A China-manufactured tunnel boring machine (TBM), said to be one of the world's biggest, has completed its role in New Zealand's biggest ever road building project.
Transport officials said on Monday that the machine, dubbed Alice, would be taken apart and returned to its German owners after its two-year project to drill two tunnels each 2.4 km long.
One of the largest TBM's ever used in the Southern Hemisphere, Alice completed its work on the Waterview Connection, a link in a motorway network through the largest city of Auckland, early Monday.
"Although it's the end of the road for Alice she will leave behind a lasting legacy, the world class tunnels she helped construct that will benefit Auckland and New Zealand for 100 years and more," New Zealand Transport Agency (NZTA) highways manager Brett Gliddon said in a statement.
Work on the twin three-lane tunnels, the longest road tunnels in the country, began in 2013, and the first tunnel was completed in September 2014.
In a rare maneuver for any TBM worldwide, Alice was then turned 180 degrees to complete the second drive.
Alice excavated enough dirt to fill 320 Olympic-sized swimming pools and installed more than 24,000 concrete segments to line both tunnels.
The NZTA planned to open the tunnels in early 2017.
The state-of-the-art machine was designed and built over 14 months at Germany's Herrenknecht factory in Guangzhou, south China's Guangdong Province, specifically to drill the Auckland tunnels.
The TBM's circular cutting head was more than 14 meters wide, the equivalent of a building four storeys high.
The 87-meter-long machine arrived in Auckland in 97 separate parts and was reassembled by a team of 30 in a 30-meter-deep trench at the tunneling site over three months.
It moved at a speed of 80 mm a minute, or 0.0005 km per hour.
