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Norilsk fuel storage subsidence could be thaw-induced, experts say

Scientists discovered that near notorious tank No. 5 there was a gutter, along which meltwater was leaking, according to the report

MOSCOW, December 21. /TASS/. Basement piles of the storage in Norilsk, where fuel spilled in May, could have subsided due to the underground waters, which had destroyed the permafrost’s layer, the Great Norilsk Expedition’s report reads. The expedition was organized by the Russian Academy of Sciences’ Siberian Branch.

“The survey has proved that there is a deep layer of meltwater amid the permafrost or complete absence of perennially frozen soils near tank number 5. Besides, the results point to changes in the soils’ physical features and the loss of their stability. The underground waters supposedly come from a lake, which is 200 meters to the north of tank number 5. Highly likely the underground drainage could have caused soils’ warming under tank number 5, which consequently entailed the subsidence of the basement’s piles,” the report reads.

According to the document, the experts have drilled a well to analyze the soils, and at the interval of between 2 and 3.1 meters they identified an aquifer. At the same time, scientists discovered that near tank No. 5 in the parent material’s base under the artificial filling there was a gutter, along which meltwater was leaking.

“Results of the thermometric studies point to a deep meltwater flow in the permafrost. In the southern part of the storage, along the lower edge of the artificial filling, the underground waters come up to the surface. Thus, the permafrost’s meltwater began to form practically immediately after the storage was commissioned, and moreover – the meltwater’s formation continues,” the experts said.

How permafrost specialists work

In August, scientists of the Melnikov Permafrost Institute (the Russian Academy of Sciences’ Siberian Branch) worked in the power plant’s area near tanks number 2-4 and from the western side of the fuel storage area, in the seasonal temporary watershed up to the place where it flows into the Daldykan River. By using geophysical methods, they identified borders of the frozen and non-frozen soils.

“The Permafrost Institute’s scientists conducted a general survey of the territory and used instruments to measure temperatures of soils in the existing and newly-drilled wells to determine the condition of the perennially frozen soils, the reasons for the conditions' changes and directions. They verified locations of the meltwaters and their boundaries in terms of the area and depth,” the report reads.

The scientists surveyed how the processes developed on the surface. They analyzed the topsoil and the depth of seasonal thawing. They observed the soils’ temperatures in existing wells and additionally in another three wells, which they had made. The lowest temperatures (of about minus 4 degrees) were registered near tank number 3. Near tank number 5 the experts registered the highest temperatures (minus 1.5 degrees).

Expedition to Taimyr

The Siberian Branch of the Russian Academy of Sciences for the first time over recent years, has sent to the Taimyr Peninsula, at the invitation of Nornickel, a big scientific expedition to conduct a large-scale examination of the area. Scientists will use the expedition’s results to present nature-friendly solutions and suggestions for industrial companies, working in the Arctic.

The expedition’s key points were watersheds of the Rivers Pyasina, Norilka and Ambarnaya and Lake Pyasino. In August, experts from 14 research institutes of the Academy of Sciences’ Siberian Branch collected samples of soils, plants and sediments and began tests at the institutes’ labs.