Radon measurements and valuation in German hard coal underground mines

Measurements of the radon concentrations by sampling in return air shafts of all hard coal mines in the area of the Chief Mines Inspectorate of the Land NW were carried out by means of a specially designed method of measurement. The dependence of radon concentrations on atmospheric pressure and fan pressure was evaluated on the basis of the measurement results available. Long-term measurements are carried out on the surface of a coal mine at return air shafts, using continuous measuring instruments. For continuous long-term measurements underground, an intrinsically-safe measuring device, which involves processing and storage of the measured values in a CMOS micro-computer, was developed. The radon concentrations which were found are low as compared with maximum levels based on dose/effect correlations put forward by the International Committee for Radiological Protection. Considering radon, the risk of the hard coal miner can therefore be regarded as negligible