Mark Hamilton: You can go fishing in a modern tailings pond



Hopefully, in reading this series, your understanding of the mining process will allow you to be aware of the predictable fear mongering of any mining project in the future.  

Nothing is portrayed to be more sinister than the failure of the tailings facility. This message of doom is usually accompanied by references to historic catastrophes that did, in fact, occur. As part of your awareness, check the dates and the location of these very real events. Did they occur in the United States? Did they occur prior to commercial jet travel? If so, be a little skeptical, not if they did occur, but wonder a bit about whether current regulations would allow such a construction.

Avery powerful image is associated with the breaking of a dam. It is also very misleading. I have no concern about the use of the term “dam”, since the agency responsible for the safe construction is called “The Alaska Dam Safety Program.”  I warn about the image of a dam, usually envisioned as a huge, tall concrete structure.  

Yet the “dam” associated with mining is much better described as a buttress. The buttress can ultimately be very tall as well, but to us it would look like half a mountain, terraced for more stability. Another misdirection of the image of a dam is that it holds back huge amounts of water. As an extra panic excitement, the water is often described as toxic.

This invites two terrifying dreads, a massive outpouring of poisoned water. Delay reaching for the panic button.  One, there is very little water held in the main tailings facility in the design put forth by Pebble Mine. The “tailings pond” that does exist is thousands of feet from the buttress, and even this pond could be drained if it became necessary. The buttress actually holds back damp sand. It’s so nearly water-free that the design calls for a sprinkler system to guard against wind carrying the dust away.  

As part of the NEPA process, a simulation of the failure of the buttress was investigated. The release of huge amounts of damp sand did not even reach the Koktoli river. No water was released.  Note: The simulation of failure of the tailings facility was a required part of the permitting process, not to investigate concerns about construction.

One more thought: The water in the tailings facility is not toxic. How do we know that? There is a test, written and conducted by EPA. They have done that test. If you have your awareness instinct working now, you might ask, “how can you know that, since the mine isn’t yet constructed?  I am very happy that such a question occurred to you.  That is exactly the kind of probe you will need to wade your way through the rhetoric you will find regarding proposed mine construction. So, let’s answer the question.

In exploring the claim, a huge number of drillings will take place to assess the deposits depth and breadth. By amassing these core samples, the developer can get a pretty accurate three-dimensional assessment of the deposit.  

It is not unusual to have many hundred drillings; Pebble mine had upwards of a thousand. These drillings yield core samples; Pebble mine compiled more than a million linear feet of core samples. Throughout the process these core samples are sent to independent assayers to determine amount of minerals in the deposit. Knowing these amounts allows the developer to calculate, and with sufficient sampling (there is a required number of independent assays needed to be able to advertise, the richness of the deposit, hence, market value.)

Using these same core samples, the EPA test of the tailings ponds involves following the processes described earlier (crushing the samples to the same micron size as is planned, flotation etc) to arrive at exactly what the process will produce in terms of tailings. These pre-construction tailings are then put underwater in a tub at the laboratory to produce the best possible estimate of the resulting water in the tailings pond. Then two different types of live fish are put in the tank, sequentially, fat head minnows, then a second test with rainbow trout. The test is for acute toxicity, defined as fish die withing 3 days, and chronic toxicity, defined as fish showing some indication of stress after 7 days. 

EPA wrote the test protocols; an independent lab did the experiment; and the results were that no fish died or indicated stress.

The tailings pond water is not toxic. We can’t have an opinion on this because toxicity is not an opinion; it’s chemistry.

These results came as no surprise, in Canada a mine with similar mineralization has a fishing tournament annually in their tailings pond.

The “Pebbled” series at Must Read Alaska is authored by Mark Hamilton. After 31 years of service to this nation, Hamilton retired as a Major General with the U. S. Army in July of 1998. He served for 12 years as President of University of Alaska, and is now President Emeritus. He worked for the Pebble Partnership for three years before retiring. 

Pebbled 1: Virtue signaling won out over science in project of the century

Pebbled 2: Environmental industry has fear-mongering down to an art

Pebbled 3: The secret history of ANWR and the hand that shaped it

Pebbled 4: When government dictates an advance prohibition

Pebbled 5: EPA ‘just didn’t have time’ to actually go to Bristol Bay

Pebbled 6: The narrative of fear

Pebbled 7: The environmentalists who cried wolf

Pebbled 8: Build your media filter based on science, not narrative

Pebbled 9: The history of hysteria

Pebbled 10: Mining 101


      • If it can’t be grown it must be mined. The world does not run long on unicorn farts and fairy dust. We just need to develop a way to do it safely, not with child labor in Nigeria.

  1. Mark-Thanks for your write ups. I don’t often agree 100% with your analysis but I appreciate you nonetheless. Pebble Mine could have used another tailing dam architect than the one responsible for Mt Polley tailing dam disaster. Two engineers were held responsible with fines levied against both. Neither of which removes the toxic materials released into Polley and Quesnel lakes and Hazeltine Creek. I would be ok with some of Pebble Mine provided the owners and prime operators lived 340 days out of year below the dam for the life of the tailing pond and mine. Additionally the companies involved set aside twice the entire clean up cost of a rupture prior to going on line.
    Otherwise the owners of Pebble have no skin in the game beyond money. When folks actually have their own lives on the line they tend to make less risk adverse decisions.

  2. Mark … You honestly think Pebble has a reasonable chance at development? Given today’s political climate, the lack of political foresight – courage – leadership, and the errant – misguided focus on social issues it’s extremely hard to envision any amount of resource development in Alaska.
    At your age, I’m guessing you’ll never see Pebble come to fruition.
    At my age (ie – 55), i give it a 1% chance of seeing this project come to fruition.
    Maybe(???), the Chineze will develop it in a few generation to come … Along with the LNG project?

    • I’ll take option #3 “Maybe(???) the CCP will develop it, along with the vast mineral deposits that were locked up in the creation of the NPS National Preserves and
      FWS Wildlife Refuges.

  3. Here is an honest question. So the fish can live fine in the pond. Thats good. Can you eat them if you catch them without restriction?

  4. And numerous hapless waterfowl have made the mistake of landing in inviting tailings pond only to find themselves dead.
    Mr. Hamilton has skin in the mining game. Trust him at your risk. The people at UA did.

  5. “defined as fish showing some indication of stress after 7 days”…..Who knew?
    So how do you stress test a fish? do they become agressive or just yell and scream at each other?

  6. Hamilton has more credibility beating seal skin drums and carving on oosiks than he does talking about the mining industry. Clown work.

    • Paul: So glad to see you here. You missed the party but there’s still a half bottle of Ripple in the kitchen.

          • In Hamilton’s pool? It’s the spiritual home of anything dead.

            Why’s this guy keep blathering about pebble when it’s so clear even to pro-development types that he’s absolutely FOS?

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