Radar probing through 600 metres of Zechstein salt

Abstract

Two radar systems were used to conduct tests in a European salt mine. Both systems obtained very good results. An electromagnetic wave speed of 122 m/ms in salt was measured in this particular mine. Using the first system, Bravo, for long range probing, several areas that appeared to contain many anhydrite stringers and other areas that appeared to have good, clean salt were found. Bravo obtained a maximum range of 592 m. At a few locations the Bravo antennas were moved in azimuth in order to pin-point the location of a particular reflection. At one of these stations, a reflection that corresponded to a known anhydrite stringer was located. With the second system, Foxtrot, which was used for short range, high resolution tests, a primary and a multiple signal were recorded from a known anhydrite layer below the mine's salt floor. At another station, Foxtrot obtained a maximum range of 47 m. The salt used for the Foxtrot tests was not as pure as in other locations within the mine. The authors believe that Foxtrot tests at other locations might yield probing distances up to 70 or 80 m.