Acquisition and signal processing of ground-penetrating radar for shallow exploration and open-pit mining

Abstract

The Australian Mineral Industries Research Association (AMIRA) has sponsored Monash University to investigate the acquisition and signal processing of ground-penetrating radar (GPR) for shallow exploration and open-pit mining. This project had three objectives: (1) to acquire high-quality GPR data sets for shallow exploration and surface mining applications under a variety of geological conditions; (2) to develop signal-processing techniques to enhance radar profiles prior to detailed interpretation; (3) to assess the accuracy of GPR and associated processing techniques through comparisons with independent measurements. Over one hundred kilometres of data were recorded at the various sponsors sites in a wide variety of geological conditions for different economic targets. Several examples are presented to demonstrate: 1) the hand-carried and vehicle-towed acquisition techniques, 2) target detection at depths down to 25 m, 3) the benefits of signal processing for good and poor quality data, 4) the use of dielectric measurements, petrophysical modelling and frequency-dependent synthetic radargrams, 5) the application of seismic interpretation concepts. The project has demonstrated commercially acceptable rates of GPR data acquisition where the penetration is satisfactory. Some of the unfavourable Australian geological conditions for radar have also been identified. Although signal processing techniques have extended the applicable range of the radar technique, additional hardware enhancements have been identified to improve the commercial application of radar. The next stage is to assess the economic feasibility of radar by comparison with competing techniques such as drilling.