3D Lithological and Structural Modeling of the Kevitsa 2D and 3D Reflection Seismic Data - A Case Study

Abstract

The Kevitsa mafic-ultramafic intrusion in northern Finland hosts a large, disseminated nickel-copper sulphide deposit. We present a 3D lithological and structural model of the Kevitsa area, obtained via modeling of 2D and 3D reflection seismic data from Kevitsa. The Kevitsa 3D model contains modeled surfaces of the contacts between the main lithological units and a model of the magmatic layering within the intrusion. The Kevitsa main mineralization is thought to be controlled by the lateral extents of this discontinuous, smaller-scale magmatic layering within the intrusion. An improved knowledge of the geometry of the intrusion, and in particular of the extent of the internal magmatic layering, provides a framework for near-mine and deep exploration in the area. Better control on the position of the basal contact of the intrusion provides an exploration target for the contact-type mineralization. The original purpose of the 3D seismic survey was to provide a structural framework for geotechnical planning of the mine, and accordingly the 3D seismic data were used to create a structural model of the 3D cube. The modeled structures reveal a complex pattern of fault and fracture zones, some of which will be important for slope stability and operational planning at the mine.