3D Modelling of Banded Iron Formation Incorporating Demagnetization ? A Case Study at the Musselwhite Mine, Ontario, Canada

Abstract

Three dimensional (3D) magnetic forward modelling of Banded Iron Formation (BIF) as high susceptibility tabular-style bodies was carried out at the Musselwhite Mine, Ontario in 2004. BIF is associated with mineralisation at the mine and the study both created and validated geologically plausible models. The models are based on drill sections, and are built from a central axis of nodes with geometrical and susceptibility attributes describing each node. The model building process reveals information about the geometrical nature of the BIF units. The results highlight the importance of understanding the interaction of the earth?s magnetic field with the geometry of these highly magnetically susceptible bodies (up to 2.5SI) when interpreting the observed magnetic anomalies. The forward modelling algorithm includes a calculation for the effect of demagnetization, and at Musselwhite this is found to be subtle in nature.