World’s largest hard rock water tunnel boring machine debuts in Dallas

World’s largest hard rock water tunnel boring machine debuts in Dallas

The City of Dallas unveiled the Big Tex tunnel-boring machine (TBM)  at the Mill Creek Drainage Relief Tunnel. The 38-ft by 230 ft long machine is the largest hard rock water tunnel boring in the world at the time tunneling begins. Big Tex will be used to dig a tunnel designed to provide flood protection for east and southeast Dallas. 

“The completion of the TBM assembly marks a major milestone in the Mill Creek Tunnel Project,” said Council Member Lee Kleinman, chair of the Transportation and Infrastructure Committee. “I’m thrilled to see this type of engineering marvel happening right here in Dallas.”

The dual-diameter aspect of the TBM will be a first-of-its-kind conversion process. Big Tex will tunnel the first 9,000 feet of the project, then our team will work completely within the tunnel to remove the outer pieces of the cutter head to convert the overall diameter from 37.7-feet to 32.6-foot diameter. Once the conversion is complete, Big Tex will continue tunneling the remaining 17,000 feet of the project alignment.

“I’m proud to say the project takes measures to minimize impacts to local residents and commercial properties, while enhancing economic value and bringing flood relief and flood protection to a large segment of our community,” said Majed Al-Ghafry, assistant city manager, City of Dallas.

Southland Holdings and it’s subsidiary companies Southland Contracting and MOLE Constructors are working on this project and will be hiring over 300 employees to work on the Mill Creek Tunnel Project.

“Big Tex will work 24 hours a day to excavate the tunnel with crews ranging in size depending on activities,” said Rachel Sackett, marketing and communications director, Southland Holdings. “With a project of this size, we are always hiring those eager to grow their career or learn a new skilled trade. We encourage those seeking job opportunities to visit our website.”

It’s considered good luck for a TBM to be given a name. With the permission of the State Fair of Texas, the TBM is named Big Tex for its size (everything is bigger in Texas), proximity to the State Fair and iconic name known around the world. 

The project is scheduled for completion in 2023.


Written by Nichelle Sullivan

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