Geophysical inversion contributions to mineral exploration: Lessons from the Footprints project

Magnetic and gravity inversions are used to create 2D or 3D models of the magnetic susceptibility and density, respectively using potential field data. Unconstrained inversions generate an output based on mathematical constraints imposed by the inversion algorithm. Constrained inversions integrate lithological, structural, and petrophysical information in the inversion process to produce more geologically meaningful results. This study analyses the validity of this assertion in the context of the NSERC-CMIC Mineral Exploration Footprints project. Unconstrained and constrained geophysical inversions were computed for three mining sites: a gold site (Canadian Malartic, Quebec), a copper site (Highland Valley, British Columbia) and a uranium site (Millennium-McArthur River, Saskatchewan). After initially computing unconstrained inversions, constrained inversions were developed using physical property measurements, which directly link geophysics to geology, and lithological boundaries extracted from an interp...