The Berkely Pit - an unfolding environmental nightmare

I don't suppose many people are aware of the Berkely Pit.  If they live anywhere in the Northwest US, they should be aware of it, and they should be knowledgeable about it.

The Berkely Pit is located in Butte, Montana.  Below is an image of where Butte lies within the Northwestern states. (Click any image to enlarge)

Below is a closer image of Butte.  Notice anything odd about the terrain?

That big scar to the Northeast of Butte is the remains of a mine.  First, the interesting history of the mine, then we can attend to the looming environmental issue.

History:  The Anaconda mine began in 1881 as an underground mine - one in which the horizontal and vertical shafts followed veins of the desired ore.  It was originally discovered by Micheal Hickey, a Civil War veteran turned prospector, and then purchased by an Irish immigrant named Marcus Daly.

Marcus Daly

Daly was a savvy mining man.  He had traveled west during the California gold rush, and then moved on to the fabulous Comstock Lode in Virginia City, Nevada.  There he gained experience in mining and prospecting, and befriended the already wealthy co-owners of the Ophir Mine, George Hearst (Father of William  Randolf Hearst), and Lloyd Tevis.

Daly traveled to Butte to have a look at a silver mine, named the Alice.  He was offered a position as mine Superintendent and accepted, receiving a percentage of the mine's profits.  Daly realized that the mine was ALSO rich in of copper ore.   He toured several other silver mines in the Butte region, and identified copper ore in nearly all of them.

It was at this point that he sold his shares in the Alice mine and purchased the Anaconda mine from Hickey.  He contacted Hearst and Tevis, as well as James Ben Ali Haggin, for financial assistance to help him develop the mine and to build a smelter.   When the silver in the area began playing out, Daly was able to quietly purchase many other mines at low prices, with the intent of  developing them as copper mines.  He reported what he intended to his associates, and they agreed to the scheme.

At that point in time, electricity was mostly a curiosity, and copper was not considered particularly valuable, other than its use as an alloy in making brass.  However Thomas Edison had recently invented the light bulb and electrified a city block in New York City.  The handwriting was on the wall for the use of copper as an industrial metal.

The various copper mines that Daly purchased made him wealthy, and something of a regional kingpin.  He built and owned a railroad, to carry ore from his mines in Butte to the nearby town of Anaconda.  There he built and operated an enormous smelter.  He founded the American Brass Company.  Daly also owned lumber interests in the Bitterroot valley, and bred race horses south of Missoula.

The Anaconda Mining Company (which including the mines, smelter and railroad) that Daly started in 1881 was sold for $39 million in 1899 to the Amalgamated Copper Mining Company.  The Amalgamated Copper Mining Company was simply a holding company that Daly owned.  Daly died a year later, in 1900.

The Rothschilds, Rockefellers and Guggenheims all had their hands in owning Anaconda Mining Company stock.  The Rockefellers in particular would corner the copper market - withholding copper until the stock shares soared, then selling their shares.  Afterwards they would flood the market with copper, tanking share prices - at which point they would buy shares again at low prices.

Back in Butte, underground mining would continue for another 50 years, however change was on the way.  In 1947, the underground Anaconda mine was closed, and clearing began for the operation of a large open pit mine.  All of the surrounding mines had long ago been purchased by the Anaconda Mining Company, so the mineral rights were in place for a large pit.  Open pit mining began in 1955, and the Berkely Pit commenced operation near the entrance of the older Berkely Mine shaft.

The Berkely Pit mine was very productive, but over time ore quality deteriorated and production costs increased.  The Berkely mine, Anaconda Smelter, and railroad were sold to the Atlantic Richfield Company (ARCO) in 1977 for the price of $700 million.  This turned out to be a very bad deal for ARCO.  Copper prices plunged to $0.60 per pound during the vicious double recession of the late 70's - early 80's.  In 1980, in an effort to stop the bleeding, ARCO halted all copper production in Butte.  In 1982, ARCO shut down the pumps that kept the mine dry.  Thus ended the operational phase of the Berkely open pit mine.  The depth of the mine was about 1800 ft. or about 1/3 of a mile deep.


Below is a postcard of Butte from the air, back in the mine's heyday.  You can see it was an impressive and thriving operation.

Closing the Berkely Pit and Anaconda smelter were not the end of the bleeding for ARCO.  Turns out ARCO had not only purchased a poorly performing copper mine.  They had also purchased a nasty environmental legacy.  In the early 1980's, the USEPA (Environmental Protection Agency) named ARCO as the "potentially responsible party" for cleanup of the Upper Clark Fork River Basin, and many of the surrounding areas polluted by nearly a century of smelting, mining operations, and leaking tailing ponds.

