Emilia Koivisto

2D reflection seismic investigations at the Kevitsa Ni-Cu-PGE deposit, northern Finland

In 2007, a 2D reflection seismic survey was conducted at the Kevitsa Ni-Cu-PGE (platinum group elements) deposit in northern Finland. The aims of the survey were to delineate the overall extent of ...

Building a 3D model of lithological contacts and near‐mine structures in the Kevitsa mining and exploration site, Northern Finland: constraints from 2D and 3D reflection seismic data

The Kevitsa mafic-ultramafic intrusion in Northern Finland hosts a large, disseminated nickel-copper sulphide ore body. The Kevitsa intrusion is an active mining and exploration site, for which we ...

3D Traveltime Tomography and Reflection Imaging for Mine Planning and Exploration in the Kevitsa Ni-Cu-PGE Mine, Finland

Summary Kevitsa disseminated Ni-Cu-PGE deposit in northern Finland is hosted by a major high velocity (6000–7500 m/s) gabbroic intrusion. The deposit is currently being mined using open-pit mining method at already over 100 m depth, and the final pit will extend to about 400–500 m depth in about 20 years, hence justifying a 3D seismic survey for its careful planning. The 3D seismic survey was carried out in 2010, before mining activities commenced, and resulted in a reflection volume rich in reflectivity, however, poor near the surface likely due to the survey setup and extremely high bedrock velocities. 3D first break tomography was performed with the main objective of linking near-surface geological information with the reflection seismic volume allowing to find a major low-velocity linear zone in the bedrock within the first 50 m depth. This was associated with a gently-dipping reflector with the same strike at 150 m depth and extending to about 500 m depth. The low-velocity zone striking in NE-SW, and originating from a gently-dipping fracture system, may contribute towards the formation of wedge blocks within the northern side of the planned open pit, which can be critical for its stability in the near future.

3D reflection seismic investigation for mine planning and exploration in the Kevitsa Ni-Cu-PGE deposit, northern Finland

A 3D reflection seismic survey was conducted over an area of about 9 km2 at the Kevitsa Ni-Cu-PGE platinum group elements deposit, northern Finland. The principal objective of the survey was to image major fault and fracture zones at depth. Understanding the geometry of these zones is important for designing a steep open-pit for mining. Initial processing results suggest that the 3D seismic survey has been successful in imaging both gently dipping and steeply dipping reflections as shallow as 50 ms or about 150 m, many of which correlate with fault systems and lithological contacts observed at the surface. Several new target areas can be identified in the seismic data that require further investigations for their mineralization potential. © 2011 Society of Exploration Geophysicists.