Publications and Case Studies

This case study evaluates the performance of the MobileMT airborne passive electromagnetic system over the El Teniente and La Huifa porphyry deposits in central Chile using field data and unconstrained inversion workflows.Results demonstrate that MobileMT delivers coherent, high-resolution resistivity imaging with strong noise immunity, successfully resolving key porphyry features such as resistive cores, conductive alteration zones, and subvertical feeder structures consistent with known geology. The system maintains data quality in both noise-affected and quiet environments, providing reliable depth penetration and structural definition. Overall, MobileMT significantly outperforms previously conducted surveys using an earlier natural-field system, offering improved interpretability and a more robust solution for porphyry exploration in complex and rugged terrains.

Advancing Deep Ore Exploration with MobileMT: Rapid 2.5D Inversion of Broadband Airborne EM Data (August 2025) in a Special MDPI Minerals Issue “Electromagnetic Inversion for Deep Ore Explorations”

“Advances in Magnetic and Electromagnetic Techniques for Mineral Exploration: Enhancing Resource Discovery”, Edited by Dr. Marc A. Vallée and Prof. Dr. Stanisław Mazur.

Minerals 2024, 14, 237.

Michael Jorgensen, Michael S. Zhdanov , Alex Gribenko, Leif Cox, Henrik E. Sabra and Alexander Prikhodko.

Minerals 2024, 14, 1130.

A brief history of the development of the natural field airborne technology is provided accompanied by a comparison of the systems technical specifications. Field examples from the latest development in the airborne electromagnetic natural fields’ domain, MobileMT, demonstrate its exploration capabilities in both conductive and resistive environments, sensitivity to any direction of geoelectrical boundary, and detectability of near-surface discrete targets along with deeper structures.

Extended Abstracts – 18th SAGA Biennial Conference & Exhibition 2024

PDAC-KEGS symposium 2024. Alexander Prikhodko, Andrei Bagrianski, Petr Kuzmin.

Alexander Prikhodko, Andrei Bagrianski, Petr Kuzmin,  Andrew Carpenter – ASEG Extended Abstracts Volume 2023 (2) – AEM2023 8th International Airborne Electromagnetics Workshop

“Innovation in the Air”: in an era where there is pressure to make discoveries faster, and with fewer geologists available to make them, it is a huge benefit that new sensor technologies are coming online to augment and expedite the exploration process.

In general, lithium brines are a challenging target for EM methods since brines are a very conductive substratum, and are often hosted and covered by conductive rocks. The highly conducive environment shields the penetration of the electromagnetic field, which limits the depth of investigation, especially for the controlled sources of primary field methods.
As the forward modeling shows, the airborne EM MobileMT system, exploiting natural electromagnetic fields, is capable of exploring lithium brines effectively.

Numerical methods have been used to simulate different ore systems models and their reflection in the MobileMT data. These documents analyzes different typical and generalized ore systems models in a broad spectrum of geoelectrical conditions, from resistive to conductive. As the theoretical results and practice show, the MobileMT airborne EM system is
able to recover subsurface geology effectively in the broad range of resistivities and depths from surface to >1 km.

Airborne electromagnetic (AEM) methods have proliferated as a tool to aid in mineral exploration since their inception. To date the focus has primarily been on airborne systems that make use of controlled source primary field transmitters, however, the utility of such systems is limited in certain geoelectrical and topographic conditions. Passive AEM methods, which exploit the principles of natural varying electromagnetic fields, remove the necessity of having a controlled source primary field transmitter and overcome its limitations, depth of penetration, first. The source of primary signal for methods exploiting natural fields is currents induced in the subsurface primarily by thunderstorms and other activity in the ionosphere. The MobileMT system is one of the latest developments in the passive field AEM technology. Four case studies are included to demonstrate the ability of the MobileMT data to aid in gold exploration programs, with particular emphasis on the system’s ability to image the deeper geoelectrical environment, thus exploring not only the location of mineralization itself, where petrophysics might be not favourable, but also on the deep structures and related processes controlling the mineralization. A wider depth range of exploration is facilitating an overall improved understanding of the geology and development of a more accurate exploration model.

To bring advantages of natural field electromagnetics into the exploration of discrete targets and mapping complex structures from the surface up to several hundred meters depth, Expert Geophysics Limited has introduced the new and special modification of the MobileMT technology – MobileMTm. High-resolution aeromagnetic data measured with two horizontally spaced sensors is included into the MobileMTm as a complementary dataset to the EM data.

The following document includes a field example of the MobileMTm system for kimberlite identification. KEGS-22 extended abstract here

“Expanding the reserve base of operating mines: Insights from an airborne MobileMT survey in the Omsukchan depression, Russian Far East” P.Kordi, A.Prikhodko, A.Bagrianski and S.Trushin; “MobileMT for porphyry exploration – model studies and field examples” A.Prikhodko and A.Bagrianski.

