BONNER – Winter work is well underway on what should be the last mass cleanup of contaminants from the banks of the Blackfoot River at the former Bonner mill site.
A third nest of polychlorniated biphenyls, or PCBs, was identified last year a couple of hundred feet from the riverbank at the site of the former compressor building.
An Envirocon excavator was making headway downward Thursday, removing dirt laced with varying degrees of PCBs that leaked from air compressors decades ago.
PCBs were used to increase viscosity in the likes of hydraulic fluid but were outlawed in the late 1970s, long before the mill's last owner, Stimson Lumber Co., arrived and not many years after Champion International bought the mill from the Anaconda Copper Mining Co.
“We just do not know where there could be any more sources,” Keith Large, project manager for the Montana Department of Environmental Quality, said Thursday. “The buildings are going to be gone. The equipment inside the buildings that leaked all the oil, they’re all gone.”
Excavation began in mid-January and the bottom of a hole 28 to 30 feet deep and some 200 feet long will be reached sometime next week. Large said the project should be wrapped up by mid-March.
Like the two phases before it, the “hottest” of the contaminated soils – in this case some 1,750 cubic yards concentrated in the middle of the site – is being hauled to an EPA hazardous waste site in southern Idaho. Three loaded trucks a day make the 600-mile trip to the site near Mountain Home.
Another 18 truckloads a day are hauling 3,300 cubic yards to Republic Services’ Missoula landfill 12 miles away. Large pointed out as a sheet of heavy plastic was laid in the bed of one of the contract trucks making the local hauls. It would be dumped along with the dirty soil in one area of the landfill. The truck would return with a load of clean soil from another part of the landfill to be stored near the dig site and used as fill when the time comes.
It’s the third and smallest cleanup project on the sawmill end of the lumber and plywood plant that were closed for good by Stimson in 2008.
Stimson and International Paper, the company that bought Champion in 2000, are footing the bill for all phases of a cleanup that began in 2010 with the removal of a cooling pond laced with PCBs and petroleum products that encroached on the Blackfoot River.
The discovery of even hotter contamination above the cooling pond site resulted in another remediation project. It was completed in 2014.
In May of the same year, mill owners Mike Boehme and Steve Nelson of Bonner Property Development LLC reported a new area of PCB contamination had been found during demolition of a brick building that once housed the “steam donkey” that ran the sawmill. Later, the structure became the compressor building and housed the equipment that replaced the mill's steam engine.
Sampling last year led to the current, climactic cleanup by Envirocon.
Steve Petrin, environmental manager for Stimson Lumber, said he’ll be glad to finally reach the end.
“But I’ll be back, I’m sure, probably a couple of times at least,” said Petrin, who was on site from the company’s Portland, Oregon, headquarters for a visit Wednesday and Thursday. “We actually have ongoing monitoring to finance. Typically our consultant does that, but we still have a finger in this.”
When Envirocon rebuilt 1,400 feet of riverbank after the cooling pond was removed, Stimson was required by the U.S. Army Corps of Engineers to continue inspections for five years. Those remain on the to-do list. Stimson is also responsible for monitoring a three-acre repository pile from the first cleanup that the mill owners and Missoula County are hatching a plan to remove.
Francis Tran of Denver, environmental engineer for the U.S. Environmental Protection Agency’s Region 8, also stopped by Bonner for a visit this week. A specialist in PCB cleanups, Tran has been assisting Montana DEQ, the lead agency in the Bonner project, since the start.
“Not many are this big,” he said.
This final phase, however, “is a small job really,” Large said. “Before there used to be about 12 people working for Envirocon. Right now it’s about six. The big heyday of this project is really kind of over, all the ‘How should we do this?’ and all the public meetings.”
“It’s good news for everybody,” said Nelson, the Missoula businessman who has partnered with Boehme to populate and energize the mill site since purchasing it in late 2011.
Seven industrial enterprises have joined the first post-mill tenant, Northwest Paint, including KettleHouse Brewing, which is building a large beer production plant in the old east log yard at the end of town.
“I think Stimson and Champion are ready for it to be done, and it’s good for us to know everything’s cleaned up,” Nelson said.
When the compressor building area is filled and leveled next month, one cleanup will remain.
Boehme and Nelson want to remove the unsightly repository pile that seems to be in the middle of everything beyond the mill site’s main gate. Despite county and community protests before the two bought the mill, Stimson was allowed by law to store some 37,000 cubic yards of the least contaminated soil from the cooling pond on site.
The owners and the county plan to remove it all to the Missoula landfill using proceeds from the Bonner Mill Tax Increment Finance district started four years ago.
As recently as two weeks ago, Nelson said it looked like that might happen by summer. But on Thursday he had an update.
“We just found out there just isn’t enough money in the TIF deal to have that done this year, so that’ll probably be a year away, I guess,” he said.
Dori Brownlow, Missoula County’s development district director, said removal of the repository pile “has been a priority out there for the TIF district.”
“But once we got an estimate on the cost, between $2 million and $3 million, it was clear the increment revenue hasn’t grown enough," Brownlow said. "We just need the increment district to be in place longer.”