Supervision of radiation protection of miners at small construction sites of old mining

More than 40 underground construction sites of old mining have been supervised by the radiation protection authority in Saxony in recent years. The paper deals with stories of underground supervisions to share the experiences with authorities and miners to improve the underground radiation protection. Supervision usually includes continuous measurements of radon activity concentrations. Some insufficient or failed radiation protection measures were found during the inspections. Instructions were given to improve the underground radiation protection immediately. A new Express- Air Screen-System (EAS) for miners was developed to shut off radon rich parts of galleries in some minutes only. The EAS will help to reduce the radon exposures of miners in the future.