From Australian outback to tunnelling industry expert in US
Bachelor of Engineering (Mining Engineering), 1996
Vice President of Operations
Tutor Perini Corporation
After starting his career as a miner in the Australian outback, Michael Cash has worked his way up the unique tunnelling industry and is currently the Vice President of Operations for Tutor Perini Corporation - a leading civil construction company in the United States that completes approximately $5 billion of works annually.
Michael has been recognised for his outstanding achievements, receiving the Young Tunneller of the Year Award in 2013 at the International Tunnelling Awards in London.
Even though humans have been tunnelling underground for thousands of years, Michael believes the industry is essentially in its infancy with great engineering and technological advances being made in the last 30 years. This is also a business with continued demand, especially in challenging subterranean environments, and one which requires absolute certainty and accuracy for public safety.
Congratulations on winning the Young Tunneller of the Year in London. Which project were you recognised for?
"I was nominated by the City of San Francisco for my work as a Contractor in developing a team to construct the New Irvington Tunnel, which is a 5.7 km long water supply tunnel that crossed seven active fault zones that supplies 85 percent of San Francisco’s drinking water. At the time, I was working for a company called Southland Contracting. We had taken over a small tunnelling outfit from Texas and within a few years had grown it to be one of the largest tunnelling contractors in the USA.
For this project I teamed up with a company called Tutor Perini (for whom I am now a Vice President), one of the largest Heavy Civil Contractors in the USA. Due to the nature of this project, we were required to use an approach that, while not necessarily technically advanced, required the melding of several techniques that made it extremely unique. Furthermore, we had to assemble and train multiple tunnel crews to enable the tunnels to be built on time. This was also very hazardous work. The tunnels were built on schedule and within budget with no lost time injuries. It was a great success all round and it was great to work in a team that really came together. It was quite a rare experience for it all to come together in the way it did."
Please explain the tunnelling industry and why you gravitated towards it:
"The tunnelling industry encompasses a diverse variety of projects, ranging from major utility infrastructure for water and power to major transportation infrastructure for roads and rail. With our ever increasing urban areas, I saw an industry which was expanding at a phenomenal pace and realised that it would provide me a great opportunity to develop a career which would allow me to grow and give me access to projects that pushed the limits of engineering and technology. Also, I love to travel and see exotic places and I saw the tunnelling industry as an avenue for meeting my obsession.
One of the most exciting aspects of working in this industry is the ever-changing demands and types of projects. Whether from the specific geologic conditions that the project is being constructed in or the very different needs of each new project, no two projects are the same and no two days’ challenges will be the same. It is not a case of building the same structure repeatedly. Also, tunnels are used to solve very complex problems in our urban environments and hence I find that we are always pushing the boundaries of what we can do. We have to deal with a lot of first offs or one offs which allows a lot of out of the box thinking. I take great pleasure that I had a big role to play in a team of people that affected the daily lives of so many, be it providing drinking water to the city of San Francisco or shortening commutes on subway or highways.
Probably the biggest misconception people have is that tunnelling is simply a matter of digging a tunnel. Many people don’t realise how unique each situation is. For the most part special equipment must be created with specific soil types and site conditions in mind. To construct the SR-99 Highway beneath the city of Seattle, we have had to design the world’s largest tunnel boring machine that has been uniquely designed for the geology of Seattle and able to safely excavate beneath downtown in earth pressures up to 7 atmospheres. The machine was manufactured in Japan, shipped to the USA in pieces and assembled onsite at a cost in excess of $85 million dollars. A massive undertaking.
For me one of the biggest changes I have witnessed is moving from the mining industry to the tunnelling industry. Even though the industries are very similar in many aspects they are very different. The mining industry uses tried and true methods to extract the ores, whereas the tunnelling industry is always pushing the envelope of what can be done."
Which major projects have you worked on? Do you have a favourite?
"The major tunnelling projects that I am currently managing include the Central Subway Project in San Francisco and the SR-99 Highway Tunnel in Seattle. The Central Subway Project is a $1.6 billion subway currently under construction in downtown San Francisco. It involves approximately 2 km of underground subway and three deep underground stations.
The SR-99 Highway Tunnel in Seattle involves the construction of 2.8 km double stacked highway tunnel that is being excavated using a 17.5m diameter Earth Pressure Balanced Tunnel Boring Machine beneath downtown Seattle. It is the world’s largest single pass tunnel and is being built at a cost of $1.5 billion."
What is the strangest or most astonishing thing you have ever found underground?
"Not long after graduating, I worked as a miner in the middle of Western Australia in a gold mine called Darlot. While excavating, we came across some native gold exposed in the side of the tunnel. It was thin leaves of gold that were embedded in a seam of white quartz about the size of a fist. So no one would steal the gold, we blasted a section of the wall, however this fist size seam expanded out to a seam that was approximately 5m in length with seams of gold all through it. It was a beautiful site and worth a lot of money and was excavated out immediately due to the security risk of it being stolen.
Other than that, I have come across many fossils and in the cities you find many interesting things as you excavate down, showing the history of the city and giving you a flavour of how things were a hundred or so years back. I have found fossils from the Jurassic Period in Texas, and cannon balls from the early Spanish Missionaries in California to sewing machines left from a buried basement in Chinatown, San Francisco."
Have you found that the industry changes depending on the country? Which projects did you work on in Australia?
"I have found that the culture of the tunnelling industry is very different in every country. North America is very innovative. North America’s geology requires extensive uses of soft ground tunnelling technology and they probably lead the world in that regard (although many Europeans would most likely object to this statement). I found England and Europe to have much more established industries, which made it difficult for a young foreigner to break into, however they methodically apply their technical know-how in a very precise manner to great success.
When I left Australia, the tunnelling industry was really only in its infancy compared to what it is today. I believe that Australia has the opportunity to develop their own unique industry."