3D Inversion of AirMt AFMAG Data

The Airborne Magnetic Tensor (AirMt) system measures the rotational invariants of the transfer functions for audiofrequency natural sources from helicopter platforms. AirMt, data are typically measured from 30 Hz to 720 Hz, giving detection depths down to 1 km or more, depending on the terrain conductivity. Given the airborne deployment, it is possible to acquire AirMt data over large areas for a relatively low cost compared to equivalent ground surveys. This makes it a practical method for mapping large-scale geological structures. We describe the theory of the AirMt system, and present a case study comparing 3D inversion results from ZTEM and AirMt surveys flown over the Nebo-Babel Ni-Cu-PGE deposit in Western Australia. Our 3D inversion results are shown to be in good agreement with the known geology of the deposits and the surrounding area.