Mining and underground excavation

An activity regarded as mining and exploration for uranium comprises all activities where the amount of uranium produced in the course of one year exceeds 10 tonnes, and where the average uranium and thorium content in the processed ore exceeds the limits laid down in Section 2 of the Nuclear Energy Decree, and where the combined concentration of uranium and thorium in products produced in the refinement process exceeds 0.5 kilogrammes per tonne.

Mining and underground excavation aimed at producing and enriching uranium or thorium is subject to permit by the Finnish Council of State. The export and import of ore concentrate with an uranium or thorium content is also subject to license by either the Radiation and Nuclear Safety Agency or the Ministry for Foreign Affairs of Finland, depending on the case.

Currenlty, Finland has no uranium mines. In the Paukkajanvaaras area in Eno, North Karelia, an amount in excess of 30 tonnes of uranium was mined at the end of the 1950s and in the beginning of the 1960s. As a result of this mining operation, a quantity of gangue and sand from ore dressing were deposited in the area, with radiation levels clearly exceeding the natural background radiation level. This waste was dealt with in the mid-1990s, and in 2001 STUK found that the tailings from this mining operation were disposed of.

Uranium can also be extracted in connection with other mining or dressing operations. Should this be the case, the uranium concentration required by profitable production is markedly lower than that required by uranium mining proper, and the waste generated in the process can be dealt with using simpler methods.

The Mårtenson open-pit mine in the Paukajanvaara areaThe Mårtenson open-pit mine in the Paukajanvaara area in Eno, North Karelia. Paukkajanvaara is the only facility in Finland that has ever produced uranium to any appreciable extent. Uranium was mined at the facility between 1958 and 1961.

The entrance to the uranium mineA photo, taken in 1974, of the entrance to the uranium mine and its concentrating plant that were in operation in the area. Today, this area has been restored to its original condition, with all of the radioactive waste being buried.

Mining and underground excavation other than uranium mines

Under the provisions of the Radiation Act, STUK supervises mining and underground excavation where such activity is not aimed at extracting uranium or thorium. The operator engaged in such activity is obligated to notify STUK of any wide-scale exploitation of natural resources whose uranium of thorium concentration exceeds 0.1kilogrammes per tonne (100ppm.) In these cases, STUK estimates whether or not the activity corresponds to that stipulated by Section 11 of the Radiation Act (592/1991), and may require the Radiation Act to submit clarifications regarding exposure to radiation as stipulated by Section 45 of the Radiation Act.

On the basis of such clarifications, STUK lays down the requirements regarding radiation safety. A radiological survey of the underlying conditions and continuous monitoring of the environmental radiation level may also be required for operations where uranium or thorium are not produced.

Those working in mines are exposed to thorium

STUK carries out radon testing in all underground mines on a regular basis. External radiation and radon gas expose those working in uranium mines to radiation. While radon may be of particular concern in underground mines, working conditions in them can be raised to an acceptable level by putting in place sufficient air conditioning equipment and by covering all areas where waste is deposited.

The entry of radon from a mining area into the air and the environment depends on factors such as the uranium content of the ore and the mining method used. Adverse impacts can be reduced through proper planning of operations. Radon concentrations are also diluted in air currents as radon is carried away from the mining area.

Radon may also be found in other underground mines than in uranium mines. In recent measurements, radon concentrations in Finnish mines have remained under the action level 400Bq/m3.

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