Special Issue "Development of Geoelectrical and Electromagnetic Methods in Mineral Exploration"

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Exploration Methods and Applications".

Deadline for manuscript submissions: 26 May 2023 | Viewed by 1568

Special Issue Editors

Université Grenoble Alpes, Université Savoie Mont-Blanc, CNRS, UMR CNRS 5204, EDYTEM, 73370 Le Bourget du Lac, France
Interests: critical zone; hydrogeophysics; volcanology; near-surface geophysics; biogeophysics
Sorbonne Université, CNRS, EPHE, METIS, F-75005 Paris, France
Interests: hydrogeology; hydrogeophysics; near surface geophysics; environmental geophysics; petrophysics
Special Issues, Collections and Topics in MDPI journals
Dr. Jacques Deparis
E-Mail Website
Guest Editor
BRGM, 45060 Orléans, France
Interests: environmental geophysics; hydrogeophysics; near surface geophysics

Special Issue Information

Dear Colleagues,

The goal of mineral exploration is the discovery of new deposits of economic value with the purpose of extracting them to feed the needs of industry. Geophysics describes a set of non-intrusive techniques useable to image the subsurface and extract their physical properties. It is used in mineral exploration to reduce risk associated with geochemical and geological data and drilling. In the last several decades, a great deal of progress has been made in the development and use of geoelectrical and electromagnetic geophysical methods in mineral exploration—especially regarding the exploration of targets located the first kilometer below the ground surface. In addition to electrical conductivity, induced polarization is a very sensitive technique that can be used to localize and decipher minerals in the subsurface of the Earth. This Special Issue targets contributions from laboratory to field measurements, numerical forward and inverse modeling, as well as petrophysical models able to connect the properties of minerals to the geophysical properties of interest. Our goal is to provide an updated view of the state-of-the-art in terms of geoelectrical and electromagnetic methods applied to mineral exploration. This Special Issue is also open to a variety of methods, including magneto-resistivity, magneto-induced polarization as well as seismoelectric and electroseismic effects, just to cite a few.

Dr. André Revil
Dr. Damien Jougnot
Dr. Jacques Deparis
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • induced polarization
  • mineral exploration
  • electrical conductivity
  • petrophysics
  • inverse modeling

Published Papers (2 papers)

