Funding measures
HiTEM was funded by the German Federal Ministry of Education and Research (BMBF) under the ERA-MIN 2 funding measure “r4 – Innovative Technologies for Resource Efficiency – Research for the Supply of Strategic Raw Materials,” as part of the research concept “Resource-Efficient Circular Economy,” under funding reference 033R164A.
Kurzbeschreibung
The motivation behind the project was the exploration of deep-seated sulfidic ore deposits with depths exceeding 500 m, using high-temperature SQUID (HTS)–based transient electromagnetic (TEM) instruments (a geophysical method). The goal was to achieve a better understanding of the spatial extent — particularly depth, formation, and prospectivity — of such deposits. The project therefore focused on developing lower-noise and more sensitive HTS sensors, reducing overall system noise, and mitigating the influence of external disturbances using so-called remote reference techniques.
In the TEM method, surface loops periodically energized with current generate varying magnetic fields that induce subsurface eddy currents. These enable geological exploration based on differing conductivities (a material property of rocks). Improved detection depth (the maximum depth from which usable signals can still be acquired) was achieved by increasing the sensitivity of the SQUID sensors used in the TEM receiver, thereby improving the usable signal-to-noise ratio (SNR). A higher SNR allows for longer recording times, since the noise limit is reached later. Extending the recording time directly translates into greater detection depth.
Enhancements at the sensor level enabled an innovation in exploration technology, improving the ability to investigate massive sulfide deposits — potential sources of high-tech metals — at depths greater than 500 m. The increased sensor sensitivity will in the future make it possible to expand current knowledge on deposit depth extents and to identify previously undetected deep deposits. This benefits the exploration of strategic raw materials, which form the basis for innovative key technologies. Beyond discovering new deposits and expanding the supply of critical raw materials, the new HTS technology also enhances the precision with which potential deposits can be characterized.
Additionally, the more detailed mapping of conductivity distributions helps position boreholes more efficiently, reducing the number of drill holes needed to delineate a deposit. This lowers costs and minimizes unnecessary ground disturbances, improving environmental sustainability and supporting greater public acceptance of mineral exploration.
The new generation of HTS systems offers improved signal quality through enhanced stability, and the increased performance of these systems has been demonstrated during the project. It is expected that final tests in mine-proximal and urban-disturbed environments will be successful, enabling prompt introduction to the international market.
