infrastructure in South Australia’s road network.

“Many South Australians know the difference the freeway and these tunnels made when they opened,” he said. “So many of us remember having to traverse over the hills along those windy roads, so it’s fantastic to reflect back on the 25 years of service from the tunnels, as we look to their future.”

“Ensuring the Heysen Tunnels are at the top of their game is vital for safety and efficiency, and that’s what the recent upgrade has delivered.”

The project included the upgraded tunnel lighting and ventilation, installation of a new automated fire suppression system, and upgrading the Intelligent Transport System. This work included the installation of more than 1,000 LED lights, six overhead gantries and more than 140 CCTV and incident detection cameras.

Although constructed to the highest standard in the late 1990s, Australian and international standards relating to road tunnel safety have developed significantly since then, so the upgrade has brought the important infrastructure in the tunnels up to current standards, ensuring the Heysen Tunnels continue to serve the South Australian community for generations to come.