Evaluation of a High-frequency Seismic Source System in Mining Application

In the year 2007 two seismic measuring campaigns were carried out in the research and teaching mine `Reiche Zeche' in Freiberg (Saxonia, Germany). 24 three-component geophones, developed by the GeoForschungsZentrum Potsdam (Germany), were deployed in small boreholes along two galleries, with geophone intervals of around 7.5 m. The maximum distance between source system and geophones was around 40 m. The seismic source system consists of two actuators, based on the magnetostrictive effect. The actuators are custom-made by ETREMA Products, Inc. (USA). For the two actuators an adaptive, real-time, closed loop control was used with a sweep signal of a bandwith ranging from 300 Hz up to 6 kHz. The Shover principle was applied for shear wave generation. During campaign 1 the source system was principally tested. The focus of campaign 2 was to test signal repeatability and compare different recording systems to optimize the source system. The Shover principle could not be successfully applied until yet.