Exploratory galleries and boreholes are classical methods used in mining when searching for ore. The high cost of such measures sets limits with respect to their number and length. When the geology is complicated, workable mineralizations may remain undetected. Attempts to explore for ores using radiowaves were made as early as the fifties. Shortwave electromagnetic radiation is transmitted through the rock. Ore absorbs more energy than the surrounding rock, thus creating a radiowave shadow (RWS). The RWS method has been developed in the sixties and seventies by BGR, Hannover (FRG), as a multifrequency method to a stage that can be used for routine work. In cooperation with BBU, Bleiberg (Austria), this method has been applied for underground exploration for lead-zinc ores since 1982. It has proved to be a useful, modern mining tool. The principle, technique and possibilities of the method are shown by way of examples.