Helena Sand and Gravel has been awarded the first of multiple contracts to excavate and transport mining waste from the Mike Horse Dam Superfund site in the headwaters of the Blackfoot River.
The Helena company submitted the winning bid of $7.2 million to the Montana Department of Environmental Quality for a two-year contract that will remove the majority of the upper Mike Horse mine tailings impoundment. The company will employ 26 workers during the project with 11 side-dump semi trailers moving waste 6.5 miles from the excavation site to a repository off U.S. Highway 279, where the waste will be stored and capped. The project starts on July 21, with hauling expected to begin by mid-August.
“It’s a really neat project in a really cool spot — not a bad place to spend the summer,” said Jason Fenhaus, project manager for Helena Sand and Gravel.
The company plans to shift four regular employees to the project, and then hire 22 more in the Helena and Lincoln areas. Helena Sand and Gravel contracted in 2010 to work on Meadow Creek Road to the impoundment. Company officials feel fortunate to get the contract, given their familiarity with the area and engineers already working on the project, Fenhaus said.
Officials plan to close Meadow Creek Road to the public during the excavation and hauling.
Because of the hazards associated with moving mine tailings, employees must undergo 40 hours of special training through OSHA called HAZWOPER before beginning work, he said.
Helena Sand and Gravel has worked on Superfund sites since 2004, Fenhaus said. The biggest challenge with the Mike Horse project is dealing with highly saturated soils and just getting the material onto street-legal vehicles. Once excavated, the contaminated soil must be moved on off-road trucks and then transferred onto the semi trailers, he said.
Fenhaus hopes to work into late October or early November, but weather will determine how long workers can haul. They plan to have the material moved by October of next year, he said.
Total funding for the cleanup, including the operation of the water treatment plant, comes in just shy of $50 million.
The Montana Department of Transportation specified a public safety plan for the project to deal with increased truck traffic, including a reduced speed limit. Meadow Creek Road intersects U.S. Highway 200 on a tight curve at the bottom of Rogers Pass. Helena Sand and Gravel will have traffic spotters east of Meadow Creek Road as well as radar speed reminder signs to alert motorists of work crews in the area.
“Safety is our top priority on this project,” said Shellie Haaland, DEQ construction manager. “We want to make sure the traveling public is aware of what we are doing and we encourage people to call us if they see anything of concern.”
In 1975, the berm on Mike Horse Dam blew out and between 100,000 and 200,000 cubic yards of mine tailings washed down the drainage and into the Blackfoot River. The waste devastated aquatic life for miles downstream.
Officials then diverted Bear Trap Creek around the impoundment and built a water treatment facility to deal with waste water from mining adits.
As the final phase of Helena Sand and Gravel’s contract, Bear Trap Creek will be returned to flow down its historic path in the bottom of the drainage, Haaland said.
“I’m quite pleased with getting this actually going, and by next year we should have the creek back in the bottom by the 40th anniversary of the blowout,” she said.
After the two-year Helena Sand and Gravel contract is up and most of the tailings have been removed, DEQ will begin dealing with the tailings washed downstream. The remaining work could take an additional two years, Haaland said.