powered by a full-volume multi-grid finite-difference solver
capable of modelling geological settings common in mineral exploration including conductivity contrasts of 1:10 000 000. MGEM generates finely meshed grids encased in larger-volume coarser grids. Finer geological details can be modelled over areas of interest and larger/regional electrical structures can be incorporated in the coarser grids. In this manner, high resolution EM data can be generated in a time frame suitable for mineral exploration.
The successful use of MGEM at Norman West (Sudbury) is detailed here:
The Voisey’s Bay Ovoid is an example that demonstrates the need for both fine and regional electrical structures. The near-surface (<20m) depth-to-top of the highly-conductive massive sulphide deposit requires a detailed conductivity grid. The regional variably-mineralized troctolite dykes that encase the ovoid require a large grid spanning multiple kilometres.
Details of MGEM modelling results for the Voisey Bay Ovoid response are available: