GIS-based spatial assessment of Au, Ni and Cu-Zn exploration conducted in Central Finnish Lapland

The objective of this Master’s project was to produce a statistical dataset on orogenic gold, magmatic nickel-copper sulfide and volcanogenic massive sulfide copper-zinc exploration performed in Finnish Central Lapland over the past 20 years and to produce a time series of areas covered by Au, Ni, Cu and Zn exploration tenements. Secondly, the aim was also to give an overview on the mining history and to create a raster intensity map of already found ore in the study area and to spatially compare this to pre-existing mineral potential maps. The study area in question is defined by the GovAda project and a considerable part of its bedrock is composed of volcanic and sedimentary rocks belonging to the Central Lapland greenstone belt. This work is mainly based on a database of exploration tenements of Finland obtained from the Finnish Safety and Chemical Agency, the Fennoscandian Ore Deposit Database, and information on historic and current mine areas and their production. The preliminary data manipulation was primarily conducted using ArcGIS in conjunction with MS Excel, and resulted in total of 1938 claims to work with. The results show that the exploration ‘boom’ in the study area has been ongoing since 2003 and that the metal prices and the amount of investment can be used as a reliable predictor of change in areas of active exploration tenements mainly for orogenic gold. In the case of magmatic Ni-Cu, the independent variables are more unstable and therefore are not as reliable. For the VMS type, it was impossible to produce a time series and calculate correlations due to the fact that there have only been 3 exploration tenements granted towards VMS exploration during the time period of interest. Based on spatial comparison of the raster intensity maps, locations of exploration tenements and mineral potential maps, the already known deposits are all located mainly in areas of high mineral potential and it would seem that most of mineral exploration has been also carried out in these high prospectivity areas. Out of the 19 known deposits in the study area, only two have been discovered since 1995. There are two mines currently in operation and mining volumes have been rising every year since 2012 and are expected to rise even more in the future. Also, the future for mineral exploration looks brighter as the investments and drilling activities have recently shown signs of recovery