LATIN GEOPHYSICS EXPLORE – 2021. 27-29 July, 2021.

EEGS’ technical magazine, FastTIMES, has published this Special Issue, which provides case examples of using geophysics for the purposes of sustainable mining by addressing some of these mine site concerns.

EAGE Mineral Exploration Symposium 2020 Extended abstracts are available now. “Exploration capabilities of airborne broadband natural electromagnetic fields measurements” is about the MobileMT technique.

EGL presented exploration capabilities of the airborne EM MobileMT technology on the virtual geophysics conference “LOOKING INTO OUR WORLD” hosted by Chile Explore Group on 7-8 October 2020.

“The airborne MobileMT EM technology was able to identify 1) the deep dome structure as the main controlling factor of the Au-Ag mineralization system; 2) other deep dome structures, in the depression, potential for new, near-surface and buried, discoveries; 3) the subvertical fault zones as feeding, fluid transport channels from the upper contact of the deep magmatic bodies to the near-surface host rocks, and following alteration and ore zones.“

“The 15 new exploration targets recently generated from data acquired by the state-of-the-art MobileMT geophysical survey, not only verify some historical targets, but also highlight the strong discovery potential in new areas on the under explored property. A new discovery within Curipamba could be significantly additive to the already robust economics of the El Domo deposit.”

The MobileMT system was used to collect data for the Holdsworth Gold Project in the Archean Superior Province in July 2018. This case study illustrates the effectiveness of the innovative MobileMT in detailed 3D resistivity mapping from the surface to depths in excess of 1 km below surface and in revealing specific shear zone alteration patterns.

In August 2018, Expert Geophysics Limited flew a test line with the MobileMT system over the Shea Creek uranium deposits area in the western Athabasca basin, just south of the former Cluff Lake mine site.

“This year, the company flew an airborne geophysical survey over the entire Curipamba district for the first time and came out with 14 new geophysical targets, some of which are deemed very large targets that could be porphyry systems. “The goal is to demonstrate that El Domo is not a one resource wonder and that there are multiple deposits within the district, such as additional VMS, epithermal gold, and/or porphyry. If this is the case, our project base and development scale could grow substantially.” Adventus also started geophysics programmes late last year at Pijili & Santiago – the standout projects from the first collection of properties. From those geophysical programmes, Adventus was able to highlight 20 potential copper-gold porphyry targets and has been consolidating groundwork on the best targets throughout 2019 for drilling, where the eventual goal is to announce one or two significant copper-gold porphyry discoveries.“

Nowadays mineral exploration industry requires extended abilities of technologies and processes used for new deposits discovery. To address these requirements the new airborne EM system “MobileMT” was developed which is in the field of Airborne Natural Source Audio Frequency Magnetotellurics, known as AFMAG. The new system is being designed with the goal to expand abilities and overcome limitations of previous technical solutions.

Early in 2019 Expert Geophysics Limited (EGL) flew a MobileMT survey for Accelerate Resources Limited over the areas of the Mt Read Cobalt Project located on the Sorrell Peninsular in western Tasmania. Inside of the flown area there is a known Co-Cu-Au occurrence/prospect under the name of Thomas Creek previously investigated by IP and Downhole EM. The MobileMT system defined the central Thomas Creek sulphide target proving the ability of the sytem not only in deep mineral exploration but in detecting near-surface and discrete targets.

Diagrams of the predicted effective depth of investigation in the MobileMT frequency range are given using an expression based on the skin depth concept. Forward modeling exercise results are illustrated in different geoelectrical situations with MobileMT effective depth of investigation estimation presented for each.

A test block near Cochrane, Ontario, Canada was flown in May 2018. The MobileMT data in 21 frequency windows from 33 Hz to 13 kHz were processed. Maps of the MobileMT data demonstrate the high lateral and depth resolution from the surface to depths over 1 km. Analysis of MobileMT data on the preliminary, pre-inversion stage is presented in this paper.

Expert Geophysics Limited has introduced the latest innovation in passive airborne electromagnetics: Mobile MagnetoTellurics (MobileMT). Designed by Dr. Petr Kuzmin, the patent-pending MobileMT technology represents the most advanced generation of airborne AFMAG technologies available today. MobileMT is the product of extensive experience in developing equipment and signal/data processing algorithms for natural electromagnetic fields measurement. This article presents the evolution of AFMAG technology that led to the revolutionary MobileMT.

The test survey was conducted near Cochrane, Ontario, Canada in January 2018. The successful MobileMT test demonstrates that the MobileMT technology is the next stage in the evolution of airborne AFMAG technologies