3D Inversion of Airborne EM Data at Mt. Milligan

Located in the Quesnel Terrane of British Columbia, the Mt. Milligan project hosts a massive tabular copper-gold porphyry deposit. While airborne time-domain electromagnetic (EM) surveys are an economical way to explore such large regions, the sheer volume of data often makes accurate 3D modeling computationally impossible for traditional methods. Without full 3D physics, operators often struggle to accurately represent complex real-world structures and deep geological targets.

Computational Geosciences Inc. (CGI) overcame these hurdles by applying proprietary adaptive OcTree mesh refinement technology. By partitioning the survey into 144 manageable sub-domains, CGI processed 8.4 million cells to produce a high-resolution model in just a few hours. This sophisticated approach allowed for the modeling of multiple scales of structure simultaneously, ensuring that even far-field conductivity effects were captured without sacrificing local detail.

The resulting 3D inversion clearly imaged critical features, including the Great Eastern Fault and its associated conductive sediments and alteration zones. By utilizing CGI’s advanced mathematics, the project team successfully maximized the value of their airborne data, gaining a precise understanding of the deposit’s subsurface geometry to better guide future exploration and drilling.

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