Detecting the Fingers of God: Optimising magnetotelluric survey design for mineral exploration

Summary

Magnetotellurics is a versatile exploration technique that can be used for imaging across scale lengths of tens to hundreds of metres, down to tens to hundreds of kilometres. Only in recent years has the potential of MT as an exploration tool been fully realised across varying depth scales. The optimum design of an MT survey for imaging the full mineral system has not yet been studied in detail, leaving questions such as, could the famous ‘Fingers of God’ conductivity anomalies that point to Olympic Dam, Wirrda Well and Vulcan deposits be resolved with larger site spacing or with a narrower period range? What about with an array instead of a transect? These questions are addressed using synthetic studies that take known conductivity anomalies that lead to mineral deposits, and trialling different survey layouts, period ranges and cover thickness to determine the ideal survey layout to make sure these features are not missed, whilst keeping survey acquisition expenditure and time to a minimum.

• magnetotellurics
• mineral exploration
• modelling
• survey design
• Olympic Dam