First piece of massive tunnel-boring machine lowered Monday

The first piece of " MamaJo" was lowered into position Monday. (Photo courtesy city of Fort Wayne.)

Construction crews at the working shaft of Fort Wayne’s deep rock sewer tunnel lowered the first piece of MamaJo, the Tunnel Boring Machine (TBM), into the ground Monday. The cutterhead was hoisted down the 220-foot working shaft. At 200 tons and 16 feet long, the cutterhead is one of the many pieces that will make up the TBM.

With a diameter of more than 19 feet and stretching more than 400 feet in length, Mamajo will begin her journey on one of the most significant public infrastructure projects in the history of Fort Wayne. She will grind through bedrock to build a five-mile-long sewer tunnel, more than 200 feet beneath the surface, with an interior diameter of 16 feet.

The tunnel is a significant portion of the effort to clean-up Fort Wayne’s rivers and protects neighborhoods from basement back-ups and street flooding and, when completed, will reduce the amount of combined sewer overflow going into the rivers by more than 90 percent — a reduction of more than 850 billion gallons on average each year.

Crews will continue lowering pieces and connecting them underground over the next two months. Full assembly of the TBM should finish by early spring of this year, and completion of boring is expected by 2021, with the tunnel becoming operational in 2023.

The name MamaJo takes the first two letters from Fort Wayne’s three rivers, the Ma from Marys, Ma from Maumee and Jo from Joseph. Residents can learn more and get tunnel updates at