© Institut für Geophysik

Deep electromagnetic sounding for mineral exploration

The collaborative research and development project DESMEX aims at developing airborne electromagnetic (EM) methods for deep exploration of mineral deposits. We focus on the implementation of the semi-airborne EM technique.
Our efforts comprise the development of novel magnetic field sensors, data processing techniques and modelling and inversion codes. Dedicated sites in Germany, Europe and worldwide are investigated in case studies to demonstrate the technologies.
DESMEX has commenced in 2015. Recently, the continuation project DESMEX II was launched. DESMEX II includes both manned helicopter and unmanned drone operations. We also aim at demonstration surveys at real-world cases to bring the technologies closer to application.

Schematics of the semi-airborne EM geometry. A time-varying current is injected into the ground using high-moment transmitters, and the scattered EM field is recorded with dedicated magnetic field sensors in a helicopter-towed bird. We use rectangular signals of ca. 10 Hz repetition rate and evaluate the frequency harmonics in the range from 10-10.000 Hz. Transmitters spreads of 1-5 km are deployed for a single flight. Multiple transmitter locations are realized within a survey
Example of a survey geometry comprising 14 transmitter installations (Thuringia, Germany). The depicted data represents the total magnetic field intensity (TMI), which is recorded as a by-product during the semi-airborne EM survey.

Funding agency: Bundesministerium für Bildung und Forschung (BMBF)
Funding program: r4 – Innovative Technologien für Ressourceneffizienz – Forschung zur Bereitstellung wirtschaftsstrategischer Rohstoffe
Funding period of DESMEX: 01 Mar 2015 – 28 Feb 2019
Funding period of DESMEX II: 01 July 2019 – 30 June 2022


r4 – Wirtschaftsstrategische Rohstoffe