The metallurgy factory and former uranium mine in Sillamäe

The Soviet Union started uranium mining and production in the top secret industrial town of Sillamäe in 1947. From 1947–1952, 270 000 tons of Dictyonema Shale was mined from an area of 5 ha at the coastal cliff at Türsamäe, near Sillamäe.

Uranium benefication in the Sillamäe metallurgy factory was started in 1948. The estimated amount of elementary uranium in the concentrate produced from the Dictyonema Shale, was 22.5 tons. The very small yield, less than 0.1%, points to a primitive technology; as a result, a large part of the uranium was left in solid waste. This production was found to be inefficient and the factory switched to other raw materials.

From 1950 to 1977, the uranium ore, more than four million tons, was obtained from Middle Asia and Eastern Europe, mostly from Czechoslovakia and East Germany. The estimated amount of elementary uranium in the U3O8 concentrate produced was almost 25 000 tons.

From 1971 to 1989, pre-processed uranium raw material was imported. The estimated amount of elementary uranium in the U3O8 concentrate produced was 74 000 tons. Additionally, from 1982 to 1989, 1350 tons of UO2, containing 40–80% uranium, was imported to Estonia.

In 1970, except for the uranium ores, the processing of loparite, obtained from the Kola Peninsula, was started. Loparite is a concentrate of tantalum, niobium, and other metals, yielding also uranium and thorium. It also yields rare earth metals, that are left in the waste at the beginning of the processing. Many of these components are toxic.

The Sillamäe radioactive waste depository
Vast amounts of the ore and concentrates ended up as waste rock that was collected in the waste depository near Sillamäe, close to the coast of the Gulf of Finland. In the early years, the benefication residues of Dictyonema Shale, were dumped directly into the sea. The uranium benefication process was stopped in Sillamäe in 1989. Rare earth production has continued.

The Sillamäe radioactive waste depository containing about 6 million tons of radioactive and toxic waste is located only 500 m west of the factory and 1200 m west of the residential areas of the town of Sillamäe. Its construction and filling has involved several stages. Three areas of the waste depository are located in an area of 1/3 square km. The dams are built of sand and do not prevent the leakage of the toxic substances into the sea.

As the depository presents a great danger to the Gulf of Finland, an expensive internationally supported project, lasting seven years has been started for its isolation.

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