FDTD modelling of the effect of conductive water on borehole radar performance

A borehole radar survey undertaken on a Witwatersrand gold mine, in a highly resistive host rock (Alberton Porphyry Formation lavas) returned poor results characterized by a fast first arrival followed by a distinctive large, low frequency pulse, on which real reflected pulse information was superimposed at much smaller amplitudes (Figure 1a). The radar that was used to acquire the data, the CSIR Miningtek Aardwolf BR40 (Vogt, 2002), has limited instantaneous dynamic range, so it is not possible to resolve desired signals in the presence of the large low frequency pulse.