By . Marie-louise Olson . and Ryan Gorman . An unknown object that fascinated the country last month when it stopped the world’s most powerful tunnel boring machine digging underneath Seattle has finally been identified. And officials are shocked. The object is nothing more than an 8-inch diameter steel pipe, but it managed to grind to a halt an $80 million machine that is five-stories high with the world’s widest cutting face. Blocked by a pipe: The left image shows the steel pipe protruding through the machine's cutterhead. It has caused the massive boring machine to grind to a halt underneath Seattle . Identified: The project crew tweeted about their discovery on Thursday . Crews struggled for weeks to reach the object that was blocking ‘Bertha’, the boring machine, from moving forward 60 feet below the surface after it got stuck on December 6. After removing enough water and dirt they finally laid eyes on the mystery object. It is a 115-foot-long well casing that was used to measure ground water in 2002 in studies for the Alaskan Way Viaduct replacement project, according to the Seattle Times. The incident has put project officials in a predicament with much to explain to tax payers, as they squabble over whose fault it is, and why the pipe was not known about before the project began. The well site was listed in reference materials provided to bidders as part of the contract specifications, according to the Washington State Department of Transportation (WSDOT). SCROLL DOWN FOR VIDEO... Taking shape: The tail end of Bertha can be seen up ahead of where a worker inspects the tunnel wall . Bertha is a five story-high drilling machine that was custom-built to drill the Alaska Way Viaduct tunnel beneath Seattle. It has more than 20 workers controlling it and drills a hole more than 57 feet in diameter. It can move six feet at a time and uses cutting tools are removable and are often replaced. For all its high technology, Bertha essentially operates blind; there are no front windows or cameras. It was named after Bertha Knight Landes, Seattle's only female mayor. ‘I don’t want people to say WSDOT . didn’t know where its own pipe was, because it did,’ said spokesman Lars . Erickson to the Times. However, . Chris Dixon, project director for contractor group Seattle Tunnel . Partners, said the builders presumed there would be no pipe in the way, . because casings are customarily removed after use. The . tunnel-machine crew first noticed metal pieces in Bertha’s conveyor . system in early December, after Bertha’s rotation shoved a 55-foot-long . segment of the pipe through the surface. But that didn’t stop the machine, which kept grinding forward just fine, according to Dixon. Officials initially thought it was likely a bolder that was blocking the massive machine. Dixon . told KIRO-TV the tunnel boring machine is able to cut through rock, . clay and concrete, but it can’t battle metal objects very well. Confusion: Matt Preedy from WSDOT, left, and Chris Dixon, project director for contractor group Seattle Tunnel Partners, right, are in conflict over whose fault it is that no one had anticipated the pipe . He . said pipes used for ground-water measuring are usually removed . afterward, which is why the crew did not expect to find the steel . casing. ‘We didn’t know the pipe was there. If we knew it was there, we would have removed it,’ said Dixon. Matt . Preedy from WSDOT refused to comment on whether the incident was due to . someone not reading the reference materials correctly. A plan for how the pipe will be removed has not yet been announced. Bertha is helping dig a tunnel that will replace the Alaskan Way Viaduct on Highway 99. The . problem with just walking down to the object is that it isn’t possible, . Bertha uses huge amounts of pressurized water to help it drill through . the earth. That water will . need to be drained for humans to safely enter. Massive: This is just one piece of Bertha, shown here while being built last year in Japan . A whole roster: It takes a team of 20 people to operate Bertha . How it works: Bertha bores through and breaks up large objects to move them out of the way on a conveyer belt . In the weeks leading up to the object being identified, many Seattlelites . joked about it being missing former Teamsters . leader Jimmy Hoffa, others thought it could be a buried train engine. Others thought it might date back to prohibition, or even further to the gold rush. Readers responding to the Seattle Times asking what they think the object is guessed everything from an asteroid to comedian Andy Kaufman or a UFO. The . number one response, though, was superstar defender Richard Sherman – . famous for shutting down opposing wide receivers almost every week, . The . tunnel is being dug to sink highway 99 underground for a two-mile . stretch down town in an effort similar to Boston’s big dig. The ambitious waterfront project was estimated to cost $3.1billion and be traffic-ready by late 2015.
'Unknown object' is an 8-inch diameter steel pipe casing .
It made the world's largest boring machine, 'Bertha', grind to a halt last month .
Officials are in conflict over why no one knew the pipe was there .
The highway tunnel is being dug 45 feet below ground .
Officials first believed it had struck a large boulder .
The $80 million boring machine is five-stories high .
