This new time-lapse video shows crews cutting and hauling away sections of the giant drill since it broke daylight in April.

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Goodbye, Bertha.

On Wednesday, crews disassembled and hauled away the last bits of the giant tunnel-boring machine from its South Lake Union disassembly pit, the Washington State Department of Transportation (WSDOT) reported.

The milestone caps four months work of taking apart the drill from both outside and inside the Highway 99 tunnel. The largest lift was 70 tons, WSDOT says.

“It was tricky, tough and impressive work, re-positioning the machine and dismantling its 8,000 tons of steel into pieces small enough to lift by crane or pull back out of the south end of the tunnel,” a WSDOT blog says.

The transportation agency released a time-lapse video Wednesday showing the whole disassembly process, following similar videos since Bertha finished its dig for the tunnel project in April.

Hitachi Zosen, the machine’s manufacturer, donated cutting tools and the control panel from Bertha to the Museum of History & Industry for future display, as well as gifted pieces of the machine’s cutterhead to the Port of Seattle, the blog says. Crews hauled most of the cutterhead, however, to a steel-recycle center in the local area.

The four-lane, tolled Highway 99 tunnel will replace the aging Alaskan Way Viaduct and is expected to open by early 2019. Crews will demolish the viaduct over nine months.

During Bertha’s dismantling, crews meanwhile worked on building the tunnel highway decks. (This interactive page breaks down the project’s progress.)

Wednesday’s milestone aside, WSDOT says it will keep its @BerthaDigsSR99 Twitter account running “because although the machine is gone, the product of her labors remains.”

Here’s a look back on Bertha’s tumultuous, years-long dig; we’ve covered the machine’s technical challenges and successes every step of the way.

  • The machine started slowly digging out of its launch pit in July  2013, beginning the 1.7-mile trip to South Lake Union. At 57 feet, 4 inches diameter, it was the world’s largest tunnel drill at the time.
  • Bertha overheated, failed to remove dirt, and was stopped by operators Dec. 6, 2013.  Contractors blamed an eight-inch diameter pipe, leftover from groundwater testing, that Bertha had hit three days before. The state maintains such a massive machine wouldn’t succumb to the pipe.
  • Crews excavated a 120-foot deep vault to lift and repair the drill’s 4 million pound front end, which machine builder Hitachi Zosen outfitted with a new circular main bearing and seals.
  • Bertha’s refurbished face was stacked and reassembled along the waterfront by August 2015, as others continued building the highway at the north and south portals.
  • On Dec. 22, 2015, Seattle Tunnel Partners workers powered up the machine.  Three weeks later, Gov. Jay Inslee suspended excavation when a sinkhole formed over the tunnel route.
  • After restarting in late February 2016, Bertha made consistent progress, with scheduled breaks for crews to inspect and replace the machine’s cutting tools. No significant soil or building settlement has been detected since then.
  • The machine broke into daylight near Seattle Center on April 4, 2017, some 29 months later than the original goal of October 2014.
  • Court disputes persist over the giant machine’s fitness when it arrived in Seattle, whether the pipe strike triggered the 2013 breakdown, and who will pay what share of a half-billion dollars in delay costs.

Material from The Seattle Times archives contributed to this report.