47
RADON EXHALATION RATE MEASUREMENTS ON AND AROUND THE PREMISES OF A FORMER COAL MINE

Peter Jovanovi è
Institute of Occupational Safety, Bohoriceva 22 a, Ljubljana, Slovenia
tel: + 386 61 1320 253, fax: + 386 61 312 562, e-mail: peter.jovanovic@zvd.si

The article presents a part of the measurements around a closed coal mine in an area of 2 km 2 where new
buildings are planned. Because of high content of natural radioactivity (U and 226 Ra) in coal and fly ash in
this area, high radon concentrations were measured. Monitoring consists of measurements on the coal mine
repository and around it. Values of radon exhalation rates were in the range from 9 x 10 -3 to 4 x 10 -1 Bqm -2
s-1 . On the areas rich with coal and coal ash, higher radon exhalation rates were determined during all
periods of the year. One location in the coal mine area was covered with soil and clay which decreased
radon exhalation rates by one order of magnitude. Radon exhalation rates measured on populated area are
also high because coal fly ash has been used for covering ground around buildings. The results of this
investigation will be useful for predicting the type of construction in case of new building on the area of
a closed mine.