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Asarco remediation

Changing channels

Plans to protect groundwater in East Helena involve building temporary bypass for Prickly Pear, removing Lower Lake dam

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Asarco

Helena Sand and Gravel employees continue their construction of a 4,000-foot-long diversion channel for Prickly Pear Creek last week. The crews have been working from 7 a.m. to 7 p.m. since July 8 to complete the project that will divert the creek away from the slag pile, which was nearly undercut in the floods of 2011, and allow the removal of 100-year-old smelter dam to begin.

EAST HELENA — Betsy Burns and her crew have had a busy summer at the former Asarco plant site, and it will be topped off this week with the rerouting of Prickly Pear Creek into a temporary diversion ditch.

Burns, a project manager for the Environmental Protection Agency, and Mark Rhodes, a construction manager for the Montana Environmental Trust Group, on Tuesday stood near the top of the 14-ton slag pile that separates East Helena from the view of the former lead-smelting site. As they surveyed the scene below them, the two discussed how a century of industrial activities is slowly and methodically being wiped off the face of the earth here.

“It’s been a really good summer,” Burns said with a broad smile. “It took us a while to get to this point, but now what we have going is pretty exciting to see.”

Demolition of the 125-year-old former Asarco lead smelter has been ongoing since 2009, which is when the three smokestacks were blasted to the ground. This year has brought additional significant changes with two of the largest buildings — the circuslike green and peach Barnum and Bailey buildings and the six-story concrete ore storage building — being torn down. Today, pulverized rubble fills their footprints, which are being covered by layers of clay and soil as part of the Phase One demolition effort. The only structures left are the bath house and wastewater plant, which are still being used, and the cisterns from the former acid plant.

“As we moved through this summer, the site has changed so much,” Burns said from her bird’s-eye view. “As part of the Phase Two demo, we took out 24 buildings.”

She turned her attention to the east of the 80-acre plant site and slag pile, where Prickly Pear Creek runs into East Helena. A mass of excavators, dump trucks and backhoes from Helena Sand and Gravel have been scurrying about from 7 a.m. to 7 p.m. since July 8 on additional former Asarco acreage to construct a three-quarter-mile temporary bypass channel for the creek. It has fine soils on the bottom, covered with gray, soccer ball-size rocks known as riprap to stabilize the banks and keep sediment runoff to a minimum.

The reasoning behind temporarily moving the creek is complicated, as is much of the work, and has a deep history here. Some state officials refer to the work as a “mini-Milltown Dam” removal effort, which eventually will enhance the stream for aquatic life and fish, plus improve the natural resources to the point where it could become a place for people to recreate.

Why move Prickly Pear Creek?

During its century of lead smelting, Asarco rerouted Prickly Pear Creek off of the plant site to the east and used the stream to create two lakes. Water from Upper Lake was pulled into the plant through a diversion and used to cool the smelted ore. That processed water was then deposited into Lower Lake, which is held back by a 14-foot-tall dam; water from Lower Lake also flowed back into Prickly Pear Creek. At times the processed water was sprayed onto Asarco’s buildings and grounds for dust control.

The problem with this use of the water, however, is that arsenic is a byproduct of the smelting process and binds with water. The arsenic-laden water coated the soils and leached downward, pushed by melting snow and rain, spreading the contamination at least 30 to 40 feet below the plant surface. East Helena is down-gradient from the Asarco plant site, so the groundwater flows toward the city and the Helena Valley.

Further up-gradient from East Helena is Prickly Pear Creek and the two lakes, meaning that groundwater seeping from those water bodies flowed into the Asarco plant site and also pushed groundwater toward the city and valley.

In recent years, arsenic — a known carcinogen — has been found in groundwater at the plant site at levels up to 30,000 times the federal public drinking water standard. If someone tapped into the onsite water and drank it, they would die within a day or two, according to experts from the Agency for Toxic Substances and Disease Registry.

Today, two groundwater plumes carrying arsenic and selenium lie underneath portions of the city and valley. The contaminant levels are nowhere near what’s found on the plant site, but they still pose a health threat if consumed. No one is certain of the source of the selenium.

Local, state and federal officials say the plumes’ migrations must be stopped, especially since the valley is full of residential wells that could become contaminated and some of the city’s wells lie in the plumes’ path. In the past, they’ve come up with a couple ideas of how to do that, which mainly involved pumping the contaminated groundwater into a treatment plant, then reinjecting it into clean soils.

But pumping and treating the water will cost hundreds of millions of dollars and may be needed forever as the groundwater flows through the contaminated soils. Officials with the EPA and the Trust say that even though Asarco paid out $94 million as part of a bankruptcy settlement, that won’t be anywhere near what it costs to remove contaminated soils and pump and treat the groundwater.

So the EPA and Trust, working in conjunction with state and local agencies, came up with a different plan to halt or slow the plume’s migration. Now that they’ve removed most of the industrial structures, they are installing an impermeable cover over the contaminated soils to keep the bulk of the rain and snow from pushing the arsenic downward. They’ll also remove the two lakes, including the Lower Lake dam, which they expect will lower the groundwater so it no longer flows through the most highly contaminated soils and pushes contaminated groundwater off-site. They call this the South Plant Hydraulic Control System.

“If we dig up the soil, we still have to put it somewhere,” Burns said. “Instead, if we cap it on site, that will eliminate the infiltration of water from above … and if we lower the groundwater level, it will help us get the groundwater out of the contaminated soils.”

