A Case History of Graphite Exploration in North Norway Integrating Various Geophysical Surveys

• Published in: Minerals
• Main Authors: Vikas Chand Baranwal, Jan Steinar Rønning, Bjørn Eskil Larsen, Yang Su, Bo Zhang, Yunhe Liu, Xiuyan Ren, Håvard Gautneb, Jomar Gellein
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2024
• Subjects: graphite exploration; frequency-domain helicopter electromagnetic (HEM); electric resistivity tomography (ERT); ground geophysics; 3D inversion; integrated geophysical study; Mineralogy; QE351-399.2; North Norway; Northern Norway; Vesterålen
• Online Access: https://doi.org/10.3390/min14030266; https://doaj.org/article/3a2fb35ce7a74f3e862d9b62cc1f12d1

Graphite is considered to be one of Europe’s most critical minerals. It is necessary for the transition from hydrocarbon fuel to electricity due to its use in batteries that power electronic devices and electric transport. In the past, high-quality exposed graphite was found in Norway without today’s advanced geophysical and geological methods. Norway is a key destination in Europe for graphite production. With an increasing demand for graphite, there have been efforts to systematically survey the country using modern geophysical and geological methods to find hidden graphite deposits. Among the various geophysical survey methods, electrical and electromagnetic (EM) methods are the first choice for the exploration of graphite due to the material’s high electrical conductivity. Airborne surveys are often used to cover a large area for a regional reconnaissance survey to locate the sites with potential mineral deposits before performing ground geophysical and geological surveys. Therefore, frequency-domain helicopter EM (HEM) and airborne magnetic surveys were performed in Northern Norway to locate interesting anomalies which were followed by ground surveys such as electrical resistivity tomography (ERT), charged-potential (CP), self-potential (SP), ground EM, and geological surveys. Some locations were also investigated with drilling and petrophysical core-sample analysis. In this paper, we present helicopter EM and magnetic data, 3D inversion of HEM data, and a successful ground follow-up survey result from the Vesterålen district in Northern Norway. The HEM survey identified previously known and new graphite occurrences, both partially exposed or buried, which were confirmed using ground surveys, drilling, and laboratory analysis of the samples.