Here's how the tunnel boring machine, or TBM, works: As the 200-ton TBM moves forward, a round cutter head studded with titanium teeth grinds into the tunnel face and splits large chunks off the rock.

The $1.6 billion dollar Central Interceptor is New Zealand's longest wastewater tunnel.

expansion achieved a major milestone as its tunnel boring machine reached its destination. Nicknamed "Chessie," the tunnel boring machine broke through the receiving pit on Two Island at Thimble ...