milltown milestone

First Load of Milltown Dam Sediment Leaves Town

By Dave Loos, 10-02-07

	Sediment from the Milltown Dam is dumped into a rail car. The first load of many -- 2.2 million cubic yards to be exact -- heads to Opportunity Tuesday. Photos by Peter Nielsen of the Missoula City-County Health Department.

The journey from one Superfund site to another begins Tuesday for thousands of tons of toxic soil at Milltown Dam at the confluence of the Blackfoot and Clark Fork Rivers.

The first of what will be hundreds of sediment-laden trains is expected to load up behind the Milltown Reservoir Sediments Superfund Site this evening, en route to the Anaconda Smelter Superfund near Opportunity, where the soil will be dumped and spread.

Officials estimate it will take more than two years to transport the approximately 2.2 million cubic yards of Milltown sediments to Opportunity. Working on a seven-day-per-week schedule, project contractor Envirocon will load up 45 rail cars every day, each filled with about 100 tons of sediment. 

The long removal process will begin with sediment dug out of the recently-constructed bypass channel.

That train will make the trip to the Anaconda site each night via Montana Rail Link, using a newly constructed repository rail spur. There, Envirocon will use an excavator to unload the soil into large dump trucks, which will move the loads a short distance to the east side of the Superfund Site.

Chris Brick, staff scientist for the Clark Fork Coalition, said this stage of the project will involve two trains. During the day, one will load up at Milltown while the other unloads in Anaconda. The first train loading up today has 28 cars. “It will take them about a week to scale up to the full 45 cars,” Brick said.

The milestone for the $100 million project comes just over a year after on-site work began at the dam, when officials began drawing down water levels in the reservoir. The entire project is targeted to be done by the end of 2009.

The Milltown Dam site is home to 6.6 million cubic yards of contaminated sediment that washed downstream from the mines in Butte and Anaconda. The 2.2 million cubic yards of arsenic-laden soil heading to Anaconda will be used as revegetation filler for the sediment ponds left there by mining operations. Mining giant ARCO is funding the bulk of the cleanup costs.

Brick said if all goes as planned, the next major project milestone could occur as early as December, when officials hope to re-route the river into the bypass channel. Next April, the dam’s old powerhouse is scheduled for demolition.

This story has been corrected. The sediments are being taken to Opportunity, not Anaconda as was previously stated.

Like this story? Get more! Sign up for our free newsletters.