Measuring methods for raw materials exploration

Drone methods are increasingly being used in raw material exploration, but are still in the phase of introduction worldwide. In terms of resolution and measurement area, they fill the gap between helicopter and ground geophysics with little logistical effort. This project specifically aims to investigate the potential of UAV electromagnetics and UAV radiometry and test suitable designs.

Drone geophysics fills the gap between helicopter and ground-based geophysics in terms of measurement area and resolution, requiring minimal logistical effort. Thanks to the rapid increase in drone performance (flight duration, payload), it is increasingly becoming a cost-effective alternative to helicopter geophysics for measurement areas up to the square kilometer range and can be carried out with minimal risk to humans in difficult or dangerous terrain. The lower payload capacity compared to helicopters necessitates specific adaptations for some methods. The UAV-Xplore project focuses primarily on aero-electromagnetics and radiometry. Methodological adaptations, both hardware-specific and in the measurement process and data processing, pursue approaches such as semi-airborne and bi-drone methods in electromagnetics, or advanced data analysis with machine learning techniques in radiometry.

With radiometric surveys, the ground can be characterized down to a depth of 50 cm. The measured values, based on standard data analysis, estimate the concentrations of U-238, Th-232, and K-40, reflecting the geological units and their mineralogy. However, only UAV electromagnetic and magnetic measurements can explore electrically conductive and magnetic structures to greater depths (tens to hundreds of meters), depending on the measurement parameters.

These methods thus complement each other for mapping and structural analysis in the subsurface. UAV radiometry can also provide mineralogically relevant information through vegetation penetration, something hyperspectral cameras or satellites cannot do.

Geosphere Austria has approximately seven years of experience with various drone geophysics methods. New approaches are being pursued, which have yielded promising results in preliminary studies and will be systematically developed and evaluated further in this project, specifically with regard to resource exploration.

DI Gerhard Kreuzer, Liftoff GmbH