By . Marie-louise Olson . and Ryan Gorman . An unknown object that fascinated the country last month when it stopped the world’s most powerful tunnel boring machine digging underneath Seattle has finally been identified. And officials are shocked. The object is nothing more than an 8-inch diameter steel pipe, but it managed to grind to a halt an $80 million machine that is five-stories high with the world’s widest cutting face. Blocked by a pipe: The left image shows the steel pipe protruding through the machine's cutterhead. It has caused the massive boring machine to grind to a halt underneath Seattle . Identified: The project crew tweeted about their discovery on Thursday . Crews struggled for weeks to reach the object that was blocking ‘Bertha’, the boring machine, from moving forward 60 feet below the surface after it got stuck on December 6. After removing enough water and dirt they finally laid eyes on the mystery object. It is a 115-foot-long well casing that was used to measure ground water in 2002 in studies for the Alaskan Way Viaduct replacement project, according to the Seattle Times. The incident has put project officials in a predicament with much to explain to tax payers, as they squabble over whose fault it is, and why the pipe was not known about before the project began. The well site was listed in reference materials provided to bidders as part of the contract specifications, according to the Washington State Department of Transportation (WSDOT). SCROLL DOWN FOR VIDEO... Taking shape: The tail end of Bertha can be seen up ahead of where a worker inspects the tunnel wall . Bertha is a five story-high drilling machine that was custom-built to drill the Alaska Way Viaduct tunnel beneath Seattle. It has more than 20 workers controlling it and drills a hole more than 57 feet in diameter. It can move six feet at a time and uses cutting tools are removable and are often replaced. For all its high technology, Bertha essentially operates blind; there are no front windows or cameras. It was named after Bertha Knight Landes, Seattle's only female mayor. ‘I don’t want people to say WSDOT . didn’t know where its own pipe was, because it did,’ said spokesman Lars . Erickson to the Times. However, . Chris Dixon, project director for contractor group Seattle Tunnel . Partners, said the builders presumed there would be no pipe in the way, . because casings are customarily removed after use. The . tunnel-machine crew first noticed metal pieces in Bertha’s conveyor . system in early December, after Bertha’s rotation shoved a 55-foot-long . segment of the pipe through the surface. But that didn’t stop the machine, which kept grinding forward just fine, according to Dixon. Officials initially thought it was likely a bolder that was blocking the massive machine. Dixon . told KIRO-TV the tunnel boring machine is able to cut through rock, . clay and concrete, but it can’t battle metal objects very well. Confusion: Matt Preedy from WSDOT, left, and Chris Dixon, project director for contractor group Seattle Tunnel Partners, right, are in conflict over whose fault it is that no one had anticipated the pipe . He . said pipes used for ground-water measuring are usually removed . afterward, which is why the crew did not expect to find the steel . casing. ‘We didn’t know the pipe was there. If we knew it was there, we would have removed it,’ said Dixon. Matt . Preedy from WSDOT refused to comment on whether the incident was due to . someone not reading the reference materials correctly. A plan for how the pipe will be removed has not yet been announced. Bertha is helping dig a tunnel that will replace the Alaskan Way Viaduct on Highway 99. The . problem with just walking down to the object is that it isn’t possible, . Bertha uses huge amounts of pressurized water to help it drill through . the earth. That water will . need to be drained for humans to safely enter. Massive: This is just one piece of Bertha, shown here while being built last year in Japan . A whole roster: It takes a team of 20 people to operate Bertha . How it works: Bertha bores through and breaks up large objects to move them out of the way on a conveyer belt . In the weeks leading up to the object being identified, many Seattlelites . joked about it being missing former Teamsters . leader Jimmy Hoffa, others thought it could be a buried train engine. Others thought it might date back to prohibition, or even further to the gold rush. Readers responding to the Seattle Times asking what they think the object is guessed everything from an asteroid to comedian Andy Kaufman or a UFO. The . number one response, though, was superstar defender Richard Sherman – . famous for shutting down opposing wide receivers almost every week, . The . tunnel is being dug to sink highway 99 underground for a two-mile . stretch down town in an effort similar to Boston’s big dig. The ambitious waterfront project was estimated to cost $3.1billion and be traffic-ready by late 2015.
8-inch diameter steel pipe, but it managed to grind to a halt an $80 million machine that is five-stories high with the world’s widest cutting KIRO-TV the tunnel boring machine is able to cut Partners, right, are in conflict over whose fault it is that no one had anticipated the pipe . He . ‘We didn’t know the pipe was there. If we knew it object is that it isn’t possible, . Bertha uses is being dug to sink highway 99 underground for a