When a sinkhole all but shut down a section of West Seventh Street last Thursday evening, St. Paul Public Works officials soon discovered they had their work cut out for them.

Large enough for a person to fall into, the hole is some 35 feet deep, and repairs could take up to two months. Contractors will dig more than 30 feet through sandstone and limestone, assess the extent of the damage and then rebuild the sanitary sewer tunnel.

The work, which got underway Monday, also will entail installing new utility connections for surrounding businesses, building out a new shaft to the surface and then replacing the road surface, according to St. Paul Public Works Director Sean Kershaw.

Those efforts will take place inches from a 20-inch water main and adjacent to vehicles, pedestrians and businesses in the busy section of West Seventh Street located between Kellogg Boulevard and Grand Avenue. To prevent a collapse and ensure worker safety, crews will install temporary supports for the entire depth of the project.

The majority of that work will be handled by specialized private contractors, Kershaw said.

It’s “still too early to determine a cause of the sinkhole on West 7th Street; however, voids are often caused by water,” Public Works spokeswoman Lisa Hiebert said by email. “We continue to monitor the area, but there are no other areas of concern that have been identified at this time.”

The affected area of West Seventh is open for local business access only, with one lane of traffic in each direction. Sidewalks remain open for pedestrians. Detours have been posted, and no impacts to water or sewer services have been reported for local businesses.

“The quick actions and expertise of our St. Paul Public Works and St. Paul Water Services crews made it possible to safely address the sinkhole on West Seventh Street,” said Mayor Melvin Carter, in a social media post on Friday. “Thank you for showing up and staying late into the night to get this done. West 7th is open for business!”