Project: Highly sensitive receiver for measuring transient electromagnetic responses in Exploration for deep buried mineral occurrences

Acronym HITEM
Duration 01/05/2016 - 30/04/2019
Project Topic The proposed collaborative research project ‘HITEM’ addresses the first topic area of the third ERA-MIN joint call (2015) towards the non-energy raw material value chain: the development of a new tool for the electromagnetic (EM) exploration of primary resources. Amongst the variety of EM methods in geophysics, the time-domain method TEM is used to generate a 3D illustration of the sub-surface electrical conductance especially for geological structures which provide a continuous conducting layer. The task in this project is to develop a new extremely high sensitive receiver based on high transition temperature superconducting quantum interference devices (HTS SQUID). New sensor fabrication and packaging technologies, innovative readout electronics and control systems have to be developed by the partners for the demonstrator in order to assess the performance in different field tests. Within the tests in Finland, South Africa and Germany a database for the development of a suitable remote reference method for TEM will be gathered. All these tasks will provide ultimate sensitivity for low frequency signals and thus enable detection of conducting resources well below 500 m. Based on the data recorded in the tests at sites with known deep deposits, which especially contain an economic grade of platinum-group-elements material often found in sulfidic deposits, new or adapted inversion and interpretation algorithms for SQUID based receiver data have to be developed and their results compared with prior knowledge of the according structures. Thus, the utmost important goal of this industrial driven proposal with partners from Finland, South Africa and Germany is to contribute to the exploration of natural resources of critical raw materials with the focus to provide European companies in the field of exploration with internationally competitive geophysical instruments and methods.
Project Results
(after finalisation)
The potential for exploring resource deposits deeper than 500 m from the surface is limited by geophysical techniques One method successfully applied to date is so called transient, time domain or pulse electro magnetics ( For volcanogenic massive sulphide deposits (VMS as a subspecies of volcanic exhalative deposits), conventional measurement techniques have already been able to achieve exploration depths of up to a few hundred metres In addition to non ferrous metals, these VMS deposits usually also contain significant amounts of platinum and platinum group elements, including platinum, palladium, ruthenium, iridium, rhodium and osmium All of them contain valuable high tech metals, which are necessary for future technologies 7 Project HITEM Highly sensitive receiver for measuring transient electromagnetic responses in Exploration for deep buried mineral occurrences Electromagnetic exploration methods, such as TEM, are excellently suited for this type of deposit, as the metals have an increased electrical conductivity Due to the previous limitation of the exploration depth, however, very little is known about the depth extension of the deposits This applies in particular to Germany, where after centuries of intensive mining, superficial resources are considered to be exhausted as far as possible In thisproject the researchers have advanced this technology in order to enable extended penetration depths and to explore VMS deposits for the acquisition of high tech metals In the HiTEM project, a higher penetration depth of the method was not achieved byincreasing the transmitter pulse moment, but by increasing the sensitivity of the sensors and the entire TEM receiver, particularly in the low frequency range This enabled to make use of later times in the TEM signal decay after the transmitter pulse hasbeen switched off This task was solved by means of new Superconducting Quantum Interference Detectors ( based on high temperature superconducting ( materials The development of robust, low noise HTS SQUID sensors was part of the work of Leibniz IPHT and was successfully realised The new sensors are faster to be fabricated, can be assembled and encapsulated in fewer processing steps as well as they are more robust in operation which makes them more cost effective For this purpose, new fabrication tools and technologies were implemented in the fabrication line The performance of the sensors wascharacterized by the advanced and adapted receiver electronics For the first time, control electronics based onhigh frequency AC Bias were developed and implemented for all three sensors In the interaction of sensors and electronics, the system noise could be reduced, especially in the low frequency frequency range, thus achieving a high signal quality and a greater depth of investigation The control electronicsand all indicators arenow fully digitaland transferred to a browser based solution, so that now no complex installation of additional software for setting the systems and system parameters is necessary The field tests in Finland and possibly other countries on representative targets of this deposit type are to be completed in this year Initial results on the improved system parameters have already been determined and validated Within the scope of further field measurements, these results will be verified in the field ( and the developed innovativemethods for the reduction of electromagnetic noise in the corresponding frequency range for TEM will be analysed, validated and optimized In addition, new inversion and interpretation methods could be further developed and implemented Due to different aspects the project had been prolonged by 6 monthsand ended in October 2019 The project results prove that the expectations of the partners involved were fulfilled Against this background, SUPRACONbelieves that a new, robust technology has been developed that will enable exploration service providers and mining companies to make more accurate statements about potential deposits This might be accompanied by a potential reduction in the number of drill holes required, as the expected deposits can be determined more accurately
Website visit project website
Network ERA-MIN
Call The Third ERA-MIN Joint Call (2015)

Project partner

Number Name Role Country
1 Supracon AG Coordinator Germany
2 BroadBand Geophysical (Pty) Ltd Partner South Africa
3 Leibniz Institute of Photonic Technology Partner Germany
4 Drillcon SMOY Partner Finland