Länsimetro (West Metro) is a new transport link between Helsinki and Espoo completely underground at a length of 14 km. The LU6E – Karhusaari track section consists of a total of 2,613 m of mining carried out in hard granite using the Drill & Blast method. Mining of three technological chambers with ventilation shafts in each of them and seven tunnel junctions are also part of the delivery. The section route is partly under sea level and it proceeds under, among other things, the foundations of the Nokia headquarter buildings. The most challenging task was to excavate sections under the sea level, in areas sensitive to seismic load due to blasting works, along with a considerable amount of grouting works. 

Mining under sea level. Mining in a seismically sensitive area under the foundation of the Nokia headquarters. Award by the contracting authority for the safest construction site of Länsimetro.