The area is the largest Superfund cleanup site in the US, and ARCO has spent additional hundreds of millions of dollars remediating the pollution.  ARCO didn't do itself any favors when they decided to shut down the pumps keeping the Berkely Pit dry - as we shall see.

Today the Berkely Pit looks like this - Photo courtesy of NASA.  The Yankee Doodle tailing pond is the bright blue water at the left side.  It looks tropical, but that's just copper sulfate in the water.  The Berkely pit is the one full of brown water.

Today we have a very serious unfolding environmental issue because of this abandoned mine.  The water in the pit looks unhealthy because it is unhealthy.  VERY unhealthy.  It is deadly poisonous.

There are many people who would flippantly say "So what?  All this stuff was in the earth before.  Ain't no different now.  What's the big deal?"  Let me briefly explain the difference.

Yes, this ore was buried in place long before mankind discovered it.  It was underground - it never interacted with the surface environment until it was uncovered.  Yes this ore was water-saturated.  Being water-saturated did not cause a water pollution problem though.  The reason the entombed ore didn't pollute the environment is because the much shallower drinking water aquifer does not mingle with water at such great depths - these waters do not mingle unless disturbed.  So, before this pit was opened, there was no issue of contaminated drinking water.

Chemistry of the water in the Berkely Pit:  Water in the pit is oxygenated, because it has been exposed to air.  When the ore was deep underground and saturated with water, there was no oxygen in the water to react and create acids.  Currently, oxygen in the water combines with pyrites (sulfides) in the ore to form sulfuric acid.  The reaction is this:  (2)H2O+(2)S+O2 yields (2)H2SO4 (Sulfuric Acid).  Since underground water is not oxygenated, there was no acid process to leach toxic metals  from the ground.

The pH of water in the Berkely Pit is about 2.5 on the 1-14 pH scale, with 1 being most acidic and 14 being most caustic or basic.  This acidic water readily dissolves metals in the ore, and as a result, the water is laced with copper, arsenic, cadmium, and zinc.  So in addition to being highly acidic, it's full of poisonous metals.

In 1995 a flock of migrating geese landed in the pit.  342 bird carcasses were recovered.  In November 2016, several thousand snow geese died in the pit while trying to avoid a snow storm.  This water is bad stuff.

When the pumps in the Berkely Pit were shut down in 1982, the pit began filling with water - both surface water, and water from the surrounding aquifer, at a rate of 1 foot per month.  Since that time, the water has risen to within about 150 ft of the surrounding ground water level.

In 2020 (that's less than two years away, folks), the water level in the pit will reach the natural groundwater level, and flow will reverse - out of the pit and into the surrounding groundwater.  The city of Butte will be the first affected, but not the last.  The entire Northwest will soon learn about the Berkely Pit.

Photo courtesy of PitWatch

As the pit water enters the aquifer, the city of Butte will feel the first effect.  After that, the polluted groundwater will enter Silver Bow Creek, which is a tributary to the Clark Fork River.  Things get a lot worse once the Clark Fork River becomes contaminated and acidized.

Below is a minor spill (3 million gallons) from the pond of the Gold King mine in Colorado's Animas River in 2015.  The duration of the spill was brief.

Below is another watershed wrecked by acidic mine discharge.

This sort of thing has happened all over the Eastern US with abandoned underground coal mines, and in Colorado with silver and gold mines. 

Below is the Clark Fork River, which stands to be killed by the acidic water in the Berkely Pit:

The Clark Fork river passes through Missoula, Montana.  The pollutants will enter the aquifer and destroy that town's source of drinking water next.  The Clark Fork discharges into Lake Pend O'Reille in northern Idaho.  The water in Lake Pend O'Reille enters one of the cleanest aquifers in North America, which is the sole source of water for all of North Idaho.  Coeur D'Alene, Spokane, and Sandpoint will have their water supply poisoned.

Lake Pend O'Reille drains out via the Pend O'Reille river.  This river is a tributary to the Columbia River.  The Columbia river, of course, is a source of irrigation and drinking water for much of the Northwestern US.  It's a vibrant habitat for migratory fish, and if polluted, could destroy the drinking water supply for Portland, Oregon, the Tri-Cities region and Vancouver, Washington.

Now for the some good news:  None of this scenario may happen at all.   A diversion was built for surface water that was flowing into the Berkely Pit.  This water was also contaminated and required treatment, having passed through mine tailings.  Diverting this water slowed the speed at which the water level in the pit was climbing. 

Sampling wells have been drilled in Butte to determine if the underground water supply has become contaminated.  So far, it has not.

A treatment plant has been built to treat and release water from the pit.  There is a "Critical Level" of water in the pit that must not be exceeded, and that level is being constantly monitored.  Below is a timeline for operation of the water treatment plant. (Courtesy of PitWatch)

 

It looks like the people in charge of remediating this mess have about 5 years left to get their act together.  Let's keep our fingers crossed.