Alara and occupational exposure in underground mines

Underground working places are usually exposed to natural radioactivity especially to radon and its decay products. Compared to the severe and direct hazards in mining and aspects of radiation protection are assumed as secondary by the miners with the exception in mining of uranium and thorium ores. The paper describes the different source terms of underground radiation exposure and points out the difficulties with the necessary measuring techniques to evaluate the airborne radiation burden. Reliable metrology under mining conditions is the premise for reducing the exposure with the help of mining techniques considering the specific situation of the deposit. In the course of operating progress of the exploitation the exposure develops dynamically and must lead to necessary improvements. In this situation the practical possibility is offered to perform an optimization in the sense of the ALARA principle. Finally the paper gives clear evidence, that only the uranium miners are sufficiently supervised and that on the other hand the overwhelming majority of the underground miners do not receive any kind of legal or practical radiation protection - in spite of the fact that it is well known among experts and has been proved by several random measurements that radiation burden exists worldwide in most of the underground mines. This should be one of the major challenges for the future work in health physics