herein). Notices Knowledge and best practice in this field are constantly changing. As new research and experience...Geological Survey discovered the nickel–copper ore field of Petsamo, and by the end of the 1930s, several...well as the large apatite-rich Sokli carbonatite complex. Rautaruukki Oy terminated their exploration activities...came into use. The remarkable Jussarö iron ore field in the archipelago near Tammisaari was discovered...Törnqvist, and J.N. Soikero. Tanner also led the annual field campaigns during the following years until 1931