Radiation protection problems connected with uranium ore mining at Kvanefjeld and uranium processing

The average content of uranium at Kvanefjeld is 340 gram per metric ton of ore, equivalent to 4200 Bq kb-1 in SI radioactivity units. The corresponding number of thorium are 850 gram per metric ton of ore and 3500 Bq kg-1. The assessment of the radiation dose from external γ-radiation is based partly on the measured radiation levels in the Kvanefjeld plateau area and in the 1980-adit, and partly on measurements, with personal dosemeters, of the doses received by the work force in the adit. The contribution to the annual effective dose equivalent from extenal γ-radiation in an open pit - mine is, on this premise, estimate to be 2.5-3.7 mSv. Planning of a uranium mining and milling enterprise involves conccern about working conditions, but the sum of the calculated dose contributions from external γ-radiation, inhaled radon/thoron-daughter products and inhaled ore dust gives roughly estimated annual effective dose equivalent for work in the open pit-mine about 3.1-16.5 mSv (compared with the annual dose limit of 50 mSv recommended by the ICRP for occupatonally employed persons). (EG)