Abstract

Neves-Corvo is currently one of the largest base metals producing mines in Europe. Discoveries of new deposits in the last 20 years suggest that the area still holds good potential for reasonable size deposits. These will probably be placed at depth and in a complex geologic environment, opening the way to the use of geophysical methods to complement geological outcrop and sparse drill-hole data. With the goal of discovering new targets for exploration, under the scope of the SmartExploration project, a new 3D geological model for a constrained gravimetric inversion was generated for the Neves-Corvo region. The geological model was built using available legacy seismic and TEM data, updated drill-hole and geological data. To supplement the geophysical information, drill-hole geochemical data were integrated into the modeling workflow using neural networks algorithms in order to provide additional predictive parameters for deep targeting at the near-mine area. To assess the possibility of the down-dip extension of one of the major deposits, 1D inversion and 3D electromagnetic forward modeling of ground-loop, time-domain data, 3D gravity inversion and a novel seismic survey took place. The seismic survey had as major goal to test the possibility of acquiring data inside the exploration drifts in an active mine. Two prototypes were successfully tested: (i) a GPS-time synchronization system for satellite denied environment and (ii) electrically driven broadband vibrator seismic source. Furthermore, the known deposit could be mapped and other reflectors are currently being investigated.

About the speaker

João Carvalho holds a PhD in Physics (Solid Earth Geophysics, 2004) and a M.Sc. in Solid Earth Geophysics (1997) both at University of Lisbon. He is a Geophysicist at Laboratório Nacional de Energia e Geologia (LNEG) in Portugal where he develops and applies seismic and potential field methods to mineral resources exploration, seismic hazard, tectonics, environment, engineering, etc. Participated in more than 30 research projects, supervised multiple post-docs, M.S. and graduation scholars. Published more than 35 papers in international peer-reviewed journals and books and over 100 abstracts in international and national congresses.