12 December 2008

Butte, America: Open Air Superfund Factory

In its heyday as an Anaconda Company mining town, Butte, Montana, was an island of mining activity surrounded by barren dirt. A large factory without walls, neighborhoods clustered around head frames where ore was lifted to the surface from deep mine shafts. Ore cares rumbled along tracks crisscrossing the town. Smelters belched arsenic and sulfur laden fumes into the air, killing grass and trees for miles around. Silver Bow Creek, the headwater tributary of the mighty Clark Fork River and once a spawning ground for huge bull trout, was an open industrial sewer. The grim reality of this hellish landscape pervaded every aspect of work and leisure.

Today, Superfund has replaced mining as the most visible feature of the Butte landscape. Like the Anaconda Company, Superfund has turned Butte into a large factory without walls. Polluted land and water have replaced ore as the raw material. Revegetation and treated water have replaced copper as the product.

Board members of the Clark Fork River Technical Assistance Committee (CFRTAC) visited Butte for a tour of the Butte Hill and Silver Bow Creek Superfund site. This EPA-funded citizens group is active in promoting good cleanup and restoration of the Clark Fork River and Milltown Dam Superfund sites. But Butte sits at the headwaters of the Clark Fork, and so CFRTAC folks are interested in what's going on upstream, too. Also, the Citizens Technical Environmental Committee (CTEC) -- a Butte-based EPA-funded citizens group -- is trying to get on its feet after years of inactivity, and so a few CTEC folks also joined the tour.

Here are John Metesh (left) of the Montana Bureau of Mines and Geology and Matt Vincent (right) of the Clark Fork Watershed Education Program. Matt set up the tour, and John was a featured speaker who explained the Butte groundwater aquifer:

The area where we began the tour is at a groundwater divide between the Berkeley Pit and Silver Bow Creek. The creek became an open, industrial sewer during the mining days. Today, the upper reach is referred to as the "Metro Storm Drain," pictured here with the city/county shops on the upper right:

All of this area sits atop a vast mine waste dump known as the Parrot Tailings. Scientists such as Metesh of the MBMG conclude that with removal of the Parrot Tailings, the ground water aquifer feeding Silver Bow Creek would recover (become clean) in less than 100 years. However, it would cost about $20 million to remove the tailings and relocate the city/county shops. EPA did not want to impose this cost on Arco-BP, the responsible party that must pay for remedy. [note problem with the engineered solution, in comments]

Instead of permanent cleanup, water will be intercepted from the Parrot Tailings/Metro Storm Drain and treated in perpetuity. Forever. And that's a long time. Pioneer Technical Services, a local engineering company, is contracted to operate the water collection and treatment plant. Collected water is treated with lime in the building (right), held in ponds where metals precipitate out as sludge, and then discharged to Silver Bow Creek:

Brad Archibald (center right), Pioneer's president, led us on a tour of the water treatment facility with the plant operator, Dave Griffis (left):

This trench ("hydraulic control channel") captures the acidic, metals-laden ground water flowing down from the Butte Hill:

Where the water is pumped into this building, mixed with lime, and distributed through the various settling ponds before discharge to Silver Bow Creek (plant interior with Michael Kustudia, CFRTAC facilitator):

Pioneer has done an excellent job of upgrading & improving the operation & effectiveness of this plant in recent years. Lime precipitation of metals is not rocket science, but it's not some guy stirring a vat with a canoe paddle, either. You get some idea of the technical control of the process by this glimpse of the control panel:

Water discharged to the creek currently meets all state water quality standards. Unfortunately, there are other sources that continue to pollute Silver Bow Creek with toxic metals:

(1) Apparently, the creek below the treatment facility is a "gaining reach," where water percolates up from the Butte Hill aquifer, bringing mining & smelting pollution with it. This pollution demonstrates that the "engineered solution" is not capturing & treating all of the ground water from the Butte Hill Superfund site. [note clarification on this point in comments]

(2) The treatment facility captures only groundwater. Surface water runoff from the Butte Hill, especially during high flow events (rainstorms, snowmelt) continues to flush polluted sediments and water into Silver Bow Creek.

Mine dumps are spread all over the Butte Hill, and still contribute metals pollution to the creek with surface run-off of rain and melting snow. For the most part, EPA has not required Arco-BP to remove these dumps. Instead, EPA has allowed a "cover up" approach: mine waste is capped, covered with 18 inches of clean soil, and planted with various seed mixes. The early treatments often used exotic grasses, but more recent treatements utilize a mix of native grasses, forbs, and shrubs.

The tour stopped near the Travona mine to examine one of the earlier cover-up treatments:

Here is the Travona head frame (aka gallows frame); visitors see the Travona as they enter Butte from the I-15/90. Oops! Who didn't check to see that the "E" is hidden from view? Butt, Montana, indeed:

Vegetation is sparse:

to non-existent on this covered-up mine dump. Old manganese tailings have poisoned even the hardy, exotic grasses:

The Butte Hill remedy is a case of "adaptive management"--an increasingly common strategy for complex Superfund sites. Instead of doing a once-and-for-all time cleanup, adaptive management is a matter of cut & try. Various small cleanup & treatment strategies are implemented -- in a somewhat piecemeal fashion -- and monitored. As in the case of the ongoing pollution of Silver Bow Creek, it is apparent that not enough is being done. At some point, it is hoped, EPA will require Arco-BP to implement additional cleanup & treatment until (eventually) clean up targets are met.

1 comment:

EcoRover said...

A friend (who would like to remain anonymous for professional reasons) that has worked in Superfund sent me a few corrections:

1. The name of the Pioneer operating engineer at the Lower Area One water treatment plant (in the photo with Brad Archibald) is Dave Griffis.

2. Another good term for "cover up" Superfund remedy strategy is "cat-box reclamation:" the waste is covered, but it still stinks & someone must deal with it in the future.

3. Although the Silver Bow Creek does gain flows from upwelling groundwater just below Butte, the situation is more complex than I described. Where the water comes from is unknown, and the quantity of water, is not well understood.

4. As John Metesh explained on the Parrot Tailings/Metro Storm Drain part of the tour (YES, I should have taken better notes), there are two serious problems with the "engineered solution" for the Butte aquifer.
a. The collection system underlying the Metro Storm Drain shows signs of clogging (and it's been just a few years).
b. The groundwater plume from the Parrot Tailings is highly variable & not fixed as EPA/Arco seemed so sure about in the remedy; it seems to be moving south & east.