An impressive sinkhole that opened up Sunday at an Uptown Minneapolis intersection was caused by a collapsed clay sewer pipe that's been in use since 1903, officials said Monday.
Curtis Stallings, general foreman of sewer construction for the city, said the sewer pipe — already stressed by age — fell apart following this year's high-frequency freeze-thaw cycle and abrupt snowmelt.
Stallings said a temporary bypass was expected Tuesday, a permanent new PVC pipe would be installed by Wednesday, and that the street should be patched up by April 21.
The sinkhole, roughly 10 feet deep and 5 feet wide, opened in the middle of the intersection of W. 27th Street and Girard Avenue S. Workers on Monday were diagnosing the hole from within, descending beneath the street and working from inside a trench shield, a reinforced box designed to protect them in the event of a cave-in.
Meanwhile, residents of the surrounding neighborhood were still able to flush their toilets because the city was running a rotation of vacuum trucks that can collect two blocks' worth of wastewater at a time.
"We have invested into the vehicles and things to make sure people can continually live their daily lives," said Stallings, who was less fazed by the girth of the sinkhole than by all the people with cameras swarming it. He's seen bigger sinkholes in his 18 years with the Public Works Department, he said.
CenterPoint Energy workers were also at the site checking the condition of the nearby gas main.
The problem comes as public works crews tackle a plethora of potholes in Minneapolis. The city has pledged $1 million extra to fill the city's pockmarked streets.
