Michigan-based Great Lakes Tunnel Constructors will construct the tunnel to house a new Line 5 in the Straits.

Great Lakes Tunnel Constructors is a partnership between Michigan firm, Jay Dee Contractors, Inc., and the U.S. affiliate of Japanese tunnel construction firm, Obayashi Corporation.

Enbridge has also selected Arup to deliver construction design documentation for the Great Lakes Tunnel Project.

The proposed tunnel is 4.1 miles (6.6km) long, mined by TBM approximately 100ft (30.5m) below the strait’s lakebed. The finished diameter is likely to be 10ft, with a one foot thick concrete lining. The estimated USD 500M project will be privately funded.

“The Great Lakes Tunnel Project is essential to Michigan’s economic vitality and long-term energy security,” said Brad Shamla, VP of U.S. Operations at Enbridge. “It will enable residents, schools and businesses to continue to receive critical fuel and the thousands of products Line 5 helps make possible while increasing environmental safeguards and protection of the Great Lakes.”

Great Lakes Tunnel Constructors’ project team has a collective track record of constructing over 400 pressurized-face tunnels consisting of more than 2.4 million feet of tunnelway. A number of those projects involved high pressure and ground condition parameters similar to those that will exist in the Straits of Mackinac.

“We are pleased to be part of the biggest infrastructure project in Michigan,” said Timothy Backers, project manager with the Great Lakes Tunnel Constructors. “We have worked successfully on some of the largest tunnel projects throughout the world, though there is an extra measure of pride in being selected to work on a project where we can make another vital contribution to our home state.”

Enbridge anticipates construction of the Great Lakes Tunnel Project will begin in 2021. Following approximately two years of construction, Enbridge expects to place the new Line 5 segment into service in 2024.