Demolition work on the Metrodome will resume soon, but it's unclear exactly when.

On Monday afternoon, demolition of the Dome was halted after a beam on the Dome unexpectedly fell out of sequence in the teardown. The 32-year-old Dome is being torn down to make way for the new $1 billion Vikings stadium that will sit roughly on the same spot in eastern downtown.

Allen Troshinsky, director of operations for stadium general contractor Mortenson Construction, told the Minnesota Sports Facilities Authority on Wednesday that an investigation is being conducted to see what exactly happened, and what, if anything, needs to be done to make sure it doesn't occur again. The authority is the public body overseeing construction of the stadium.

Troshinsky estimated that demolition will commence in the "next several days," but he declined to be more specific. The stadium's tight construction deadline — which calls for the new facility to open by July 2016 — has not been compromised by the excavation incident.

No one was injured on Monday, and all debris fell within the demolition safety zone, so no passersby were at risk of injury.

Crews for St. Paul-based subcontractor Frattalone Cos. were working to bring down a section of ring beam in the east-southeast section about 1 p.m. when an adjacent section unexpectedly came down. No equipment was damaged.

Meanwhile, work continues elsewhere on the site, including excavation work and the installation of concrete columns on the site's east side. A second construction crane is expected to arrive this week, with a third coming in March, Troshinsky said. About 100 people are currently working on site; that number is expected to increase soon.

Janet Moore • 612-673-7752