21 May 2008

Yankee Doodle Tailings Pond: Another Mine Waste Site near Butte

Below Butte's Moulton Reservoir and above the Berkeley Pit/Continental Pit area lies the Yankee Doodle Tailings Pond. It is formed by a tailings dam more than six hundred feet high. I am not certain when this area was first used for tailings disposal, but the Anaconda Copper Mining Company concentrator built in 1964 was a significant contributor. Today, Dennis Washington's Montana Resources. (MR) operation discharges its slurry waste onto the Yankee Doodle pond.

Here's a map of the roughly one thousand acre (nearly two square miles) tailings pond:

And here's a Continental Divide view of the Berkeley Pit (left) and tailings pond (right); (photo by Todd Trigsted):

You can visit the Yankee Doodle Tailings Pond by driving north on the Moulton Road from Walkerville. Watch for a user-created ATV troad after you pass Butte's municipal water treatment plant, about a mile north of town.

When MRI shutdown in July 2000 due to high electricity prices brought on by deregulation (interestingly, MR/Washington had lobbied for deregulation, believing it would lower prices), the tailings pond went dry. When wind conditions were right, Butte suffered from duststorms like this (photo by Derek Pruitt, Montana Standard newspaper):

Citizen complaints and a $121,200 fine forced MR to treat the dry pond surface (beginning with pumping water over them and ending with capping) to prevent blowing dust. To help poor Dennis Washington resume mining operations, Butte gave MR a $2 million loan and reduced taxes. By December 2003, MR was once again pumping its 25 cfs slurry onto the Yankee Doodle Tailings Pond (photo by Stephen Jennings, Montana State University):

The upper end of the tailings pond, where water rushes down from Yankee Doodle Creek, is an unearthly blue color:

Like many people, I had assumed this color was from copper sulfate and other heavy metals salts. My colleage, Chris Gammons, in Geological Engineering has done some testing, however, and he tells me the color is primarily from suspended clay sediments. You can see the color nicely in this shoreline view:

The mine waste slurry discharged by MR is very high in lime (which MR uses to precipitate and recover metals). The lime, and resulting high pH, causes the water in the Yankee Doodle pond to be low in metals (Chris did point out that it might be high in metalloids such as arsenic or selenium). The non-toxic nature of the water in Yankee Doodle Tailings Pond explains why it is used so heavily by waterfowl, and why one doesn't find dead ducks floating on the surface:

Still, there is a million yards or more of mine waste stored behind the Yankee Doodle tailings dam. Though it will probably end up being capped and vegetated if and when mining ceases, that is a decision that will have to be made in the future--perhaps as yet another Superfund site is added to the Upper Clark Fork River complex.

9 comments:

Anonymous said...

I'd like to know what kind of risk Butte faces should Yankee Doodle liquify in a major earthquake.

Pat Munday said...

According to EPA/MT DNRC sponsored seismic stability evaluations on the Yankee Doodle Tailings Pond (International Engineering, Inc; 1981 and Harding Lawson Associates, 1993) the dam is "safe." The Superfund Record of Decision (i.e. "remedy") for the Butte Mine Flooding Operable Unit requires dam monitoring (OU 03, 09/29/1994).

This said, the HLA evaluation stated, "Liquefaction is predicted to occur in the top 50 feet of the dam after an earthquake equivalent to 6.5 magnitude." This would make a big splash in the Berkeley Pit.

The faults in the Butte area are considered inactive.

As my seismologist friend "Quakes" puts it, "In an event much greater than 6.5, the failure of the Yankee Doodle Tailings Dam and the subsequent rush of slurry into the Berkeley Pit would probably be the least of Butte's worries, given the high proportion of masonry construction prone to failure in a seismic event."

I'm not sure this gives me much solace, but it does make me glad I live and work up on the Butte hill, and not down on the flats!

Anonymous said...

Thought you would like to know that the current BSB administration (Babb) is passing the Silver Lake electrical charges onto the Butte-Silver Bow drinking water rate payers. Silver LAke water is used in their mining process. Like Dennis Washington can't afford it!

Anonymous said...

considering the fact that these tailings dams fail on a regular basis, not just due to seismic activity but also due to saturation, I am wondering if the city has any emergency protocols in place in the event of a failure. I am a resident of butte and have never heard of any emergency plan. That worries me.

EcoRover said...

Supposedly, the Berkeley Pit would absorb the flood if the Yankee Doodle Tailings Pond dam were to fail.

I have no idea if that is true, but the PitWatch group, Butte government, and EPA are all on record to that effect.

Personally, I'm glad I live in Walkerville and not in some "flats" neighborhood below the Pit!

Anonymous said...

I would like to know some dates or measures about the slurry waste pumping system in this mine...
e.g.
The pumping line long, diameter and kind of material.
the pumping high.
The kind and power of the pumps.

I will appreciate to somebody.

Carlos Javier

EcoRover said...

Hi Carlos, the information you seek is not available to the general public. You need to contact the mine owner/operator, Montana Resources (a Dennis Washington corporation).

Anonymous said...

Well what if the pit freezes? you know how a pop explodes if it freezes what would the pit with all the metals do they keep it from freezing beecause ive never heard of them freezing? and recently its been about 25 below every morning so does it freeze the tailings pond or the pit?

EcoRover said...

Anonymous, there is a large submarine in the bottom of the Pit. When it gets cold, they fill it with charcoal and fire it up to keep the water from freezing. Seriously, though, I have no idea what you are talking about.