The recoverymission to get Bertha running again is a massive undertaking, due in part to the sheer scale of the machine

Big Bertha: World’s Largest Tunneling Machine To Be Rescued

Big Bertha, the world’s largest tunneling machine, is currently at rest underneath Seattle, yet engineers have devised a way to re-animate the stranded behemoth.

One of the world’s biggest recovery missions is planned for Bertha, which has lain dormant since striking an underground obstacle 1,000 feet into a planned two-mile dig last December, Gizmodo reports. Due to the sheer scale on which Bertha operates, the rescue will be a massive undertaking. If all goes according to plan, Bertha will be operating again in March of 2015, 16 months after she came to a halt, as The Inquisitr reported.

To begin with, crews will need to dig a vertical tunnel to reach Bertha before bringing a specialized crane on-site to remove the machine’s nose, which weighs a staggering 2,000 tons. Before the drilling mechanism is reattached, it will be reinforced with nearly 200 tons of steel. Japanese engineers from the company that built the tunneling machine will also work to repair Bertha’s precision bearings, which were damaged by debris, according to The New York Times.

Bertha currently sits 120 feet underground, which makes reattaching the nose an intricate and delicate process, despite the scale of the engineering involved. Project managers have compared re-fitting Bertha’s massive drill to placing a rebuilt engine into a family car. With a diameter of 57.5 feet, or five stories across, the sheer size of Bertha leaves little room for engineering error.

Exactly what stopped Bertha in its tracks is a subject of much dispute with huge amounts of money at stake. The company that built the tunneling machine contends that a buried eight-inch-diameter steel pipe is to blame for Bertha’s malfunctions, yet transportation experts for the state say the the pipe likely had nothing to do with the problems. Chris Dixon, the project manager at Seattle Tunnel Partners, says that the pipe was not identified in the contract, and therefore is the state’s responsibility. The pipe was installed in 2002 to monitor groundwater.

Whatever the eventual outcome of the dispute, it will still be some time before Bertha returns to digging its tunnel under Seattle.

[Image via 4plebs]