When he died in 1925, Montana "copper king" and U.S. Sen. William
Andrews Clarkthe eighth richest American of his timeleft behind
an ostentatious legacy: impressive mansions in Butte and New York City,
a major railroad in Nevada, an important collection of European art donated
to the Corcoran Gallery in Washington, D.C. But his most significant bequest
remained deeply hidden for decades. And it was revealed only because of
a small wooden dam he had ordered built in 1905 near the tiny Montana
community of Milltown.
The Milltown dammade of timber cribs filled with rockswas
built to generate electricity for sawmills and for the young city of Missoula,
a few miles downstream. The power surged through wires made of copper
from Clark's own mines 120 miles upriver. "This is an important day
for Missoula," trumpeted the Daily Missoulian when the dam
was completed in 1908 and its reservoir began to fill. "The city
will have a supply of electric power second to no municipality in the
Nearly a century later, the aging dam still provides a few megawatts of
electricity. What it generates best, though, is anxiety.
In 1981, a routine check of drinking water in homes near the dam revealed
arsenic levels as high as 500 parts per billion (ppb), 12.5 times the
existing federal limit (and 50 times the standard set in 2002). Vegetables
in backyard gardens were also laden with the carcinogen. One spinach sample
had 2,660 ppb of arsenic; a head of lettuce registered 1,410 ppb. Normal
levels are 1 ppb.
After months of research, investigators found that the source of contamination
lay beneath the placid waters of the Milltown dam. In deep sediment that
had collected over decades in the dam's reservoir, scientists discovered
thousands of tons of arsenic, lead, cadmium, copper, iron, zinc and manganesewaste
products sent downriver from the copper mines of Butte and Anaconda, the
source of William Clark's wealth.
In the years since the sediment was discovered, the people of Missoula
have grown increasingly worried that the dam is a disaster waiting to
befall them. If an ice floe hits, as nearly occurred in 1996, or if an
earthquake trembles, as some geologists predict, the dam would breech.
The trickle of toxins that now seeps through the dam could become a poisonous
flood, polluting the aquifers of Montana's second largest city and contaminating
the river for miles.
The fate of the Milltown dam will soon be decided by the Environmental
Protection Agency (EPA), with a recommendation issued this fall and a
final decision early next year. Many have called for dredging the sediment
and removing the dama permanent but expensive solution. Others (including
Atlantic Richfield Co., which inherited the liability and must pay the
bill) prefer the cheaper option of reinforcing the dam and monitoring
But the dam sediment has turned out to be just an indicator of a far larger
disaster, the proverbial canary in the mineshaft. Milltown's arsenic plume
led investigators to far worse problems upstream, at the smelters of Anaconda,
the enormous metal ore waste piles of Opportunity Ponds and the mine shafts
of Butte. And then there's the infamous Berkeley Pit, the milewide strip
mine in Butte that became an international rallying cry for environmentalists
when an ill-fated flock of geese landed on its acid waters in 1995 and
never took flight again.
The little dam that Clark built thus revealed the most enduring legacy
of Montana's copper mines: an environmental nightmare that will take at
least a billion dollars to remedy and decadesif not centuriesto
Hazards of hardrock
Hardrock mines have generated countless tons of valuable metals and vast
quantities of durable toxins, and these benefits and costs of mining tend
to fall upon very different parties. Within the Ninth District, Montana,
South Dakota and Wisconsin are the states most affected by the promises
and problems of hardrock mines, so the questions that confront the citizens
of Missoula are being faced by others as well: How did the problems become
so extreme? What is to be done with the toxic legacy left by decades of
And who will pay?
Fingers point, understandably, at the hardrock mining industry, the companies
that extract metal from hardrock ores (as opposed to coal, gas and oil,
where mining practices differ considerably). It is an industry already
facing hard timestough global competition, declining ore quality
and historically low prices [see the July
2002 fedgazette]. It is also an industry whose products we
need or desire: Copper carries our electricity; zinc coats our auto parts;
gold is our quintessential, if somewhat archaic, symbol of wealth.
The industry itself reminds us that it also creates jobs and economic
multipliers. Click on the National Mining Association's Web site and you'll
learn that the "mining industry is vital to the state's economy"
in every state of the Union, including Delaware where it employs 100 people
and mines $14 worth of metal per resident. But despite its undeniable
contributions, the hardrock mining industry is facing profound skepticism
about the benefit/risk ratio it presents and growing doubt about whether
the economic privileges and protections it long has enjoyed should be
Burden of gilt
Dead are the days when a lucky gold miner could dig a nugget from the
wall of a mine shaft or pan a few flakes from a stream. With the richest
deposits played out long ago, gold mining in the United States now involves
crushing tons of rock, piling it in huge heaps and spraying those heaps
with cyanide to dissolve microscopic gold deposits from its ore. The technique,
called "cyanide heap leaching," is tremendously cost-efficient.
But cyanide carries obvious risks, and over the last two decades mining-related
cyanide spills have occurred with disturbing regularity. According to
industry data supplied to the EPA, 1.6 million pounds of cyanide were
released into the environment by hardrock miners in 2000 alone.
Large-scale cyanide heap leach mines have been around since 1979, when
Pegasus Gold, incorporated in Canada, opened the Zortman-Landusky mines
near Hays, Mont. State permitting authorities allowed the mining complex
to expand nine times over the next decade despite numerous cyanide spills.
But not until the EPA pressured the state after discovering cyanide, arsenic
and lead leaking from each of the mine's seven drainages in 1993 did Montana
file suit against Pegasus for violating state water laws. The EPA filed
its own suit in 1995 and the company settled out of court, admitting no
guilt but paying a fine, establishing a reclamation bond to cover future
damage and agreeing to implement a detailed pollution control plan.
