After more than a year of plowing more than 200 feet below the streets of metropolitan Cleveland and Lake Erie, Mackenzie, the 1,500-ton tunnel boring machine, completed her three-mile journey of clearing the way for a new 24-ft diameter tunnel that will help address longstanding sewage and stormwater pollution in Northeast Ohio.

According to the Northeast Ohio Regional Sewer District (NEORSD), Mackenzie broke through the last barrier of shale separating her and the new Euclid Creek Tunnel’s shaft 5 at 1:27 am Wednesday morning, August 21. 

The 18,000-ft tunnel is part of the NEORSD’s Project Clean Lake, a $3 billion, 25-year program to address combined sewage overflow (CSO) problems that have plagued the region for decades. When complete in 2015, the $197 million tunnel will control more than 60 million gallons of CSO flows during rain events.

Five additional tunnels are planned, joining the already complete 75-million gallon Mill Creek Tunnel, plus treatment plant and stormwater management system enhancements.

Mackenzie was manufactured in Germany by Herrenknecht, with some parts incorporated in China during her assembly and testing phase. Named for the daughter of an employee of McNally-Kiewit, contractor for the Euclid Creek Tunnel, the 300-ft long TBM may be less well known as some of the other TBMs currently working on major U.S. infrastructure projects, but she was the first to be given a Twitter handle.

Mackenzie’s feed debuted in May 2012, just before her 345,000-lb, 27-ft diameter cutterhead was lowered underground.

“The Sewer District has several huge programs underway, and social media has helped us share them and their value more creatively,” explains John Gonzalez, NEORSD’s Senior Communications Specialist & Social Media Coordinator who has been one of Mackenzie’s “voices” for the past year. “Most of our Twitter activity takes place on our mascot and spokesdrop Wally Waterdrop’s account, but we created a Mackenzie handle with the thought that the two voices could play off of each other.”

Gonzalez says that while Mackenzie’s tweets were initially limited, “when I saw DC Water's LadyBird tweet and saw the connections she had, I loved it.”

As other TBMs joined the Twittersphere, Mackenzie became part of an exclusive Twitter “roundtable” that helped share information across the industry and the general public about each project’s challenges and progress. NEORSD also provided #TrackMac tweets that provided GPS snapshots of Mackenzie’s location, and “home movies” on YouTube and other social media platforms.

Her boring work done, Mackenzie will be disassembled, cleaned up, and prepared for a new assignment. Gonzalez says it’s unlikely other equipment on NEORSD’s major projects will become part of the Twitterati, but that could change as the use of social media to connect with the public continues to evolve.

“If a new account will help customers or colleagues better understand our work in the community, industry, or environment and we can keep it current, we’ll consider it,” he says.