Two calibration pilots to ensure that DEXPLORE’s geophysical innovations meet the set KPIs.
These correspond to two small mining areas in Spain, to obtain reliable geophysical data for the targeted depth (at least 600 m). The pilots include both metallic and non-metallic minerals with varying mineralization configurations.
One pilot in Estonia for running the final validation of DEXPLORE’s geophysical innovations.
The ultimate objective of this final pilot is to develop updated ore models for the Estonian Precambrian basement using the DEXPLORE integrated surface-to-subsurface exploration package.
Calibration Pilots
Since not all remote sensing and geophysical methods are equally effective in all geological settings, we have selected two interesting areas in Spain with specific mineralization features that will allow us to calibrate the DEXPLORE geophysical technologies: dissemination – Cu and associated minerals (ATALAYA), and along planar structures – Fluorite (MINERSA).
The selected mines count on well-structured geochemical, petrophysical, core drilling information, and even a developed ore model, so they are the perfect scenario for running initial validation tests of the airborne and land-based techniques optimized into the frame of DEXPLORE, before to jump into the final validation pilot where new areas or areas with outdated mineral models will be studied.
In both pilots TerraDat and XCALIBUR aim to run surveys focused on the identification of mineralization while evaluating main geological units and structures. The surveys will include a seismic line and a UAV gravity flight, where several aspects related to the acquisition and processing will be evaluated for optimizing the seismic exploration.
Asturias
MINERSA Fluorite mine (North of Spain): Strata bound mineralization of Fluorite occurs as open-space fillings and as replacement of the limestone host rock in the proximity of the base of the Triassic succession, ca. 250-300 m thick. Extensional faults feed the host rock.
Conventional geophysical exploration is not applicable as common base metals are absent. However, since the mineralization is fracture-related and also occurs in the vicinity of the basin margins, the use of geophysical techniques for the detection of these structures (impossible to identify at the surface due to the absence of outcrops) is of key importance in the exploration of these deposits at depths >500 m.
Luque Cabal, C., Gutiérrez Clavero, M., y Pando, L.. y PANDO, L. “Contribución de la geología minera al conocimiento de la cuenca permotriásica asturiana”. Trabajos de Geología, Universidad de Oviedo, 30 (2010): 361-385.
Andalucia
ATALAYA Cu, Nickel, Zinc mine (South of Spain): Located on the Iberian Pyrite Belt (Devonian), Masa Valverde deposit (up to 900 m depth) is embedded in volcanic- and sediment-hosted massive sulphide (VSHMS). Mineralization occurs as dissemination of metallic minerals. Geophysical surveys led to the discovery and delineation of a new massive sulphide orebody, 1km east of Masa Valverde, and the continuity between both deposits at depth is expected. However, the difficulty and the highly expensive drilling methods to approach these targets in depth is a key challenge in mineral exploration. DEXPLORE new technological exploration methods expect to confirm the continuity suspect while making an improvement in the knowledge at regional and deposit scales.
Modified from Donaire, T. et al., (2008): “Geología de la zona Surportuguesa”. En: Olías et al. (Eds), Geología de Huelva. Lugares de Interés Geológico. Servicio de Publicaciones de la Universidad de Huelva, 14-19; and Simancas, J. F., et al. “Crustal structure of the transpressional Variscan orogen of SW Iberia: SW Iberia deep seismic reflection profile (IBERSEIS).” Tectonics 22.6 (2003).
Final validation pilot (TRL5)
DEXPLORE attention regarding new ore and mineral models for deep-land CRM and SRM deposits will be focused on the NE of Estonia – Precambrian basement, an extension of the Fennoscandian Shield’s rock complexes mirroring the geological structures and metallogenic features in Southern Finland and South-Central Sweden.
Across this Precambrian basement there is a promising geological context for deep-seated primary CRM/SRM –metamorphic basement with abundant sulphides (pyrite, pyrrhotite, sphalerite, galena and others) covered by a 100 m to 780 m -thick sedimentary sequence.
Estonia
In NE Estonia, two significant basement complexes with prominent metalliferous anomalies have been discerned, the Alutaguse and Jõhvi zones. According to recent and exhaustive geochemical surveys supported by historical geological and geophysical studies, the Alutaguse and Jõhvi zones have shown high anomaly concentrations of CRM, particularly Cu, Zn and magnetite for Fe resources. Additionally, Mn and Mo are present in relatively significant concentrations. High Cu-Pb-Zn concentrations are often related to gneisses that contain graphite. Notably, recent public investigations into carbon (C) concentrations in this area are lacking, indicating a potential target for further research. These formations resemble to the deposits in the Berslagen ore provinces of Sweden and potentially, those in the Orijärvi region of Southern Finland.
DEXPLORE exploration and geological characterization of the Estonian Precambrian basement will begin with the collection and integration of all available information to assess the current state of knowledge and identify potential gaps. It will culminate in ore models based on data obtained from DEXPLORE’s advanced surface-to-subsurface exploration package.
Siim, Nirgi, and Soesoo Alvar. “Geology and geochemistry of a Paleoproterozoic iron mineralization in North-Eastern Estonia.” Труды Карельского научного центра Российской академии наук 10 (2021): 25-43.
