Clark Fork Coalition Missoula Montana

With the words “Blackfoot” and “River,” most people conjure up visions of one of Montana’s renowned dream streams, with water tumbling out of mountains cut out by the ice age, providing habitat and shelter, sustenance and food, the simple pulse of life. This is an accurate snapshot of the Blackfoot, yes. But it doesn’t tell the full story. That story would include the massive tailings dam looming over the river’s very origins at the Continental Divide.

Built in the 1940s, miners used metals-laced tailings to build the Mike Horse dam with the idea that it would be a way to contain and manage their toxic mining waste. The selected dam site was across the mouth of Beartrap Creek just above its confluence with Mike Horse Creek, where the Blackfoot officially begins. The shallow reservoir became the resting place for metals-laced tailings from the Mike Horse Mine and other gold, copper, and zinc mines scattered around the river's headwaters. Unfortunately, these metals didn’t always stay put.

Read on for background on the issue, or go immediately to our Action page for details about writing to the Forest Service requesting that the agency remove Mike Horse Dam.

Threats 

The Mike Horse Mine became a serious polluting menace to the Blackfoot in 1975 when its tailings dam blew out, spilling deadly levels of lead, copper, and zinc into the upper Blackfoot. The mine's corporate owner, ASARCO, rebuilt the dam shortly thereafter, and cleanup of the river's headwaters has slogged along, fairly ineffectively, ever since.

The situation at Mike Horse took a serious wrong turn in 1993 when—instead of declaring it a state Superfund site—Montana’s Dept. of Environmental Quality (DEQ) agreed to let ASARCO experiment with a “voluntary” cleanup. The attraction to the state, apparently, was that cleanup would be immediate. This approach has mostly failed. And now ASARCO is sinking into bankruptcy. To further complicate matters, the cleanup is on federal, state, and private land, which mires the project in jurisdictional squabbles.

Possibly the biggest concern at the Mike Horse site is the safety of the shored-up tailings dam. Water is seeping through the base of the dam—which is constructed with 2 million cubic yards of toxic tailings—raising the possibility that it could be eroding from within. Then there’s the dam’s spillway: it is not up to standards, and is putting the structure at risk of overtopping in a large flood. On top of all this, it is uncertain how the dam would fare in an earthquake of the magnitude one could expect in the geologically active upper Blackfoot. A permanent fix is needed for the dam, and it is needed soon.

Solutions

The good news is that the fix for the Mike Horse problem is not hard—the technology to clean up this mess has been around for 50 years. The mine tailings need to be moved to high and dry land and stored in a safe repository, away from the creek.

Other impaired stretches of the Blackfoot have been on the receiving end of millions of restoration dollars and miles of conservation legwork from landowners, environmental groups, and agency specialists. And it’s paying off in the form of cleaner water, healthier streambanks, and increased native trout populations. In fact, there’s been a marked and measurable difference in the vitality of the river these last 15 years.

What’s more, the state of Montana and the Forest Service are planning multi-million dollar cleanups of the worst of the tailings that the dam deposited in the upper river after it blew out in 1975. In the context of these giant cleanup investments, then, it would be foolish to leave a permanent metals-laden hazard looming at the very head of the watershed, threatening to undo all that's been accomplished thus far.

News & Updates 

The Forest Service owns the property underlying the Mike Horse dam, and is in charge of sorting out this whole mess. In January of 2005, the agency released an engineering report, confirming that for the last 15 or 20 years, water has been seeping through the dam, eroding the structure from within through a process known as “piping.” That’s huge cause for concern. If left unchecked, this piping could lead to dam failure, particularly when water levels in the reservoir are high. It also makes the structure vulnerable to failure if the area has an earthquake of the magnitude that occurs about once every 500 years. Such earthquakes are rare, but as we know from events in the Indian Ocean, they can and do happen.

A collapse of the Mike Horse tailings dam would spell disaster for the Blackfoot River. So clearly, the status quo is unacceptable. So what comes next? Through an abbreviated Superfund process known as an Engineering Evaluation and Cost Analysis (or “EECA,” in Superfund-speak), the Forest Service has now developed alternatives for fixing the problem. These range from reinforcing the dam and leaving it in place, to removing all or part of it and eliminating the reservoir behind it. The EECA document was released July 17, 2006 and can be downloaded at the Forest Service’s Mike Horse web site. (To weigh-in with the click or two of the mouse go to our action alert page.)

Friends of the Blackfoot need to push strongly for total dam removal. It is the only solution that permanently eliminates the threat posed to the Blackfoot.

Unfortunately, once the Forest Service comes up with a plan for the dam, there is no ready source of funds to do the actual work. That’s because the party primarily responsible for the mess under Superfund is the now-bankrupt ASARCO. Remember this company? It deftly negotiated a sweetheart deal with the federal Justice Dept. two years ago, when the company was transferring its assets to a Mexican holding firm. That settlement effectively limits ASARCO’s contribution to a fraction of what the project is likely to cost. Another company, BP/ARCO, is theoretically on the hook for cleanup, since it operated the Mike Horse site for a time in the 1970s, but it will take time, resources, and political will for the government to go after the company. The more likely scenario is that the Forest Service will be looking to Congress to fund a substantial portion of the work.

So what can a friend of the Blackfoot do? Speak up. Write letters to your newspapers. Talk to friends and neighbors. The Forest Service needs to hear that you value this irreplaceable river, and that leaving a mountain of metals-laced waste at its headwaters forever is not an acceptable option. Millions of private and tax dollars and thousands of hours of careful work have been invested in the Blackfoot since the last time the Mike Horse dam blew out. A repeat of that mess is not an option.

Write to the Forest Service today and ask the agency to remove the tailings dam that threatens the Blackfoot River. Be sure to type “Mike Horse EECA” in the subject line.

Library 

For a fuller picture of the history, challenges, and opportunities at the Mike Horse mine, check out the following:

Mike Horse Dam fact sheet (produced by the Clark Fork Coalition) (PDF, 2.1MB, 2 pages)

Mike Horse Dam FAQ (produced by the Clark Fork Coalition) (PDF, 1.0MB, 2 pages)

Studies show Mike Horse dam slowly deteriorating, Eve Byron, Helena Independent Record, 5 Jan. 2005

Wounding the West: Montana, Mining, and the Environment, by David Stiller, University of Nebraska Press, 2000 (212 pages, photos, maps)

Upper Blackfoot Mining Complex, Reclamation Activities and Accomplishments (a Montana DEQ website for details about cleanup work)