Miners annual exposure and the outlet air

The air in all underground mines is contaminated by radioactive gas radon. The presence of it is the potential danger for the health of workers. The measure of this danger is the annual exposure of miners. It may be evaluated using several techniques, but all of them base on measurements carried out in the work-places. The measurements lead in this way, form the problems in choosing the optimal measurements' strategy. It is known that mines are large and dynamic (in the physical sense) objects. The air contamination change both in time and places as well and the changes are in the order to magnitude frequently. Authors were searching for a new method which can average the air contamination's level and which is simple in use. The proposed method bases on measurements carried out in outlet air stream in mines. These streams are sum of many local streams, so they carry information on average radiation in the air on work-places. The main idea of the method is to correlate parameters of the contamination's distribution measured in the outlet air streams with the appropriate parameters of contamination's distribution measured in the work-places. It was proved that the geometric mean obtained from the measurements in the outlet air can be correlated with the geometric mean and the geometric standard deviation of the measurements' distribution obtained in the work-places. The determination coefficient is 0.87 and 0.59 respectively. The idea of the method may be useful in all situations, where the air contamination frequently vary and is no possibility to take continuous measurements in all work-places. (author)