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Research

Article
Estimation of Electrical Spectra of Irregular Embedded Samples
Minerals 2023, 13(3), 412; https://doi.org/10.3390/min13030412 - 15 Mar 2023
Viewed by 248
Abstract
In order to interpret spectral induced polarization (SIP) data measured in the field for the purpose of mineral exploration, laboratory investigations are necessary that establish relationships between electrical parameters and mineral properties. For massive ores, and in particular for seafloor massive sulfides (SMSs), [...] Read more.
In order to interpret spectral induced polarization (SIP) data measured in the field for the purpose of mineral exploration, laboratory investigations are necessary that establish relationships between electrical parameters and mineral properties. For massive ores, and in particular for seafloor massive sulfides (SMSs), samples may be difficult to obtain, and it is often not desired to cut cylindrical plugs out of the available hand pieces. We suggest a method to obtain the electrical spectra of hand pieces from measurements on the samples embedded in a non-polarizing medium, in our case quartz sand. As such, destroying potentially precious samples is not necessary. The frequency-dependent phase spectrum of the sample is calculated by dividing the bulk spectrum with a so-called dilution factor, which is obtained from numerical simulation and has a real and constant value. We evaluate the method with a set of SMS samples where conventional cylindrical plugs are available. We can estimate the phase shift maximum of 73% of the samples with a deviation less than 50% from the reference. The estimation quality slightly decreases if the dilution factor is approximated by the volumetric share of the sample. We consider the performance acceptable if the general difficulty to obtain reproducible and representative laboratory measurements for massive sulfides is taken into account. Full article
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Article
Integrated Interpretation of Electrical Resistivity Tomography for Evaporite Rock Exploration: A Case Study of the Messinian Gypsum in the Sorbas Basin (Almería, Spain)
Minerals 2023, 13(2), 136; https://doi.org/10.3390/min13020136 - 17 Jan 2023
Viewed by 903
Abstract
In this study, we conduct an investigation of the Sorbas Basin (Almería, Spain) on the Messinian gypsum unit using geophysical prospecting methods. Geophysical electrical resistivity tomography (ERT) methods were applied to study the subsurface of this gypsum unit, the exploitation of which could [...] Read more.
In this study, we conduct an investigation of the Sorbas Basin (Almería, Spain) on the Messinian gypsum unit using geophysical prospecting methods. Geophysical electrical resistivity tomography (ERT) methods were applied to study the subsurface of this gypsum unit, the exploitation of which could be of interest economically, with different commercial specifications for alabastrine and selenitic gypsums. For the interpretation of the different ERT images, the data for the surface geology, borehole cores, and seismic refraction conducted at a point within the ERT profiles were used. The results obtained from this investigation can be used as a reference for other similar studies in other regions. It was observed that selenitic gypsum is more resistive than alabastrine gypsum; therefore, the diagenetic processes of dehydration (anhydritization) and hydration (gypsification) increase the “percolation” phenomenon through possibly ensuring a greater connectivity of the shale matrix. Fracturing and moisture can be used to fully determine the resistivity of the purest and most resistive gypsum, to the point of considerably lowering the resistivity in an entire area affected by fracturing. The use of different tests with different lengths for the same profile can help one better understand the structure of the gypsum body in the subsurface, especially when there are shale intercalations or more- or less-pure levels of gypsum that do not reach a value of a few meters in thickness, because these thinner levels of a few meters are not defined in the ERT images when the test is performed at depths of up to 75 m. Full article
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Tentative title: Estimation of electrical spectra of irregular embedded samples
Authors: Malte Wichmann and Andreas Hördt, TU Braunschweig
Abstract:
In order to interpret spectral induced polarization( SIP) data measured in the field for the purpose of mineral exploration, laboratory investigations are necessary that establish relationships between electrical parameters and mineral properties. For massive ores, and in particular for seafloor massive sulfides (SMS), samples may be difficult to obtain, and it is often not desired to cut cylindrical plugs, out of the available hand pieces. We suggest a method to obtain the electrical spectra of hand pieces from measurements on the samples embedded in a non-polarizing medium, in our case quartz sand. This way, destroying potentially precious samples is not necessary. The frequency-dependent phase spectrum of the sample is calculated by dividing the bulk spectrum with a so-called dilution factor, which is obtained from numerical simulation and has a real and constant value. We evaluate the method with a set of SMS samples where conventional cylindrical plugs are available. We can estimate the phase shift maximum of 73% of the samples with a deviation less than 50% from the reference. The estimation quality slightly decreases if the dilution factor is approximated by volumetric share of the sample. We consider the performance acceptable if the general difficulty to obtain reproducible and representative laboratory measurements for massive sulfides is taken into account.

Tentative title: Measurement of dried seafloor massive sulphides
Authors: Malte Wichmann and Andreas Hördt, TU Braunschweig
Abstract:
We carried out spectral induced polarization (SIP) measurements on a set of dried seafloor massive sulphide samples and compared the results with those obtained with the same samples fully saturated with NaCl solution. We find that the conductivity and polarizability are generally high for both dried and saturated samples, i.e. exhibiting phase shifts in the order of 100s of mrad and imaginary conductivities up to 1 S/m. Depending on the particular sample, the polarizabilities of the dried samples remain as high as for the saturated samples, or are slightly reduced. The high polarizability of dried samples and the fact that polarizability cannot be destroyed by drying are significant observations, because most of the existing theories to explain the polarization of mineralized rock assume a pore space filled with an electrolyte. We also found that the often used agar gel is unsuitable to couple the dried samples to the electrodes, because it releases water into the sample. Coupling with plasticine is a feasible alternative, because significantly less fluid is absorbed by the sample when it is incorporated into the sample holder.

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