About $21.9 million out of the $94 million pot from Asarco’s bankruptcy settlement has been spent since 2009. However, Cindy Brooks, the trust manager, notes that they’ve made about $5.2 million in investments, the sale of some of the slag pile and the sale of almost three acres to American Chemet, which is adjacent to the Asarco site.

About $80 million remains from the settlement.

How to move the creek

So far this summer, they’ve just about drained Upper Lake, which has dropped the groundwater flowing into the plant site by about 10 feet, Burns said. Once Prickly Pear is diverted next week, they’ll be able to remove the dam that held back Lower Lake. The hope is this will further lower groundwater levels.

When the creek is diverted, East Helena residents may notice a few days of “off-colored” water, Burns said. But she doesn’t expect it will carry any contaminants.

Meanwhile, they’ll reconstruct the Prickly Pear Creek channel within the next few years, making it more meandering and pulling it away from the slag pile. Two years ago during a high-water event, the creek significantly undercut a portion of the 14-ton pile, leading to fears that it may fall into the creek and dam it.

Burns notes that the South Plant Hydraulic Control System and soil capping efforts are only part of the interim measures being put in place.

“We’ll see how effective these will be, then see what additional measures may be necessary,” Burn said. “The Corrective Measure Study will address the final remedy for the plumes.”

Kit Johnson, an East Helena city councilman, is pleased with the cleanup effort that’s underway.

“I think they’re doing an awesome job,” Johnson said. “They are doing neat things for the reclamation of the creek.”

His community has been a company town since 1888, when the Asarco smelter started to produce lead bullion from diverse concentrates and ores culled from mines throughout the nation. The company provided good-paying jobs for hundreds of East Helena families and was like a benevolent parent, hosting Fourth of July festivities, sponsoring the Smelterite baseball team and even creating a skating rink for children.

The smelter also produced tons of contaminants, and in 1984, the EPA declared East Helena a Superfund Cleanup Site. The company spent millions of dollars in cleanup costs, including replacing almost every yard in the city that was contaminated with lead and arsenic spread from the three large smokestacks.

Asarco was sold to the giant international mining company Grupo Mexico in 1999. Grupo “temporarily idled” the smelter in 2001, which turned into a permanent closure. After bankruptcy proceedings, in 2009 Asarco turned over the smelter property and parcels to the west and north of East Helena, as well as the $94 million, to the trust.

The plan calls for the eventual sale of the parcels or turning some of the land into open space for parks or similar uses, with any income being used for water treatment or other long-term cleanup measures. Trust beneficiaries are the state of Montana and its residents, as well as the United States.

Johnson said while East Helena residents were fiercely supportive of Asarco in the past, most people have moved on and are anxiously awaiting some kind of redevelopment and restoration of the former plant site.

“We have a lot of potential and possibilities, whether it be industrial or manufacturing jobs, for that site,” Johnson said. “I’m thinking long-term — two, three, even eight generations down the road — what the community will look like. It is changing. It’s no longer a company town that’s supportive of spewing chemicals into the air.”

State eyes future too

The Montana Department of Justice’s Natural Resources Damage Program also received $5.9 million from Asarco as part of the bankruptcy settlement, to be used for projects that will restore injured or lost natural resources due to the company’s activities. That state agency is closely watching the EPA and trust activities, since some of the DOJ settlement dollars could be used for projects on or adjacent to the plant site.

Doug Martin, who oversaw the Milltown Dam removal near Missoula for the Natural Resources Damage Program, says that generally speaking, the EPA and trust have come up with a good plan. But he knows from experience that Mother Nature is fickle, and that even the best laid plans can take a bad turn. In addition, at this point the EPA and trust only have put together a “60 percent” realignment design, which means that the work is underway while 40 percent of the project remains fuzzy.

That’s why he’s requested peer reviews for the EPA’s realignment plan, especially from the Army Corps of Engineers, to ensure that any red flags might be raised early on in the process.

“They will learn a lot; we learned a lot in Milltown after we moved the water and removed sediments, then learned what was beneath the sediments,” Martin said.

“One of our concerns is the effect of the changes going on there and what could be deposited downstream,” adds Rob Collins, an attorney with the Natural Resources Damage Program. “Most of the cobble material that we know moves through the system, because of the (Asarco) dam, didn’t move beyond that and now it will.

“So what’s going in will come out. That means that if 500 tons come into the upper reach, 500 tons should go out of the lower reaches.”

Both are cautiously optimistic, though, that the EPA is correct in that any materials will move through East Helena and continue downstream, to be deposited in a natural fashion as they were prior to Asarco’s manipulation of the stream.

However, they note that East Helena only came into being as Prickly Pear Creek was being altered, so the impact of moving it again can only be modeled at this point. Collins also notes that the original Prickly Pear Creek channel flowed underneath the middle of the slag pile, so the EPA and Trust will have to take measures to ensure the stream doesn’t return to its historic route.

“That’s why we’ve asked for the peer review from the Corps of Engineers to see if they find any fatal flaws,” Martin said.

Reporter Eve Byron: 447-4076 or eve.byron@helenair.com

Follow Eve on Twitter @IR_EveByron

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EPA nears completion of the bypass for Prickly Pear Creek as they continue clean up work at the old Asarco lead smelter.

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