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A Semi-Airborne Em Study of the Hope Ore Deposit (Namibia) Using a Drone-Based Concept
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, NSG2022 3rd Conference on Airborne, Drone and Robotic Geophysics, Sep 2022, Volume 2022, p.1 - 5
Abstract
Summary
Unmanned aerial vehicles (UAVs) are ideally suited as carriers for passive receiver instruments. To demonstrate the capability of UAVs for semi-airborne electromagnetic (EM) application, we have conducted a drone-based semi-airborne EM survey at the Hope ore body (Namibia), a well-explored volcanogenic massive sulfide deposit. The conductive deposit is embedded in a resistive sediment and is a perfect case study target for methods that are sensitive to electrical conductivity. The semi-airborne method differs from conventional airborne EM methods by the installation of powerful ground-based transmitters facilitating greater penetration depths. By determining magnetic transfer functions and estimating 2D subsurface conductivity models on that basis, we aim to image the characteristics of the deposit.
We have determined consistent transfer functions up to 2km distance to the employed transmitters at frequencies ranging from 32Hz to 4kHz. However, there remain challenges such as UAV-related EM noise limiting the data quality. It was possible to estimate conclusive inversion models, map the extent of the conductive target successfully, and track down the ore body to a depth of more than 300m. It is yet unclear to which depth the Hope deposit can be resolved — this would require an extension of the survey.
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