3M set for soil removal
3M's cleanup of a chemical-contaminated former waste site in southeast Woodbury is under way.
Crews were on site this week and the company next week will begin excavating soil contaminated with perfluorochemicals, or PFCs, from two areas within the 40 acres once used by the company as a landfill. Excavation and refill of the areas will continue into October.
The company used the former municipal and industrial dump site from 1960 to 1966 to dispose waste from its Cottage Grove Chemolite plant. That waste contained PFCs. 3M reached an agreement with the Minnesota Pollution Control Agency in 2007 to clean the site east of Woodbury Drive and south of Dale Road.
Contaminated soil removal this fall will be concentrated in two areas totaling about 2 acres, said Katie Winogrodzki, 3M project manager and geoenvironmental engineer. The company plans to excavate a third dump site of about 2 acres next summer or fall, she said.
When excavation begins in the coming days, crews first will remove 4 feet of topsoil from the two areas and set it aside to be used as refill. It was used as landfill cover and is free of the PFCs, 3M officials said.
Below the landfill cover is 8 to 12 feet of contaminated soil that will be dug out and hauled from the site. Mike Corbin, an engineer with 3M contractor Weston Solutions, said 11,500 cubic yards of soil will be removed.
Trucks with large dumping trailers will transport most of the contaminated soil to SKB Disposal in Rosemount. Plastic will be used to prevent the contaminated soil from contacting the trailer bed. Once the excavated soil is delivered to SKB, loads of clean dirt provided by SKB will be hauled to the 3M location for use as fill.
Any soil that includes a concentration of solvents higher than is allowed to be disposed at SKB will be transported to a Michigan disposal site, Winogrodzki said.
Trucks hauling contaminated soil must use a specific 17-mile route. They will travel south on County Road 19 before heading north on Highway 61. From Highway 61 they will travel west on I-494 and then south on Highway 52.
Trucks will only haul between 9 a.m. and 3 p.m. 3M says an average of 25 truck trips will be made daily.
"We're trying to avoid those rush-hour patterns on the local highways," Corbin said.
3M's remediation plan already includes a well system to contain groundwater at the site. That well system, which pumps the water underground for use at 3M's Cottage Grove manufacturing plant, will continue to be used after the excavation.
3M must pay for the remediation. Company officials did not say how much that will cost, but an estimate included in a 2008 3M filing with the Pollution Control Agency put the project cost at $12.7 million, said Walker Smith, a senior information officer with the agency.
Bill Nelson, 3M's environmental communications manager, said the company will spend whatever is needed to properly remove contaminates from the site.
"Our goal is an effective clean-up," Nelson said.