The Gilt Edge Mine, near Deadwood, S.D., was another Ninth District mine
with repeated cyanide spills during its 11-year history. Run by Brohm
Mining, a subsidiary of Canadian-owned Dakota Mining Co., Gilt Edge had
its first spill within the first year of production, was fined by the
state's Department of Environment and Natural Resources (DENR) and told
to improve its cyanide capture process. But spills continued.
Numerous other mines in the district have had similar cyanide problems,
and spills recurred at many of these sites even after state authorities
caught and fined the mine operators. To prevent future problems, Montana
voters approved a 1998 ballot initiative banning cyanide heap leaching.
A bill prohibiting cyanide use at mines died in committee at the Wisconsin
Legislature in 2002. But as it turned out, while government authorities
and environmental groups were focusing on cyanide spills, a far more serious
problem was developing.
Most metals we mine are located in hardrock that also holds sulfur compounds.
Deep within the earth those compounds pose no problems. But when the rock
is crushed and exposed to air and water, it begins to generate sulfuric
acid. The acid dissolves other heavy metalsselenium, lead, cadmiumand
as it flows into nearby rivers, lakes and underground aquifers, the acidic
solution kills aquatic life and renders water supplies poisonous. Cyanide
spills are harmful, but acid mine drainage is an environmental and economic
"Zortman-Landusky is generating a large amount of acid that we currently
can control," said Jim Kuipers, a Boulder, Mont., mineral engineer
who managed hardrock mines in the United States and overseas for a dozen
years and now consults with state and tribal governments, and citizen
groups. "It'll be generating 10 times that amount in 20 years. A
lot of these things are just maturing. It takes time to cook. As you expose
the sulfides longer to oxygen and water, and the bacteria have a chance
to go to work, it just continually generates."
When acid mine drainage (AMD) was discovered at the Gilt Edge Mine in
the mid-1990s, state officials pushed Brohm Mining to address the problem
and bump up reclamation bonding from $1.2 million to $6 million to ensure
that cleanup costs would be covered. But Brohm's parent, Dakota Mining,
went bankrupt in July 1999. "It's one of those sad stories where
about the time that we recognized the problem with the acid mine drainage,
that was the time the company was in financial problems," said Mike
Cepak, the DENR engineer in charge of site reclamation.
Now the state of South Dakota is left with massive piles of
acid-generating rock and three pits filled with millions of gallons of
acidic water. Two of the pits are "a burgundy red," said Cepak,
because of metals dissolved in the acid. The third pit is being treated
with an experimental mix of lime, ethanol and molasses in the hope of
generating a biochemical brew sufficient to buffer the acid. The experiment
has failed so far, but the side effects are interesting. "It's kind
of Prestone green," said Cepak, and the alcohol levels are
high-proof. "If it wasn't denatured, it would be quite a party out
What will it cost to reclaim the Gilt Edge mine? "That's
a big question right now," Cepak answered as he listed the
steps that will be taken to clean up the mine site: Capping waste
piles with a plastic geomembrane so rain doesn't penetrate; regrading
land to encourage water runoff; revegetating the denuded landscapes.
"The work that we're looking at right now is going to cost
around $30 million, and then we still have to do the water treatment
and take care of the pits," he said. "I have no idea
how much that will add to the cost. It could easily double to
$60 million. That's just a guess. It could be even more. With
this type of acid mine drainage, the main problem is it's a reaction
that could last for centuries, so you have to plan for forever,
Unfortunately, Gilt Edge isn't the Ninth District's only AMD problem.
Virtually every gold mine in the area, as well as copper mines
in Butte and elsewhere, will require water treatment for years.
And while the biochemistry and geology are still too unclear to
permit accurate guesses about the time it will take to mitigate
damage at any given site, nobody thinks it can be done quickly.
"The predictions the best in the industry have been able
to come up with" for acid drainage at Zortman-Landusky, said
Kuipers, "suggest that we're going to be treating for at
least 1,000 to 10,000 years there. And at Golden Sunlight [near
Whitehall], I think 7,000 years is what they're predicting for
a period of water treatment."
While acid mine drainage is the most daunting of mine cleanup
chores, other hazards must also be addressed. In fish taken from
streams near the closed Beal Mountain mine site in Montana, for
example, the U.S. Forest Service has found abnormally high selenium
levels. "Not every mine has an acid drainage issue,"
noted Kuipers, "but may have a thallium issue or a selenium
issue or a nitrates issue. It just seems like every one has something."
Indeed, hardrock mining has such a widespread environmental impact
that it has topped the EPA's Toxic Release Inventory every year
since 1998, when the industry was first included in the list.
In 2000, the most recent year available, hardrock mining companies
were responsible for over 47 percent of all toxic waste released
into the nation's air and water. The National Mining Association
responds that the industry's 2000 releases were "generally
lower" than in 1999 and that the data aren't necessarily
indicative of health risks because they don't report on levels
of human exposure or on the toxicity of specific pollutants.
Still, the Western Governors' Association has been concerned enough
to compile a list of streams polluted by hardrock mines; it concluded
that mine wastes have contaminated 3,346 miles of rivers in six
Western states, including 1,118 miles in Montana alone. And the
scale of the cleanup task is immense. According to South Dakota's
DENR, there are 900 inactive and abandoned mines in four of that
state's western counties in the Black Hills. Not all pose serious
environmental risks, but cleanup costs will be substantial nonetheless.
In the United States as a whole, according to the Mineral Policy
Center, an environmental group in Washington, D.C, there are approximately
550,000 abandoned mines, with cleanup costs ranging as high as