The three-year, $343 million project designed to rebuild the "can of worms" interchange through Lincoln Park will be delayed a full year, the Minnesota Department of Transportation said Wednesday.

The MnDOT office in Duluth said it requires more time to figure out what it's going to do with contaminated materials that have been located under the elevated sections of freeway throughout the project.

The massive project was designed to reduce merging hazards, allow heavy loads, and take many of the raised sections of Interstate 35 to ground level. The project was scheduled to begin in May. Some ancillary work will remain on the calendar to begin later this fall, MnDOT said, but significant lane closures won't begin until next year.

“One of the main reasons we are delaying the project is unfortunately there is so much contamination in the work area," MnDOT spokesperson Pippi Mayfield said. "By delaying the work on I-35 a year, we can get a better handle on how to treat the contaminated soil and water.”

The delay means that the most disruptive elements of the project won't start until 2021. Beginning next spring, each direction of I-35 will be reduced to one lane. Starting that fall, the northbound lane will remain on the interstate, while southbound traffic will move to Lower Michigan Street. The lane restrictions will continue through 2023, and final touches on the project may now stretch into 2024, MnDOT officials said.

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Jodi Slick, chief executive officer for Ecolibrium 3, a Lincoln Park development organization, told the News Tribune the deferral of the project was something of a relief, adding that she has appreciated MnDOT's professionalism and outreach throughout the planning stages.

"They've been very strategic over time, and we think this is a good decision for the project," Slick said. "Specifically to the Lincoln Park neighbor, this timing is actually probably preferred; it gives us one additional year to get some of the infrastructure and development pieces in place in the neighborhood."

The project at the confluence of I-35, Interstate 535 and U.S. Highway 53 has proven to be more complex than it even appears on the surface. In November, MnDOT announced cost overruns of $100 million, necessitating the need to defer two major portions of the work on Highway 53 through the heart of the Lincoln Park neighborhood and I-535 through the port.

Duane Hill, district engineer for MnDOT in Duluth, said the project's budget remains at $343 million, and the latest delay won't change that.

"The parts that we deferred are pretty significant in cost," he said, "and we don't anticipate being able to bring those back into the project at this time."

Asked if the one-year delay creates a risk of increasing project costs, Hill said better examination of the contaminants "is actually going to help manage the project within the budget."

"We think there are some opportunities, if we have a few more months to work on it, to treat the soil appropriately, environmentally and do it in a more economical manner," Hill said. "So we just made a joint decision with the contractor that it would be best to delay the start of the project to give us basically five more months to work on our our plan."

Some work will still get underway by this September to satisfy a $20 million grant from the U.S. Department of Transportation. Hill said there may be intermittent lane closures, but much of the work would involve things like bridge substructures that won't affect traffic. He said cranes and other heavy equipment will probably arrive on scene and work through the winter months.

The News Tribune previously has addressed with MnDOT engineers the soil and water contaminant issues that have emerged in preparation work for the project.

The complexity of the situation was not lost on the engineers when they addressed cost overruns in December:

  • Water: There’s a high water table throughout the project, meaning water is not far down with any dig. Every hole will require wells or water to be pumped or have sheet piling driven to hold back the intrusion of water. Contaminated water will need to be treated, either by the nearby Western Lake Superior Sanitary District or by costly on-site treatments. “It's preliminary, but it looks like a good deal of the water can be taken by WLSSD — but not all of it,” Pat Huston, major projects and assistant district engineer, said in December.

  • Soil: MnDOT has produced something of a heat map, which shows the worst and most contaminated soils on the project following a path along and under the I-35 corridor. Everything glowing red features contaminants such as asbestos-containing materials from the days when buildings were leveled and their remains sown into the ground. Much of the dirt will have to be trucked (an endless $2 per minute service) to certified landfills and replaced with new, clean fill. What can be salvaged and used as fill currently has nowhere to go, as stockpile areas are limited throughout the corridor. The state won’t use the enticing BNSF railyard because the engineers say the railroad would want the state to indemnify it against whatever happens in the future at the site.

News Tribune staff writer Tom Olsen contributed to this report.

This story was updated at 5:13 p.m. March 11 with additional information and quotes from MnDOT officials. It was originally posted at 1:41 p.m. March 11.