New constraints on an existing mineral resource through 3D seismic

Abstract

The Kevitsa nickel-copper deposit in northern Finland is a large, low-grade, mafic-hosted accumululation of disseminated sulphides with rare, spatially restricted occurences of net-textured to semi-massive sulphides. The mineable limits of the resource grow or shrink with commodity prices, but it has also been recognised that subtle mafic layering in the intrusion controls subhorizontal layering of sulphides. The net-textured and semi-massive mineralisation styles occur near the base of the intrusion. Data from a 3D seismic survey demonstrate the unpredicted ability to image the sub-horizontal mafic layering, as well as the expected reflections at the base of the intrusion in contact with interlayered volcanic and sedimentary country rocks. The ability to trace the lateral extents of the mafic layering, backed up by analysis of borehole sonic and density logging, offers the possibility to predict the ultimate envelope of the resource. The interpretation of the base of the intrusion provides a horizon along which to target the net-textured to semi-massive contact sulphides.