Tailings on the Baltic: Remediation at Sillamäe

By Cheryl Rofer

April 17, 2023

IMAGE: Port of Sillamäe. Photo by Rey2 on Wikimedia, used under CC BY-SA 4.0.


Video Story

Cheryl Rofer worked at the Los Alamos National Laboratory from 1965 to 2001. She describes her efforts in Estonia to stabilize and clean up a radioactive tailings pond left there by the Soviet Union.



Interviewed by Nick Roth.

CHERYL ROFER: We were all scrambling during the 1990s to deal with issues in the former Soviet Union, and I wish I had known a whole lot more about what was expected by the State Department. I’m the kind of person who says yes rather easily and figures it out later.

I’m Cheryl Rofer, and I’m retired from the Los Alamos National Laboratory. I blog, and I tweet, and travel, and have a lot of fun.

The story begins in 1992. I had been working at Los Alamos as a manager of the Environmental Restoration Program.

One of my contacts in the director’s office gave me a brochure from a place called Silmet in Estonia. It was a plant that produced rare earths, and it had something that they called the waste depository. And my contact in the director’s office said, “Write a proposal on this.” And so I did. I included in a number of colleagues. And the proposal basically went nowhere. I later learned that Estonia was quite busy with other issues. The Soviets did not leave Estonia until 1994.

There’s quite a long history to the Silmet plant. It goes back to 1946. And there was a hope that it could refine uranium from some of the black shales in Estonia. Estonia has kind of an unusual geologic situation, and it has an oil shale that has much more carbon in it than American oil shale does. So they burn it directly, but it produces a lot of ash. And associated with that is a black shale that contains uranium.

And the Soviet Union in 1946 wanted uranium, because the United States had exploded the atomic bombs over Japan, and the Soviet Union, by golly, was going to catch up. So they built the plant to refine uranium from the oil shale.

That turned out not to work. It’s very difficult to get uranium out of black shale, and nobody’s ever done it successfully. But they had the plant. So they brought in uranium ore from other places around the Soviet Union and refined that. And what’s left over, they produced what’s called yellow cake. And what’s left over after they get the uranium and the yellow cake out of the ore is the tailings.

What it was was an enormous tailings pond, a kilometer long and half a kilometer wide, right on the Baltic Sea. The dam was maybe 25 meters from the sea. It was an open tailings pond. The rain went through it and washed minerals from the pond, both radioactive and heavy metals, into the sea. And furthermore, the whole thing was set on a base, a subsurface base of what is called the Cambrian blue clay, which has precisely the consistency of modeling clay. And it is blue, surprisingly, for a rock.

But the problem with having all those tons of material on it was that the whole thing could just slide into the sea, which the members of the working group did not want to happen. There were members from Sweden, Norway, Denmark, Finland, I think Germany, and there was a fellow from Russia who had been involved in the plant when it was under the Soviet Union and when it was operating.

So fast forward to 1997. One of our program managers came back from meeting in Lithuania and said he had met a person who had been the Minister of Environment in Estonia and who was charged with cleaning up this place. Now, the proposal I had written put me into a database at the lab, and he looked up Estonia, and there were precisely two people out of a thousand or more who had anything to do with Estonia. And it turned out I knew exactly the place he was talking about, although I didn’t know much about it. So that was in December of 1997.

NATO, at the time, wanted the laboratory to host what it called its Advanced Research Workshops, particularly with the countries of the former Soviet Union. So again, I was told to write a proposal, this time to send to the person in Estonia, whose name was Tonus Kaasik. And I did that. We faxed the proposal to Estonia just before the Christmas break. And when I came back on January 5th, there was a reply in the pile of faxes that said, “We are having a meeting of the Silmet International Expert Reference Group in Tallinn on January 21st. Please come.”

I’m the kind of person who says yes rather easily and figures it out later. It would’ve been nice though to have had a better idea of what was ahead. Although, we did get counterintelligence briefings. And the counterintelligence people said to me, “Just find out what’s going on over there, and you can tell us when you come back.” We just didn’t know.

So that was about two weeks. The Industrial Health Group gave me all my shots, or as many as they could. We got the travel arrangements, and I did have a passport, fortunately. And January 17th, I was on my way to Denver, and overnighted in Denver, from which I went to Chicago and then Frankfurt and Tallinn.

We had a meeting of this International Expert Reference Group. It was run by Jan Olaf Snihs, a Swedish man who was retired from the Swedish Radiological Protection Agency and who had done this kind of thing, also in the Balkans, with depleted uranium ammunition in the soil. And they were looking at what had been called the waste depository in that brochure that I had gotten back in 1992.

I went to the meeting and finally understood a little bit more about the situation. And I was going with an eye to writing a proposal for NATO. So the evening after the meeting, Tonus and Aunti and I met with the vice chair of the Estonian Academy of Sciences, and we made a plan for a proposal to NATO, which we eventually fleshed out, got to NATO, NATO accepted it, and we had a meeting in Tallinn in October of international experts on how this tailing pond might be remediated.

We went from there to, Tonus and I wrote a book, or edited a book with contributions from these experts. And Tonus took the book to the EU and said, “We need 25 million euros to remediate this thing.” And the EU gave them the money. The Estonians contracted to a German firm, and some other firms and separated this tailings pond from the groundwater and put what they call an engineered cover on it.

In order to stabilize the thing and keep it from sliding into the Baltic Sea, pilings were driven below the blue clay to stabilize it. And the dam was re-stabilized. The whole thing was re-contoured and what they call an engineered cover was put on top. It’s layers of sand, and rocks, and soil in such a manner so that it makes the water go around rather than through.

As director of the NATO Advanced Research Workshop, I had to give a welcoming talk. Tonus was the co-director. We would have one American and one from the other country. And I decided that it would be a good thing to say a few words in Estonian, and not just a few token words, but I wanted to say a whole paragraph.

So language has been a real issue in the countries of the former Soviet Union. The Russians would at times try to force Russian as the only acceptable language. And so it’s a point of sensitivity.

And so I did develop a whole paragraph. I had traveled around the country for a week before the conference and so I started out my paragraph, I started in English, and then I shifted and said, Mina tahan oelda nüüd mõnad sõnad ilusast maast. And the room became very quiet. And I went through the paragraph. That sentence was, I would now like to say a few words about your beautiful country. And I managed to make it through the entire paragraph. I probably didn’t pronounce everything right and Estonians are very precise in pronunciation. But after the talk, people came up and shook my hand and said, thank you. And it clearly meant a lot to them.

Well, I had a little bit of good sense to start out with. When you work at a place like Los Alamos you learn what you can and can’t say and shouldn’t shouldn’t say to some degree. So there was that, but when you’re dealing internationally it’s a little bit different. And so there were times when I kind of wondered, but I obviously didn’t do anything too terribly wrong.

The views expressed in this post are those of the author and not necessarily those of the Stanley Center for Peace and Security or any other agency, institution, or partner.



Cheryl Rofer
Former Project Leader, Los Alamos National Laboratory

Cheryl Rofer worked at the Los Alamos National Laboratory from 1965 to 2001. She developed an essential spectrum for laser isotope separation, managed environmental cleanups at the laboratory and a program to develop a disposal method for hazardous waste, and worked with Estonia and Kazakhstan to clean up environmental problems left by the Soviet Union. Since retirement, she has been active in local groups having to do with world affairs and Manhattan Project history. She explains scientific aspects of the news on social media. In addition to her technical articles, a book, and multiple interviews, she has reviewed the television series “Manhattan” and the Santa Fe performance of “Dr. Atomic” for Physics Today.

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