Ontario Power Generation

Building a Monster Tunnel

Digging a tunnel 14.4 metres (47.3 feet) wide, at a depth of up to 140 metres (500 feet), and for a total distance of 10.2 kilometres (6.3 miles) is a task of major magnitude. Where do you start? The short answer is safety: safety first and safety last. The long answer is, make safety your top priority and then stick to that priority no matter what conditions you encounter.

Who Builds It?

OPG contracted Strabag AG, an Austrian construction firm, to build the Niagara Tunnel. This company is recognized worldwide for its expertise in tunnel construction. The majority of the workers who make it happen, however, are Canadian.

What You Need: The World's Biggest Rock Muncher

To build a tunnel of the size that OPG envisions, you need a very, very big drilling machine. So in 2006, the Strabag experts shipped in machinery parts from all over the world to the job site at Niagara Falls. They brought parts in by road, by sea, and by rail. And then they built the largest hard-rock Tunnel Boring Machine (TBM) in the world: Big Becky. At an incredible 150 metres (500 feet) in length and 14.4 metres (47.3 feet) in height, Big Becky deserves her name. She weighs more than 4,000 tonnes (4,400 tons).

What's it Called?


Does "big" suit Big Becky? Get a better idea of the immensity of this giant drilling machine by spotting the workers at the top of the machine.

According to tradition, a Tunnel Boring Machine needs a name before work begins. The students in Mr. Dyck's Grade 6 class at Port Weller Public School in St. Catharines wanted to enter the naming contest for the giant drill. They knew the important role Sir Adam Beck had played in developing hydroelectricity in Ontario. However, they couldn't name the Tunnel Boring Machine after him because, like ships, all Tunnel Boring Machines have female names. So the class converted Adam Beck's last name to "Becky" and added the descriptor "Big" to create their award-winning entry.



What's in a name? Mr. Dyck's Grade 6 class was the proud winner of the Tunnel Boring Machine naming contest.

What is it? A showerhead? A space capsule? Not even close. It's just the largest hard rock Tunnel Boring Machine in the world!

• Number of hard rock boring machines in the world equal to the size of the Niagara Tunnel Boring Machine (TBM): 0
  
  
• Diameter in metres of the TBM compared to the Chunnel boring machine: 14.4 vs. 8.6
  
  
• Length in kilometres of the Niagara Tunnel: 10.2
  
  
• Cubic metres of rock and dirt it will chew through: 1.7 million
  
  
• Cubic metres of concrete needed to line the Niagara Tunnel: 400,000
  
  
• Cubic metres per second of water entering the Niagara Tunnel: 500
  
  
• Annual kilowatt hours of new electricity to be produced for Ontario: 1.6 billion
  
  
• Number of homes this electricity can serve: 160,000
  
  

• Imbokodo—A TBM used to drill a tunnel for a high-speed railway line in South Africa. "Imbokodo" means "rock," the name of honour given to the brave women who marched against injustices in South Africa in 1956.
  
  
• Xiaolongnu—A TBM used to drill a tunnel for a railway line in Hong Kong. Xiaolongnu was named after the heroine of a popular martial arts book, "The Return of the Condor Heroes."
  
  
• Pipi—One of two TBMs used to drill an undersea tunnel for a desalination project in Australia. "Pipi" was the name of a precocious heroine of a Swedish book for children.
  
  
• Delilah—A TBM used to drill a tunnel for a sewage improvement project in the United Kingdom.