A novel approach combining geomagnetic and hyperspectral drone-borne data. Advances in remote sensing based mineral exploration and environmental monitoring.

The demand for raw materials is constantly growing for more than twenty years in our modern societies. Therefore, there is an acute necessity for the exploration of new deposits to sustain the need for high-technology metals. Remote or formerly non-lucrative mineral deposits suddenly become attractive to the industry. Thus, non-invasive and efficient tools for a sustainable exploration are required to fit our present societal requirements.
We identified light-weight drone technology as one of the disruptive technologies in that respect. Further, making use of these unmanned aerial systems (UAS) with multiple sensors will boost non-invasive exploration.
We present a novel approach for non-invasive mineral exploration based on the integration of remote sensing techniques. Advantages of UAS in this context are that they are fast, easily deployable and deliver high resolution data with short turn-around times. We combine light-weight UAS technology with a hyperspectral sensor and a fluxgate magnetometer. Both datasets of high-resolution hyperspectral surface data and subsurface data using the Earth’s magnetic field are merged. This allows us to identify surficial rock exposures and estimates the subsurface proportions of the aforesaid targets. We also measure the extent of the impact of exploration and mining operations on the environment (e.g., Acid rock drainage) using precise hyperspectral mapping.
An octocopter platform carrying the hyperspectral sensor system maps the area of interest and a fixed-wing UAS acquires magnetic data. Hyperspectral data is corrected for topographic effects and automatically georeferenced. Magnetic data is calibrated for orientation effects of the UAS. External and diurnal induced field fluctuations are rectified with base station data. Validation of the measurements is achieved with traditional field methods and in situ sampling. Ground spectroscopy, X-ray diffraction and fluorescence are used to validate the results. We tested this approach in Namibia, Greenland, Finland and Germany.
The results are promising and demonstrate that drone-based exploration becomes more attractive and feasible to the mining industry and the geoscientific community.