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oa A New 2D Seismic Survey and 3D Forward Modelling over the Lombador VMS Deposit, Portugal
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, NSG2020 3rd Conference on Geophysics for Mineral Exploration and Mining, Dec 2020, Volume 2020, p.1 - 5
Abstract
Seismic methods are an affordable and effective way of studying the subsurface for mineral exploration, particularly when target depths are beyond what other geophysical methods can resolve (e.g., > 500 m). With the goal of testing new technologies for exploration in highly challenging mining areas, a seismic survey was conducted at the Neves-Corvo mine, south Portugal. The seismic data acquired consisted of two perpendicular 2D surface profiles positioned above the known Lombador deposit. Due to active mining operations, the data show a highly noisy nature. To supress the noise, carefully designed processing algorithms were applied enhancing reflections present in the data, interpreted to originate from lithological contacts and the Lombador deposit. These interpretations were validated using 3D exploding reflector modelling taking advantage of the known deposit geometry. Additionally, source points activated in an exploration tunnels located approximately 650m below the surface were synchronized and simultaneously recorded on the surface via a newly-developed GPS-time system. Providing a unique opportunity for estimating seismic velocities between the tunnel and surface profiles, using them as a guide for time-to-depth conversion and helping identify a low-velocity zone in the southern portion of the surface profile that may be related to lithological contacts or observed faulting.
